Index: flang/runtime/CMakeLists.txt
===================================================================
--- flang/runtime/CMakeLists.txt
+++ flang/runtime/CMakeLists.txt
@@ -42,7 +42,9 @@
   edit-input.cpp
   edit-output.cpp
   environment.cpp
+  extrema.cpp
   file.cpp
+  findloc.cpp
   format.cpp
   internal-unit.cpp
   iostat.cpp
@@ -55,8 +57,10 @@
   numeric.cpp
   random.cpp
   reduction.cpp
+  product.cpp
   stat.cpp
   stop.cpp
+  sum.cpp
   terminator.cpp
   tools.cpp
   transformational.cpp
Index: flang/runtime/extrema.cpp
===================================================================
--- /dev/null
+++ flang/runtime/extrema.cpp
@@ -0,0 +1,592 @@
+//===-- runtime/extrema.cpp -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Implements MAXLOC, MINLOC, MAXVAL, & MINVAL for all required operand types
+// and shapes and (for MAXLOC & MINLOC) result integer kinds.
+
+#include "character.h"
+#include "reduction-templates.h"
+#include "reduction.h"
+#include "flang/Common/long-double.h"
+#include <cinttypes>
+
+namespace Fortran::runtime {
+// MAXLOC & MINLOC
+
+template <typename T, bool IS_MAX, bool BACK> struct NumericCompare {
+  using Type = T;
+  explicit NumericCompare(std::size_t /*elemLen; ignored*/) {}
+  bool operator()(const T &value, const T &previous) const {
+    if (value == previous) {
+      return BACK;
+    } else if constexpr (IS_MAX) {
+      return value > previous;
+    } else {
+      return value < previous;
+    }
+  }
+};
+
+template <typename T, bool IS_MAX, bool BACK> class CharacterCompare {
+public:
+  using Type = T;
+  explicit CharacterCompare(std::size_t elemLen)
+      : chars_{elemLen / sizeof(T)} {}
+  bool operator()(const T &value, const T &previous) const {
+    int cmp{CharacterScalarCompare<T>(&value, &previous, chars_, chars_)};
+    if (cmp == 0) {
+      return BACK;
+    } else if constexpr (IS_MAX) {
+      return cmp > 0;
+    } else {
+      return cmp < 0;
+    }
+  }
+
+private:
+  std::size_t chars_;
+};
+
+template <typename COMPARE> class ExtremumLocAccumulator {
+public:
+  using Type = typename COMPARE::Type;
+  ExtremumLocAccumulator(const Descriptor &array, std::size_t chars = 0)
+      : array_{array}, argRank_{array.rank()}, compare_{array.ElementBytes()} {
+    Reinitialize();
+  }
+  void Reinitialize() {
+    // per standard: result indices are all zero if no data
+    for (int j{0}; j < argRank_; ++j) {
+      extremumLoc_[j] = 0;
+    }
+    previous_ = nullptr;
+  }
+  int argRank() const { return argRank_; }
+  template <typename A> void GetResult(A *p, int zeroBasedDim = -1) {
+    if (zeroBasedDim >= 0) {
+      *p = extremumLoc_[zeroBasedDim] -
+          array_.GetDimension(zeroBasedDim).LowerBound() + 1;
+    } else {
+      for (int j{0}; j < argRank_; ++j) {
+        p[j] = extremumLoc_[j] - array_.GetDimension(j).LowerBound() + 1;
+      }
+    }
+  }
+  template <typename IGNORED> bool AccumulateAt(const SubscriptValue at[]) {
+    const auto &value{*array_.Element<Type>(at)};
+    if (!previous_ || compare_(value, *previous_)) {
+      previous_ = &value;
+      for (int j{0}; j < argRank_; ++j) {
+        extremumLoc_[j] = at[j];
+      }
+    }
+    return true;
+  }
+
+private:
+  const Descriptor &array_;
+  int argRank_;
+  SubscriptValue extremumLoc_[maxRank];
+  const Type *previous_{nullptr};
+  COMPARE compare_;
+};
+
+template <typename ACCUMULATOR, typename CPPTYPE>
+static void LocationHelper(const char *intrinsic, Descriptor &result,
+    const Descriptor &x, int kind, const Descriptor *mask,
+    Terminator &terminator) {
+  ACCUMULATOR accumulator{x};
+  DoTotalReduction<CPPTYPE>(x, 0, mask, accumulator, intrinsic, terminator);
+  ApplyIntegerKind<LocationResultHelper<ACCUMULATOR>::template Functor, void>(
+      kind, terminator, accumulator, result);
+}
+
+template <TypeCategory CAT, int KIND, bool IS_MAX,
+    template <typename, bool, bool> class COMPARE>
+inline void DoMaxOrMinLoc(const char *intrinsic, Descriptor &result,
+    const Descriptor &x, int kind, const char *source, int line,
+    const Descriptor *mask, bool back) {
+  using CppType = CppTypeFor<CAT, KIND>;
+  Terminator terminator{source, line};
+  if (back) {
+    LocationHelper<ExtremumLocAccumulator<COMPARE<CppType, IS_MAX, true>>,
+        CppType>(intrinsic, result, x, kind, mask, terminator);
+  } else {
+    LocationHelper<ExtremumLocAccumulator<COMPARE<CppType, IS_MAX, false>>,
+        CppType>(intrinsic, result, x, kind, mask, terminator);
+  }
+}
+
+template <TypeCategory CAT, bool IS_MAX> struct TypedMaxOrMinLocHelper {
+  template <int KIND> struct Functor {
+    void operator()(const char *intrinsic, Descriptor &result,
+        const Descriptor &x, int kind, const char *source, int line,
+        const Descriptor *mask, bool back) const {
+      DoMaxOrMinLoc<TypeCategory::Integer, KIND, IS_MAX, NumericCompare>(
+          intrinsic, result, x, kind, source, line, mask, back);
+    }
+  };
+};
+
+template <bool IS_MAX>
+inline void TypedMaxOrMinLoc(const char *intrinsic, Descriptor &result,
+    const Descriptor &x, int kind, const char *source, int line,
+    const Descriptor *mask, bool back) {
+  int rank{x.rank()};
+  SubscriptValue extent[1]{rank};
+  result.Establish(TypeCategory::Integer, kind, nullptr, 1, extent,
+      CFI_attribute_allocatable);
+  result.GetDimension(0).SetBounds(1, extent[0]);
+  Terminator terminator{source, line};
+  if (int stat{result.Allocate()}) {
+    terminator.Crash(
+        "%s: could not allocate memory for result; STAT=%d", intrinsic, stat);
+  }
+  CheckIntegerKind(terminator, kind, intrinsic);
+  auto catKind{x.type().GetCategoryAndKind()};
+  RUNTIME_CHECK(terminator, catKind.has_value());
+  switch (catKind->first) {
+  case TypeCategory::Integer:
+    ApplyIntegerKind<
+        TypedMaxOrMinLocHelper<TypeCategory::Integer, IS_MAX>::template Functor,
+        void>(catKind->second, terminator, intrinsic, result, x, kind, source,
+        line, mask, back);
+    break;
+  case TypeCategory::Real:
+    ApplyFloatingPointKind<
+        TypedMaxOrMinLocHelper<TypeCategory::Real, IS_MAX>::template Functor,
+        void>(catKind->second, terminator, intrinsic, result, x, kind, source,
+        line, mask, back);
+    break;
+  case TypeCategory::Character:
+    ApplyCharacterKind<TypedMaxOrMinLocHelper<TypeCategory::Character,
+                           IS_MAX>::template Functor,
+        void>(catKind->second, terminator, intrinsic, result, x, kind, source,
+        line, mask, back);
+    break;
+  default:
+    terminator.Crash(
+        "%s: Bad data type code (%d) for array", intrinsic, x.type().raw());
+  }
+}
+
+extern "C" {
+void RTNAME(Maxloc)(Descriptor &result, const Descriptor &x, int kind,
+    const char *source, int line, const Descriptor *mask, bool back) {
+  TypedMaxOrMinLoc<true>("MAXLOC", result, x, kind, source, line, mask, back);
+}
+void RTNAME(Minloc)(Descriptor &result, const Descriptor &x, int kind,
+    const char *source, int line, const Descriptor *mask, bool back) {
+  TypedMaxOrMinLoc<false>("MINLOC", result, x, kind, source, line, mask, back);
+}
+} // extern "C"
+
+// MAXLOC/MINLOC with DIM=
+
+template <TypeCategory CAT, int KIND, bool IS_MAX,
+    template <typename, bool, bool> class COMPARE, bool BACK>
+static void DoPartialMaxOrMinLocDirection(const char *intrinsic,
+    Descriptor &result, const Descriptor &x, int kind, int dim,
+    const Descriptor *mask, Terminator &terminator) {
+  using CppType = CppTypeFor<CAT, KIND>;
+  using Accumulator = ExtremumLocAccumulator<COMPARE<CppType, IS_MAX, BACK>>;
+  Accumulator accumulator{x};
+  ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor, void>(
+      kind, terminator, result, x, dim, mask, terminator, intrinsic,
+      accumulator);
+}
+
+template <TypeCategory CAT, int KIND, bool IS_MAX,
+    template <typename, bool, bool> class COMPARE>
+inline void DoPartialMaxOrMinLoc(const char *intrinsic, Descriptor &result,
+    const Descriptor &x, int kind, int dim, const Descriptor *mask, bool back,
+    Terminator &terminator) {
+  if (back) {
+    DoPartialMaxOrMinLocDirection<CAT, KIND, IS_MAX, COMPARE, true>(
+        intrinsic, result, x, kind, dim, mask, terminator);
+  } else {
+    DoPartialMaxOrMinLocDirection<CAT, KIND, IS_MAX, COMPARE, false>(
+        intrinsic, result, x, kind, dim, mask, terminator);
+  }
+}
+
+template <TypeCategory CAT, bool IS_MAX,
+    template <typename, bool, bool> class COMPARE>
+struct DoPartialMaxOrMinLocHelper {
+  template <int KIND> struct Functor {
+    void operator()(const char *intrinsic, Descriptor &result,
+        const Descriptor &x, int kind, int dim, const Descriptor *mask,
+        bool back, Terminator &terminator) const {
+      DoPartialMaxOrMinLoc<CAT, KIND, IS_MAX, COMPARE>(
+          intrinsic, result, x, kind, dim, mask, back, terminator);
+    }
+  };
+};
+
+template <bool IS_MAX>
+inline void TypedPartialMaxOrMinLoc(const char *intrinsic, Descriptor &result,
+    const Descriptor &x, int kind, int dim, const char *source, int line,
+    const Descriptor *mask, bool back) {
+  Terminator terminator{source, line};
+  CheckIntegerKind(terminator, kind, intrinsic);
+  auto catKind{x.type().GetCategoryAndKind()};
+  RUNTIME_CHECK(terminator, catKind.has_value());
+  switch (catKind->first) {
+  case TypeCategory::Integer:
+    ApplyIntegerKind<DoPartialMaxOrMinLocHelper<TypeCategory::Integer, IS_MAX,
+                         NumericCompare>::template Functor,
+        void>(catKind->second, terminator, intrinsic, result, x, kind, dim,
+        mask, back, terminator);
+    break;
+  case TypeCategory::Real:
+    ApplyFloatingPointKind<DoPartialMaxOrMinLocHelper<TypeCategory::Real,
+                               IS_MAX, NumericCompare>::template Functor,
+        void>(catKind->second, terminator, intrinsic, result, x, kind, dim,
+        mask, back, terminator);
+    break;
+  case TypeCategory::Character:
+    ApplyCharacterKind<DoPartialMaxOrMinLocHelper<TypeCategory::Character,
+                           IS_MAX, CharacterCompare>::template Functor,
+        void>(catKind->second, terminator, intrinsic, result, x, kind, dim,
+        mask, back, terminator);
+    break;
+  default:
+    terminator.Crash(
+        "%s: Bad data type code (%d) for array", intrinsic, x.type().raw());
+  }
+}
+
+extern "C" {
+void RTNAME(MaxlocDim)(Descriptor &result, const Descriptor &x, int kind,
+    int dim, const char *source, int line, const Descriptor *mask, bool back) {
+  TypedPartialMaxOrMinLoc<true>(
+      "MAXLOC", result, x, kind, dim, source, line, mask, back);
+}
+void RTNAME(MinlocDim)(Descriptor &result, const Descriptor &x, int kind,
+    int dim, const char *source, int line, const Descriptor *mask, bool back) {
+  TypedPartialMaxOrMinLoc<false>(
+      "MINLOC", result, x, kind, dim, source, line, mask, back);
+}
+} // extern "C"
+
+// MAXVAL and MINVAL
+
+template <TypeCategory CAT, int KIND, bool IS_MAXVAL> struct MaxOrMinIdentity {
+  using Type = CppTypeFor<CAT, KIND>;
+  static constexpr Type Value() {
+    return IS_MAXVAL ? std::numeric_limits<Type>::lowest()
+                     : std::numeric_limits<Type>::max();
+  }
+};
+
+// std::numeric_limits<> may not know int128_t
+template <bool IS_MAXVAL>
+struct MaxOrMinIdentity<TypeCategory::Integer, 16, IS_MAXVAL> {
+  using Type = CppTypeFor<TypeCategory::Integer, 16>;
+  static constexpr Type Value() {
+    return IS_MAXVAL ? Type{1} << 127 : ~Type{0} >> 1;
+  }
+};
+
+template <TypeCategory CAT, int KIND, bool IS_MAXVAL>
+class NumericExtremumAccumulator {
+public:
+  using Type = CppTypeFor<CAT, KIND>;
+  explicit NumericExtremumAccumulator(const Descriptor &array)
+      : array_{array} {}
+  void Reinitialize() {
+    extremum_ = MaxOrMinIdentity<CAT, KIND, IS_MAXVAL>::Value();
+  }
+  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
+    *p = extremum_;
+  }
+  bool Accumulate(Type x) {
+    if constexpr (IS_MAXVAL) {
+      if (x > extremum_) {
+        extremum_ = x;
+      }
+    } else if (x < extremum_) {
+      extremum_ = x;
+    }
+    return true;
+  }
+  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
+    return Accumulate(*array_.Element<A>(at));
+  }
+
+private:
+  const Descriptor &array_;
+  Type extremum_{MaxOrMinIdentity<CAT, KIND, IS_MAXVAL>::Value()};
+};
+
+template <TypeCategory CAT, int KIND, bool IS_MAXVAL>
+inline CppTypeFor<CAT, KIND> TotalNumericMaxOrMin(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask,
+    const char *intrinsic) {
+  return GetTotalReduction<CAT, KIND>(x, source, line, dim, mask,
+      NumericExtremumAccumulator<CAT, KIND, IS_MAXVAL>{x}, intrinsic);
+}
+
+template <TypeCategory CAT, int KIND, bool IS_MAXVAL,
+    template <TypeCategory, int, bool> class ACCUMULATOR>
+static void DoMaxOrMin(Descriptor &result, const Descriptor &x, int dim,
+    const Descriptor *mask, const char *intrinsic, Terminator &terminator) {
+  using Type = CppTypeFor<CAT, KIND>;
+  if (dim == 0 || x.rank() == 1) {
+    // Total reduction
+    result.Establish(x.type(), x.ElementBytes(), nullptr, 0, nullptr,
+        CFI_attribute_allocatable);
+    if (int stat{result.Allocate()}) {
+      terminator.Crash(
+          "%s: could not allocate memory for result; STAT=%d", intrinsic, stat);
+    }
+    ACCUMULATOR<CAT, KIND, IS_MAXVAL> accumulator{x};
+    DoTotalReduction<Type>(x, dim, mask, accumulator, intrinsic, terminator);
+    accumulator.GetResult(result.OffsetElement<Type>());
+  } else {
+    // Partial reduction
+    using Accumulator = ACCUMULATOR<CAT, KIND, IS_MAXVAL>;
+    Accumulator accumulator{x};
+    PartialReduction<Accumulator, CAT, KIND>(
+        result, x, dim, mask, terminator, intrinsic, accumulator);
+  }
+}
+
+template <TypeCategory CAT, bool IS_MAXVAL> struct MaxOrMinHelper {
+  template <int KIND> struct Functor {
+    void operator()(Descriptor &result, const Descriptor &x, int dim,
+        const Descriptor *mask, const char *intrinsic,
+        Terminator &terminator) const {
+      DoMaxOrMin<CAT, KIND, IS_MAXVAL, NumericExtremumAccumulator>(
+          result, x, dim, mask, intrinsic, terminator);
+    }
+  };
+};
+
+template <bool IS_MAXVAL>
+inline void NumericMaxOrMin(Descriptor &result, const Descriptor &x, int dim,
+    const char *source, int line, const Descriptor *mask,
+    const char *intrinsic) {
+  Terminator terminator{source, line};
+  auto type{x.type().GetCategoryAndKind()};
+  RUNTIME_CHECK(terminator, type);
+  switch (type->first) {
+  case TypeCategory::Integer:
+    ApplyIntegerKind<
+        MaxOrMinHelper<TypeCategory::Integer, IS_MAXVAL>::template Functor,
+        void>(
+        type->second, terminator, result, x, dim, mask, intrinsic, terminator);
+    break;
+  case TypeCategory::Real:
+    ApplyFloatingPointKind<
+        MaxOrMinHelper<TypeCategory::Real, IS_MAXVAL>::template Functor, void>(
