diff --git a/clang/lib/Headers/wasm_simd128.h b/clang/lib/Headers/wasm_simd128.h
--- a/clang/lib/Headers/wasm_simd128.h
+++ b/clang/lib/Headers/wasm_simd128.h
@@ -1197,8 +1197,8 @@
 
 static __inline__ v128_t __DEFAULT_FN_ATTRS
 wasm_u8x16_narrow_i16x8(v128_t __a, v128_t __b) {
-  return (v128_t)__builtin_wasm_narrow_u_i8x16_i16x8((__u16x8)__a,
-                                                     (__u16x8)__b);
+  return (v128_t)__builtin_wasm_narrow_u_i8x16_i16x8((__i16x8)__a,
+                                                     (__i16x8)__b);
 }
 
 static __inline__ v128_t __DEFAULT_FN_ATTRS
@@ -1209,8 +1209,8 @@
 
 static __inline__ v128_t __DEFAULT_FN_ATTRS
 wasm_u16x8_narrow_i32x4(v128_t __a, v128_t __b) {
-  return (v128_t)__builtin_wasm_narrow_u_i16x8_i32x4((__u32x4)__a,
-                                                     (__u32x4)__b);
+  return (v128_t)__builtin_wasm_narrow_u_i16x8_i32x4((__i32x4)__a,
+                                                     (__i32x4)__b);
 }
 
 static __inline__ v128_t __DEFAULT_FN_ATTRS
diff --git a/clang/test/Headers/wasm.c b/clang/test/Headers/wasm.c
--- a/clang/test/Headers/wasm.c
+++ b/clang/test/Headers/wasm.c
@@ -1,7 +1,7 @@
 // NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --force-update
 // REQUIRES: webassembly-registered-target, asserts
 
-// RUN: %clang %s -O2 -emit-llvm -S -o - -target wasm32-unknown-unknown -msimd128 -Wcast-qual -Werror | FileCheck %s
+// RUN: %clang %s -O2 -emit-llvm -S -o - -target wasm32-unknown-unknown -msimd128 -Wcast-qual -fno-lax-vector-conversions -Werror | FileCheck %s
 
 #include <wasm_simd128.h>