[Clang][X86] Add avx512 __builtin_ia32_select* constexpr handling #152705

RKSimon · 2025-08-08T12:49:27Z

This should allow us to constexpr many avx512 predicated intrinsics where they wrap basic intrinsics that are already constexpr

Fixes #152321

github-actions · 2025-08-08T12:52:57Z

✅ With the latest revision this PR passed the C/C++ code formatter.

llvmbot · 2025-08-11T09:05:05Z

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-backend-x86

Author: Simon Pilgrim (RKSimon)

Changes

This should allow us to constexpr many avx512 predicated intrinsics where they wrap basic intrinsics that are already constexpr

Fixes #152321

Patch is 45.67 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/152705.diff

14 Files Affected:

(modified) clang/include/clang/Basic/BuiltinsX86.td (+24-24)
(modified) clang/lib/AST/ExprConstant.cpp (+45)
(modified) clang/lib/Headers/avx512bitalgintrin.h (+4-4)
(modified) clang/lib/Headers/avx512fintrin.h (+4-4)
(modified) clang/lib/Headers/avx512vlbitalgintrin.h (+8-8)
(modified) clang/lib/Headers/avx512vlintrin.h (+18-9)
(modified) clang/lib/Headers/avx512vpopcntdqintrin.h (+8-8)
(modified) clang/lib/Headers/avx512vpopcntdqvlintrin.h (+15-13)
(modified) clang/test/CodeGen/X86/avx512bitalg-builtins.c (+6)
(modified) clang/test/CodeGen/X86/avx512f-builtins.c (+5)
(modified) clang/test/CodeGen/X86/avx512vl-builtins.c (+9)
(modified) clang/test/CodeGen/X86/avx512vlbitalg-builtins.c (+12)
(modified) clang/test/CodeGen/X86/avx512vpopcntdq-builtins.c (+4)
(modified) clang/test/CodeGen/X86/avx512vpopcntdqvl-builtins.c (+8)

diff --git a/clang/include/clang/Basic/BuiltinsX86.td b/clang/include/clang/Basic/BuiltinsX86.td
index 3efc0be8fa698..4f1dfddb53402 100644
--- a/clang/include/clang/Basic/BuiltinsX86.td
+++ b/clang/include/clang/Basic/BuiltinsX86.td
@@ -4241,99 +4241,99 @@ let Features = "avx512fp16,evex512", Attributes = [NoThrow, Const, RequiredVecto
   def vfcmulcph512_mask : X86Builtin<"_Vector<16, float>(_Vector<16, float>, _Vector<16, float>, _Vector<16, float>, unsigned short, _Constant int)">;
 }
 
-let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectb_128 : X86Builtin<"_Vector<16, char>(unsigned short, _Vector<16, char>, _Vector<16, char>)">;
 }
 
-let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectb_256 : X86Builtin<"_Vector<32, char>(unsigned int, _Vector<32, char>, _Vector<32, char>)">;
 }
 
-let Features = "avx512bw,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512bw,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectb_512 : X86Builtin<"_Vector<64, char>(unsigned long long int, _Vector<64, char>, _Vector<64, char>)">;
 }
 
-let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectw_128 : X86Builtin<"_Vector<8, short>(unsigned char, _Vector<8, short>, _Vector<8, short>)">;
 }
 
-let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512bw,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectw_256 : X86Builtin<"_Vector<16, short>(unsigned short, _Vector<16, short>, _Vector<16, short>)">;
 }
 
-let Features = "avx512bw,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512bw,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectw_512 : X86Builtin<"_Vector<32, short>(unsigned int, _Vector<32, short>, _Vector<32, short>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectd_128 : X86Builtin<"_Vector<4, int>(unsigned char, _Vector<4, int>, _Vector<4, int>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectd_256 : X86Builtin<"_Vector<8, int>(unsigned char, _Vector<8, int>, _Vector<8, int>)">;
 }
 
-let Features = "avx512f,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512f,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectd_512 : X86Builtin<"_Vector<16, int>(unsigned short, _Vector<16, int>, _Vector<16, int>)">;
 }
 
-let Features = "avx512fp16,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512fp16,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectph_128 : X86Builtin<"_Vector<8, _Float16>(unsigned char, _Vector<8, _Float16>, _Vector<8, _Float16>)">;
 }
 
-let Features = "avx512fp16,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512fp16,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectph_256 : X86Builtin<"_Vector<16, _Float16>(unsigned short, _Vector<16, _Float16>, _Vector<16, _Float16>)">;
 }
 