+        type->second, terminator, result, x, dim, mask, intrinsic, terminator);
+    break;
+  default:
+    terminator.Crash("%s: bad type code %d", intrinsic, x.type().raw());
+  }
+}
+
+template <TypeCategory, int KIND, bool IS_MAXVAL>
+class CharacterExtremumAccumulator {
+public:
+  using Type = CppTypeFor<TypeCategory::Character, KIND>;
+  explicit CharacterExtremumAccumulator(const Descriptor &array)
+      : array_{array}, charLen_{array_.ElementBytes() / KIND} {}
+  void Reinitialize() { extremum_ = nullptr; }
+  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
+    static_assert(std::is_same_v<A, Type>);
+    if (extremum_) {
+      std::memcpy(p, extremum_, charLen_);
+    } else {
+      // empty array: result is all zero-valued characters
+      std::memset(p, 0, charLen_);
+    }
+  }
+  bool Accumulate(const Type *x) {
+    if (!extremum_) {
+      extremum_ = x;
+    } else {
+      int cmp{CharacterScalarCompare(x, extremum_, charLen_, charLen_)};
+      if (IS_MAXVAL == (cmp > 0)) {
+        extremum_ = x;
+      }
+    }
+    return true;
+  }
+  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
+    return Accumulate(array_.Element<A>(at));
+  }
+
+private:
+  const Descriptor &array_;
+  std::size_t charLen_;
+  const Type *extremum_{nullptr};
+};
+
+template <bool IS_MAXVAL> struct CharacterMaxOrMinHelper {
+  template <int KIND> struct Functor {
+    void operator()(Descriptor &result, const Descriptor &x, int dim,
+        const Descriptor *mask, const char *intrinsic,
+        Terminator &terminator) const {
+      DoMaxOrMin<TypeCategory::Character, KIND, IS_MAXVAL,
+          CharacterExtremumAccumulator>(
+          result, x, dim, mask, intrinsic, terminator);
+    }
+  };
+};
+
+template <bool IS_MAXVAL>
+inline void CharacterMaxOrMin(Descriptor &result, const Descriptor &x, int dim,
+    const char *source, int line, const Descriptor *mask,
+    const char *intrinsic) {
+  Terminator terminator{source, line};
+  auto type{x.type().GetCategoryAndKind()};
+  RUNTIME_CHECK(terminator, type && type->first == TypeCategory::Character);
+  ApplyCharacterKind<CharacterMaxOrMinHelper<IS_MAXVAL>::template Functor,
+      void>(
+      type->second, terminator, result, x, dim, mask, intrinsic, terminator);
+}
+
+extern "C" {
+CppTypeFor<TypeCategory::Integer, 1> RTNAME(MaxvalInteger1)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 1, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+CppTypeFor<TypeCategory::Integer, 2> RTNAME(MaxvalInteger2)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 2, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+CppTypeFor<TypeCategory::Integer, 4> RTNAME(MaxvalInteger4)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 4, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+CppTypeFor<TypeCategory::Integer, 8> RTNAME(MaxvalInteger8)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 8, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+#ifdef __SIZEOF_INT128__
+CppTypeFor<TypeCategory::Integer, 16> RTNAME(MaxvalInteger16)(
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 16, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+#endif
+
+// TODO: REAL(2 & 3)
+CppTypeFor<TypeCategory::Real, 4> RTNAME(MaxvalReal4)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 4, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+CppTypeFor<TypeCategory::Real, 8> RTNAME(MaxvalReal8)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 8, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+#if LONG_DOUBLE == 80
+CppTypeFor<TypeCategory::Real, 10> RTNAME(MaxvalReal10)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 10, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+#elif LONG_DOUBLE == 128
+CppTypeFor<TypeCategory::Real, 16> RTNAME(MaxvalReal16)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 16, true>(
+      x, source, line, dim, mask, "MAXVAL");
+}
+#endif
+
+void RTNAME(MaxvalCharacter)(Descriptor &result, const Descriptor &x,
+    const char *source, int line, const Descriptor *mask) {
+  CharacterMaxOrMin<true>(result, x, 0, source, line, mask, "MAXVAL");
+}
+
+CppTypeFor<TypeCategory::Integer, 1> RTNAME(MinvalInteger1)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 1, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+CppTypeFor<TypeCategory::Integer, 2> RTNAME(MinvalInteger2)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 2, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+CppTypeFor<TypeCategory::Integer, 4> RTNAME(MinvalInteger4)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 4, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+CppTypeFor<TypeCategory::Integer, 8> RTNAME(MinvalInteger8)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 8, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+#ifdef __SIZEOF_INT128__
+CppTypeFor<TypeCategory::Integer, 16> RTNAME(MinvalInteger16)(
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Integer, 16, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+#endif
+
+// TODO: REAL(2 & 3)
+CppTypeFor<TypeCategory::Real, 4> RTNAME(MinvalReal4)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 4, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+CppTypeFor<TypeCategory::Real, 8> RTNAME(MinvalReal8)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 8, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+#if LONG_DOUBLE == 80
+CppTypeFor<TypeCategory::Real, 10> RTNAME(MinvalReal10)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 10, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+#elif LONG_DOUBLE == 128
+CppTypeFor<TypeCategory::Real, 16> RTNAME(MinvalReal16)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return TotalNumericMaxOrMin<TypeCategory::Real, 16, false>(
+      x, source, line, dim, mask, "MINVAL");
+}
+#endif
+
+void RTNAME(MinvalCharacter)(Descriptor &result, const Descriptor &x,
+    const char *source, int line, const Descriptor *mask) {
+  CharacterMaxOrMin<false>(result, x, 0, source, line, mask, "MINVAL");
+}
+
+void RTNAME(MaxvalDim)(Descriptor &result, const Descriptor &x, int dim,
+    const char *source, int line, const Descriptor *mask) {
+  if (x.type().IsCharacter()) {
+    CharacterMaxOrMin<true>(result, x, dim, source, line, mask, "MAXVAL");
+  } else {
+    NumericMaxOrMin<true>(result, x, dim, source, line, mask, "MAXVAL");
+  }
+}
+void RTNAME(MinvalDim)(Descriptor &result, const Descriptor &x, int dim,
+    const char *source, int line, const Descriptor *mask) {
+  if (x.type().IsCharacter()) {
+    CharacterMaxOrMin<false>(result, x, dim, source, line, mask, "MINVAL");
+  } else {
+    NumericMaxOrMin<false>(result, x, dim, source, line, mask, "MINVAL");
+  }
+}
+} // extern "C"
+} // namespace Fortran::runtime
Index: flang/runtime/findloc.cpp
===================================================================
--- /dev/null
+++ flang/runtime/findloc.cpp
@@ -0,0 +1,342 @@
+//===-- runtime/findloc.cpp -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Implements FINDLOC for all required operand types and shapes and result
+// integer kinds.
+
+#include "character.h"
+#include "reduction-templates.h"
+#include "reduction.h"
+#include "flang/Common/long-double.h"
+#include <cinttypes>
+#include <complex>
+
+namespace Fortran::runtime {
+
+template <TypeCategory CAT1, int KIND1, TypeCategory CAT2, int KIND2>
+struct Equality {
+  using Type1 = CppTypeFor<CAT1, KIND1>;
+  using Type2 = CppTypeFor<CAT2, KIND2>;
+  bool operator()(const Descriptor &array, const SubscriptValue at[],
+      const Descriptor &target) const {
+    return *array.Element<Type1>(at) == *target.OffsetElement<Type2>();
+  }
+};
+
+template <int KIND1, int KIND2>
+struct Equality<TypeCategory::Complex, KIND1, TypeCategory::Complex, KIND2> {
+  using Type1 = CppTypeFor<TypeCategory::Complex, KIND1>;
+  using Type2 = CppTypeFor<TypeCategory::Complex, KIND2>;
+  bool operator()(const Descriptor &array, const SubscriptValue at[],
+      const Descriptor &target) const {
+    const Type1 &xz{*array.Element<Type1>(at)};
+    const Type2 &tz{*target.OffsetElement<Type2>()};
+    return xz.real() == tz.real() && xz.imag() == tz.imag();
+  }
+};
+
+template <int KIND1, TypeCategory CAT2, int KIND2>
+struct Equality<TypeCategory::Complex, KIND1, CAT2, KIND2> {
+  using Type1 = CppTypeFor<TypeCategory::Complex, KIND1>;
+  using Type2 = CppTypeFor<CAT2, KIND2>;
+  bool operator()(const Descriptor &array, const SubscriptValue at[],
+      const Descriptor &target) const {
+    const Type1 &z{*array.Element<Type1>(at)};
+    return z.imag() == 0 && z.real() == *target.OffsetElement<Type2>();
+  }
+};
+
+template <TypeCategory CAT1, int KIND1, int KIND2>
+struct Equality<CAT1, KIND1, TypeCategory::Complex, KIND2> {
+  using Type1 = CppTypeFor<CAT1, KIND1>;
+  using Type2 = CppTypeFor<TypeCategory::Complex, KIND2>;
+  bool operator()(const Descriptor &array, const SubscriptValue at[],
+      const Descriptor &target) const {
+    const Type2 &z{*target.OffsetElement<Type2>()};
+    return *array.Element<Type1>(at) == z.real() && z.imag() == 0;
+  }
+};
+
+template <int KIND> struct CharacterEquality {
+  using Type = CppTypeFor<TypeCategory::Character, KIND>;
+  bool operator()(const Descriptor &array, const SubscriptValue at[],
+      const Descriptor &target) const {
+    return CharacterScalarCompare<Type>(array.Element<Type>(at),
+               target.OffsetElement<Type>(),
+               array.ElementBytes() / static_cast<unsigned>(KIND),
+               target.ElementBytes() / static_cast<unsigned>(KIND)) == 0;
+  }
+};
+
+struct LogicalEquivalence {
+  bool operator()(const Descriptor &array, const SubscriptValue at[],
+      const Descriptor &target) const {
+    return IsLogicalElementTrue(array, at) ==
+        IsLogicalElementTrue(target, at /*ignored*/);
+  }
+};
+
+template <typename EQUALITY> class LocationAccumulator {
+public:
+  LocationAccumulator(
+      const Descriptor &array, const Descriptor &target, bool back)
+      : array_{array}, target_{target}, back_{back} {
+    Reinitialize();
+  }
+  void Reinitialize() {
+    // per standard: result indices are all zero if no data
+    for (int j{0}; j < rank_; ++j) {
+      location_[j] = 0;
+    }
+  }
+  template <typename A> void GetResult(A *p, int zeroBasedDim = -1) {
+    if (zeroBasedDim >= 0) {
+      *p = location_[zeroBasedDim] -
+          array_.GetDimension(zeroBasedDim).LowerBound() + 1;
+    } else {
+      for (int j{0}; j < rank_; ++j) {
+        p[j] = location_[j] - array_.GetDimension(j).LowerBound() + 1;
+      }
+    }
+  }
+  template <typename IGNORED> bool AccumulateAt(const SubscriptValue at[]) {
+    if (equality_(array_, at, target_)) {
+      for (int j{0}; j < rank_; ++j) {
+        location_[j] = at[j];
+      }
+      return back_;
+    } else {
+      return true;
+    }
+  }
+
+private:
+  const Descriptor &array_;
+  const Descriptor &target_;
+  const bool back_{false};
+  const int rank_{array_.rank()};
+  SubscriptValue location_[maxRank];
+  const EQUALITY equality_{};
+};
+
+template <TypeCategory XCAT, int XKIND, TypeCategory TARGET_CAT>
+struct TotalNumericFindlocHelper {
+  template <int TARGET_KIND> struct Functor {
+    void operator()(Descriptor &result, const Descriptor &x,
+        const Descriptor &target, int kind, int dim, const Descriptor *mask,
+        bool back, Terminator &terminator) const {
+      using Eq = Equality<XCAT, XKIND, TARGET_CAT, TARGET_KIND>;
+      using Accumulator = LocationAccumulator<Eq>;
+      Accumulator accumulator{x, target, back};
+      DoTotalReduction<void>(x, dim, mask, accumulator, "FINDLOC", terminator);
+      ApplyIntegerKind<LocationResultHelper<Accumulator>::template Functor,
+          void>(kind, terminator, accumulator, result);
+    }
+  };
+};
+
+template <TypeCategory CAT,
+    template <TypeCategory XCAT, int XKIND, TypeCategory TARGET_CAT>
+    class HELPER>
+struct NumericFindlocHelper {
+  template <int KIND> struct Functor {
+    void operator()(TypeCategory targetCat, int targetKind, Descriptor &result,
+        const Descriptor &x, const Descriptor &target, int kind, int dim,
+        const Descriptor *mask, bool back, Terminator &terminator) const {
+      switch (targetCat) {
+      case TypeCategory::Integer:
+        ApplyIntegerKind<
+            HELPER<CAT, KIND, TypeCategory::Integer>::template Functor, void>(
+            targetKind, terminator, result, x, target, kind, dim, mask, back,
+            terminator);
+        break;
+      case TypeCategory::Real:
+        ApplyFloatingPointKind<
+            HELPER<CAT, KIND, TypeCategory::Real>::template Functor, void>(
+            targetKind, terminator, result, x, target, kind, dim, mask, back,
+            terminator);
+        break;
+      case TypeCategory::Complex:
+        ApplyFloatingPointKind<
+            HELPER<CAT, KIND, TypeCategory::Complex>::template Functor, void>(
+            targetKind, terminator, result, x, target, kind, dim, mask, back,
+            terminator);
+        break;
+      default:
+        terminator.Crash(
+            "FINDLOC: bad target category %d for array category %d",
+            static_cast<int>(targetCat), static_cast<int>(CAT));
+      }
+    }
+  };
+};
+
+template <int KIND> struct CharacterFindlocHelper {
+  void operator()(Descriptor &result, const Descriptor &x,
+      const Descriptor &target, int kind, const Descriptor *mask, bool back,
+      Terminator &terminator) {
+    using Accumulator = LocationAccumulator<CharacterEquality<KIND>>;
+    Accumulator accumulator{x, target, back};
+    DoTotalReduction<void>(x, 0, mask, accumulator, "FINDLOC", terminator);
+    ApplyIntegerKind<LocationResultHelper<Accumulator>::template Functor, void>(
+        kind, terminator, accumulator, result);
+  }
+};
+
+static void LogicalFindlocHelper(Descriptor &result, const Descriptor &x,
+    const Descriptor &target, int kind, const Descriptor *mask, bool back,
+    Terminator &terminator) {
+  using Accumulator = LocationAccumulator<LogicalEquivalence>;
+  Accumulator accumulator{x, target, back};
+  DoTotalReduction<void>(x, 0, mask, accumulator, "FINDLOC", terminator);
+  ApplyIntegerKind<LocationResultHelper<Accumulator>::template Functor, void>(
+      kind, terminator, accumulator, result);
+}
+
+extern "C" {
+void RTNAME(Findloc)(Descriptor &result, const Descriptor &x,
+    const Descriptor &target, int kind, const char *source, int line,
+    const Descriptor *mask, bool back) {
+  int rank{x.rank()};
+  SubscriptValue extent[1]{rank};
+  result.Establish(TypeCategory::Integer, kind, nullptr, 1, extent,
+      CFI_attribute_allocatable);
+  result.GetDimension(0).SetBounds(1, extent[0]);
+  Terminator terminator{source, line};
+  if (int stat{result.Allocate()}) {
+    terminator.Crash(
+        "FINDLOC: could not allocate memory for result; STAT=%d", stat);
+  }
+  CheckIntegerKind(terminator, kind, "FINDLOC");
