handle 32-bit bitcasts int <-> float properly

3 files changed, 21 insertions, 3 deletions

diff --git a/src/intertyper.js b/src/intertyper.js
index cf1d28ed..d03810d4 100644
--- a/src/intertyper.js
+++ b/src/intertyper.js
@@ -647,7 +647,7 @@ function intertyper(data, sidePass, baseLineNums) {
       item.type = item.tokens[4].text; // The final type
       Types.needAnalysis[item.type] = 0;
       var to = getTokenIndexByText(item.tokens, 'to');
-      item.params = [parseLLVMSegment(item.tokens.slice(2, to))];
+      item.params = [parseLLVMSegment(item.tokens.slice(1, to))];
       item.ident = item.params[0].ident;
       item.type2 = item.tokens[1].text; // The original type
       Types.needAnalysis[item.type2] = 0;
diff --git a/src/jsifier.js b/src/jsifier.js
index 62cab3d5..e52d3a00 100644
--- a/src/jsifier.js
+++ b/src/jsifier.js
@@ -1032,7 +1032,10 @@ function JSify(data, functionsOnly, givenFunctions) {
   makeFuncLineActor('mathop', processMathop);
 
   makeFuncLineActor('bitcast', function(item) {
-    return finalizeLLVMParameter(item.params[0]);
+    return processMathop({
+      op: 'bitcast', variant: null, type: item.type,
+      param1: item.params[0]
+    });
   });
 
   function makeFunctionCall(ident, params, funcData, type) {
diff --git a/src/parseTools.js b/src/parseTools.js
index d4ef27eb..cc59f150 100644
--- a/src/parseTools.js
+++ b/src/parseTools.js
@@ -1815,7 +1815,22 @@ function processMathop(item) {
       assert(bitsLeft <= 32, 'Cannot truncate to more than 32 bits, since we use a native & op');
       return '((' + ident1 + ') & ' + (Math.pow(2, bitsLeft)-1) + ')';
     }
-    case 'bitcast': return ident1;
+    case 'bitcast': {
+      // Most bitcasts are no-ops for us. However, the exception is int to float and float to int
+      var inType = item.param1.type;
+      var outType = item.type;
+      if ((inType in Runtime.INT_TYPES && outType in Runtime.FLOAT_TYPES) ||
+          (inType in Runtime.FLOAT_TYPES && outType in Runtime.INT_TYPES)) {
+        assert(USE_TYPED_ARRAYS == 2, 'Can only bitcast ints <-> floats with typed arrays mode 2');
+        assert(inType == 'i32' || inType == 'float', 'Can only bitcast ints <-> floats with 32 bits, for now');
+        if (inType in Runtime.INT_TYPES) {
+          return '(tempDoubleI32[0] = ' + ident1 + ',tempDoubleF32[0])';
+        } else {
+          return '(tempDoubleF32[0] = ' + ident1 + ',tempDoubleI32[0])';
+        }
+      }
+      return ident1;
+    }
     default: throw 'Unknown mathcmp op: ' + item.op;
   }
 }