-let Features = "avx512fp16,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512fp16,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectph_512 : X86Builtin<"_Vector<32, _Float16>(unsigned int, _Vector<32, _Float16>, _Vector<32, _Float16>)">;
 }
 
-let Features = "avx512bf16,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512bf16,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectpbf_128 : X86Builtin<"_Vector<8, __bf16>(unsigned char, _Vector<8, __bf16>, _Vector<8, __bf16>)">;
 }
 
-let Features = "avx512bf16,avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512bf16,avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectpbf_256 : X86Builtin<"_Vector<16, __bf16>(unsigned short, _Vector<16, __bf16>, _Vector<16, __bf16>)">;
 }
 
-let Features = "avx512bf16,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512bf16,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectpbf_512 : X86Builtin<"_Vector<32, __bf16>(unsigned int, _Vector<32, __bf16>, _Vector<32, __bf16>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectq_128 : X86Builtin<"_Vector<2, long long int>(unsigned char, _Vector<2, long long int>, _Vector<2, long long int>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectq_256 : X86Builtin<"_Vector<4, long long int>(unsigned char, _Vector<4, long long int>, _Vector<4, long long int>)">;
 }
 
-let Features = "avx512f,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512f,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectq_512 : X86Builtin<"_Vector<8, long long int>(unsigned char, _Vector<8, long long int>, _Vector<8, long long int>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectps_128 : X86Builtin<"_Vector<4, float>(unsigned char, _Vector<4, float>, _Vector<4, float>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectps_256 : X86Builtin<"_Vector<8, float>(unsigned char, _Vector<8, float>, _Vector<8, float>)">;
 }
 
-let Features = "avx512f,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512f,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectps_512 : X86Builtin<"_Vector<16, float>(unsigned short, _Vector<16, float>, _Vector<16, float>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
   def selectpd_128 : X86Builtin<"_Vector<2, double>(unsigned char, _Vector<2, double>, _Vector<2, double>)">;
 }
 
-let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
+let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
   def selectpd_256 : X86Builtin<"_Vector<4, double>(unsigned char, _Vector<4, double>, _Vector<4, double>)">;
 }
 
-let Features = "avx512f,evex512", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
+let Features = "avx512f,evex512", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
   def selectpd_512 : X86Builtin<"_Vector<8, double>(unsigned char, _Vector<8, double>, _Vector<8, double>)">;
 }
 
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 5cf2b9a0355ab..6595d8c69f0b2 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -11688,6 +11688,51 @@ bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) {
 
     return Success(APValue(ResultElements.data(), ResultElements.size()), E);
   }
+  case X86::BI__builtin_ia32_selectb_128:
+  case X86::BI__builtin_ia32_selectb_256:
+  case X86::BI__builtin_ia32_selectb_512:
+  case X86::BI__builtin_ia32_selectw_128:
+  case X86::BI__builtin_ia32_selectw_256:
+  case X86::BI__builtin_ia32_selectw_512:
+  case X86::BI__builtin_ia32_selectd_128:
+  case X86::BI__builtin_ia32_selectd_256:
+  case X86::BI__builtin_ia32_selectd_512:
+  case X86::BI__builtin_ia32_selectq_128:
+  case X86::BI__builtin_ia32_selectq_256:
+  case X86::BI__builtin_ia32_selectq_512:
+  case X86::BI__builtin_ia32_selectph_128:
+  case X86::BI__builtin_ia32_selectph_256:
+  case X86::BI__builtin_ia32_selectph_512:
+  case X86::BI__builtin_ia32_selectpbf_128:
+  case X86::BI__builtin_ia32_selectpbf_256:
+  case X86::BI__builtin_ia32_selectpbf_512:
+  case X86::BI__builtin_ia32_selectps_128:
+  case X86::BI__builtin_ia32_selectps_256:
+  case X86::BI__builtin_ia32_selectps_512:
+  case X86::BI__builtin_ia32_selectpd_128:
+  case X86::BI__builtin_ia32_selectpd_256:
+  case X86::BI__builtin_ia32_selectpd_512: {
+    // AVX512 predicated move: "Result = Mask[] ? LHS[] : RHS[]".
+    APValue SourceMask, SourceLHS, SourceRHS;
+    if (!EvaluateAsRValue(Info, E->getArg(0), SourceMask) ||
+        !EvaluateAsRValue(Info, E->getArg(1), SourceLHS) ||
+        !EvaluateAsRValue(Info, E->getArg(2), SourceRHS))
+      return false;
+
+    APSInt Mask = SourceMask.getInt();
+    QualType DestEltTy = E->getType()->castAs<VectorType>()->getElementType();
+    unsigned SourceLen = SourceLHS.getVectorLength();
+    SmallVector<APValue, 4> ResultElements;
+    ResultElements.reserve(SourceLen);
+
+    for (unsigned EltNum = 0; EltNum < SourceLen; ++EltNum) {
+      const APValue &LHS = SourceLHS.getVectorElt(EltNum);
+      const APValue &RHS = SourceRHS.getVectorElt(EltNum);
+      ResultElements.push_back(Mask[EltNum] ? LHS : RHS);
+    }
+
+    return Success(APValue(ResultElements.data(), ResultElements.size()), E);
+  }
   }
 }
 