+  auto xType{x.type().GetCategoryAndKind()};
+  auto targetType{target.type().GetCategoryAndKind()};
+  RUNTIME_CHECK(terminator, xType.has_value() && targetType.has_value());
+  switch (xType->first) {
+  case TypeCategory::Integer:
+    ApplyIntegerKind<NumericFindlocHelper<TypeCategory::Integer,
+                         TotalNumericFindlocHelper>::template Functor,
+        void>(xType->second, terminator, targetType->first, targetType->second,
+        result, x, target, kind, 0, mask, back, terminator);
+    break;
+  case TypeCategory::Real:
+    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Real,
+                               TotalNumericFindlocHelper>::template Functor,
+        void>(xType->second, terminator, targetType->first, targetType->second,
+        result, x, target, kind, 0, mask, back, terminator);
+    break;
+  case TypeCategory::Complex:
+    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Complex,
+                               TotalNumericFindlocHelper>::template Functor,
+        void>(xType->second, terminator, targetType->first, targetType->second,
+        result, x, target, kind, 0, mask, back, terminator);
+    break;
+  case TypeCategory::Character:
+    RUNTIME_CHECK(terminator,
+        targetType->first == TypeCategory::Character &&
+            targetType->second == xType->second);
+    ApplyCharacterKind<CharacterFindlocHelper, void>(xType->second, terminator,
+        result, x, target, kind, mask, back, terminator);
+    break;
+  case TypeCategory::Logical:
+    RUNTIME_CHECK(terminator, targetType->first == TypeCategory::Logical);
+    LogicalFindlocHelper(result, x, target, kind, mask, back, terminator);
+    break;
+  default:
+    terminator.Crash(
+        "FINDLOC: Bad data type code (%d) for array", x.type().raw());
+  }
+}
+} // extern "C"
+
+// FINDLOC with DIM=
+
+template <TypeCategory XCAT, int XKIND, TypeCategory TARGET_CAT>
+struct PartialNumericFindlocHelper {
+  template <int TARGET_KIND> struct Functor {
+    void operator()(Descriptor &result, const Descriptor &x,
+        const Descriptor &target, int kind, int dim, const Descriptor *mask,
+        bool back, Terminator &terminator) const {
+      using Eq = Equality<XCAT, XKIND, TARGET_CAT, TARGET_KIND>;
+      using Accumulator = LocationAccumulator<Eq>;
+      Accumulator accumulator{x, target, back};
+      ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor,
+          void>(kind, terminator, result, x, dim, mask, terminator, "FINDLOC",
+          accumulator);
+    }
+  };
+};
+
+template <int KIND> struct PartialCharacterFindlocHelper {
+  void operator()(Descriptor &result, const Descriptor &x,
+      const Descriptor &target, int kind, int dim, const Descriptor *mask,
+      bool back, Terminator &terminator) {
+    using Accumulator = LocationAccumulator<CharacterEquality<KIND>>;
+    Accumulator accumulator{x, target, back};
+    ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor,
+        void>(kind, terminator, result, x, dim, mask, terminator, "FINDLOC",
+        accumulator);
+  }
+};
+
+static void PartialLogicalFindlocHelper(Descriptor &result, const Descriptor &x,
+    const Descriptor &target, int kind, int dim, const Descriptor *mask,
+    bool back, Terminator &terminator) {
+  using Accumulator = LocationAccumulator<LogicalEquivalence>;
+  Accumulator accumulator{x, target, back};
+  ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor, void>(
+      kind, terminator, result, x, dim, mask, terminator, "FINDLOC",
+      accumulator);
+}
+
+extern "C" {
+void RTNAME(FindlocDim)(Descriptor &result, const Descriptor &x,
+    const Descriptor &target, int kind, int dim, const char *source, int line,
+    const Descriptor *mask, bool back) {
+  Terminator terminator{source, line};
+  CheckIntegerKind(terminator, kind, "FINDLOC");
+  auto xType{x.type().GetCategoryAndKind()};
+  auto targetType{target.type().GetCategoryAndKind()};
+  RUNTIME_CHECK(terminator, xType.has_value() && targetType.has_value());
+  switch (xType->first) {
+  case TypeCategory::Integer:
+    ApplyIntegerKind<NumericFindlocHelper<TypeCategory::Integer,
+                         PartialNumericFindlocHelper>::template Functor,
+        void>(xType->second, terminator, targetType->first, targetType->second,
+        result, x, target, kind, dim, mask, back, terminator);
+    break;
+  case TypeCategory::Real:
+    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Real,
+                               PartialNumericFindlocHelper>::template Functor,
+        void>(xType->second, terminator, targetType->first, targetType->second,
+        result, x, target, kind, dim, mask, back, terminator);
+    break;
+  case TypeCategory::Complex:
+    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Complex,
+                               PartialNumericFindlocHelper>::template Functor,
+        void>(xType->second, terminator, targetType->first, targetType->second,
+        result, x, target, kind, dim, mask, back, terminator);
+    break;
+  case TypeCategory::Character:
+    RUNTIME_CHECK(terminator,
+        targetType->first == TypeCategory::Character &&
+            targetType->second == xType->second);
+    ApplyCharacterKind<PartialCharacterFindlocHelper, void>(xType->second,
+        terminator, result, x, target, kind, dim, mask, back, terminator);
+    break;
+  case TypeCategory::Logical:
+    RUNTIME_CHECK(terminator, targetType->first == TypeCategory::Logical);
+    PartialLogicalFindlocHelper(
+        result, x, target, kind, dim, mask, back, terminator);
+    break;
+  default:
+    terminator.Crash(
+        "FINDLOC: Bad data type code (%d) for array", x.type().raw());
+  }
+}
+} // extern "C"
+} // namespace Fortran::runtime
Index: flang/runtime/product.cpp
===================================================================
--- /dev/null
+++ flang/runtime/product.cpp
@@ -0,0 +1,163 @@
+//===-- runtime/product.cpp -----------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Implements PRODUCT for all required operand types and shapes.
+
+#include "reduction-templates.h"
+#include "reduction.h"
+#include "flang/Common/long-double.h"
+#include <cinttypes>
+#include <complex>
+
+namespace Fortran::runtime {
+template <typename INTERMEDIATE> class NonComplexProductAccumulator {
+public:
+  explicit NonComplexProductAccumulator(const Descriptor &array)
+      : array_{array} {}
+  void Reinitialize() { product_ = 1; }
+  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
+    *p = static_cast<A>(product_);
+  }
+  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
+    product_ *= *array_.Element<A>(at);
+    return product_ != 0;
+  }
+
+private:
+  const Descriptor &array_;
+  INTERMEDIATE product_{1};
+};
+
+template <typename PART> class ComplexProductAccumulator {
+public:
+  explicit ComplexProductAccumulator(const Descriptor &array) : array_{array} {}
+  void Reinitialize() { product_ = std::complex<PART>{1, 0}; }
+  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
+    using ResultPart = typename A::value_type;
+    *p = {static_cast<ResultPart>(product_.real()),
+        static_cast<ResultPart>(product_.imag())};
+  }
+  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
+    product_ *= *array_.Element<A>(at);
+    return true;
+  }
+
+private:
+  const Descriptor &array_;
+  std::complex<PART> product_{1, 0};
+};
+
+extern "C" {
+CppTypeFor<TypeCategory::Integer, 1> RTNAME(ProductInteger1)(
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 1>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x},
+      "PRODUCT");
+}
+CppTypeFor<TypeCategory::Integer, 2> RTNAME(ProductInteger2)(
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 2>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x},
+      "PRODUCT");
+}
+CppTypeFor<TypeCategory::Integer, 4> RTNAME(ProductInteger4)(
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 4>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x},
+      "PRODUCT");
+}
+CppTypeFor<TypeCategory::Integer, 8> RTNAME(ProductInteger8)(
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 8>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 8>>{x},
+      "PRODUCT");
+}
+#ifdef __SIZEOF_INT128__
+CppTypeFor<TypeCategory::Integer, 16> RTNAME(ProductInteger16)(
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 16>(x, source, line, dim,
+      mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 16>>{x},
+      "PRODUCT");
+}
+#endif
+
+// TODO: real/complex(2 & 3)
+CppTypeFor<TypeCategory::Real, 4> RTNAME(ProductReal4)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 4>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
+      "PRODUCT");
+}
+CppTypeFor<TypeCategory::Real, 8> RTNAME(ProductReal8)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 8>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
+      "PRODUCT");
+}
+#if LONG_DOUBLE == 80
+CppTypeFor<TypeCategory::Real, 10> RTNAME(ProductReal10)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 10>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 10>>{x},
+      "PRODUCT");
+}
+#elif LONG_DOUBLE == 128
+CppTypeFor<TypeCategory::Real, 16> RTNAME(ProductReal16)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 16>(x, source, line, dim, mask,
+      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 16>>{x},
+      "PRODUCT");
+}
+#endif
+
+void RTNAME(CppProductComplex4)(CppTypeFor<TypeCategory::Complex, 4> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 4>(x, source, line, dim,
+      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
+      "PRODUCT");
+}
+void RTNAME(CppProductComplex8)(CppTypeFor<TypeCategory::Complex, 8> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 8>(x, source, line, dim,
+      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
+      "PRODUCT");
+}
+#if LONG_DOUBLE == 80
+void RTNAME(CppProductComplex10)(CppTypeFor<TypeCategory::Complex, 10> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 10>(x, source, line, dim,
+      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 10>>{x},
+      "PRODUCT");
+}
+#elif LONG_DOUBLE == 128
+void RTNAME(CppProductComplex16)(CppTypeFor<TypeCategory::Complex, 16> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 16>(x, source, line, dim,
+      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 16>>{x},
+      "PRODUCT");
+}
+#endif
+
+void RTNAME(ProductDim)(Descriptor &result, const Descriptor &x, int dim,
+    const char *source, int line, const Descriptor *mask) {
+  TypedPartialNumericReduction<NonComplexProductAccumulator,
+      NonComplexProductAccumulator, ComplexProductAccumulator>(
+      result, x, dim, source, line, mask, "PRODUCT");
+}
+} // extern "C"
+} // namespace Fortran::runtime
Index: flang/runtime/reduction-templates.h
===================================================================
--- /dev/null
+++ flang/runtime/reduction-templates.h
@@ -0,0 +1,323 @@
+//===-- runtime/reduction-templates.h -------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Generic function templates used by various reduction transformation
+// intrinsic functions (SUM, PRODUCT, &c.)
+//
+// * Partial reductions (i.e., those with DIM= arguments that are not
+//   required to be 1 by the rank of the argument) return arrays that
+//   are dynamically allocated in a caller-supplied descriptor.
+// * Total reductions (i.e., no DIM= argument) with FINDLOC, MAXLOC, & MINLOC
+//   return integer vectors of some kind, not scalars; a caller-supplied
+//   descriptor is used
+// * Character-valued reductions (MAXVAL & MINVAL) return arbitrary
+//   length results, dynamically allocated in a caller-supplied descriptor
+
+#ifndef FORTRAN_RUNTIME_REDUCTION_TEMPLATES_H_
+#define FORTRAN_RUNTIME_REDUCTION_TEMPLATES_H_
+
+#include "cpp-type.h"
+#include "descriptor.h"
+#include "terminator.h"
+#include "tools.h"
+
+namespace Fortran::runtime {
+
+// Reductions are implemented with *accumulators*, which are instances of
+// classes that incrementally build up the result (or an element thereof) during
+// a traversal of the unmasked elements of an array.  Each accumulator class
+// supports a constructor (which captures a reference to the array), an
+// AccumulateAt() member function that applies supplied subscripts to the
+// array and does something with a scalar element, and a GetResult()
+// member function that copies a final result into its destination.
+
+// Total reduction of the array argument to a scalar (or to a vector in the
+// cases of FINDLOC, MAXLOC, & MINLOC).  These are the cases without DIM= or
+// cases where the argument has rank 1 and DIM=, if present, must be 1.
+template <typename TYPE, typename ACCUMULATOR>
+inline void DoTotalReduction(const Descriptor &x, int dim,
+    const Descriptor *mask, ACCUMULATOR &accumulator, const char *intrinsic,
+    Terminator &terminator) {
+  if (dim < 0 || dim > 1) {
+    terminator.Crash(
+        "%s: bad DIM=%d for argument with rank %d", intrinsic, dim, x.rank());
+  }
+  SubscriptValue xAt[maxRank];
+  x.GetLowerBounds(xAt);
+  if (mask) {
+    CheckConformability(x, *mask, terminator, intrinsic, "ARRAY", "MASK");
+    SubscriptValue maskAt[maxRank];
+    mask->GetLowerBounds(maskAt);
+    if (mask->rank() > 0) {
+      for (auto elements{x.Elements()}; elements--;
+           x.IncrementSubscripts(xAt), mask->IncrementSubscripts(maskAt)) {
+        if (IsLogicalElementTrue(*mask, maskAt)) {
+          accumulator.template AccumulateAt<TYPE>(xAt);
+        }
+      }
+      return;
+    } else if (!IsLogicalElementTrue(*mask, maskAt)) {
+      // scalar MASK=.FALSE.: return identity value
+      return;
+    }
+  }
+  // No MASK=, or scalar MASK=.TRUE.
+  for (auto elements{x.Elements()}; elements--; x.IncrementSubscripts(xAt)) {
+    if (!accumulator.template AccumulateAt<TYPE>(xAt)) {
+      break; // cut short, result is known
+    }
+  }
+}
+
+template <TypeCategory CAT, int KIND, typename ACCUMULATOR>
+inline CppTypeFor<CAT, KIND> GetTotalReduction(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask,
+    ACCUMULATOR &&accumulator, const char *intrinsic) {
+  Terminator terminator{source, line};
+  RUNTIME_CHECK(terminator, TypeCode(CAT, KIND) == x.type());
+  using CppType = CppTypeFor<CAT, KIND>;
+  DoTotalReduction<CppType>(x, dim, mask, accumulator, intrinsic, terminator);
+  CppType result;
+#ifdef _MSC_VER // work around MSVC spurious error
+  accumulator.GetResult(&result);
+#else
+  accumulator.template GetResult(&result);
+#endif
+  return result;
+}
+
+// For reductions on a dimension, e.g. SUM(array,DIM=2) where the shape
+// of the array is [2,3,5], the shape of the result is [2,5] and
+// result(j,k) = SUM(array(j,:,k)), possibly modified if the array has
+// lower bounds other than one.  This utility subroutine creates an
+// array of subscripts [j,_,k] for result subscripts [j,k] so that the
+// elemets of array(j,:,k) can be reduced.
