5 files changed, 19 insertions, 5 deletions
diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index f00004b1f..d9618d8fd 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -539,6 +539,12 @@ private:
     return call;
   }
 
+  Expression* truncateToInt32(Expression* value) {
+    if (value->type == i64) return builder.makeUnary(UnaryOp::WrapInt64, value);
+    // either i32, or a call_import whose type we don't know yet (but would be legalized to i32 anyhow)
+    return value;
+  }
+
   Function* processFunction(Ref ast);
 };
 
@@ -1432,7 +1438,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
     } else if (what == IF) {
       auto* condition = process(ast[1]);
       auto* ifTrue = process(ast[2]);
-      return builder.makeIf(condition, ifTrue, !!ast[3] ? process(ast[3]) : nullptr);
+      return builder.makeIf(truncateToInt32(condition), ifTrue, !!ast[3] ? process(ast[3]) : nullptr);
     } else if (what == CALL) {
       if (ast[1][0] == NAME) {
         IString name = ast[1][1]->getIString();
diff --git a/test/wasm-only.fromasm b/test/wasm-only.fromasm
index e8f8cfc79..26d6cde4f 100644
--- a/test/wasm-only.fromasm
+++ b/test/wasm-only.fromasm
@@ -290,7 +290,9 @@
   )
   (func $ifValue64 (param $0 i64) (param $1 i64) (result i64)
     (if i64
-      (get_local $1)
+      (i32.wrap/i64
+        (get_local $1)
+      )
       (call $call2
         (get_local $0)
       )
diff --git a/test/wasm-only.fromasm.imprecise b/test/wasm-only.fromasm.imprecise
index b27eb3f9b..ec74eb35b 100644
--- a/test/wasm-only.fromasm.imprecise
+++ b/test/wasm-only.fromasm.imprecise
@@ -218,7 +218,9 @@
   )
   (func $ifValue64 (param $0 i64) (param $1 i64) (result i64)
     (if i64
-      (get_local $1)
+      (i32.wrap/i64
+        (get_local $1)
+      )
       (call $call2
         (get_local $0)
       )
diff --git a/test/wasm-only.fromasm.imprecise.no-opts b/test/wasm-only.fromasm.imprecise.no-opts
index 90a5eeccd..d9490bf9b 100644
--- a/test/wasm-only.fromasm.imprecise.no-opts
+++ b/test/wasm-only.fromasm.imprecise.no-opts
@@ -613,7 +613,9 @@
     (local $$9 i64)
     (local $$10 i64)
     (if
-      (get_local $$6)
+      (i32.wrap/i64
+        (get_local $$6)
+      )
       (block
         (set_local $$9
           (call $call2
diff --git a/test/wasm-only.fromasm.no-opts b/test/wasm-only.fromasm.no-opts
index 1ea6753ef..1959a2937 100644
--- a/test/wasm-only.fromasm.no-opts
+++ b/test/wasm-only.fromasm.no-opts
@@ -661,7 +661,9 @@
     (local $$9 i64)
     (local $$10 i64)
     (if
-      (get_local $$6)
+      (i32.wrap/i64
+        (get_local $$6)
+      )
       (block
         (set_local $$9
           (call $call2