diff --git a/clang/lib/Headers/avx512bitalgintrin.h b/clang/lib/Headers/avx512bitalgintrin.h
index 9a1ff8f39734f..76c1a158b223f 100644
--- a/clang/lib/Headers/avx512bitalgintrin.h
+++ b/clang/lib/Headers/avx512bitalgintrin.h
@@ -32,7 +32,7 @@ _mm512_popcnt_epi16(__m512i __A)
   return (__m512i)__builtin_elementwise_popcount((__v32hu)__A);
 }
 
-static __inline__ __m512i __DEFAULT_FN_ATTRS
+static __inline__ __m512i __DEFAULT_FN_ATTRS_CONSTEXPR
 _mm512_mask_popcnt_epi16(__m512i __A, __mmask32 __U, __m512i __B)
 {
   return (__m512i) __builtin_ia32_selectw_512((__mmask32) __U,
@@ -40,7 +40,7 @@ _mm512_mask_popcnt_epi16(__m512i __A, __mmask32 __U, __m512i __B)
               (__v32hi) __A);
 }
 
-static __inline__ __m512i __DEFAULT_FN_ATTRS
+static __inline__ __m512i __DEFAULT_FN_ATTRS_CONSTEXPR
 _mm512_maskz_popcnt_epi16(__mmask32 __U, __m512i __B)
 {
   return _mm512_mask_popcnt_epi16((__m512i) _mm512_setzero_si512(),
@@ -54,7 +54,7 @@ _mm512_popcnt_epi8(__m512i __A)
   return (__m512i)__builtin_elementwise_popcount((__v64qu)__A);
 }
 
-static __inline__ __m512i __DEFAULT_FN_ATTRS
+static __inline__ __m512i __DEFAULT_FN_ATTRS_CONSTEXPR
 _mm512_mask_popcnt_epi8(__m512i __A, __mmask64 __U, __m512i __B)
 {
   return (__m512i) __builtin_ia32_selectb_512((__mmask64) __U,
@@ -62,7 +62,7 @@ _mm512_mask_popcnt_epi8(__m512i __A, __mmask64 __U, __m512i __B)
               (__v64qi) __A);
 }
 
-static __inline__ __m512i __DEFAULT_FN_ATTRS
+static __inline__ __m512i __DEFAULT_FN_ATTRS_CONSTEXPR
 _mm512_maskz_popcnt_epi8(__mmask64 __U, __m512i __B)
 {
   return _mm512_mask_popcnt_epi8((__m512i) _mm512_setzero_si512(),
diff --git a/clang/lib/Headers/avx512fintrin.h b/clang/lib/Headers/avx512fintrin.h
index 95b80cc59bb02..00ef9bb0ace9e 100644
--- a/clang/lib/Headers/avx512fintrin.h
+++ b/clang/lib/Headers/avx512fintrin.h
@@ -8962,7 +8962,7 @@ _mm512_mask_cvtpslo_pd (__m512d __W, __mmask8 __U, __m512 __A)
   return (__m512d) _mm512_mask_cvtps_pd(__W, __U, _mm512_castps512_ps256(__A));
 }
 
-static __inline__ __m512d __DEFAULT_FN_ATTRS512
+static __inline__ __m512d __DEFAULT_FN_ATTRS512_CONSTEXPR
 _mm512_mask_mov_pd (__m512d __W, __mmask8 __U, __m512d __A)
 {
   return (__m512d) __builtin_ia32_selectpd_512 ((__mmask8) __U,
@@ -8970,7 +8970,7 @@ _mm512_mask_mov_pd (__m512d __W, __mmask8 __U, __m512d __A)
               (__v8df) __W);
 }
 