+inline void GetExpandedSubscripts(SubscriptValue at[],
+    const Descriptor &descriptor, int zeroBasedDim,
+    const SubscriptValue from[]) {
+  descriptor.GetLowerBounds(at);
+  int rank{descriptor.rank()};
+  int j{0};
+  for (; j < zeroBasedDim; ++j) {
+    at[j] += from[j] - 1 /*lower bound*/;
+  }
+  for (++j; j < rank; ++j) {
+    at[j] += from[j - 1] - 1;
+  }
+}
+
+template <typename TYPE, typename ACCUMULATOR>
+inline void ReduceDimToScalar(const Descriptor &x, int zeroBasedDim,
+    SubscriptValue subscripts[], TYPE *result, ACCUMULATOR &accumulator) {
+  SubscriptValue xAt[maxRank];
+  GetExpandedSubscripts(xAt, x, zeroBasedDim, subscripts);
+  const auto &dim{x.GetDimension(zeroBasedDim)};
+  SubscriptValue at{dim.LowerBound()};
+  for (auto n{dim.Extent()}; n-- > 0; ++at) {
+    xAt[zeroBasedDim] = at;
+    if (!accumulator.template AccumulateAt<TYPE>(xAt)) {
+      break;
+    }
+  }
+#ifdef _MSC_VER // work around MSVC spurious error
+  accumulator.GetResult(result, zeroBasedDim);
+#else
+  accumulator.template GetResult(result, zeroBasedDim);
+#endif
+}
+
+template <typename TYPE, typename ACCUMULATOR>
+inline void ReduceDimMaskToScalar(const Descriptor &x, int zeroBasedDim,
+    SubscriptValue subscripts[], const Descriptor &mask, TYPE *result,
+    ACCUMULATOR &accumulator) {
+  SubscriptValue xAt[maxRank], maskAt[maxRank];
+  GetExpandedSubscripts(xAt, x, zeroBasedDim, subscripts);
+  GetExpandedSubscripts(maskAt, mask, zeroBasedDim, subscripts);
+  const auto &xDim{x.GetDimension(zeroBasedDim)};
+  SubscriptValue xPos{xDim.LowerBound()};
+  const auto &maskDim{mask.GetDimension(zeroBasedDim)};
+  SubscriptValue maskPos{maskDim.LowerBound()};
+  for (auto n{x.GetDimension(zeroBasedDim).Extent()}; n-- > 0;
+       ++xPos, ++maskPos) {
+    maskAt[zeroBasedDim] = maskPos;
+    if (IsLogicalElementTrue(mask, maskAt)) {
+      xAt[zeroBasedDim] = xPos;
+      if (!accumulator.template AccumulateAt<TYPE>(xAt)) {
+        break;
+      }
+    }
+  }
+#ifdef _MSC_VER // work around MSVC spurious error
+  accumulator.GetResult(result, zeroBasedDim);
+#else
+  accumulator.template GetResult(result, zeroBasedDim);
+#endif
+}
+
+// Utility: establishes & allocates the result array for a partial
+// reduction (i.e., one with DIM=).
+static void CreatePartialReductionResult(Descriptor &result,
+    const Descriptor &x, int dim, Terminator &terminator, const char *intrinsic,
+    TypeCode typeCode) {
+  int xRank{x.rank()};
+  if (dim < 1 || dim > xRank) {
+    terminator.Crash("%s: bad DIM=%d for rank %d", intrinsic, dim, xRank);
+  }
+  int zeroBasedDim{dim - 1};
+  SubscriptValue resultExtent[maxRank];
+  for (int j{0}; j < zeroBasedDim; ++j) {
+    resultExtent[j] = x.GetDimension(j).Extent();
+  }
+  for (int j{zeroBasedDim + 1}; j < xRank; ++j) {
+    resultExtent[j - 1] = x.GetDimension(j).Extent();
+  }
+  result.Establish(typeCode, x.ElementBytes(), nullptr, xRank - 1, resultExtent,
+      CFI_attribute_allocatable);
+  for (int j{0}; j + 1 < xRank; ++j) {
+    result.GetDimension(j).SetBounds(1, resultExtent[j]);
+  }
+  if (int stat{result.Allocate()}) {
+    terminator.Crash(
+        "%s: could not allocate memory for result; STAT=%d", intrinsic, stat);
+  }
+}
+
+// Partial reductions with DIM=
+
+template <typename ACCUMULATOR, TypeCategory CAT, int KIND>
+inline void PartialReduction(Descriptor &result, const Descriptor &x, int dim,
+    const Descriptor *mask, Terminator &terminator, const char *intrinsic,
+    ACCUMULATOR &accumulator) {
+  CreatePartialReductionResult(
+      result, x, dim, terminator, intrinsic, TypeCode{CAT, KIND});
+  SubscriptValue at[maxRank];
+  result.GetLowerBounds(at);
+  INTERNAL_CHECK(at[0] == 1);
+  using CppType = CppTypeFor<CAT, KIND>;
+  if (mask) {
+    CheckConformability(x, *mask, terminator, intrinsic, "ARRAY", "MASK");
+    SubscriptValue maskAt[maxRank]; // contents unused
+    if (mask->rank() > 0) {
+      for (auto n{result.Elements()}; n-- > 0; result.IncrementSubscripts(at)) {
+        accumulator.Reinitialize();
+        ReduceDimMaskToScalar<CppType, ACCUMULATOR>(
+            x, dim - 1, at, *mask, result.Element<CppType>(at), accumulator);
+      }
+      return;
+    } else if (!IsLogicalElementTrue(*mask, maskAt)) {
+      // scalar MASK=.FALSE.
+      accumulator.Reinitialize();
+      for (auto n{result.Elements()}; n-- > 0; result.IncrementSubscripts(at)) {
+        accumulator.GetResult(result.Element<CppType>(at));
+      }
+      return;
+    }
+  }
+  // No MASK= or scalar MASK=.TRUE.
+  for (auto n{result.Elements()}; n-- > 0; result.IncrementSubscripts(at)) {
+    accumulator.Reinitialize();
+    ReduceDimToScalar<CppType, ACCUMULATOR>(
+        x, dim - 1, at, result.Element<CppType>(at), accumulator);
+  }
+}
+
+template <template <typename> class ACCUM>
+struct PartialIntegerReductionHelper {
+  template <int KIND> struct Functor {
+    static constexpr int Intermediate{
+        std::max(KIND, 4)}; // use at least "int" for intermediate results
+    void operator()(Descriptor &result, const Descriptor &x, int dim,
+        const Descriptor *mask, Terminator &terminator,
+        const char *intrinsic) const {
+      using Accumulator =
+          ACCUM<CppTypeFor<TypeCategory::Integer, Intermediate>>;
+      Accumulator accumulator{x};
+      PartialReduction<Accumulator, TypeCategory::Integer, KIND>(
+          result, x, dim, mask, terminator, intrinsic, accumulator);
+    }
+  };
+};
+
+template <template <typename> class INTEGER_ACCUM>
+inline void PartialIntegerReduction(Descriptor &result, const Descriptor &x,
+    int dim, int kind, const Descriptor *mask, const char *intrinsic,
+    Terminator &terminator) {
+  ApplyIntegerKind<
+      PartialIntegerReductionHelper<INTEGER_ACCUM>::template Functor, void>(
+      kind, terminator, result, x, dim, mask, terminator, intrinsic);
+}
+
+template <TypeCategory CAT, template <typename> class ACCUM>
+struct PartialFloatingReductionHelper {
+  template <int KIND> struct Functor {
+    static constexpr int Intermediate{
+        std::max(KIND, 8)}; // use at least "double" for intermediate results
+    void operator()(Descriptor &result, const Descriptor &x, int dim,
+        const Descriptor *mask, Terminator &terminator,
+        const char *intrinsic) const {
+      using Accumulator = ACCUM<CppTypeFor<TypeCategory::Real, Intermediate>>;
+      Accumulator accumulator{x};
+      PartialReduction<Accumulator, CAT, KIND>(
+          result, x, dim, mask, terminator, intrinsic, accumulator);
+    }
+  };
+};
+
+template <template <typename> class INTEGER_ACCUM,
+    template <typename> class REAL_ACCUM,
+    template <typename> class COMPLEX_ACCUM>
+inline void TypedPartialNumericReduction(Descriptor &result,
+    const Descriptor &x, int dim, const char *source, int line,
+    const Descriptor *mask, const char *intrinsic) {
+  Terminator terminator{source, line};
+  auto catKind{x.type().GetCategoryAndKind()};
+  RUNTIME_CHECK(terminator, catKind.has_value());
+  switch (catKind->first) {
+  case TypeCategory::Integer:
+    PartialIntegerReduction<INTEGER_ACCUM>(
+        result, x, dim, catKind->second, mask, intrinsic, terminator);
+    break;
+  case TypeCategory::Real:
+    ApplyFloatingPointKind<PartialFloatingReductionHelper<TypeCategory::Real,
+                               REAL_ACCUM>::template Functor,
+        void>(catKind->second, terminator, result, x, dim, mask, terminator,
+        intrinsic);
+    break;
+  case TypeCategory::Complex:
+    ApplyFloatingPointKind<PartialFloatingReductionHelper<TypeCategory::Complex,
+                               COMPLEX_ACCUM>::template Functor,
+        void>(catKind->second, terminator, result, x, dim, mask, terminator,
+        intrinsic);
+    break;
+  default:
+    terminator.Crash("%s: invalid type code %d", intrinsic, x.type().raw());
+  }
+}
+
+template <typename ACCUMULATOR> struct LocationResultHelper {
+  template <int KIND> struct Functor {
+    void operator()(ACCUMULATOR &accumulator, const Descriptor &result) const {
+      accumulator.GetResult(
+          result.OffsetElement<CppTypeFor<TypeCategory::Integer, KIND>>());
+    }
+  };
+};
+
+template <typename ACCUMULATOR> struct PartialLocationHelper {
+  template <int KIND> struct Functor {
+    void operator()(Descriptor &result, const Descriptor &x, int dim,
+        const Descriptor *mask, Terminator &terminator, const char *intrinsic,
+        ACCUMULATOR &accumulator) const {
+      PartialReduction<ACCUMULATOR, TypeCategory::Integer, KIND>(
+          result, x, dim, mask, terminator, intrinsic, accumulator);
+    }
+  };
+};
+
+} // namespace Fortran::runtime
+#endif // FORTRAN_RUNTIME_REDUCTION_TEMPLATES_H_
Index: flang/runtime/reduction.cpp
===================================================================
--- flang/runtime/reduction.cpp
+++ flang/runtime/reduction.cpp
@@ -6,623 +6,18 @@
 //
 //===----------------------------------------------------------------------===//
 
-// Implements ALL, ANY, COUNT, FINDLOC, IPARITY, MAXLOC, MAXVAL, MINLOC, MINVAL,
-// PARITY, PRODUCT, and SUM for all required operand types and shapes and,
-// for FINDLOC, MAXLOC, & MINLOC, kinds of results.
+// Implements ALL, ANY, COUNT, IPARITY, & PARITY for all required operand
+// types and shapes.
 //
-// * Real and complex SUM reductions attempt to reduce floating-point
-//   cancellation on intermediate results by adding up partial sums
-//   for positive and negative elements independently.
-// * Partial reductions (i.e., those with DIM= arguments that are not
-//   required to be 1 by the rank of the argument) return arrays that
-//   are dynamically allocated in a caller-supplied descriptor.
-// * Total reductions (i.e., no DIM= argument) with FINDLOC, MAXLOC, & MINLOC
-//   return integer vectors of some kind, not scalars; a caller-supplied
-//   descriptor is used
-// * Character-valued reductions (MAXVAL & MINVAL) return arbitrary
-//   length results, dynamically allocated in a caller-supplied descriptor
+// FINDLOC, SUM, and PRODUCT are in their own eponymous source files;
+// MAXLOC, MINLOC, MAXVAL, and MINVAL are in extrema.cpp.
 
 #include "reduction.h"
-#include "character.h"
-#include "cpp-type.h"
-#include "terminator.h"
-#include "tools.h"
-#include "flang/Common/long-double.h"
+#include "reduction-templates.h"
 #include <cinttypes>
-#include <complex>
-#include <limits>
-#include <type_traits>
 
 namespace Fortran::runtime {
 
-// Generic reduction templates
-
-// Reductions are implemented with *accumulators*, which are instances of
-// classes that incrementally build up the result (or an element thereof) during
-// a traversal of the unmasked elements of an array.  Each accumulator class
-// supports a constructor (which captures a reference to the array), an
-// AccumulateAt() member function that applies supplied subscripts to the
-// array and does something with a scalar element, and a GetResult()
-// member function that copies a final result into its destination.
-
-// Total reduction of the array argument to a scalar (or to a vector in the
-// cases of FINDLOC, MAXLOC, & MINLOC).  These are the cases without DIM= or
-// cases where the argument has rank 1 and DIM=, if present, must be 1.
-template <typename TYPE, typename ACCUMULATOR>
-inline void DoTotalReduction(const Descriptor &x, int dim,
-    const Descriptor *mask, ACCUMULATOR &accumulator, const char *intrinsic,
-    Terminator &terminator) {
-  if (dim < 0 || dim > 1) {
-    terminator.Crash(
-        "%s: bad DIM=%d for argument with rank %d", intrinsic, dim, x.rank());
-  }
-  SubscriptValue xAt[maxRank];
-  x.GetLowerBounds(xAt);
-  if (mask) {
-    CheckConformability(x, *mask, terminator, intrinsic, "ARRAY", "MASK");
-    SubscriptValue maskAt[maxRank];
-    mask->GetLowerBounds(maskAt);
-    if (mask->rank() > 0) {
-      for (auto elements{x.Elements()}; elements--;
-           x.IncrementSubscripts(xAt), mask->IncrementSubscripts(maskAt)) {
-        if (IsLogicalElementTrue(*mask, maskAt)) {
-          accumulator.template AccumulateAt<TYPE>(xAt);
-        }
-      }
-      return;
-    } else if (!IsLogicalElementTrue(*mask, maskAt)) {
-      // scalar MASK=.FALSE.: return identity value
-      return;
-    }
-  }
-  // No MASK=, or scalar MASK=.TRUE.
-  for (auto elements{x.Elements()}; elements--; x.IncrementSubscripts(xAt)) {
-    if (!accumulator.template AccumulateAt<TYPE>(xAt)) {
-      break; // cut short, result is known
-    }
-  }
-}
-
-template <TypeCategory CAT, int KIND, typename ACCUMULATOR>
-inline CppTypeFor<CAT, KIND> GetTotalReduction(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask,
-    ACCUMULATOR &&accumulator, const char *intrinsic) {
-  Terminator terminator{source, line};
-  RUNTIME_CHECK(terminator, TypeCode(CAT, KIND) == x.type());
-  using CppType = CppTypeFor<CAT, KIND>;
-  DoTotalReduction<CppType>(x, dim, mask, accumulator, intrinsic, terminator);
-  CppType result;
-#ifdef _MSC_VER // work around MSVC spurious error
-  accumulator.GetResult(&result);
-#else
-  accumulator.template GetResult(&result);
-#endif
-  return result;
-}
-
-// For reductions on a dimension, e.g. SUM(array,DIM=2) where the shape
-// of the array is [2,3,5], the shape of the result is [2,5] and
-// result(j,k) = SUM(array(j,:,k)), possibly modified if the array has
-// lower bounds other than one.  This utility subroutine creates an
-// array of subscripts [j,_,k] for result subscripts [j,k] so that the
-// elemets of array(j,:,k) can be reduced.
