From 267f592ca0cc251e8b26372546ea8545bf2b4a27 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Wed, 13 Aug 2025 08:53:26 +0100
Subject: [PATCH] [Headers][X86] Allow _mm_cmov_si128/_mm256_cmov_si256
 intrinsics to be used in constexpr (#153236)

---
 clang/lib/Headers/xopintrin.h         | 14 ++++++++++++--
 clang/test/CodeGen/X86/xop-builtins.c |  3 +++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Headers/xopintrin.h b/clang/lib/Headers/xopintrin.h
index 976cdf4902a4..fb88a9060574 100644
--- a/clang/lib/Headers/xopintrin.h
+++ b/clang/lib/Headers/xopintrin.h
@@ -20,6 +20,14 @@
 #define __DEFAULT_FN_ATTRS __attribute__((__always_inline__, __nodebug__, __target__("xop"), __min_vector_width__(128)))
 #define __DEFAULT_FN_ATTRS256 __attribute__((__always_inline__, __nodebug__, __target__("xop"), __min_vector_width__(256)))
 
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+#define __DEFAULT_FN_ATTRS_CONSTEXPR __DEFAULT_FN_ATTRS constexpr
+#define __DEFAULT_FN_ATTRS256_CONSTEXPR __DEFAULT_FN_ATTRS256 constexpr
+#else
+#define __DEFAULT_FN_ATTRS_CONSTEXPR __DEFAULT_FN_ATTRS
+#define __DEFAULT_FN_ATTRS256_CONSTEXPR __DEFAULT_FN_ATTRS256
+#endif
+
 static __inline__ __m128i __DEFAULT_FN_ATTRS
 _mm_maccs_epi16(__m128i __A, __m128i __B, __m128i __C)
 {
@@ -182,13 +190,13 @@ _mm_hsubq_epi32(__m128i __A)
   return (__m128i)__builtin_ia32_vphsubdq((__v4si)__A);
 }
 
-static __inline__ __m128i __DEFAULT_FN_ATTRS
+static __inline__ __m128i __DEFAULT_FN_ATTRS_CONSTEXPR
 _mm_cmov_si128(__m128i __A, __m128i __B, __m128i __C)
 {
   return (__m128i)(((__v2du)__A & (__v2du)__C) | ((__v2du)__B & ~(__v2du)__C));
 }
 
-static __inline__ __m256i __DEFAULT_FN_ATTRS256
+static __inline__ __m256i __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_cmov_si256(__m256i __A, __m256i __B, __m256i __C)
 {
   return (__m256i)(((__v4du)__A & (__v4du)__C) | ((__v4du)__B & ~(__v4du)__C));
@@ -766,5 +774,7 @@ _mm256_frcz_pd(__m256d __A)
 
 #undef __DEFAULT_FN_ATTRS
 #undef __DEFAULT_FN_ATTRS256
+#undef __DEFAULT_FN_ATTRS_CONSTEXPR
+#undef __DEFAULT_FN_ATTRS256_CONSTEXPR
 
 #endif /* __XOPINTRIN_H */
diff --git a/clang/test/CodeGen/X86/xop-builtins.c b/clang/test/CodeGen/X86/xop-builtins.c
index e05ed92d9fa1..eb9f832ac9b0 100644
--- a/clang/test/CodeGen/X86/xop-builtins.c
+++ b/clang/test/CodeGen/X86/xop-builtins.c
@@ -9,6 +9,7 @@
 
 
 #include <x86intrin.h>
+#include "builtin_test_helpers.h"
 
 // NOTE: This should match the tests in llvm/test/CodeGen/X86/xop-intrinsics-fast-isel.ll
 
@@ -182,6 +183,7 @@ __m128i test_mm_cmov_si128(__m128i a, __m128i b, __m128i c) {
   // CHECK-NEXT: %{{.*}} = or <2 x i64> [[AND]], [[ANDN]]
   return _mm_cmov_si128(a, b, c);
 }
+TEST_CONSTEXPR(match_v4si(_mm_cmov_si128((__m128i)(__v4si){+1,+2,+3,+4}, (__m128i)(__v4si){-4,-3,-2,-1}, (__m128i)(__v4si){-1,0,0,-1}), +1, -3, -2, +4));
 
 __m256i test_mm256_cmov_si256(__m256i a, __m256i b, __m256i c) {
   // CHECK-LABEL: test_mm256_cmov_si256
@@ -191,6 +193,7 @@ __m256i test_mm256_cmov_si256(__m256i a, __m256i b, __m256i c) {
   // CHECK-NEXT: %{{.*}} = or <4 x i64> [[AND]], [[ANDN]]
   return _mm256_cmov_si256(a, b, c);
 }
+TEST_CONSTEXPR(match_v4di(_mm256_cmov_si256((__m256i)(__v4di){+1,+2,+3,+4}, (__m256i)(__v4di){-4,-3,-2,-1}, (__m256i)(__v4di){0,-1,0,-1}), -4, +2, -2, +4));
 
 __m128i test_mm_perm_epi8(__m128i a, __m128i b, __m128i c) {
   // CHECK-LABEL: test_mm_perm_epi8