-static __inline__ __m512d __DEFAULT_FN_ATTRS512
+static __inline__ __m512d __DEFAULT_FN_ATTRS512_CONSTEXPR
 _mm512_maskz_mov_pd (__mmask8 __U, __m512d __A)
 {
   return (__m512d) __builtin_ia32_selectpd_512 ((__mmask8) __U,
@@ -8978,7 +8978,7 @@ _mm512_maskz_mov_pd (__mmask8 __U, __m512d __A)
               (__v8df) _mm512_setzero_pd ());
 }
 
-static __inline__ __m512 __DEFAULT_FN_ATTRS512
+static __inline__ __m512 __DEFAULT_FN_ATTRS512_CONSTEXPR
 _mm512_mask_mov_ps (__m512 __W, __mmask16 __U, __m512 __A)
 {
   return (__m512) __builtin_ia32_selectps_512 ((__mmask16) __U,
@@ -8986,7 +8986,7 @@ _mm512_mask_mov_ps (__m512 __W, __mmask16 __U, __m512 __A)
              (__v16sf) __W);
 }
 
-static __inline__ __m512 __DEFAULT_FN_ATTRS512
+static __inline__ __m512 __DEFAULT_FN_ATTRS512_CONSTEXPR
 _mm512_maskz_mov_ps (__mmask16 __U, __m512 __A)
 {
   return (__m512) __builtin_ia32_selectps_512 ((__mmask16) __U,
diff --git a/clang/lib/Headers/avx512vlbitalgintrin.h b/clang/lib/Headers/avx512vlbitalgintrin.h
index 739e78aab753d..e29a149df5f90 100644
--- a/clang/lib/Headers/avx512vlbitalgintrin.h
+++ b/clang/lib/Headers/avx512vlbitalgintrin.h
@@ -38,7 +38,7 @@ _mm256_popcnt_epi16(__m256i __A)
   return (__m256i)__builtin_elementwise_popcount((__v16hu)__A);
 }
 
-static __inline__ __m256i __DEFAULT_FN_ATTRS256
+static __inline__ __m256i __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_mask_popcnt_epi16(__m256i __A, __mmask16 __U, __m256i __B)
 {
   return (__m256i) __builtin_ia32_selectw_256((__mmask16) __U,
@@ -46,7 +46,7 @@ _mm256_mask_popcnt_epi16(__m256i __A, __mmask16 __U, __m256i __B)
               (__v16hi) __A);
 }
 
-static __inline__ __m256i __DEFAULT_FN_ATTRS256
+static __inline__ __m256i __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_maskz_popcnt_epi16(__mmask16 __U, __m256i __B)
 {
   return _mm256_mask_popcnt_epi16((__m256i) _mm256_setzero_si256(),
@@ -60,7 +60,7 @@ _mm_popcnt_epi16(__m128i __A)
   return (__m128i)__builtin_elementwise_popcount((__v8hu)__A);
 }
 
-static __inline__ __m128i __DEFAULT_FN_ATTRS128
+static __inline__ __m128i __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_mask_popcnt_epi16(__m128i __A, __mmask8 __U, __m128i __B)
 {
   return (__m128i) __builtin_ia32_selectw_128((__mmask8) __U,
@@ -68,7 +68,7 @@ _mm_mask_popcnt_epi16(__m128i __A, __mmask8 __U, __m128i __B)
               (__v8hi) __A);
 }
 
-static __inline__ __m128i __DEFAULT_FN_ATTRS128
+static __inline__ __m128i __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_maskz_popcnt_epi16(__mmask8 __U, __m128i __B)
 {
   return _mm_mask_popcnt_epi16((__m128i) _mm_setzero_si128(),
@@ -82,7 +82,7 @@ _mm256_popcnt_epi8(__m256i __A)
   return (__m256i)__builtin_elementwise_popcount((__v32qu)__A);
 }
 
-static __inline__ __m256i __DEFAULT_FN_ATTRS256
+static __inline__ __m256i __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_mask_popcnt_epi8(__m256i __A, __mmask32 __U, __m256i __B)
 {
   return (__m256i) __builtin_ia32_selectb_256((__mmask32) __U,
@@ -90,7 +90,7 @@ _mm256_mask_popcnt_epi8(__m256i __A, __mmask32 __U, __m256i __B)
               (__v32qi) __A);
 }
 
