https://github.com/mooori created https://github.com/llvm/llvm-project/pull/168700
Partly resolves #160514 Enables usage of the following x86 intrinsics in `constexpr`: ``` _mm256_shuffle_i64x2 _mm256_shuffle_f64x2 _mm512_shuffle_i64x2 _mm512_shuffle_f64x2 _mm256_shuffle_i32x4 _mm256_shuffle_f32x4 _mm512_shuffle_i32x4 _mm512_shuffle_f32x4 ``` If it makes sense, I would like to add support for the remaining intrinsics from #160514 in a follow up PR. My understanding is that `_mm*_mask*_shuffle_*` cannot simply reuse `interp__builtin_ia32_shuffle_generic` / `evalShuffleGeneric`. So it would be great to first see if I'm on the right track with this PR before carrying on. (cc @RKSimon as I'm not permitted to request reviews.) >From bdfc0fe8df0bb34cb9dfcffe90dd5d827ab93766 Mon Sep 17 00:00:00 2001 From: Moritz Zielke <[email protected]> Date: Mon, 17 Nov 2025 13:33:10 +0100 Subject: [PATCH] [Clang] Allow AVX/AVX512 subvector shuffles in constexpr --- clang/include/clang/Basic/BuiltinsX86.td | 6 ++- clang/lib/AST/ByteCode/InterpBuiltin.cpp | 33 ++++++++++++++ clang/lib/AST/ExprConstant.cpp | 51 ++++++++++++++++++++++ clang/test/CodeGen/X86/avx512f-builtins.c | 5 +++ clang/test/CodeGen/X86/avx512vl-builtins.c | 4 ++ 5 files changed, 97 insertions(+), 2 deletions(-) diff --git a/clang/include/clang/Basic/BuiltinsX86.td b/clang/include/clang/Basic/BuiltinsX86.td index 7a14c6ec21a1a..272704c8451a7 100644 --- a/clang/include/clang/Basic/BuiltinsX86.td +++ b/clang/include/clang/Basic/BuiltinsX86.td @@ -2464,7 +2464,8 @@ let Features = "avx512vl", def pternlogq256_maskz : X86Builtin<"_Vector<4, long long int>(_Vector<4, long long int>, _Vector<4, long long int>, _Vector<4, long long int>, _Constant int, unsigned char)">; } -let Features = "avx512f", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in { +let Features = "avx512f", + Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in { def shuf_f32x4 : X86Builtin<"_Vector<16, float>(_Vector<16, float>, _Vector<16, float>, _Constant int)">; def shuf_f64x2 : X86Builtin<"_Vector<8, double>(_Vector<8, double>, _Vector<8, double>, _Constant int)">; def shuf_i32x4 : X86Builtin<"_Vector<16, int>(_Vector<16, int>, _Vector<16, int>, _Constant int)">; @@ -2476,7 +2477,8 @@ let Features = "avx512f", Attributes = [NoThrow, Const, Constexpr, RequiredVecto def shufps512 : X86Builtin<"_Vector<16, float>(_Vector<16, float>, _Vector<16, float>, _Constant int)">; } -let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in { +let Features = "avx512vl", + Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in { def shuf_f32x4_256 : X86Builtin<"_Vector<8, float>(_Vector<8, float>, _Vector<8, float>, _Constant int)">; def shuf_f64x2_256 : X86Builtin<"_Vector<4, double>(_Vector<4, double>, _Vector<4, double>, _Constant int)">; def shuf_i32x4_256 : X86Builtin<"_Vector<8, int>(_Vector<8, int>, _Vector<8, int>, _Constant int)">; diff --git a/clang/lib/AST/ByteCode/InterpBuiltin.cpp b/clang/lib/AST/ByteCode/InterpBuiltin.cpp index 5a96320e12b6f..8e0d254bdddc9 100644 --- a/clang/lib/AST/ByteCode/InterpBuiltin.cpp +++ b/clang/lib/AST/ByteCode/InterpBuiltin.cpp @@ -4718,6 +4718,39 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call, return