[libc-commits] [libc] [libc] Fix op_tests Memcmp guard to require SSE4.1 (PR #196572)

[Jeff Bailey via libc-commits]

https://github.com/kaladron created https://github.com/llvm/llvm-project/pull/196572

The is_vector<__m128i> specialisation in op_x86.h is gated on __SSE4_1__, but op_tests.cpp included generic::Memcmp<__m128i> under the weaker __SSE2__ guard. On baseline x86-64 (where __SSE2__ is always defined but __SSE4_1__ may not be), this caused a static_assert failure in is_element_type_v.

Changed the guard from __SSE2__ to __SSE4_1__ to match the specialisation requirement, consistent with how BcmpImplementations already guards its __m128i entry.

Assisted-by: Automated tooling, human reviewed.

>From d88a50903356fbee0817cba95239bfe234bc219b Mon Sep 17 00:00:00 2001
From: Jeff Bailey <jbailey at raspberryginger.com>
Date: Fri, 8 May 2026 17:23:07 +0100
Subject: [PATCH] [libc] Fix op_tests Memcmp guard to require SSE4.1

The is_vector<__m128i> specialisation in op_x86.h is gated on
__SSE4_1__, but op_tests.cpp included generic::Memcmp<__m128i> under
the weaker __SSE2__ guard. On baseline x86-64 (where __SSE2__ is
always defined but __SSE4_1__ may not be), this caused a
static_assert failure in is_element_type_v.

Changed the guard from __SSE2__ to __SSE4_1__ to match the
specialisation requirement, consistent with how BcmpImplementations
already guards its __m128i entry.

Assisted-by: Automated tooling, human reviewed.
---
 libc/test/src/string/memory_utils/op_tests.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libc/test/src/string/memory_utils/op_tests.cpp b/libc/test/src/string/memory_utils/op_tests.cpp
index 06089a89d9aac..9d26056a720f3 100644
--- a/libc/test/src/string/memory_utils/op_tests.cpp
+++ b/libc/test/src/string/memory_utils/op_tests.cpp
@@ -299,7 +299,7 @@ TYPED_TEST(LlvmLibcOpTest, Bcmp, BcmpImplementations) {
 
 using MemcmpImplementations = testing::TypeList<
 #if defined(LIBC_TARGET_ARCH_IS_X86_64) && !defined(LIBC_TARGET_OS_IS_WINDOWS)
-#ifdef __SSE2__
+#ifdef __SSE4_1__
     generic::Memcmp<__m128i>, //
 #endif
 #ifdef __AVX2__