-static __inline__ __m256i __DEFAULT_FN_ATTRS256
+static __inline__ __m256i __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_maskz_popcnt_epi8(__mmask32 __U, __m256i __B)
 {
   return _mm256_mask_popcnt_epi8((__m256i) _mm256_setzero_si256(),
@@ -104,7 +104,7 @@ _mm_popcnt_epi8(__m128i __A)
   return (__m128i)__builtin_elementwise_popcount((__v16qu)__A);
 }
 
-static __inline__ __m128i __DEFAULT_FN_ATTRS128
+static __inline__ __m128i __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_mask_popcnt_epi8(__m128i __A, __mmask16 __U, __m128i __B)
 {
   return (__m128i) __builtin_ia32_selectb_128((__mmask16) __U,
@@ -112,7 +112,7 @@ _mm_mask_popcnt_epi8(__m128i __A, __mmask16 __U, __m128i __B)
               (__v16qi) __A);
 }
 
-static __inline__ __m128i __DEFAULT_FN_ATTRS128
+static __inline__ __m128i __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_maskz_popcnt_epi8(__mmask16 __U, __m128i __B)
 {
   return _mm_mask_popcnt_epi8((__m128i) _mm_setzero_si128(),
diff --git a/clang/lib/Headers/avx512vlintrin.h b/clang/lib/Headers/avx512vlintrin.h
index cbad39acad84f..fd1bd291ecbcb 100644
--- a/clang/lib/Headers/avx512vlintrin.h
+++ b/clang/lib/Headers/avx512vlintrin.h
@@ -23,6 +23,14 @@
                  __target__("avx512vl,no-evex512"),                            \
                  __min_vector_width__(256)))
 
+#if defined(__cplusplus) && (__cplusplus >= 201103L)
+#define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS128 constexpr
+#define __DEFAULT_FN_ATTRS256_CONSTEXPR __DEFAULT_FN_ATTRS256 constexpr
+#else
+#define __DEFAULT_FN_ATTRS128_CONSTEXPR __DEFAULT_FN_ATTRS128
+#define __DEFAULT_FN_ATTRS256_CONSTEXPR __DEFAULT_FN_ATTRS256
+#endif
+
 typedef short __v2hi __attribute__((__vector_size__(4)));
 typedef char __v4qi __attribute__((__vector_size__(4)));
 typedef char __v2qi __attribute__((__vector_size__(2)));
@@ -8258,7 +8266,7 @@ _mm256_maskz_moveldup_ps (__mmask8 __U, __m256 __A)
                                        (__v4si)_mm_shuffle_epi32((A), (I)), \
                                        (__v4si)_mm_setzero_si128()))
 
-static __inline__ __m128d __DEFAULT_FN_ATTRS128
+static __inline__ __m128d __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_mask_mov_pd (__m128d __W, __mmask8 __U, __m128d __A)
 {
   return (__m128d) __builtin_ia32_selectpd_128 ((__mmask8) __U,
@@ -8266,7 +8274,7 @@ _mm_mask_mov_pd (__m128d __W, __mmask8 __U, __m128d __A)
               (__v2df) __W);
 }
 
-static __inline__ __m128d __DEFAULT_FN_ATTRS128
+static __inline__ __m128d __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_maskz_mov_pd (__mmask8 __U, __m128d __A)
 {
   return (__m128d) __builtin_ia32_selectpd_128 ((__mmask8) __U,
@@ -8274,7 +8282,7 @@ _mm_maskz_mov_pd (__mmask8 __U, __m128d __A)
               (__v2df) _mm_setzero_pd ());
 }
 
-static __inline__ __m256d __DEFAULT_FN_ATTRS256
+static __inline__ __m256d __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_mask_mov_pd (__m256d __W, __mmask8 __U, __m256d __A)
 {
   return (__m256d) __builtin_ia32_selectpd_256 ((__mmask8) __U,
@@ -8282,7 +8290,7 @@ _mm256_mask_mov_pd (__m256d __W, __mmask8 __U, __m256d __A)
               (__v4df) __W);
 }
 
-static __inline__ __m256d __DEFAULT_FN_ATTRS256
+static __inline__ __m256d __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_maskz_mov_pd (__mmask8 __U, __m256d __A)
 {
   return (__m256d) __builtin_ia32_selectpd_256 ((__mmask8) __U,
@@ -8290,7 +8298,7 @@ _mm256_maskz_mov_pd (__mmask8 __U, __m256d __A)
               (__v4df) _mm256_setzero_pd ());
 }
 