interp__builtin_elementwise_triop(S, OpPC, Call, llvm::APIntOps::fshr); + case X86::BI__builtin_ia32_shuf_f32x4_256: + case X86::BI__builtin_ia32_shuf_i32x4_256: + case X86::BI__builtin_ia32_shuf_f64x2_256: + case X86::BI__builtin_ia32_shuf_i64x2_256: + case X86::BI__builtin_ia32_shuf_f32x4: + case X86::BI__builtin_ia32_shuf_i32x4: + case X86::BI__builtin_ia32_shuf_f64x2: + case X86::BI__builtin_ia32_shuf_i64x2: { + // Destination and sources A, B all have the same type. + QualType VecQT = Call->getArg(0)->getType(); + const auto *VecT = VecQT->castAs<VectorType>(); + unsigned NumElems = VecT->getNumElements(); + unsigned ElemBits = S.getASTContext().getTypeSize(VecT->getElementType()); + constexpr unsigned LaneBits = 128u; + unsigned NumLanes = (NumElems * ElemBits) / LaneBits; + unsigned NumElemsPerLane = LaneBits / ElemBits; + + return interp__builtin_ia32_shuffle_generic( + S, OpPC, Call, + [NumLanes, NumElemsPerLane](unsigned DstIdx, unsigned ShuffleMask) { + // DstIdx determines source. ShuffleMask selects lane in source. + unsigned BitsPerElem = NumLanes / 2; + unsigned IndexMask = (1u << BitsPerElem) - 1; + unsigned Lane = DstIdx / NumElemsPerLane; + unsigned SrcIdx = (Lane < NumLanes / 2) ? 0 : 1; + unsigned BitIdx = BitsPerElem * Lane; + unsigned SrcLaneIdx = (ShuffleMask >> BitIdx) & IndexMask; + unsigned ElemInLane = DstIdx % NumElemsPerLane; + unsigned IdxToPick = SrcLaneIdx * NumElemsPerLane + ElemInLane; + return std::pair<unsigned, int>{SrcIdx, IdxToPick}; + }); + } + case X86::BI__builtin_ia32_insertf32x4_256: case X86::BI__builtin_ia32_inserti32x4_256: case X86::BI__builtin_ia32_insertf64x2_256: diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 74f6e3acb6b39..999669f7539cd 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -50,6 +50,7 @@ #include "clang/AST/RecordLayout.h" #include "clang/AST/StmtVisitor.h" #include "clang/AST/Type.h" +#include "clang/AST/TypeBase.h" #include "clang/AST/TypeLoc.h" #include "clang/Basic/Builtins.h" #include "clang/Basic/DiagnosticSema.h" @@ -13461,6 +13462,56 @@ bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) { return Success(APValue(ResultElements.data(), ResultElements.size()), E); } + case X86::BI__builtin_ia32_shuf_f32x4_256: + case X86::BI__builtin_ia32_shuf_i32x4_256: + case X86::BI__builtin_ia32_shuf_f64x2_256: + case X86::BI__builtin_ia32_shuf_i64x2_256: + case X86::BI__builtin_ia32_shuf_f32x4: + case X86::BI__builtin_ia32_shuf_i32x4: + case X86::BI__builtin_ia32_shuf_f64x2: + case X86::BI__builtin_ia32_shuf_i64x2: { + APValue SourceA, SourceB; + if (!EvaluateAsRValue(Info, E->getArg(0), SourceA) || + !EvaluateAsRValue(Info, E->getArg(1), SourceB)) + return false; + + APSInt Imm; + if (!EvaluateInteger(E->getArg(2), Imm, Info)) + return false; + + // Destination and sources A, B all have the same type. + unsigned NumElems = SourceA.getVectorLength(); + const VectorType *VT = E->getArg(0)->getType()->castAs<VectorType>(); + QualType ElemQT = VT->getElementType(); + unsigned ElemBits = Info.Ctx.getTypeSize(ElemQT); + constexpr unsigned LaneBits = 128u; + unsigned NumLanes = (NumElems * ElemBits) / LaneBits; + unsigned NumElemsPerLane = LaneBits / ElemBits; + + unsigned DstLen = SourceA.getVectorLength(); + SmallVector<APValue, 16> ResultElements; + ResultElements.reserve(DstLen); + + APValue R; + if (!evalShuffleGeneric( + Info, E, R, + [NumLanes, NumElemsPerLane](unsigned DstIdx, unsigned ShuffleMask) + -> std::pair<unsigned, int> { + // DstIdx determines source. ShuffleMask selects lane in source. + unsigned BitsPerElem = NumLanes / 2; + unsigned IndexMask = (1u << BitsPerElem) - 1; + unsigned Lane = DstIdx / NumElemsPerLane; + unsigned SrcIdx = (Lane < NumLanes / 2) ? 