-inline void GetExpandedSubscripts(SubscriptValue at[],
-    const Descriptor &descriptor, int zeroBasedDim,
-    const SubscriptValue from[]) {
-  descriptor.GetLowerBounds(at);
-  int rank{descriptor.rank()};
-  int j{0};
-  for (; j < zeroBasedDim; ++j) {
-    at[j] += from[j] - 1 /*lower bound*/;
-  }
-  for (++j; j < rank; ++j) {
-    at[j] += from[j - 1] - 1;
-  }
-}
-
-template <typename TYPE, typename ACCUMULATOR>
-inline void ReduceDimToScalar(const Descriptor &x, int zeroBasedDim,
-    SubscriptValue subscripts[], TYPE *result, ACCUMULATOR &accumulator) {
-  SubscriptValue xAt[maxRank];
-  GetExpandedSubscripts(xAt, x, zeroBasedDim, subscripts);
-  const auto &dim{x.GetDimension(zeroBasedDim)};
-  SubscriptValue at{dim.LowerBound()};
-  for (auto n{dim.Extent()}; n-- > 0; ++at) {
-    xAt[zeroBasedDim] = at;
-    if (!accumulator.template AccumulateAt<TYPE>(xAt)) {
-      break;
-    }
-  }
-#ifdef _MSC_VER // work around MSVC spurious error
-  accumulator.GetResult(result, zeroBasedDim);
-#else
-  accumulator.template GetResult(result, zeroBasedDim);
-#endif
-}
-
-template <typename TYPE, typename ACCUMULATOR>
-inline void ReduceDimMaskToScalar(const Descriptor &x, int zeroBasedDim,
-    SubscriptValue subscripts[], const Descriptor &mask, TYPE *result,
-    ACCUMULATOR &accumulator) {
-  SubscriptValue xAt[maxRank], maskAt[maxRank];
-  GetExpandedSubscripts(xAt, x, zeroBasedDim, subscripts);
-  GetExpandedSubscripts(maskAt, mask, zeroBasedDim, subscripts);
-  const auto &xDim{x.GetDimension(zeroBasedDim)};
-  SubscriptValue xPos{xDim.LowerBound()};
-  const auto &maskDim{mask.GetDimension(zeroBasedDim)};
-  SubscriptValue maskPos{maskDim.LowerBound()};
-  for (auto n{x.GetDimension(zeroBasedDim).Extent()}; n-- > 0;
-       ++xPos, ++maskPos) {
-    maskAt[zeroBasedDim] = maskPos;
-    if (IsLogicalElementTrue(mask, maskAt)) {
-      xAt[zeroBasedDim] = xPos;
-      if (!accumulator.template AccumulateAt<TYPE>(xAt)) {
-        break;
-      }
-    }
-  }
-#ifdef _MSC_VER // work around MSVC spurious error
-  accumulator.GetResult(result, zeroBasedDim);
-#else
-  accumulator.template GetResult(result, zeroBasedDim);
-#endif
-}
-
-// Utility: establishes & allocates the result array for a partial
-// reduction (i.e., one with DIM=).
-static void CreatePartialReductionResult(Descriptor &result,
-    const Descriptor &x, int dim, Terminator &terminator, const char *intrinsic,
-    TypeCode typeCode) {
-  int xRank{x.rank()};
-  if (dim < 1 || dim > xRank) {
-    terminator.Crash("%s: bad DIM=%d for rank %d", intrinsic, dim, xRank);
-  }
-  int zeroBasedDim{dim - 1};
-  SubscriptValue resultExtent[maxRank];
-  for (int j{0}; j < zeroBasedDim; ++j) {
-    resultExtent[j] = x.GetDimension(j).Extent();
-  }
-  for (int j{zeroBasedDim + 1}; j < xRank; ++j) {
-    resultExtent[j - 1] = x.GetDimension(j).Extent();
-  }
-  result.Establish(typeCode, x.ElementBytes(), nullptr, xRank - 1, resultExtent,
-      CFI_attribute_allocatable);
-  for (int j{0}; j + 1 < xRank; ++j) {
-    result.GetDimension(j).SetBounds(1, resultExtent[j]);
-  }
-  if (int stat{result.Allocate()}) {
-    terminator.Crash(
-        "%s: could not allocate memory for result; STAT=%d", intrinsic, stat);
-  }
-}
-
-// Partial reductions with DIM=
-
-template <typename ACCUMULATOR, TypeCategory CAT, int KIND>
-inline void PartialReduction(Descriptor &result, const Descriptor &x, int dim,
-    const Descriptor *mask, Terminator &terminator, const char *intrinsic,
-    ACCUMULATOR &accumulator) {
-  CreatePartialReductionResult(
-      result, x, dim, terminator, intrinsic, TypeCode{CAT, KIND});
-  SubscriptValue at[maxRank];
-  result.GetLowerBounds(at);
-  INTERNAL_CHECK(at[0] == 1);
-  using CppType = CppTypeFor<CAT, KIND>;
-  if (mask) {
-    CheckConformability(x, *mask, terminator, intrinsic, "ARRAY", "MASK");
-    SubscriptValue maskAt[maxRank]; // contents unused
-    if (mask->rank() > 0) {
-      for (auto n{result.Elements()}; n-- > 0; result.IncrementSubscripts(at)) {
-        accumulator.Reinitialize();
-        ReduceDimMaskToScalar<CppType, ACCUMULATOR>(
-            x, dim - 1, at, *mask, result.Element<CppType>(at), accumulator);
-      }
-      return;
-    } else if (!IsLogicalElementTrue(*mask, maskAt)) {
-      // scalar MASK=.FALSE.
-      accumulator.Reinitialize();
-      for (auto n{result.Elements()}; n-- > 0; result.IncrementSubscripts(at)) {
-        accumulator.GetResult(result.Element<CppType>(at));
-      }
-      return;
-    }
-  }
-  // No MASK= or scalar MASK=.TRUE.
-  for (auto n{result.Elements()}; n-- > 0; result.IncrementSubscripts(at)) {
-    accumulator.Reinitialize();
-    ReduceDimToScalar<CppType, ACCUMULATOR>(
-        x, dim - 1, at, result.Element<CppType>(at), accumulator);
-  }
-}
-
-template <template <typename> class ACCUM>
-struct PartialIntegerReductionHelper {
-  template <int KIND> struct Functor {
-    static constexpr int Intermediate{
-        std::max(KIND, 4)}; // use at least "int" for intermediate results
-    void operator()(Descriptor &result, const Descriptor &x, int dim,
-        const Descriptor *mask, Terminator &terminator,
-        const char *intrinsic) const {
-      using Accumulator =
-          ACCUM<CppTypeFor<TypeCategory::Integer, Intermediate>>;
-      Accumulator accumulator{x};
-      PartialReduction<Accumulator, TypeCategory::Integer, KIND>(
-          result, x, dim, mask, terminator, intrinsic, accumulator);
-    }
-  };
-};
-
-template <template <typename> class INTEGER_ACCUM>
-inline void PartialIntegerReduction(Descriptor &result, const Descriptor &x,
-    int dim, int kind, const Descriptor *mask, const char *intrinsic,
-    Terminator &terminator) {
-  ApplyIntegerKind<
-      PartialIntegerReductionHelper<INTEGER_ACCUM>::template Functor, void>(
-      kind, terminator, result, x, dim, mask, terminator, intrinsic);
-}
-
-template <TypeCategory CAT, template <typename> class ACCUM>
-struct PartialFloatingReductionHelper {
-  template <int KIND> struct Functor {
-    static constexpr int Intermediate{
-        std::max(KIND, 8)}; // use at least "double" for intermediate results
-    void operator()(Descriptor &result, const Descriptor &x, int dim,
-        const Descriptor *mask, Terminator &terminator,
-        const char *intrinsic) const {
-      using Accumulator = ACCUM<CppTypeFor<TypeCategory::Real, Intermediate>>;
-      Accumulator accumulator{x};
-      PartialReduction<Accumulator, CAT, KIND>(
-          result, x, dim, mask, terminator, intrinsic, accumulator);
-    }
-  };
-};
-
-template <template <typename> class INTEGER_ACCUM,
-    template <typename> class REAL_ACCUM,
-    template <typename> class COMPLEX_ACCUM>
-inline void TypedPartialNumericReduction(Descriptor &result,
-    const Descriptor &x, int dim, const char *source, int line,
-    const Descriptor *mask, const char *intrinsic) {
-  Terminator terminator{source, line};
-  auto catKind{x.type().GetCategoryAndKind()};
-  RUNTIME_CHECK(terminator, catKind.has_value());
-  switch (catKind->first) {
-  case TypeCategory::Integer:
-    PartialIntegerReduction<INTEGER_ACCUM>(
-        result, x, dim, catKind->second, mask, intrinsic, terminator);
-    break;
-  case TypeCategory::Real:
-    ApplyFloatingPointKind<PartialFloatingReductionHelper<TypeCategory::Real,
-                               REAL_ACCUM>::template Functor,
-        void>(catKind->second, terminator, result, x, dim, mask, terminator,
-        intrinsic);
-    break;
-  case TypeCategory::Complex:
-    ApplyFloatingPointKind<PartialFloatingReductionHelper<TypeCategory::Complex,
-                               COMPLEX_ACCUM>::template Functor,
-        void>(catKind->second, terminator, result, x, dim, mask, terminator,
-        intrinsic);
-    break;
-  default:
-    terminator.Crash("%s: invalid type code %d", intrinsic, x.type().raw());
-  }
-}
-
-// SUM()
-
-template <typename INTERMEDIATE> class IntegerSumAccumulator {
-public:
-  explicit IntegerSumAccumulator(const Descriptor &array) : array_{array} {}
-  void Reinitialize() { sum_ = 0; }
-  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
-    *p = static_cast<A>(sum_);
-  }
-  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
-    sum_ += *array_.Element<A>(at);
-    return true;
-  }
-
-private:
-  const Descriptor &array_;
-  INTERMEDIATE sum_{0};
-};
-
-template <typename INTERMEDIATE> class RealSumAccumulator {
-public:
-  explicit RealSumAccumulator(const Descriptor &array) : array_{array} {}
-  void Reinitialize() { positives_ = negatives_ = inOrder_ = 0; }
-  template <typename A> A Result() const {
-    auto sum{static_cast<A>(positives_ + negatives_)};
-    return std::isfinite(sum) ? sum : static_cast<A>(inOrder_);
-  }
-  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
-    *p = Result<A>();
-  }
-  template <typename A> bool Accumulate(A x) {
-    // Accumulate the nonnegative and negative elements independently
-    // to reduce cancellation; also record an in-order sum for use
-    // in case of overflow.
-    if (x >= 0) {
-      positives_ += x;
-    } else {
-      negatives_ += x;
-    }
-    inOrder_ += x;
-    return true;
-  }
-  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
-    return Accumulate(*array_.Element<A>(at));
-  }
-
-private:
-  const Descriptor &array_;
-  INTERMEDIATE positives_{0.0}, negatives_{0.0}, inOrder_{0.0};
-};
-
-template <typename PART> class ComplexSumAccumulator {
-public:
-  explicit ComplexSumAccumulator(const Descriptor &array) : array_{array} {}
-  void Reinitialize() {
-    reals_.Reinitialize();
-    imaginaries_.Reinitialize();
-  }
-  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
-    using ResultPart = typename A::value_type;
-    *p = {reals_.template Result<ResultPart>(),
-        imaginaries_.template Result<ResultPart>()};
-  }
-  template <typename A> bool Accumulate(const A &z) {
-    reals_.Accumulate(z.real());
-    imaginaries_.Accumulate(z.imag());
-    return true;
-  }
-  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
-    return Accumulate(*array_.Element<A>(at));
-  }
-
-private:
-  const Descriptor &array_;
-  RealSumAccumulator<PART> reals_{array_}, imaginaries_{array_};
-};
-
-extern "C" {
-CppTypeFor<TypeCategory::Integer, 1> RTNAME(SumInteger1)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 1>(x, source, line, dim, mask,
-      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x}, "SUM");
-}
-CppTypeFor<TypeCategory::Integer, 2> RTNAME(SumInteger2)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 2>(x, source, line, dim, mask,
-      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x}, "SUM");
-}
-CppTypeFor<TypeCategory::Integer, 4> RTNAME(SumInteger4)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 4>(x, source, line, dim, mask,
-      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x}, "SUM");
-}
-CppTypeFor<TypeCategory::Integer, 8> RTNAME(SumInteger8)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 8>(x, source, line, dim, mask,
-      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 8>>{x}, "SUM");
-}
-#ifdef __SIZEOF_INT128__
-CppTypeFor<TypeCategory::Integer, 16> RTNAME(SumInteger16)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 16>(x, source, line, dim,
-      mask, IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 16>>{x},
-      "SUM");
-}
-#endif
-
-// TODO: real/complex(2 & 3)
-CppTypeFor<TypeCategory::Real, 4> RTNAME(SumReal4)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 4>(
-      x, source, line, dim, mask, RealSumAccumulator<double>{x}, "SUM");
-}
-CppTypeFor<TypeCategory::Real, 8> RTNAME(SumReal8)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 8>(
-      x, source, line, dim, mask, RealSumAccumulator<double>{x}, "SUM");
-}
-#if LONG_DOUBLE == 80
-CppTypeFor<TypeCategory::Real, 10> RTNAME(SumReal10)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 10>(
-      x, source, line, dim, mask, RealSumAccumulator<long double>{x}, "SUM");
-}
-#elif LONG_DOUBLE == 128
-CppTypeFor<TypeCategory::Real, 16> RTNAME(SumReal16)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 16>(
-      x, source, line, dim, mask, RealSumAccumulator<long double>{x}, "SUM");
-}
-#endif
-
-void RTNAME(CppSumComplex4)(CppTypeFor<TypeCategory::Complex, 4> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 4>(
-      x, source, line, dim, mask, ComplexSumAccumulator<double>{x}, "SUM");
-}
-void RTNAME(CppSumComplex8)(CppTypeFor<TypeCategory::Complex, 8> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 8>(
-      x, source, line, dim, mask, ComplexSumAccumulator<double>{x}, "SUM");
-}
-#if LONG_DOUBLE == 80
-void RTNAME(CppSumComplex10)(CppTypeFor<TypeCategory::Complex, 10> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 10>(
-      x, source, line, dim, mask, ComplexSumAccumulator<long double>{x}, "SUM");
-}
-#elif LONG_DOUBLE == 128
-void RTNAME(CppSumComplex16)(CppTypeFor<TypeCategory::Complex, 16> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 16>(
-      x, source, line, dim, mask, ComplexSumAccumulator<long double>{x}, "SUM");
-}
-#endif
-
-void RTNAME(SumDim)(Descriptor &result, const Descriptor &x, int dim,
-    const char *source, int line, const Descriptor *mask) {
-  TypedPartialNumericReduction<IntegerSumAccumulator, RealSumAccumulator,
-      ComplexSumAccumulator>(result, x, dim, source, line, mask, "SUM");
-}
-} // extern "C"
-
-// PRODUCT()
-
-template <typename INTERMEDIATE> class NonComplexProductAccumulator {
-public:
-  explicit NonComplexProductAccumulator(const Descriptor &array)
-      : array_{array} {}
-  void Reinitialize() { product_ = 1; }
-  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
-    *p = static_cast<A>(product_);
-  }
-  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
-    product_ *= *array_.Element<A>(at);
-    return product_ != 0;
-  }
-
-private:
-  const Descriptor &array_;
-  INTERMEDIATE product_{1};
-};
-
-template <typename PART> class ComplexProductAccumulator {
-public:
-  explicit ComplexProductAccumulator(const Descriptor &array) : array_{array} {}
-  void Reinitialize() { product_ = std::complex<PART>{1, 0}; }
-  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
-    using ResultPart = typename A::value_type;
-    *p = {static_cast<ResultPart>(product_.real()),
-        static_cast<ResultPart>(product_.imag())};
-  }
-  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
-    product_ *= *array_.Element<A>(at);
-    return true;
-  }
-
-private:
-  const Descriptor &array_;
-  std::complex<PART> product_{1, 0};
-};
-
-extern "C" {
-CppTypeFor<TypeCategory::Integer, 1> RTNAME(ProductInteger1)(
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 1>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x},
-      "PRODUCT");
-}
-CppTypeFor<TypeCategory::Integer, 2> RTNAME(ProductInteger2)(
