fix asm2wasm f64->f32->i32 bitcast (#412)

4 files changed, 18 insertions, 0 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index f905d2047..974a06bf3 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -1579,6 +1579,10 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
                 auto conv = allocator.alloc<Unary>();
                 conv->op = ReinterpretFloat;
                 conv->value = process(writtenValue);
+                if (conv->value->type == f64) {
+                  // this has an implicit f64->f32 in the write to memory
+                  conv->value = builder.makeUnary(DemoteFloat64, conv->value, f32);
+                }
                 conv->type = WasmType::i32;
                 return conv;
               }
diff --git a/test/unit.asm.js b/test/unit.asm.js
index df731148a..da4269873 100644
--- a/test/unit.asm.js
+++ b/test/unit.asm.js
@@ -207,9 +207,11 @@ function asm(global, env, buffer) {
   function bitcasts(i, f) {
     i = i | 0;
     f = Math_fround(f);
+    var d = 0.0;
     (HEAP32[tempDoublePtr >> 2] = i, Math_fround(HEAPF32[tempDoublePtr >> 2])); // i32->f32
     (HEAP32[tempDoublePtr >> 2] = i, +HEAPF32[tempDoublePtr >> 2]); // i32->f32, no fround
     (HEAPF32[tempDoublePtr >> 2] = f, HEAP32[tempDoublePtr >> 2] | 0); // f32->i32
+    (HEAPF32[tempDoublePtr >> 2] = d, HEAP32[tempDoublePtr >> 2] | 0); // f64 with implict f32 conversion, ->i32
   }
 
   function z() {
diff --git a/test/unit.fromasm b/test/unit.fromasm
index eda3ea485..41e1154b5 100644
--- a/test/unit.fromasm
+++ b/test/unit.fromasm
@@ -460,6 +460,7 @@
     )
   )
   (func $bitcasts (param $i i32) (param $f f32)
+    (local $d f64)
     (f32.reinterpret/i32
       (get_local $i)
     )
@@ -471,6 +472,11 @@
     (i32.reinterpret/f32
       (get_local $f)
     )
+    (i32.reinterpret/f32
+      (f32.demote/f64
+        (get_local $d)
+      )
+    )
   )
   (func $z
     (nop)
diff --git a/test/unit.fromasm.imprecise b/test/unit.fromasm.imprecise
index 2d7147edb..3c8a7d917 100644
--- a/test/unit.fromasm.imprecise
+++ b/test/unit.fromasm.imprecise
@@ -454,6 +454,7 @@
     )
   )
   (func $bitcasts (param $i i32) (param $f f32)
+    (local $d f64)
     (f32.reinterpret/i32
       (get_local $i)
     )
@@ -465,6 +466,11 @@
     (i32.reinterpret/f32
       (get_local $f)
     )
+    (i32.reinterpret/f32
+      (f32.demote/f64
+        (get_local $d)
+      )
+    )
   )
   (func $z
     (nop)