diff --git a/src/alloy/compiler/passes/constant_propagation_pass.cc b/src/alloy/compiler/passes/constant_propagation_pass.cc
index a481d18af..5804ed218 100644
--- a/src/alloy/compiler/passes/constant_propagation_pass.cc
+++ b/src/alloy/compiler/passes/constant_propagation_pass.cc
@@ -371,7 +371,7 @@ int ConstantPropagationPass::Run(HIRBuilder* builder) {
       case OPCODE_CNTLZ:
         if (i->src1.value->IsConstant()) {
           v->set_zero(v->type);
-          v->CountLeadingZeros(i->src1.value->constant);
+          v->CountLeadingZeros(i->src1.value);
           i->Remove();
         }
         break;
diff --git a/src/alloy/hir/value.cc b/src/alloy/hir/value.cc
index f70d6ceb2..10fc62cad 100644
--- a/src/alloy/hir/value.cc
+++ b/src/alloy/hir/value.cc
@@ -560,19 +560,19 @@ void Value::ByteSwap() {
   }
 }
 
-void Value::CountLeadingZeros(const ConstantValue& src) {
-  switch (type) {
+void Value::CountLeadingZeros(const Value* other) {
+  switch (other->type) {
   case INT8_TYPE:
-    constant.i8 = __lzcnt16(src.i8) - 8;
+    constant.i8 = static_cast<uint8_t>(__lzcnt16(other->constant.i8) - 8);
     break;
   case INT16_TYPE:
-    constant.i8 = __lzcnt16(src.i16);
+    constant.i8 = static_cast<uint8_t>(__lzcnt16(other->constant.i16));
     break;
   case INT32_TYPE:
-    constant.i8 = __lzcnt(src.i32);
+    constant.i8 = static_cast<uint8_t>(__lzcnt(other->constant.i32));
     break;
   case INT64_TYPE:
-    constant.i8 = __lzcnt64(src.i64);
+    constant.i8 = static_cast<uint8_t>(__lzcnt64(other->constant.i64));
     break;
   default:
     XEASSERTALWAYS();
diff --git a/src/alloy/hir/value.h b/src/alloy/hir/value.h
index e3af4906f..9a1f668f5 100644
--- a/src/alloy/hir/value.h
+++ b/src/alloy/hir/value.h
@@ -393,7 +393,7 @@ public:
   void Shr(Value* other);
   void Sha(Value* other);
   void ByteSwap();
-  void CountLeadingZeros(const ConstantValue& src);
+  void CountLeadingZeros(const Value* other);
   bool Compare(Opcode opcode, Value* other);
 };