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 2>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x},
-      "PRODUCT");
-}
-CppTypeFor<TypeCategory::Integer, 4> RTNAME(ProductInteger4)(
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 4>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x},
-      "PRODUCT");
-}
-CppTypeFor<TypeCategory::Integer, 8> RTNAME(ProductInteger8)(
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 8>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 8>>{x},
-      "PRODUCT");
-}
-#ifdef __SIZEOF_INT128__
-CppTypeFor<TypeCategory::Integer, 16> RTNAME(ProductInteger16)(
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Integer, 16>(x, source, line, dim,
-      mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Integer, 16>>{x},
-      "PRODUCT");
-}
-#endif
-
-// TODO: real/complex(2 & 3)
-CppTypeFor<TypeCategory::Real, 4> RTNAME(ProductReal4)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 4>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
-      "PRODUCT");
-}
-CppTypeFor<TypeCategory::Real, 8> RTNAME(ProductReal8)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 8>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
-      "PRODUCT");
-}
-#if LONG_DOUBLE == 80
-CppTypeFor<TypeCategory::Real, 10> RTNAME(ProductReal10)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 10>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 10>>{x},
-      "PRODUCT");
-}
-#elif LONG_DOUBLE == 128
-CppTypeFor<TypeCategory::Real, 16> RTNAME(ProductReal16)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return GetTotalReduction<TypeCategory::Real, 16>(x, source, line, dim, mask,
-      NonComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 16>>{x},
-      "PRODUCT");
-}
-#endif
-
-void RTNAME(CppProductComplex4)(CppTypeFor<TypeCategory::Complex, 4> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 4>(x, source, line, dim,
-      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
-      "PRODUCT");
-}
-void RTNAME(CppProductComplex8)(CppTypeFor<TypeCategory::Complex, 8> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 8>(x, source, line, dim,
-      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 8>>{x},
-      "PRODUCT");
-}
-#if LONG_DOUBLE == 80
-void RTNAME(CppProductComplex10)(CppTypeFor<TypeCategory::Complex, 10> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 10>(x, source, line, dim,
-      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 10>>{x},
-      "PRODUCT");
-}
-#elif LONG_DOUBLE == 128
-void RTNAME(CppProductComplex16)(CppTypeFor<TypeCategory::Complex, 16> &result,
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  result = GetTotalReduction<TypeCategory::Complex, 16>(x, source, line, dim,
-      mask, ComplexProductAccumulator<CppTypeFor<TypeCategory::Real, 16>>{x},
-      "PRODUCT");
-}
-#endif
-
-void RTNAME(ProductDim)(Descriptor &result, const Descriptor &x, int dim,
-    const char *source, int line, const Descriptor *mask) {
-  TypedPartialNumericReduction<NonComplexProductAccumulator,
-      NonComplexProductAccumulator, ComplexProductAccumulator>(
-      result, x, dim, source, line, mask, "PRODUCT");
-}
-} // extern "C"
-
 // IPARITY()
 
 template <typename INTERMEDIATE> class IntegerXorAccumulator {
@@ -686,923 +81,6 @@
 }
 }
 
-// MAXLOC & MINLOC
-
-template <typename T, bool IS_MAX, bool BACK> struct NumericCompare {
-  using Type = T;
-  explicit NumericCompare(std::size_t /*elemLen; ignored*/) {}
-  bool operator()(const T &value, const T &previous) const {
-    if (value == previous) {
-      return BACK;
-    } else if constexpr (IS_MAX) {
-      return value > previous;
-    } else {
-      return value < previous;
-    }
-  }
-};
-
-template <typename T, bool IS_MAX, bool BACK> class CharacterCompare {
-public:
-  using Type = T;
-  explicit CharacterCompare(std::size_t elemLen)
-      : chars_{elemLen / sizeof(T)} {}
-  bool operator()(const T &value, const T &previous) const {
-    int cmp{CharacterScalarCompare<T>(&value, &previous, chars_, chars_)};
-    if (cmp == 0) {
-      return BACK;
-    } else if constexpr (IS_MAX) {
-      return cmp > 0;
-    } else {
-      return cmp < 0;
-    }
-  }
-
-private:
-  std::size_t chars_;
-};
-
-template <typename COMPARE> class ExtremumLocAccumulator {
-public:
-  using Type = typename COMPARE::Type;
-  ExtremumLocAccumulator(const Descriptor &array, std::size_t chars = 0)
-      : array_{array}, argRank_{array.rank()}, compare_{array.ElementBytes()} {
-    Reinitialize();
-  }
-  void Reinitialize() {
-    // per standard: result indices are all zero if no data
-    for (int j{0}; j < argRank_; ++j) {
-      extremumLoc_[j] = 0;
-    }
-    previous_ = nullptr;
-  }
-  int argRank() const { return argRank_; }
-  template <typename A> void GetResult(A *p, int zeroBasedDim = -1) {
-    if (zeroBasedDim >= 0) {
-      *p = extremumLoc_[zeroBasedDim];
-    } else {
-      for (int j{0}; j < argRank_; ++j) {
-        p[j] = extremumLoc_[j];
-      }
-    }
-  }
-  template <typename IGNORED> bool AccumulateAt(const SubscriptValue at[]) {
-    const auto &value{*array_.Element<Type>(at)};
-    if (!previous_ || compare_(value, *previous_)) {
-      previous_ = &value;
-      for (int j{0}; j < argRank_; ++j) {
-        extremumLoc_[j] = at[j];
-      }
-    }
-    return true;
-  }
-
-private:
-  const Descriptor &array_;
-  int argRank_;
-  SubscriptValue extremumLoc_[maxRank];
-  const Type *previous_{nullptr};
-  COMPARE compare_;
-};
-
-template <typename ACCUMULATOR> struct LocationResultHelper {
-  template <int KIND> struct Functor {
-    void operator()(ACCUMULATOR &accumulator, const Descriptor &result) const {
-      accumulator.GetResult(
-          result.OffsetElement<CppTypeFor<TypeCategory::Integer, KIND>>());
-    }
-  };
-};
-
-template <typename ACCUMULATOR, typename CPPTYPE>
-static void LocationHelper(const char *intrinsic, Descriptor &result,
-    const Descriptor &x, int kind, const Descriptor *mask,
-    Terminator &terminator) {
-  ACCUMULATOR accumulator{x};
-  DoTotalReduction<CPPTYPE>(x, 0, mask, accumulator, intrinsic, terminator);
-  ApplyIntegerKind<LocationResultHelper<ACCUMULATOR>::template Functor, void>(
-      kind, terminator, accumulator, result);
-}
-
-template <TypeCategory CAT, int KIND, bool IS_MAX,
-    template <typename, bool, bool> class COMPARE>
-inline void DoMaxOrMinLoc(const char *intrinsic, Descriptor &result,
-    const Descriptor &x, int kind, const char *source, int line,
-    const Descriptor *mask, bool back) {
-  using CppType = CppTypeFor<CAT, KIND>;
-  Terminator terminator{source, line};
-  if (back) {
-    LocationHelper<ExtremumLocAccumulator<COMPARE<CppType, IS_MAX, true>>,
-        CppType>(intrinsic, result, x, kind, mask, terminator);
-  } else {
-    LocationHelper<ExtremumLocAccumulator<COMPARE<CppType, IS_MAX, false>>,
-        CppType>(intrinsic, result, x, kind, mask, terminator);
-  }
-}
-
-template <TypeCategory CAT, bool IS_MAX> struct TypedMaxOrMinLocHelper {
-  template <int KIND> struct Functor {
-    void operator()(const char *intrinsic, Descriptor &result,
-        const Descriptor &x, int kind, const char *source, int line,
-        const Descriptor *mask, bool back) const {
-      DoMaxOrMinLoc<TypeCategory::Integer, KIND, IS_MAX, NumericCompare>(
-          intrinsic, result, x, kind, source, line, mask, back);
-    }
-  };
-};
-
-template <bool IS_MAX>
-inline void TypedMaxOrMinLoc(const char *intrinsic, Descriptor &result,
-    const Descriptor &x, int kind, const char *source, int line,
-    const Descriptor *mask, bool back) {
-  int rank{x.rank()};
-  SubscriptValue extent[1]{rank};
-  result.Establish(TypeCategory::Integer, kind, nullptr, 1, extent,
-      CFI_attribute_allocatable);
-  result.GetDimension(0).SetBounds(1, extent[0]);
-  Terminator terminator{source, line};
-  if (int stat{result.Allocate()}) {
-    terminator.Crash(
-        "%s: could not allocate memory for result; STAT=%d", intrinsic, stat);
-  }
-  CheckIntegerKind(terminator, kind, intrinsic);
-  auto catKind{x.type().GetCategoryAndKind()};
-  RUNTIME_CHECK(terminator, catKind.has_value());
-  switch (catKind->first) {
-  case TypeCategory::Integer:
-    ApplyIntegerKind<
-        TypedMaxOrMinLocHelper<TypeCategory::Integer, IS_MAX>::template Functor,
-        void>(catKind->second, terminator, intrinsic, result, x, kind, source,
-        line, mask, back);
-    break;
-  case TypeCategory::Real:
-    ApplyFloatingPointKind<
-        TypedMaxOrMinLocHelper<TypeCategory::Real, IS_MAX>::template Functor,
-        void>(catKind->second, terminator, intrinsic, result, x, kind, source,
-        line, mask, back);
-    break;
-  case TypeCategory::Character:
-    ApplyCharacterKind<TypedMaxOrMinLocHelper<TypeCategory::Character,
-                           IS_MAX>::template Functor,
-        void>(catKind->second, terminator, intrinsic, result, x, kind, source,
-        line, mask, back);
-    break;
-  default:
-    terminator.Crash(
-        "%s: Bad data type code (%d) for array", intrinsic, x.type().raw());
-  }
-}
-
-extern "C" {
-void RTNAME(Maxloc)(Descriptor &result, const Descriptor &x, int kind,
-    const char *source, int line, const Descriptor *mask, bool back) {
-  TypedMaxOrMinLoc<true>("MAXLOC", result, x, kind, source, line, mask, back);
-}
-void RTNAME(Minloc)(Descriptor &result, const Descriptor &x, int kind,
-    const char *source, int line, const Descriptor *mask, bool back) {
-  TypedMaxOrMinLoc<false>("MINLOC", result, x, kind, source, line, mask, back);
-}
-} // extern "C"
-
-// MAXLOC/MINLOC with DIM=
-
-template <typename ACCUMULATOR> struct PartialLocationHelper {
-  template <int KIND> struct Functor {
-    void operator()(Descriptor &result, const Descriptor &x, int dim,
-        const Descriptor *mask, Terminator &terminator, const char *intrinsic,
-        ACCUMULATOR &accumulator) const {
-      PartialReduction<ACCUMULATOR, TypeCategory::Integer, KIND>(
-          result, x, dim, mask, terminator, intrinsic, accumulator);
-    }
-  };
-};
-
-template <TypeCategory CAT, int KIND, bool IS_MAX,
-    template <typename, bool, bool> class COMPARE, bool BACK>
-static void DoPartialMaxOrMinLocDirection(const char *intrinsic,
-    Descriptor &result, const Descriptor &x, int kind, int dim,
-    const Descriptor *mask, Terminator &terminator) {
-  using CppType = CppTypeFor<CAT, KIND>;
-  using Accumulator = ExtremumLocAccumulator<COMPARE<CppType, IS_MAX, BACK>>;
-  Accumulator accumulator{x};
-  ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor, void>(
-      kind, terminator, result, x, dim, mask, terminator, intrinsic,
-      accumulator);
-}
-
-template <TypeCategory CAT, int KIND, bool IS_MAX,
-    template <typename, bool, bool> class COMPARE>
-inline void DoPartialMaxOrMinLoc(const char *intrinsic, Descriptor &result,
-    const Descriptor &x, int kind, int dim, const Descriptor *mask, bool back,
-    Terminator &terminator) {
-  if (back) {
-    DoPartialMaxOrMinLocDirection<CAT, KIND, IS_MAX, COMPARE, true>(
-        intrinsic, result, x, kind, dim, mask, terminator);
-  } else {
-    DoPartialMaxOrMinLocDirection<CAT, KIND, IS_MAX, COMPARE, false>(
-        intrinsic, result, x, kind, dim, mask, terminator);
-  }
-}
-
-template <TypeCategory CAT, bool IS_MAX,
-    template <typename, bool, bool> class COMPARE>
-struct DoPartialMaxOrMinLocHelper {
-  template <int KIND> struct Functor {
-    void operator()(const char *intrinsic, Descriptor &result,
-        const Descriptor &x, int kind, int dim, const Descriptor *mask,
-        bool back, Terminator &terminator) const {
-      DoPartialMaxOrMinLoc<CAT, KIND, IS_MAX, COMPARE>(
-          intrinsic, result, x, kind, dim, mask, back, terminator);
-    }
-  };
-};
-
-template <bool IS_MAX>
-inline void TypedPartialMaxOrMinLoc(const char *intrinsic, Descriptor &result,
-    const Descriptor &x, int kind, int dim, const char *source, int line,
-    const Descriptor *mask, bool back) {
-  Terminator terminator{source, line};
-  CheckIntegerKind(terminator, kind, intrinsic);
-  auto catKind{x.type().GetCategoryAndKind()};
-  RUNTIME_CHECK(terminator, catKind.has_value());
-  switch (catKind->first) {
-  case TypeCategory::Integer:
-    ApplyIntegerKind<DoPartialMaxOrMinLocHelper<TypeCategory::Integer, IS_MAX,
-                         NumericCompare>::template Functor,
-        void>(catKind->second, terminator, intrinsic, result, x, kind, dim,
-        mask, back, terminator);
-    break;
-  case TypeCategory::Real:
-    ApplyFloatingPointKind<DoPartialMaxOrMinLocHelper<TypeCategory::Real,
-                               IS_MAX, NumericCompare>::template Functor,
-        void>(catKind->second, terminator, intrinsic, result, x, kind, dim,
-        mask, back, terminator);
-    break;
-  case TypeCategory::Character:
-    ApplyCharacterKind<DoPartialMaxOrMinLocHelper<TypeCategory::Character,
-                           IS_MAX, CharacterCompare>::template Functor,
-        void>(catKind->second, terminator, intrinsic, result, x, kind, dim,
-        mask, back, terminator);
-    break;
-  default:
-    terminator.Crash(
-        "%s: Bad data type code (%d) for array", intrinsic, x.type().raw());
-  }
-}
-
-extern "C" {
-void RTNAME(MaxlocDim)(Descriptor &result, const Descriptor &x, int kind,
-    int dim, const char *source, int line, const Descriptor *mask, bool back) {
-  TypedPartialMaxOrMinLoc<true>(
-      "MAXLOC", result, x, kind, dim, source, line, mask, back);
-}
-void RTNAME(MinlocDim)(Descriptor &result, const Descriptor &x, int kind,
-    int dim, const char *source, int line, const Descriptor *mask, bool back) {
-  TypedPartialMaxOrMinLoc<false>(
-      "MINLOC", result, x, kind, dim, source, line, mask, back);
-}
-} // extern "C"
-
-// FINDLOC
-
-template <TypeCategory CAT1, int KIND1, TypeCategory CAT2, int KIND2>
-struct Equality {
-  using Type1 = CppTypeFor<CAT1, KIND1>;
-  using Type2 = CppTypeFor<CAT2, KIND2>;
-  bool operator()(const Descriptor &array, const SubscriptValue at[],
-      const Descriptor &target) const {
-    return *array.Element<Type1>(at) == *target.OffsetElement<Type2>();
-  }
-};
-
-template <int KIND1, int KIND2>
-struct Equality<TypeCategory::Complex, KIND1, TypeCategory::Complex, KIND2> {
-  using Type1 = CppTypeFor<TypeCategory::Complex, KIND1>;
-  using Type2 = CppTypeFor<TypeCategory::Complex, KIND2>;
-  bool operator()(const Descriptor &array, const SubscriptValue at[],
-      const Descriptor &target) const {
-    const Type1 &xz{*array.Element<Type1>(at)};
-    const Type2 &tz{*target.OffsetElement<Type2>()};
-    return xz.real() == tz.real() && xz.imag() == tz.imag();
-  }
-};
-
-template <int KIND1, TypeCategory CAT2, int KIND2>
-struct Equality<TypeCategory::Complex, KIND1, CAT2, KIND2> {
