5 files changed, 26 insertions, 7 deletions
diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index ada026176..ed8c75e56 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -485,6 +485,14 @@ private:
     return detectSign(ast, Math_fround) == ASM_UNSIGNED;
   }
 
+  bool isParentUnsignedCoercion(Ref parent) {
+    // parent may not exist, or may be a non-relevant node
+    if (!!parent && parent->isArray() && parent[0] == BINARY && isUnsignedCoercion(parent)) {
+      return true;
+    }
+    return false;
+  }
+
   BinaryOp parseAsmBinaryOp(IString op, Ref left, Ref right, Expression* leftWasm, Expression* rightWasm) {
     WasmType leftType = leftWasm->type;
     bool isInteger = leftType == WasmType::i32;
@@ -735,11 +743,16 @@ private:
   }
 
   // Some conversions might trap, so emit them safely if necessary
-  Expression* makeTrappingFloatToInt(Expression* value) {
+  Expression* makeTrappingFloatToInt(bool signed_, Expression* value) {
     if (trapMode == TrapMode::Allow) {
       auto ret = allocator.alloc<Unary>();
       ret->value = value;
-      ret->op = ret->value->type == f64 ? TruncSFloat64ToInt32 : TruncSFloat32ToInt32;
+      bool isF64 = ret->value->type == f64;
+      if (signed_) {
+        ret->op = isF64 ? TruncSFloat64ToInt32 : TruncSFloat32ToInt32;
+      } else {
+        ret->op = isF64 ? TruncUFloat64ToInt32 : TruncUFloat32ToInt32;
+      }
       ret->type = WasmType::i32;
       return ret;
     }
@@ -1752,7 +1765,8 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
       } else if (ast[1] == B_NOT) {
         // ~, might be ~~ as a coercion or just a not
         if (ast[2]->isArray(UNARY_PREFIX) && ast[2][1] == B_NOT) {
-          return makeTrappingFloatToInt(process(ast[2][2]));
+          // if we have an unsigned coercion on us, it is an unsigned op
+          return makeTrappingFloatToInt(!isParentUnsignedCoercion(astStackHelper.getParent()), process(ast[2][2]));
         }
         // no bitwise unary not, so do xor with -1
         auto ret = allocator.alloc<Binary>();
diff --git a/test/emcc_hello_world.fromasm.imprecise b/test/emcc_hello_world.fromasm.imprecise
index 20af7061a..3aa9ed739 100644
--- a/test/emcc_hello_world.fromasm.imprecise
+++ b/test/emcc_hello_world.fromasm.imprecise
@@ -4530,7 +4530,7 @@
                    (i32.store
                     (get_local $7)
                     (tee_local $5
-                     (i32.trunc_s/f64
+                     (i32.trunc_u/f64
                       (get_local $15)
                      )
                     )
diff --git a/test/emcc_hello_world.fromasm.imprecise.no-opts b/test/emcc_hello_world.fromasm.imprecise.no-opts
index 7faa18088..d33f824e2 100644
--- a/test/emcc_hello_world.fromasm.imprecise.no-opts
+++ b/test/emcc_hello_world.fromasm.imprecise.no-opts
@@ -9847,7 +9847,7 @@
            (loop $while-in60
             (block $while-out59
              (set_local $$conv216$i
-              (i32.trunc_s/f64
+              (i32.trunc_u/f64
                (get_local $$y$addr$4$i)
               )
              )
diff --git a/test/unit.fromasm.imprecise b/test/unit.fromasm.imprecise
index 18eba6cee..3254980d9 100644
--- a/test/unit.fromasm.imprecise
+++ b/test/unit.fromasm.imprecise
@@ -1124,6 +1124,11 @@
   )
  )
  (func $f2u (param $0 f64) (result i32)
+  (i32.trunc_u/f64
+   (get_local $0)
+  )
+ )
+ (func $f2s (param $0 f64) (result i32)
   (i32.trunc_s/f64
    (get_local $0)
   )
@@ -1140,7 +1145,7 @@
    )
   )
   (drop
-   (call $f2u
+   (call $f2s
     (f64.const 100)
    )
   )
diff --git a/test/unit.fromasm.imprecise.no-opts b/test/unit.fromasm.imprecise.no-opts
index 109afbf26..736f51222 100644
--- a/test/unit.fromasm.imprecise.no-opts
+++ b/test/unit.fromasm.imprecise.no-opts
@@ -1873,7 +1873,7 @@
  )
  (func $f2u (param $x f64) (result i32)
   (return
-   (i32.trunc_s/f64
+   (i32.trunc_u/f64
     (get_local $x)
    )
   )