[WebAssembly] Fix argument types in SIMD narrowing intrinsics

The builtins were updated to take signed parameters in 627a526, but the
intrinsics that use those builtins were not updated as well. The intrinsic test
did not catch this sign mismatch because it is only reported as an error under
-fno-lax-vector-conversions.

This commit fixes the type mismatch and adds -fno-lax-vector-conversions to the
test to catch similar problems in the future.

Differential Revision: https://reviews.llvm.org/D101979

clang/lib/Headers/wasm_simd128.h

@@ -1197,8 +1197,8 @@ wasm_i8x16_narrow_i16x8(v128_t __a, v128_t __b) {
 
 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 @@ wasm_i16x8_narrow_i32x4(v128_t __a, v128_t __b) {
 
 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

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>