0 : 1; + unsigned BitIdx = BitsPerElem * Lane; + unsigned SrcLaneIdx = (ShuffleMask >> BitIdx) & IndexMask; + unsigned ElemInLane = DstIdx % NumElemsPerLane; + unsigned IdxToPick = SrcLaneIdx * NumElemsPerLane + ElemInLane; + return {SrcIdx, IdxToPick}; + })) + return false; + return Success(R, E); + } + case X86::BI__builtin_ia32_insertf32x4_256: case X86::BI__builtin_ia32_inserti32x4_256: case X86::BI__builtin_ia32_insertf64x2_256: diff --git a/clang/test/CodeGen/X86/avx512f-builtins.c b/clang/test/CodeGen/X86/avx512f-builtins.c index eb25aa538e9a3..4881700bb5a66 100644 --- a/clang/test/CodeGen/X86/avx512f-builtins.c +++ b/clang/test/CodeGen/X86/avx512f-builtins.c @@ -6747,6 +6747,7 @@ __m512 test_mm512_shuffle_f32x4(__m512 __A, __m512 __B) { // CHECK: shufflevector <16 x float> %{{.*}}, <16 x float> %{{.*}}, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 16, i32 17, i32 18, i32 19> return _mm512_shuffle_f32x4(__A, __B, 4); } +TEST_CONSTEXPR(match_m512(_mm512_shuffle_f32x4(((__m512){1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f, 12.0f, 13.0f, 14.0f, 15.0f, 16.0f}), ((__m512){10.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0, 90.0, 100.0, 110.0, 120.0, 130.0, 140.0, 150.0, 160.0}), 0b11111111), 13.0f, 14.0f, 15.0f, 16.0f, 13.0f, 14.0f, 15.0f, 16.0f, 130.0, 140.0, 150.0, 160.0, 130.0, 140.0, 150.0, 160.0)); __m512 test_mm512_mask_shuffle_f32x4(__m512 __W, __mmask16 __U, __m512 __A, __m512 __B) { // CHECK-LABEL: test_mm512_mask_shuffle_f32x4 @@ -6767,6 +6768,7 @@ __m512d test_mm512_shuffle_f64x2(__m512d __A, __m512d __B) { // CHECK: shufflevector <8 x double> %{{.*}}, <8 x double> %{{.*}}, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 8, i32 9> return _mm512_shuffle_f64x2(__A, __B, 4); } +TEST_CONSTEXPR(match_m512d(_mm512_shuffle_f64x2(((__m512d){1.0,2.0,3.0,4.0,5.0,6.0,7.0,8.0}), ((__m512d){10.0,20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0}), 0b10101100), 1.0, 2.0, 7.0, 8.0, 50.0, 60.0, 50.0, 60.0)); __m512d test_mm512_mask_shuffle_f64x2(__m512d __W, __mmask8 __U, __m512d __A, __m512d __B) { // CHECK-LABEL: test_mm512_mask_shuffle_f64x2 @@ -6787,6 +6789,8 @@ __m512i test_mm512_shuffle_i32x4(__m512i __A, __m512i __B) { // CHECK: shufflevector <16 x i32> %{{.*}}, <16 x i32> %{{.*}}, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 16, i32 17, i32 18, i32 19, i32 16, i32 17, i32 18, i32 19> return _mm512_shuffle_i32x4(__A, __B, 4); } +TEST_CONSTEXPR(match_v16si(_mm512_shuffle_i32x4(((__m512i)(__v16si){1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16}), ((__m512i)(__v16si){10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160}), 0), 1, 2, 3, 4, 1, 2, 3, 4, 10, 20, 30, 40, 10, 20, 30, 40)); + __m512i test_mm512_mask_shuffle_i32x4(__m512i __W, __mmask16 __U, __m512i __A, __m512i __B) { // CHECK-LABEL: test_mm512_mask_shuffle_i32x4 @@ -6807,6 +6811,7 @@ __m512i test_mm512_shuffle_i64x2(__m512i __A, __m512i __B) { // CHECK: shufflevector <8 x i64> %{{.