diff --git a/flang/lib/Decimal/big-radix-floating-point.h b/flang/lib/Decimal/big-radix-floating-point.h
--- a/flang/lib/Decimal/big-radix-floating-point.h
+++ b/flang/lib/Decimal/big-radix-floating-point.h
@@ -350,9 +350,9 @@
   constexpr Raw Infinity() const {
     return (Raw{Real::maxExponent} << Real::significandBits) | SignBit();
   }
-  static constexpr Raw NaN() {
+  constexpr Raw NaN(bool isQuiet = true) {
     return (Raw{Real::maxExponent} << Real::significandBits) |
-        (Raw{1} << (Real::significandBits - 2));
+        (Raw{1} << (Real::significandBits - (isQuiet ? 1 : 2))) | SignBit();
   }
 
   Digit digit_[maxDigits]; // in little-endian order: digit_[0] is LSD
diff --git a/flang/lib/Decimal/decimal-to-binary.cpp b/flang/lib/Decimal/decimal-to-binary.cpp
--- a/flang/lib/Decimal/decimal-to-binary.cpp
+++ b/flang/lib/Decimal/decimal-to-binary.cpp
@@ -407,36 +407,40 @@
     return result;
   } else {
     // Could not parse a decimal floating-point number.  p has been
-    // advanced over any leading spaces.
-    if ((!limit || limit >= p + 3) && toupper(p[0]) == 'N' &&
-        toupper(p[1]) == 'A' && toupper(p[2]) == 'N') {
+    // advanced over any leading spaces.  Most Fortran compilers set
+    // the sign bit for -NaN.
+    const char *q{p};
+    if (!limit || q < limit) {
+      isNegative_ = *q == '-';
+      if (isNegative_ || *q == '+') {
+        ++q;
+      }
+    }
+    if ((!limit || limit >= q + 3) && toupper(q[0]) == 'N' &&
+        toupper(q[1]) == 'A' && toupper(q[2]) == 'N') {
       // NaN
-      p += 3;
+      p = q + 3;
+      bool isQuiet{true};
       if ((!limit || p < limit) && *p == '(') {
         int depth{1};
         do {
           ++p;
           if (limit && p >= limit) {
             // Invalid input
-            return {Real{NaN()}, Invalid};
+            return {Real{NaN(false)}, Invalid};
           } else if (*p == '(') {
             ++depth;
           } else if (*p == ')') {
             --depth;
+          } else if (*p != ' ') {
+            // Implementation dependent, but other compilers
+            // all return quiet NaNs.
           }
         } while (depth > 0);
         ++p;
       }
-      return {Real{NaN()}};
-    } else {
-      // Try to parse Inf, maybe with a sign
-      const char *q{p};
-      if (!limit || q < limit) {
-        isNegative_ = *q == '-';
-        if (isNegative_ || *q == '+') {
-          ++q;
-        }
-      }
+      return {Real{NaN(isQuiet)}};
+    } else { // Inf?
       if ((!limit || limit >= q + 3) && toupper(q[0]) == 'I' &&
           toupper(q[1]) == 'N' && toupper(q[2]) == 'F') {
         if ((!limit || limit >= q + 8) && toupper(q[3]) == 'I' &&
diff --git a/flang/runtime/edit-output.cpp b/flang/runtime/edit-output.cpp
--- a/flang/runtime/edit-output.cpp
+++ b/flang/runtime/edit-output.cpp
@@ -247,8 +247,8 @@
   }
 }
 
-template <int binaryPrecision>
-decimal::ConversionToDecimalResult RealOutputEditing<binaryPrecision>::Convert(
+template <int KIND>
+decimal::ConversionToDecimalResult RealOutputEditing<KIND>::Convert(
     int significantDigits, enum decimal::FortranRounding rounding, int flags) {
   auto converted{decimal::ConvertToDecimal<binaryPrecision>(buffer_,
       sizeof buffer_, static_cast<enum decimal::DecimalConversionFlags>(flags),
@@ -262,8 +262,8 @@
 }
 
 // 13.7.2.3.3 in F'2018
-template <int binaryPrecision>
-bool RealOutputEditing<binaryPrecision>::EditEorDOutput(const DataEdit &edit) {
+template <int KIND>
+bool RealOutputEditing<KIND>::EditEorDOutput(const DataEdit &edit) {
   addSpaceBeforeCharacter(io_);
   int editDigits{edit.digits.value_or(0)}; // 'd' field
   int editWidth{edit.width.value_or(0)}; // 'w' field
@@ -389,8 +389,8 @@
 }
 
 // 13.7.2.3.2 in F'2018
-template <int binaryPrecision>
-bool RealOutputEditing<binaryPrecision>::EditFOutput(const DataEdit &edit) {
+template <int KIND>
+bool RealOutputEditing<KIND>::EditFOutput(const DataEdit &edit) {
   addSpaceBeforeCharacter(io_);
   int fracDigits{edit.digits.value_or(0)}; // 'd' field
   const int editWidth{edit.width.value_or(0)}; // 'w' field
@@ -496,8 +496,8 @@
 }
 
 // 13.7.5.2.3 in F'2018
-template <int binaryPrecision>
-DataEdit RealOutputEditing<binaryPrecision>::EditForGOutput(DataEdit edit) {
+template <int KIND>
+DataEdit RealOutputEditing<KIND>::EditForGOutput(DataEdit edit) {
   edit.descriptor = 'E';
   int editWidth{edit.width.value_or(0)};
   int significantDigits{
@@ -536,9 +536,8 @@
 }
 
 // 13.10.4 in F'2018
-template <int binaryPrecision>
-bool RealOutputEditing<binaryPrecision>::EditListDirectedOutput(
-    const DataEdit &edit) {
+template <int KIND>
+bool RealOutputEditing<KIND>::EditListDirectedOutput(const DataEdit &edit) {
   decimal::ConversionToDecimalResult converted{Convert(1, edit.modes.round)};
   if (IsInfOrNaN(converted)) {
     return EditEorDOutput(edit);
@@ -558,8 +557,8 @@
 }
 
 // 13.7.5.2.6 in F'2018
-template <int binaryPrecision>
-bool RealOutputEditing<binaryPrecision>::EditEXOutput(const DataEdit &) {
+template <int KIND>
+bool RealOutputEditing<KIND>::EditEXOutput(const DataEdit &) {
   io_.GetIoErrorHandler().Crash(
       "not yet implemented: EX output editing"); // TODO
 }