Index: flang/lib/Evaluate/real.cpp
===================================================================
--- flang/lib/Evaluate/real.cpp
+++ flang/lib/Evaluate/real.cpp
@@ -439,7 +439,7 @@
 
 template <typename W, int P> std::string Real<W, P>::DumpHexadecimal() const {
   if (IsNotANumber()) {
-    return "NaN 0x"s + word_.Hexadecimal();
+    return "NaN0x"s + word_.Hexadecimal();
   } else if (IsNegative()) {
     return "-"s + Negate().DumpHexadecimal();
   } else if (IsInfinite()) {
Index: flang/unittests/Evaluate/real.cpp
===================================================================
--- flang/unittests/Evaluate/real.cpp
+++ flang/unittests/Evaluate/real.cpp
@@ -24,7 +24,7 @@
     std::uint64_t raw;
     const char *expected;
   } table[] = {
-      {0x7f876543, "NaN 0x7f876543"},
+      {0x7f876543, "NaN0x7f876543"},
       {0x7f800000, "Inf"},
       {0xff800000, "-Inf"},
       {0x00000000, "0.0"},