*}}, <8 x i64> %{{.*}}, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 8, i32 9> return _mm512_shuffle_i64x2(__A, __B, 4); } +TEST_CONSTEXPR(match_m512i(_mm512_shuffle_i64x2(((__m512i){1, 2, 3, 4, 5, 6, 7, 8}), ((__m512i){10, 20, 30, 40, 50, 60, 70, 80}), 0b11000110), 5, 6, 3, 4, 10, 20, 70, 80)); __m512i test_mm512_mask_shuffle_i64x2(__m512i __W, __mmask8 __U, __m512i __A, __m512i __B) { // CHECK-LABEL: test_mm512_mask_shuffle_i64x2 diff --git a/clang/test/CodeGen/X86/avx512vl-builtins.c b/clang/test/CodeGen/X86/avx512vl-builtins.c index e05b1ddf7b69a..aff775c7f7b3c 100644 --- a/clang/test/CodeGen/X86/avx512vl-builtins.c +++ b/clang/test/CodeGen/X86/avx512vl-builtins.c @@ -8989,6 +8989,7 @@ __m256 test_mm256_shuffle_f32x4(__m256 __A, __m256 __B) { // CHECK: shufflevector <8 x float> %{{.*}}, <8 x float> %{{.*}}, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 12, i32 13, i32 14, i32 15> return _mm256_shuffle_f32x4(__A, __B, 3); } +TEST_CONSTEXPR(match_m256(_mm256_shuffle_f32x4(((__m256){1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0}), ((__m256){10.0, 20.0, 30.0, 40.0, 50.0, 60.0, 70.0, 80.0}), 1), 5.0, 6.0, 7.0, 8.0, 10.0, 20.0, 30.0, 40.0)); __m256 test_mm256_mask_shuffle_f32x4(__m256 __W, __mmask8 __U, __m256 __A, __m256 __B) { // CHECK-LABEL: test_mm256_mask_shuffle_f32x4 @@ -9009,6 +9010,7 @@ __m256d test_mm256_shuffle_f64x2(__m256d __A, __m256d __B) { // CHECK: shufflevector <4 x double> %{{.*}}, <4 x double> %{{.*}}, <4 x i32> <i32 2, i32 3, i32 6, i32 7> return _mm256_shuffle_f64x2(__A, __B, 3); } +TEST_CONSTEXPR(match_m256d(_mm256_shuffle_f64x2(((__m256d){1.0, 2.0, 3.0, 4.0}), ((__m256d){10.0, 20.0, 30.0, 40.0}), 3), 3.0, 4.0, 30.0, 40.0)); __m256d test_mm256_mask_shuffle_f64x2(__m256d __W, __mmask8 __U, __m256d __A, __m256d __B) { // CHECK-LABEL: test_mm256_mask_shuffle_f64x2 @@ -9031,6 +9033,7 @@ __m256i test_mm256_shuffle_i32x4(__m256i __A, __m256i __B) { // CHECK: shufflevector <8 x i32> %{{.*}}, <8 x i32> %{{.*}}, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 12, i32 13, i32 14, i32 15> return _mm256_shuffle_i32x4(__A, __B, 3); } +TEST_CONSTEXPR(match_v8si(_mm256_shuffle_i32x4(((__m256i)(__v8si){1, 2, 3, 4, 5, 6, 7, 8}), ((__m256i)(__v8si){10, 20, 30, 40, 50, 60, 70, 80}), 0), 1, 2, 3, 4, 10, 20, 30, 40)); __m256i test_mm256_mask_shuffle_i32x4(__m256i __W, __mmask8 __U, __m256i __A, __m256i __B) { // CHECK-LABEL: test_mm256_mask_shuffle_i32x4 @@ -9051,6 +9054,7 @@ __m256i test_mm256_shuffle_i64x2(__m256i __A, __m256i __B) { // CHECK: shufflevector <4 x i64> %{{.*}}, <4 x i64> %{{.*}}, <4 x i32> <i32 2, i32 3, i32 6, i32 7> return _mm256_shuffle_i64x2(__A, __B, 3); } +TEST_CONSTEXPR(match_m256i(_mm256_shuffle_i64x2(((__m256i){1ULL, 2ULL, 3ULL, 4ULL}), ((__m256i){10ULL, 20ULL, 30ULL, 40ULL}), 2), 1ULL, 2ULL, 30ULL, 40ULL)); __m256i test_mm256_mask_shuffle_i64x2(__m256i __W, __mmask8 __U, __m256i __A, __m256i __B) { // CHECK-LABEL: test_mm256_mask_shuffle_i64x2 _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
