Only use bitcast in Builder::ret for non-native integers

Author: antoyo

src/builder.rs

@@ -539,9 +539,15 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
 
     fn ret(&mut self, mut value: RValue<'gcc>) {
         let expected_return_type = self.current_func().get_return_type();
-        if !expected_return_type.is_compatible_with(value.get_type()) {
-            // NOTE: due to opaque pointers now being used, we need to bitcast here.
-            value = self.context.new_bitcast(self.___location, value, expected_return_type);
+        let value_type = value.get_type();
+        if !expected_return_type.is_compatible_with(value_type) {
+            // NOTE: due to opaque pointers now being used, we need to (bit)cast here.
+            if self.is_native_int_type(value_type) && self.is_native_int_type(expected_return_type)
+            {
+                value = self.context.new_cast(self.___location, value, expected_return_type);
+            } else {
+                value = self.context.new_bitcast(self.___location, value, expected_return_type);
+            }
         }
         self.llbb().end_with_return(self.___location, value);
     }