wasm2asm: Implement float<->int conversions (#1550)

This commit lifts the same conversion strategy that `emcc` takes to convert
between floats point numbers and integers, and it should implement all the
various matrices of i32/u32/i64/u64 to f32/f64

Some refactoring was performed in the i64->i32 pass to allow for temporary
variables to get allocated which have types other than i32, but otherwise this
contains a pretty direct translation of `emcc`'s operations to `wasm2asm`.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/emscripten-optimizer/simple_ast.h b/src/emscripten-optimizer/simple_ast.h
index 62bf975f0..64aab7708 100644
--- a/src/emscripten-optimizer/simple_ast.h
+++ b/src/emscripten-optimizer/simple_ast.h
@@ -836,6 +836,19 @@ struct JSPrinter {
   }
 
   static char* numToString(double d, bool finalize=true) {
+    if (std::isnan(d)) {
+      if (std::signbit(d)) {
+        return (char*) "-NaN";
+      } else {
+        return (char*) "NaN";
+      }
+    } else if (!std::isfinite(d)) {
+      if (std::signbit(d)) {
+        return (char*) "-Infinity";
+      } else {
+        return (char*) "Infinity";
+      }
+    }
     bool neg = d < 0;
     if (neg) d = -d;
     // try to emit the fewest necessary characters
@@ -1046,6 +1059,8 @@ struct JSPrinter {
       ensure(1); // we temporarily append a 0
       char *curr = buffer + last; // ensure might invalidate
       buffer[used] = 0;
+      if (strstr(curr, "Infinity")) return;
+      if (strstr(curr, "NaN")) return;
       if (strchr(curr, '.')) return; // already a decimal point, all good
       char *e = strchr(curr, 'e');
       if (!e) {