-static __inline__ __m128 __DEFAULT_FN_ATTRS128
+static __inline__ __m128 __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_mask_mov_ps (__m128 __W, __mmask8 __U, __m128 __A)
 {
   return (__m128) __builtin_ia32_selectps_128 ((__mmask8) __U,
@@ -8298,7 +8306,7 @@ _mm_mask_mov_ps (__m128 __W, __mmask8 __U, __m128 __A)
              (__v4sf) __W);
 }
 
-static __inline__ __m128 __DEFAULT_FN_ATTRS128
+static __inline__ __m128 __DEFAULT_FN_ATTRS128_CONSTEXPR
 _mm_maskz_mov_ps (__mmask8 __U, __m128 __A)
 {
   return (__m128) __builtin_ia32_selectps_128 ((__mmask8) __U,
@@ -8306,7 +8314,7 @@ _mm_maskz_mov_ps (__mmask8 __U, __m128 __A)
              (__v4sf) _mm_setzero_ps ());
 }
 
-static __inline__ __m256 __DEFAULT_FN_ATTRS256
+static __inline__ __m256 __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_mask_mov_ps (__m256 __W, __mmask8 __U, __m256 __A)
 {
   return (__m256) __builtin_ia32_selectps_256 ((__mmask8) __U,
@@ -8314,7 +8322,7 @@ _mm256_mask_mov_ps (__m256 __W, __mmask8 __U, __m256 __A)
              (__v8sf) __W);
 }
 
-static __inline__ __m256 __DEFAULT_FN_ATTRS256
+static __inline__ __m256 __DEFAULT_FN_ATTRS256_CONSTEXPR
 _mm256_maskz_mov_ps (__mmask8 __...
[truncated]

Fixes llvm#152321

RKSimon · 2025-08-14T06:58:31Z

ping?

RKSimon · 2025-08-18T07:01:02Z

Ping?

phoebewang

LGTM.

tbaederr · 2025-08-18T09:31:50Z

This introduced an unused variable:

/home/tbaeder/code/llvm-project/clang/lib/AST/ExprConstant.cpp:11818:14: warning: unused variable 'DestEltTy' [-Wunused-variable]
 11818 |     QualType DestEltTy = E->getType()->castAs<VectorType>()->getElementType();
       |              ^~~~~~~~~

RKSimon requested a review from phoebewang August 8, 2025 12:49

RKSimon force-pushed the x86-avx512-select-constexpr branch 3 times, most recently from de0a2d3 to d294c88 Compare August 11, 2025 09:00

RKSimon marked this pull request as ready for review August 11, 2025 09:04

llvmbot added clang Clang issues not falling into any other category backend:X86 clang:frontend Language frontend issues, e.g. anything involving "Sema" clang:headers Headers provided by Clang, e.g. for intrinsics labels Aug 11, 2025

[Clang][X86] Add avx512 __builtin_ia32_select* constexpr handling

ceff509

Fixes llvm#152321

RKSimon force-pushed the x86-avx512-select-constexpr branch from d294c88 to ceff509 Compare August 13, 2025 07:57

clang-format

2d99c13

RKSimon mentioned this pull request Aug 14, 2025

[Headers][X86] Allow integer/fp absolute intrinsics to be used in constexpr #153556

Closed

RKSimon added 4 commits August 14, 2025 09:44

Merge branch 'upstream' into x86-avx512-select-constexpr

3319ea6

Merge branch 'main' into x86-avx512-select-constexpr

7bab5e7

Merge branch 'main' into x86-avx512-select-constexpr

5f74595

Merge branch 'main' into x86-avx512-select-constexpr

31af14c

phoebewang approved these changes Aug 18, 2025

View reviewed changes

Merge branch 'main' into x86-avx512-select-constexpr

2bb4d2d

RKSimon merged commit ce5276f into llvm:main Aug 18, 2025
9 checks passed

RKSimon deleted the x86-avx512-select-constexpr branch August 18, 2025 08:37

RKSimon added a commit that referenced this pull request Aug 18, 2025

Remove unused variable introduced in #152705

169b43d

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[Clang][X86] Add avx512 __builtin_ia32_select* constexpr handling #152705

[Clang][X86] Add avx512 __builtin_ia32_select* constexpr handling #152705

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[Clang][X86] Add avx512 __builtin_ia32_select* constexpr handling #152705

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