be very careful when converting doubles to ints in asm2wasm

3 files changed, 8 insertions, 2 deletions

diff --git a/src/asm2wasm.h b/src/asm2wasm.h
index 8dcefec0e..51536663d 100644
--- a/src/asm2wasm.h
+++ b/src/asm2wasm.h
@@ -935,7 +935,7 @@ Function* Asm2WasmBuilder::processFunction(Ref ast) {
       double num = ast[1]->getNumber();
       if (isInteger32(num)) {
         ret->value.type = WasmType::i32;
-        ret->value.i32 = num;
+        ret->value.i32 = toInteger32(num);
       } else {
         ret->value.type = WasmType::f64;
         ret->value.f64 = num;
diff --git a/src/emscripten-optimizer/optimizer-shared.cpp b/src/emscripten-optimizer/optimizer-shared.cpp
index 24c19cd79..6a8bbf9b5 100644
--- a/src/emscripten-optimizer/optimizer-shared.cpp
+++ b/src/emscripten-optimizer/optimizer-shared.cpp
@@ -19,6 +19,12 @@ bool isInteger32(double x) {
   return isInteger(x) && (x == (int32_t)x || x == (uint32_t)x);
 }
 
+int32_t toInteger32(double x) {
+  if (x == (int32_t)x) return (int32_t)x;
+  assert(x == (uint32_t)x);
+  return (uint32_t)x;
+}
+
 int parseInt(const char *str) {
   int ret = *str - '0';
   while (*(++str)) {
diff --git a/src/emscripten-optimizer/optimizer.h b/src/emscripten-optimizer/optimizer.h
index faef2cccb..12d0671eb 100644
--- a/src/emscripten-optimizer/optimizer.h
+++ b/src/emscripten-optimizer/optimizer.h
@@ -102,8 +102,8 @@ struct AsmData {
 };
 
 bool isInteger(double x);
-
 bool isInteger32(double x);
+int32_t toInteger32(double x);
 
 extern cashew::IString ASM_FLOAT_ZERO;