Merge pull request #151 from WebAssembly/nan

Output NaN payloads only

1 files changed, 12 insertions, 13 deletions

diff --git a/src/wasm.h b/src/wasm.h
index 91c318034..97e0bfc12 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -58,6 +58,7 @@
 #include "emscripten-optimizer/simple_ast.h"
 #include "mixed_arena.h"
 #include "pretty_printing.h"
+#include "support/utilities.h"
 
 namespace wasm {
 
@@ -190,12 +191,11 @@ struct Literal {
 
   static void printFloat(std::ostream &o, float f) {
     if (isnan(f)) {
-      union {
-        float ff;
-        uint32_t ll;
-      } u;
-      u.ff = f;
-      o << "nan:0x" << std::hex << u.ll << std::dec;
+      const char *sign = std::signbit(f) ? "-" : "";
+      o << sign << "nan";
+      if (uint32_t payload = ~0xffc00000u & bit_cast<uint32_t>(f)) {
+        o << ":0x" << std::hex << payload << std::dec;
+      }
       return;
     }
     printDouble(o, f);
@@ -207,16 +207,15 @@ struct Literal {
       return;
     }
     if (isnan(d)) {
-      union {
-        double dd;
-        uint64_t ll;
-      } u;
-      u.dd = d;
-      o << "nan:0x" << std::hex << u.ll << std::dec;
+      const char *sign = std::signbit(d) ? "-" : "";
+      o << sign << "nan";
+      if (uint64_t payload = ~0xfff8000000000000ull & bit_cast<uint64_t>(d)) {
+        o << ":0x" << std::hex << payload << std::dec;
+      }
       return;
     }
     if (!std::isfinite(d)) {
-      o << (d < 0 ? "-infinity" : "infinity");
+      o << (std::signbit(d) ? "-infinity" : "infinity");
       return;
     }
     const char *text = cashew::JSPrinter::numToString(d);