diff --git a/flang/lib/Optimizer/Transforms/SimplifyIntrinsics.cpp b/flang/lib/Optimizer/Transforms/SimplifyIntrinsics.cpp
--- a/flang/lib/Optimizer/Transforms/SimplifyIntrinsics.cpp
+++ b/flang/lib/Optimizer/Transforms/SimplifyIntrinsics.cpp
@@ -180,10 +180,12 @@
   // end function RTNAME(Sum)<T>_simplified
   auto zero = [](fir::FirOpBuilder builder, mlir::Location loc,
                  mlir::Type elementType) {
-    return elementType.isa<mlir::FloatType>()
-               ? builder.createRealConstant(loc, elementType,
-                                            llvm::APFloat(0.0))
-               : builder.createIntegerConstant(loc, elementType, 0);
+    if (auto ty = elementType.dyn_cast<mlir::FloatType>()) {
+      const llvm::fltSemantics &sem = ty.getFloatSemantics();
+      return builder.createRealConstant(loc, elementType,
+                                        llvm::APFloat::getZero(sem));
+    }
+    return builder.createIntegerConstant(loc, elementType, 0);
   };
 
   auto genBodyOp = [](fir::FirOpBuilder builder, mlir::Location loc,
@@ -464,17 +466,22 @@
   unsigned rank = getDimCount(args[0]);
   if (dimAndMaskAbsent && rank == 1) {
     mlir::Location loc = call.getLoc();
-    mlir::Type type;
     fir::FirOpBuilder builder(call, kindMap);
-    if (funcName.endswith("Integer4")) {
-      type = mlir::IntegerType::get(builder.getContext(), 32);
-    } else if (funcName.endswith("Real8")) {
-      type = mlir::FloatType::getF64(builder.getContext());
-    } else {
+
+    // Support only floating point and integer results now.
+    mlir::Type resultType = call.getResult(0).getType();
+    if (!resultType.isa<mlir::FloatType>() &&
+        !resultType.isa<mlir::IntegerType>())
       return;
-    }
-    auto typeGenerator = [&type](fir::FirOpBuilder &builder) {
-      return genNoneBoxType(builder, type);
+
+    auto argType = getArgElementType(args[0]);
+    if (!argType)
+      return;
+    assert(*argType == resultType &&
+           "Argument/result types mismatch in reduction");
+
+    auto typeGenerator = [&resultType](fir::FirOpBuilder &builder) {
+      return genNoneBoxType(builder, resultType);
     };
     mlir::func::FuncOp newFunc =
         getOrCreateFunction(builder, funcName, typeGenerator, genBodyFunc);
diff --git a/flang/test/Transforms/simplifyintrinsics.fir b/flang/test/Transforms/simplifyintrinsics.fir
--- a/flang/test/Transforms/simplifyintrinsics.fir
+++ b/flang/test/Transforms/simplifyintrinsics.fir
@@ -153,6 +153,65 @@
 
