fix double compares

4 files changed, 28 insertions, 3 deletions

diff --git a/src/asm2wasm.cpp b/src/asm2wasm.cpp
index 609909ab8..b02b4aa52 100644
--- a/src/asm2wasm.cpp
+++ b/src/asm2wasm.cpp
@@ -780,6 +780,7 @@ Function* Asm2WasmModule::processFunction(Ref ast) {
         ret->op = relational;
         ret->left = process(ast[2]);
         ret->right = process(ast[3]);
+        ret->inputType = ret->left->type;
         return ret;
       }
     } else if (what == NUM) {
@@ -899,6 +900,7 @@ Function* Asm2WasmModule::processFunction(Ref ast) {
         ret->op = Eq;
         ret->left = process(ast[2]);
         ret->right = allocator.alloc<Const>()->set(Literal(0));
+        ret->inputType = ret->left->type;
         return ret;
       }
       abort_on("bad unary", ast);
diff --git a/src/wasm.h b/src/wasm.h
index 5a48aa3f2..2e383d83b 100644
--- a/src/wasm.h
+++ b/src/wasm.h
@@ -225,7 +225,7 @@ enum HostOp {
 
 class Expression {
 public:
-  WasmType type;
+  WasmType type; // the type of the expression: its output, not necessarily its input(s)
 
   Expression() : type(type) {}
 
@@ -607,15 +607,16 @@ public:
 class Compare : public Expression {
 public:
   RelationalOp op;
+  WasmType inputType;
   Expression *left, *right;
 
   Compare() {
-    type = WasmType::i32;
+    type = WasmType::i32; // output is always i32
   }
 
   std::ostream& print(std::ostream &o, unsigned indent) override {
     o << '(';
-    prepareColor(o) << printWasmType(type) << '.';
+    prepareColor(o) << printWasmType(inputType) << '.';
     switch (op) {
       case Eq:  o << "eq"; break;
       case Ne:  o << "ne"; break;
diff --git a/test/unit.asm.js b/test/unit.asm.js
index 80bab6242..2b599d99a 100644
--- a/test/unit.asm.js
+++ b/test/unit.asm.js
@@ -15,6 +15,12 @@ function () {
     var temp = 0.0;
     temp = t + u + (-u) + (-t);
   }
+  function doubleCompares(x, y) {
+    x = +x;
+    y = +y;
+    if (x < y) return +x;
+    return +y;
+  }
 
   function z() {
   }
diff --git a/test/unit.wast b/test/unit.wast
index 2c16af17d..9e4b19eb4 100644
--- a/test/unit.wast
+++ b/test/unit.wast
@@ -51,6 +51,22 @@
       )
     )
   )
+  (func $doubleCompares (param $x f64) (param $y f64) (result f64)
+    (block $topmost
+      (if
+        (f64.lt
+          (get_local $x)
+          (get_local $y)
+        )
+        (break $topmost
+          (get_local $x)
+        )
+      )
+      (break $topmost
+        (get_local $y)
+      )
+    )
+  )
   (func $z
     (nop)
   )