-  using Type1 = CppTypeFor<TypeCategory::Complex, KIND1>;
-  using Type2 = CppTypeFor<CAT2, KIND2>;
-  bool operator()(const Descriptor &array, const SubscriptValue at[],
-      const Descriptor &target) const {
-    const Type1 &z{*array.Element<Type1>(at)};
-    return z.imag() == 0 && z.real() == *target.OffsetElement<Type2>();
-  }
-};
-
-template <TypeCategory CAT1, int KIND1, int KIND2>
-struct Equality<CAT1, KIND1, TypeCategory::Complex, KIND2> {
-  using Type1 = CppTypeFor<CAT1, KIND1>;
-  using Type2 = CppTypeFor<TypeCategory::Complex, KIND2>;
-  bool operator()(const Descriptor &array, const SubscriptValue at[],
-      const Descriptor &target) const {
-    const Type2 &z{*target.OffsetElement<Type2>()};
-    return *array.Element<Type1>(at) == z.real() && z.imag() == 0;
-  }
-};
-
-template <int KIND> struct CharacterEquality {
-  using Type = CppTypeFor<TypeCategory::Character, KIND>;
-  bool operator()(const Descriptor &array, const SubscriptValue at[],
-      const Descriptor &target) const {
-    return CharacterScalarCompare<Type>(array.Element<Type>(at),
-               target.OffsetElement<Type>(),
-               array.ElementBytes() / static_cast<unsigned>(KIND),
-               target.ElementBytes() / static_cast<unsigned>(KIND)) == 0;
-  }
-};
-
-struct LogicalEquivalence {
-  bool operator()(const Descriptor &array, const SubscriptValue at[],
-      const Descriptor &target) const {
-    return IsLogicalElementTrue(array, at) ==
-        IsLogicalElementTrue(target, at /*ignored*/);
-  }
-};
-
-template <typename EQUALITY> class LocationAccumulator {
-public:
-  LocationAccumulator(
-      const Descriptor &array, const Descriptor &target, bool back)
-      : array_{array}, target_{target}, back_{back} {
-    Reinitialize();
-  }
-  void Reinitialize() {
-    // per standard: result indices are all zero if no data
-    for (int j{0}; j < rank_; ++j) {
-      location_[j] = 0;
-    }
-  }
-  template <typename A> void GetResult(A *p, int zeroBasedDim = -1) {
-    if (zeroBasedDim >= 0) {
-      *p = location_[zeroBasedDim];
-    } else {
-      for (int j{0}; j < rank_; ++j) {
-        p[j] = location_[j];
-      }
-    }
-  }
-  template <typename IGNORED> bool AccumulateAt(const SubscriptValue at[]) {
-    if (equality_(array_, at, target_)) {
-      for (int j{0}; j < rank_; ++j) {
-        location_[j] = at[j];
-      }
-      return back_;
-    } else {
-      return true;
-    }
-  }
-
-private:
-  const Descriptor &array_;
-  const Descriptor &target_;
-  const bool back_{false};
-  const int rank_{array_.rank()};
-  SubscriptValue location_[maxRank];
-  const EQUALITY equality_{};
-};
-
-template <TypeCategory XCAT, int XKIND, TypeCategory TARGET_CAT>
-struct TotalNumericFindlocHelper {
-  template <int TARGET_KIND> struct Functor {
-    void operator()(Descriptor &result, const Descriptor &x,
-        const Descriptor &target, int kind, int dim, const Descriptor *mask,
-        bool back, Terminator &terminator) const {
-      using Eq = Equality<XCAT, XKIND, TARGET_CAT, TARGET_KIND>;
-      using Accumulator = LocationAccumulator<Eq>;
-      Accumulator accumulator{x, target, back};
-      DoTotalReduction<void>(x, dim, mask, accumulator, "FINDLOC", terminator);
-      ApplyIntegerKind<LocationResultHelper<Accumulator>::template Functor,
-          void>(kind, terminator, accumulator, result);
-    }
-  };
-};
-
-template <TypeCategory CAT,
-    template <TypeCategory XCAT, int XKIND, TypeCategory TARGET_CAT>
-    class HELPER>
-struct NumericFindlocHelper {
-  template <int KIND> struct Functor {
-    void operator()(TypeCategory targetCat, int targetKind, Descriptor &result,
-        const Descriptor &x, const Descriptor &target, int kind, int dim,
-        const Descriptor *mask, bool back, Terminator &terminator) const {
-      switch (targetCat) {
-      case TypeCategory::Integer:
-        ApplyIntegerKind<
-            HELPER<CAT, KIND, TypeCategory::Integer>::template Functor, void>(
-            targetKind, terminator, result, x, target, kind, dim, mask, back,
-            terminator);
-        break;
-      case TypeCategory::Real:
-        ApplyFloatingPointKind<
-            HELPER<CAT, KIND, TypeCategory::Real>::template Functor, void>(
-            targetKind, terminator, result, x, target, kind, dim, mask, back,
-            terminator);
-        break;
-      case TypeCategory::Complex:
-        ApplyFloatingPointKind<
-            HELPER<CAT, KIND, TypeCategory::Complex>::template Functor, void>(
-            targetKind, terminator, result, x, target, kind, dim, mask, back,
-            terminator);
-        break;
-      default:
-        terminator.Crash(
-            "FINDLOC: bad target category %d for array category %d",
-            static_cast<int>(targetCat), static_cast<int>(CAT));
-      }
-    }
-  };
-};
-
-template <int KIND> struct CharacterFindlocHelper {
-  void operator()(Descriptor &result, const Descriptor &x,
-      const Descriptor &target, int kind, const Descriptor *mask, bool back,
-      Terminator &terminator) {
-    using Accumulator = LocationAccumulator<CharacterEquality<KIND>>;
-    Accumulator accumulator{x, target, back};
-    DoTotalReduction<void>(x, 0, mask, accumulator, "FINDLOC", terminator);
-    ApplyIntegerKind<LocationResultHelper<Accumulator>::template Functor, void>(
-        kind, terminator, accumulator, result);
-  }
-};
-
-static void LogicalFindlocHelper(Descriptor &result, const Descriptor &x,
-    const Descriptor &target, int kind, const Descriptor *mask, bool back,
-    Terminator &terminator) {
-  using Accumulator = LocationAccumulator<LogicalEquivalence>;
-  Accumulator accumulator{x, target, back};
-  DoTotalReduction<void>(x, 0, mask, accumulator, "FINDLOC", terminator);
-  ApplyIntegerKind<LocationResultHelper<Accumulator>::template Functor, void>(
-      kind, terminator, accumulator, result);
-}
-
-extern "C" {
-void RTNAME(Findloc)(Descriptor &result, const Descriptor &x,
-    const Descriptor &target, int kind, const char *source, int line,
-    const Descriptor *mask, bool back) {
-  int rank{x.rank()};
-  SubscriptValue extent[1]{rank};
-  result.Establish(TypeCategory::Integer, kind, nullptr, 1, extent,
-      CFI_attribute_allocatable);
-  result.GetDimension(0).SetBounds(1, extent[0]);
-  Terminator terminator{source, line};
-  if (int stat{result.Allocate()}) {
-    terminator.Crash(
-        "FINDLOC: could not allocate memory for result; STAT=%d", stat);
-  }
-  CheckIntegerKind(terminator, kind, "FINDLOC");
-  auto xType{x.type().GetCategoryAndKind()};
-  auto targetType{target.type().GetCategoryAndKind()};
-  RUNTIME_CHECK(terminator, xType.has_value() && targetType.has_value());
-  switch (xType->first) {
-  case TypeCategory::Integer:
-    ApplyIntegerKind<NumericFindlocHelper<TypeCategory::Integer,
-                         TotalNumericFindlocHelper>::template Functor,
-        void>(xType->second, terminator, targetType->first, targetType->second,
-        result, x, target, kind, 0, mask, back, terminator);
-    break;
-  case TypeCategory::Real:
-    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Real,
-                               TotalNumericFindlocHelper>::template Functor,
-        void>(xType->second, terminator, targetType->first, targetType->second,
-        result, x, target, kind, 0, mask, back, terminator);
-    break;
-  case TypeCategory::Complex:
-    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Complex,
-                               TotalNumericFindlocHelper>::template Functor,
-        void>(xType->second, terminator, targetType->first, targetType->second,
-        result, x, target, kind, 0, mask, back, terminator);
-    break;
-  case TypeCategory::Character:
-    RUNTIME_CHECK(terminator,
-        targetType->first == TypeCategory::Character &&
-            targetType->second == xType->second);
-    ApplyCharacterKind<CharacterFindlocHelper, void>(xType->second, terminator,
-        result, x, target, kind, mask, back, terminator);
-    break;
-  case TypeCategory::Logical:
-    RUNTIME_CHECK(terminator, targetType->first == TypeCategory::Logical);
-    LogicalFindlocHelper(result, x, target, kind, mask, back, terminator);
-    break;
-  default:
-    terminator.Crash(
-        "FINDLOC: Bad data type code (%d) for array", x.type().raw());
-  }
-}
-} // extern "C"
-
-// FINDLOC with DIM=
-
-template <TypeCategory XCAT, int XKIND, TypeCategory TARGET_CAT>
-struct PartialNumericFindlocHelper {
-  template <int TARGET_KIND> struct Functor {
-    void operator()(Descriptor &result, const Descriptor &x,
-        const Descriptor &target, int kind, int dim, const Descriptor *mask,
-        bool back, Terminator &terminator) const {
-      using Eq = Equality<XCAT, XKIND, TARGET_CAT, TARGET_KIND>;
-      using Accumulator = LocationAccumulator<Eq>;
-      Accumulator accumulator{x, target, back};
-      ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor,
-          void>(kind, terminator, result, x, dim, mask, terminator, "FINDLOC",
-          accumulator);
-    }
-  };
-};
-
-template <int KIND> struct PartialCharacterFindlocHelper {
-  void operator()(Descriptor &result, const Descriptor &x,
-      const Descriptor &target, int kind, int dim, const Descriptor *mask,
-      bool back, Terminator &terminator) {
-    using Accumulator = LocationAccumulator<CharacterEquality<KIND>>;
-    Accumulator accumulator{x, target, back};
-    ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor,
-        void>(kind, terminator, result, x, dim, mask, terminator, "FINDLOC",
-        accumulator);
-  }
-};
-
-static void PartialLogicalFindlocHelper(Descriptor &result, const Descriptor &x,
-    const Descriptor &target, int kind, int dim, const Descriptor *mask,
-    bool back, Terminator &terminator) {
-  using Accumulator = LocationAccumulator<LogicalEquivalence>;
-  Accumulator accumulator{x, target, back};
-  ApplyIntegerKind<PartialLocationHelper<Accumulator>::template Functor, void>(
-      kind, terminator, result, x, dim, mask, terminator, "FINDLOC",
-      accumulator);
-}
-
-extern "C" {
-void RTNAME(FindlocDim)(Descriptor &result, const Descriptor &x,
-    const Descriptor &target, int kind, int dim, const char *source, int line,
-    const Descriptor *mask, bool back) {
-  Terminator terminator{source, line};
-  CheckIntegerKind(terminator, kind, "FINDLOC");
-  auto xType{x.type().GetCategoryAndKind()};
-  auto targetType{target.type().GetCategoryAndKind()};
-  RUNTIME_CHECK(terminator, xType.has_value() && targetType.has_value());
-  switch (xType->first) {
-  case TypeCategory::Integer:
-    ApplyIntegerKind<NumericFindlocHelper<TypeCategory::Integer,
-                         PartialNumericFindlocHelper>::template Functor,
-        void>(xType->second, terminator, targetType->first, targetType->second,
-        result, x, target, kind, dim, mask, back, terminator);
-    break;
-  case TypeCategory::Real:
-    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Real,
-                               PartialNumericFindlocHelper>::template Functor,
-        void>(xType->second, terminator, targetType->first, targetType->second,
-        result, x, target, kind, dim, mask, back, terminator);
-    break;
-  case TypeCategory::Complex:
-    ApplyFloatingPointKind<NumericFindlocHelper<TypeCategory::Complex,
-                               PartialNumericFindlocHelper>::template Functor,
-        void>(xType->second, terminator, targetType->first, targetType->second,
-        result, x, target, kind, dim, mask, back, terminator);
-    break;
-  case TypeCategory::Character:
-    RUNTIME_CHECK(terminator,
-        targetType->first == TypeCategory::Character &&
-            targetType->second == xType->second);
-    ApplyCharacterKind<PartialCharacterFindlocHelper, void>(xType->second,
-        terminator, result, x, target, kind, dim, mask, back, terminator);
-    break;
-  case TypeCategory::Logical:
-    RUNTIME_CHECK(terminator, targetType->first == TypeCategory::Logical);
-    PartialLogicalFindlocHelper(
-        result, x, target, kind, dim, mask, back, terminator);
-    break;
-  default:
-    terminator.Crash(
-        "FINDLOC: Bad data type code (%d) for array", x.type().raw());
-  }
-}
-} // extern "C"
-
-// MAXVAL and MINVAL
-
-template <TypeCategory CAT, int KIND, bool IS_MAXVAL> struct MaxOrMinIdentity {
-  using Type = CppTypeFor<CAT, KIND>;
-  static constexpr Type Value() {
-    return IS_MAXVAL ? std::numeric_limits<Type>::lowest()
-                     : std::numeric_limits<Type>::max();
-  }
-};
-
-// std::numeric_limits<> may not know int128_t
-template <bool IS_MAXVAL>
-struct MaxOrMinIdentity<TypeCategory::Integer, 16, IS_MAXVAL> {
-  using Type = CppTypeFor<TypeCategory::Integer, 16>;
-  static constexpr Type Value() {
-    return IS_MAXVAL ? Type{1} << 127 : ~Type{0} >> 1;
-  }
-};
-
-template <TypeCategory CAT, int KIND, bool IS_MAXVAL>
-class NumericExtremumAccumulator {
-public:
-  using Type = CppTypeFor<CAT, KIND>;
-  explicit NumericExtremumAccumulator(const Descriptor &array)
-      : array_{array} {}
-  void Reinitialize() {
-    extremum_ = MaxOrMinIdentity<CAT, KIND, IS_MAXVAL>::Value();
-  }
-  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
-    *p = extremum_;
-  }
-  bool Accumulate(Type x) {
-    if constexpr (IS_MAXVAL) {
-      if (x > extremum_) {
-        extremum_ = x;
-      }
-    } else if (x < extremum_) {
-      extremum_ = x;
-    }
-    return true;
-  }
-  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
-    return Accumulate(*array_.Element<A>(at));
-  }
-
-private:
-  const Descriptor &array_;
-  Type extremum_{MaxOrMinIdentity<CAT, KIND, IS_MAXVAL>::Value()};
-};
-
-template <TypeCategory CAT, int KIND, bool IS_MAXVAL>
-inline CppTypeFor<CAT, KIND> TotalNumericMaxOrMin(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask,
-    const char *intrinsic) {
-  return GetTotalReduction<CAT, KIND>(x, source, line, dim, mask,
-      NumericExtremumAccumulator<CAT, KIND, IS_MAXVAL>{x}, intrinsic);
-}
-
-template <TypeCategory CAT, int KIND, bool IS_MAXVAL,
-    template <TypeCategory, int, bool> class ACCUMULATOR>
-static void DoMaxOrMin(Descriptor &result, const Descriptor &x, int dim,
-    const Descriptor *mask, const char *intrinsic, Terminator &terminator) {
-  using Type = CppTypeFor<CAT, KIND>;
-  if (dim == 0 || x.rank() == 1) {
-    // Total reduction
-    result.Establish(x.type(), x.ElementBytes(), nullptr, 0, nullptr,
-        CFI_attribute_allocatable);
-    if (int stat{result.Allocate()}) {
-      terminator.Crash(
-          "%s: could not allocate memory for result; STAT=%d", intrinsic, stat);
-    }
-    ACCUMULATOR<CAT, KIND, IS_MAXVAL> accumulator{x};
-    DoTotalReduction<Type>(x, dim, mask, accumulator, intrinsic, terminator);