 // -----
 
+// Call to SUM with 1D F32 is replaced.
+module attributes {fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", llvm.target_triple = "native"} {
+  func.func @sum_1d_real(%arg0: !fir.ref<!fir.array<10xf32>> {fir.bindc_name = "a"}) -> f32 {
+    %c10 = arith.constant 10 : index
+    %0 = fir.alloca f32 {bindc_name = "sum_1d_real", uniq_name = "_QFsum_1d_realEsum_1d_real"}
+    %1 = fir.shape %c10 : (index) -> !fir.shape<1>
+    %2 = fir.embox %arg0(%1) : (!fir.ref<!fir.array<10xf32>>, !fir.shape<1>) -> !fir.box<!fir.array<10xf32>>
+    %3 = fir.absent !fir.box<i1>
+    %c0 = arith.constant 0 : index
+    %4 = fir.address_of(@_QQcl.2E2F6973756D5F352E66393000) : !fir.ref<!fir.char<1,13>>
+    %c5_i32 = arith.constant 5 : i32
+    %5 = fir.convert %2 : (!fir.box<!fir.array<10xf32>>) -> !fir.box<none>
+    %6 = fir.convert %4 : (!fir.ref<!fir.char<1,13>>) -> !fir.ref<i8>
+    %7 = fir.convert %c0 : (index) -> i32
+    %8 = fir.convert %3 : (!fir.box<i1>) -> !fir.box<none>
+    %9 = fir.call @_FortranASumReal4(%5, %6, %c5_i32, %7, %8) : (!fir.box<none>, !fir.ref<i8>, i32, i32, !fir.box<none>) -> f32
+    fir.store %9 to %0 : !fir.ref<f32>
+    %10 = fir.load %0 : !fir.ref<f32>
+    return %10 : f32
+  }
+  func.func private @_FortranASumReal4(!fir.box<none>, !fir.ref<i8>, i32, i32, !fir.box<none>) -> f32 attributes {fir.runtime}
+  fir.global linkonce @_QQcl.2E2F6973756D5F352E66393000 constant : !fir.char<1,13> {
+    %0 = fir.string_lit "./isum_5.f90\00"(13) : !fir.char<1,13>
+    fir.has_value %0 : !fir.char<1,13>
+  }
+}
+
+
+// CHECK-LABEL:   func.func @sum_1d_real(
+// CHECK-SAME:                           %[[A:.*]]: !fir.ref<!fir.array<10xf32>> {fir.bindc_name = "a"}) -> f32 {
+// CHECK:           %[[CINDEX_10:.*]] = arith.constant 10 : index
+// CHECK:           %[[SHAPE:.*]] = fir.shape %[[CINDEX_10]] : (index) -> !fir.shape<1>
+// CHECK:           %[[A_BOX_F32:.*]] = fir.embox %[[A]](%[[SHAPE]]) : (!fir.ref<!fir.array<10xf32>>, !fir.shape<1>) -> !fir.box<!fir.array<10xf32>>
+// CHECK:           %[[A_BOX_NONE:.*]] = fir.convert %[[A_BOX_F32]] : (!fir.box<!fir.array<10xf32>>) -> !fir.box<none>
+// CHECK-NOT:       fir.call @_FortranASumReal4({{.*}})
+// CHECK:           %[[RES:.*]] = fir.call @_FortranASumReal4_simplified(%[[A_BOX_NONE]]) : (!fir.box<none>) -> f32
+// CHECK-NOT:       fir.call @_FortranASumReal4({{.*}})
+// CHECK:           return %{{.*}} : f32
+// CHECK:         }
+
+// CHECK-LABEL:   func.func private @_FortranASumReal4_simplified(
+// CHECK-SAME:                                                    %[[ARR:.*]]: !fir.box<none>) -> f32 attributes {llvm.linkage = #llvm.linkage<linkonce_odr>} {
+// CHECK:           %[[CINDEX_0:.*]] = arith.constant 0 : index
+// CHECK:           %[[ARR_BOX_F32:.*]] = fir.convert %[[ARR]] : (!fir.box<none>) -> !fir.box<!fir.array<?xf32>>
+// CHECK:           %[[DIMS:.*]]:3 = fir.box_dims %[[ARR_BOX_F32]], %[[CINDEX_0]] : (!fir.box<!fir.array<?xf32>>, index) -> (index, index, index)
+// CHECK:           %[[CINDEX_1:.*]] = arith.constant 1 : index
+// CHECK:           %[[EXTENT:.*]] = arith.subi %[[DIMS]]#1, %[[CINDEX_1]] : index
+// CHECK:           %[[ZERO:.*]] = arith.constant 0.000000e+00 : f32
+// CHECK:           %[[RES:.*]] = fir.do_loop %[[ITER:.*]] = %[[CINDEX_0]] to %[[EXTENT]] step %[[CINDEX_1]] iter_args(%[[SUM]] = %[[ZERO]]) -> (f32) {
+// CHECK:             %[[ITEM:.*]] = fir.coordinate_of %[[ARR_BOX_F32]], %[[ITER]] : (!fir.box<!fir.array<?xf32>>, index) -> !fir.ref<f32>
+// CHECK:             %[[ITEM_VAL:.*]] = fir.load %[[ITEM]] : !fir.ref<f32>
+// CHECK:             %[[NEW_SUM:.*]] = arith.addf %[[ITEM_VAL]], %[[SUM]] : f32
+// CHECK:             fir.result %[[NEW_SUM]] : f32
+// CHECK:           }
+// CHECK:           return %[[RES]] : f32
+// CHECK:         }
+
+// -----
+
 // Call to SUM with 1D COMPLEX array is not replaced.
 module attributes {fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", llvm.target_triple = "native"} {
   func.func @sum_1d_complex(%arg0: !fir.ref<!fir.array<10x!fir.complex<4>>> {fir.bindc_name = "a"}) -> !fir.complex<4> {