-    accumulator.GetResult(result.OffsetElement<Type>());
-  } else {
-    // Partial reduction
-    using Accumulator = ACCUMULATOR<CAT, KIND, IS_MAXVAL>;
-    Accumulator accumulator{x};
-    PartialReduction<Accumulator, CAT, KIND>(
-        result, x, dim, mask, terminator, intrinsic, accumulator);
-  }
-}
-
-template <TypeCategory CAT, bool IS_MAXVAL> struct MaxOrMinHelper {
-  template <int KIND> struct Functor {
-    void operator()(Descriptor &result, const Descriptor &x, int dim,
-        const Descriptor *mask, const char *intrinsic,
-        Terminator &terminator) const {
-      DoMaxOrMin<CAT, KIND, IS_MAXVAL, NumericExtremumAccumulator>(
-          result, x, dim, mask, intrinsic, terminator);
-    }
-  };
-};
-
-template <bool IS_MAXVAL>
-inline void NumericMaxOrMin(Descriptor &result, const Descriptor &x, int dim,
-    const char *source, int line, const Descriptor *mask,
-    const char *intrinsic) {
-  Terminator terminator{source, line};
-  auto type{x.type().GetCategoryAndKind()};
-  RUNTIME_CHECK(terminator, type);
-  switch (type->first) {
-  case TypeCategory::Integer:
-    ApplyIntegerKind<
-        MaxOrMinHelper<TypeCategory::Integer, IS_MAXVAL>::template Functor,
-        void>(
-        type->second, terminator, result, x, dim, mask, intrinsic, terminator);
-    break;
-  case TypeCategory::Real:
-    ApplyFloatingPointKind<
-        MaxOrMinHelper<TypeCategory::Real, IS_MAXVAL>::template Functor, void>(
-        type->second, terminator, result, x, dim, mask, intrinsic, terminator);
-    break;
-  default:
-    terminator.Crash("%s: bad type code %d", intrinsic, x.type().raw());
-  }
-}
-
-template <TypeCategory, int KIND, bool IS_MAXVAL>
-class CharacterExtremumAccumulator {
-public:
-  using Type = CppTypeFor<TypeCategory::Character, KIND>;
-  explicit CharacterExtremumAccumulator(const Descriptor &array)
-      : array_{array}, charLen_{array_.ElementBytes() / KIND} {}
-  void Reinitialize() { extremum_ = nullptr; }
-  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
-    static_assert(std::is_same_v<A, Type>);
-    if (extremum_) {
-      std::memcpy(p, extremum_, charLen_);
-    } else {
-      // empty array: result is all zero-valued characters
-      std::memset(p, 0, charLen_);
-    }
-  }
-  bool Accumulate(const Type *x) {
-    if (!extremum_) {
-      extremum_ = x;
-    } else {
-      int cmp{CharacterScalarCompare(x, extremum_, charLen_, charLen_)};
-      if (IS_MAXVAL == (cmp > 0)) {
-        extremum_ = x;
-      }
-    }
-    return true;
-  }
-  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
-    return Accumulate(array_.Element<A>(at));
-  }
-
-private:
-  const Descriptor &array_;
-  std::size_t charLen_;
-  const Type *extremum_{nullptr};
-};
-
-template <bool IS_MAXVAL> struct CharacterMaxOrMinHelper {
-  template <int KIND> struct Functor {
-    void operator()(Descriptor &result, const Descriptor &x, int dim,
-        const Descriptor *mask, const char *intrinsic,
-        Terminator &terminator) const {
-      DoMaxOrMin<TypeCategory::Character, KIND, IS_MAXVAL,
-          CharacterExtremumAccumulator>(
-          result, x, dim, mask, intrinsic, terminator);
-    }
-  };
-};
-
-template <bool IS_MAXVAL>
-inline void CharacterMaxOrMin(Descriptor &result, const Descriptor &x, int dim,
-    const char *source, int line, const Descriptor *mask,
-    const char *intrinsic) {
-  Terminator terminator{source, line};
-  auto type{x.type().GetCategoryAndKind()};
-  RUNTIME_CHECK(terminator, type && type->first == TypeCategory::Character);
-  ApplyCharacterKind<CharacterMaxOrMinHelper<IS_MAXVAL>::template Functor,
-      void>(
-      type->second, terminator, result, x, dim, mask, intrinsic, terminator);
-}
-
-extern "C" {
-CppTypeFor<TypeCategory::Integer, 1> RTNAME(MaxvalInteger1)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 1, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-CppTypeFor<TypeCategory::Integer, 2> RTNAME(MaxvalInteger2)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 2, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-CppTypeFor<TypeCategory::Integer, 4> RTNAME(MaxvalInteger4)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 4, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-CppTypeFor<TypeCategory::Integer, 8> RTNAME(MaxvalInteger8)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 8, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-#ifdef __SIZEOF_INT128__
-CppTypeFor<TypeCategory::Integer, 16> RTNAME(MaxvalInteger16)(
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 16, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-#endif
-
-// TODO: REAL(2 & 3)
-CppTypeFor<TypeCategory::Real, 4> RTNAME(MaxvalReal4)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 4, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-CppTypeFor<TypeCategory::Real, 8> RTNAME(MaxvalReal8)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 8, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-#if LONG_DOUBLE == 80
-CppTypeFor<TypeCategory::Real, 10> RTNAME(MaxvalReal10)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 10, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-#elif LONG_DOUBLE == 128
-CppTypeFor<TypeCategory::Real, 16> RTNAME(MaxvalReal16)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 16, true>(
-      x, source, line, dim, mask, "MAXVAL");
-}
-#endif
-
-void RTNAME(MaxvalCharacter)(Descriptor &result, const Descriptor &x,
-    const char *source, int line, const Descriptor *mask) {
-  CharacterMaxOrMin<true>(result, x, 0, source, line, mask, "MAXVAL");
-}
-
-CppTypeFor<TypeCategory::Integer, 1> RTNAME(MinvalInteger1)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 1, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-CppTypeFor<TypeCategory::Integer, 2> RTNAME(MinvalInteger2)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 2, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-CppTypeFor<TypeCategory::Integer, 4> RTNAME(MinvalInteger4)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 4, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-CppTypeFor<TypeCategory::Integer, 8> RTNAME(MinvalInteger8)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 8, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-#ifdef __SIZEOF_INT128__
-CppTypeFor<TypeCategory::Integer, 16> RTNAME(MinvalInteger16)(
-    const Descriptor &x, const char *source, int line, int dim,
-    const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Integer, 16, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-#endif
-
-// TODO: REAL(2 & 3)
-CppTypeFor<TypeCategory::Real, 4> RTNAME(MinvalReal4)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 4, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-CppTypeFor<TypeCategory::Real, 8> RTNAME(MinvalReal8)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 8, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-#if LONG_DOUBLE == 80
-CppTypeFor<TypeCategory::Real, 10> RTNAME(MinvalReal10)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 10, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-#elif LONG_DOUBLE == 128
-CppTypeFor<TypeCategory::Real, 16> RTNAME(MinvalReal16)(const Descriptor &x,
-    const char *source, int line, int dim, const Descriptor *mask) {
-  return TotalNumericMaxOrMin<TypeCategory::Real, 16, false>(
-      x, source, line, dim, mask, "MINVAL");
-}
-#endif
-
-void RTNAME(MinvalCharacter)(Descriptor &result, const Descriptor &x,
-    const char *source, int line, const Descriptor *mask) {
-  CharacterMaxOrMin<false>(result, x, 0, source, line, mask, "MINVAL");
-}
-
-void RTNAME(MaxvalDim)(Descriptor &result, const Descriptor &x, int dim,
-    const char *source, int line, const Descriptor *mask) {
-  if (x.type().IsCharacter()) {
-    CharacterMaxOrMin<true>(result, x, dim, source, line, mask, "MAXVAL");
-  } else {
-    NumericMaxOrMin<true>(result, x, dim, source, line, mask, "MAXVAL");
-  }
-}
-void RTNAME(MinvalDim)(Descriptor &result, const Descriptor &x, int dim,
-    const char *source, int line, const Descriptor *mask) {
-  if (x.type().IsCharacter()) {
-    CharacterMaxOrMin<false>(result, x, dim, source, line, mask, "MINVAL");
-  } else {
-    NumericMaxOrMin<false>(result, x, dim, source, line, mask, "MINVAL");
-  }
-}
-
-} // extern "C"
-
 // ALL, ANY, COUNT, & PARITY
 
 enum class LogicalReduction { All, Any, Parity };
Index: flang/runtime/sum.cpp
===================================================================
--- /dev/null
+++ flang/runtime/sum.cpp
@@ -0,0 +1,187 @@
+//===-- runtime/sum.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// Implements SUM for all required operand types and shapes.
+//
+// Real and complex SUM reductions attempt to reduce floating-point
+// cancellation on intermediate results by adding up partial sums
+// for positive and negative elements independently.
+
+#include "reduction-templates.h"
+#include "reduction.h"
+#include "flang/Common/long-double.h"
+#include <cinttypes>
+#include <complex>
+
+namespace Fortran::runtime {
+
+template <typename INTERMEDIATE> class IntegerSumAccumulator {
+public:
+  explicit IntegerSumAccumulator(const Descriptor &array) : array_{array} {}
+  void Reinitialize() { sum_ = 0; }
+  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
+    *p = static_cast<A>(sum_);
+  }
+  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
+    sum_ += *array_.Element<A>(at);
+    return true;
+  }
+
+private:
+  const Descriptor &array_;
+  INTERMEDIATE sum_{0};
+};
+
+template <typename INTERMEDIATE> class RealSumAccumulator {
+public:
+  explicit RealSumAccumulator(const Descriptor &array) : array_{array} {}
+  void Reinitialize() { positives_ = negatives_ = inOrder_ = 0; }
+  template <typename A> A Result() const {
+    auto sum{static_cast<A>(positives_ + negatives_)};
+    return std::isfinite(sum) ? sum : static_cast<A>(inOrder_);
+  }
+  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
+    *p = Result<A>();
+  }
+  template <typename A> bool Accumulate(A x) {
+    // Accumulate the nonnegative and negative elements independently
+    // to reduce cancellation; also record an in-order sum for use
+    // in case of overflow.
+    if (x >= 0) {
+      positives_ += x;
+    } else {
+      negatives_ += x;
+    }
+    inOrder_ += x;
+    return true;
+  }
+  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
+    return Accumulate(*array_.Element<A>(at));
+  }
+
+private:
+  const Descriptor &array_;
+  INTERMEDIATE positives_{0.0}, negatives_{0.0}, inOrder_{0.0};
+};
+
+template <typename PART> class ComplexSumAccumulator {
+public:
+  explicit ComplexSumAccumulator(const Descriptor &array) : array_{array} {}
+  void Reinitialize() {
+    reals_.Reinitialize();
+    imaginaries_.Reinitialize();
+  }
+  template <typename A> void GetResult(A *p, int /*zeroBasedDim*/ = -1) const {
+    using ResultPart = typename A::value_type;
+    *p = {reals_.template Result<ResultPart>(),
+        imaginaries_.template Result<ResultPart>()};
+  }
+  template <typename A> bool Accumulate(const A &z) {
+    reals_.Accumulate(z.real());
+    imaginaries_.Accumulate(z.imag());
+    return true;
+  }
+  template <typename A> bool AccumulateAt(const SubscriptValue at[]) {
+    return Accumulate(*array_.Element<A>(at));
+  }
+
+private:
+  const Descriptor &array_;
+  RealSumAccumulator<PART> reals_{array_}, imaginaries_{array_};
+};
+
+extern "C" {
+CppTypeFor<TypeCategory::Integer, 1> RTNAME(SumInteger1)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 1>(x, source, line, dim, mask,
+      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x}, "SUM");
+}
+CppTypeFor<TypeCategory::Integer, 2> RTNAME(SumInteger2)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 2>(x, source, line, dim, mask,
+      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x}, "SUM");
+}
+CppTypeFor<TypeCategory::Integer, 4> RTNAME(SumInteger4)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 4>(x, source, line, dim, mask,
+      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 4>>{x}, "SUM");
+}
+CppTypeFor<TypeCategory::Integer, 8> RTNAME(SumInteger8)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 8>(x, source, line, dim, mask,
+      IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 8>>{x}, "SUM");
+}
+#ifdef __SIZEOF_INT128__
+CppTypeFor<TypeCategory::Integer, 16> RTNAME(SumInteger16)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Integer, 16>(x, source, line, dim,
+      mask, IntegerSumAccumulator<CppTypeFor<TypeCategory::Integer, 16>>{x},
+      "SUM");
+}
+#endif
+
+// TODO: real/complex(2 & 3)
+CppTypeFor<TypeCategory::Real, 4> RTNAME(SumReal4)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 4>(
+      x, source, line, dim, mask, RealSumAccumulator<double>{x}, "SUM");
+}
+CppTypeFor<TypeCategory::Real, 8> RTNAME(SumReal8)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 8>(
+      x, source, line, dim, mask, RealSumAccumulator<double>{x}, "SUM");
+}
+#if LONG_DOUBLE == 80
+CppTypeFor<TypeCategory::Real, 10> RTNAME(SumReal10)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 10>(
+      x, source, line, dim, mask, RealSumAccumulator<long double>{x}, "SUM");
+}
+#elif LONG_DOUBLE == 128
+CppTypeFor<TypeCategory::Real, 16> RTNAME(SumReal16)(const Descriptor &x,
+    const char *source, int line, int dim, const Descriptor *mask) {
+  return GetTotalReduction<TypeCategory::Real, 16>(
+      x, source, line, dim, mask, RealSumAccumulator<long double>{x}, "SUM");
+}
+#endif
+
+void RTNAME(CppSumComplex4)(CppTypeFor<TypeCategory::Complex, 4> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 4>(
+      x, source, line, dim, mask, ComplexSumAccumulator<double>{x}, "SUM");
+}
+void RTNAME(CppSumComplex8)(CppTypeFor<TypeCategory::Complex, 8> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 8>(
+      x, source, line, dim, mask, ComplexSumAccumulator<double>{x}, "SUM");
+}
+#if LONG_DOUBLE == 80
+void RTNAME(CppSumComplex10)(CppTypeFor<TypeCategory::Complex, 10> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 10>(
+      x, source, line, dim, mask, ComplexSumAccumulator<long double>{x}, "SUM");
+}
+#elif LONG_DOUBLE == 128
+void RTNAME(CppSumComplex16)(CppTypeFor<TypeCategory::Complex, 16> &result,
+    const Descriptor &x, const char *source, int line, int dim,
+    const Descriptor *mask) {
+  result = GetTotalReduction<TypeCategory::Complex, 16>(
+      x, source, line, dim, mask, ComplexSumAccumulator<long double>{x}, "SUM");
+}
+#endif
+
+void RTNAME(SumDim)(Descriptor &result, const Descriptor &x, int dim,
+    const char *source, int line, const Descriptor *mask) {
+  TypedPartialNumericReduction<IntegerSumAccumulator, RealSumAccumulator,
+      ComplexSumAccumulator>(result, x, dim, source, line, mask, "SUM");
+}
+} // extern "C"
+} // namespace Fortran::runtime