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[clang][X86] Allow VALIGND/Q element-shift intrinsics in constexpr evaluation #168206

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[clang][X86] Allow VALIGND/Q element-shift intrinsics in constexpr evaluation #168206

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5e69309
[clang][X86] VectorExprEvaluator::VisitCallExpr / InterpretBuiltin - …
0xzre Nov 15, 2025
3fe153e
fix vars & clang format
0xzre Nov 16, 2025
d17b6de
add test using TEST_CONSTEXPR on avx512*builtins.cpp
0xzre Nov 16, 2025
85ad38f
remove uneeded bytecode test
0xzre Nov 16, 2025
2450447
high perf circular queues & fix format
0xzre Nov 19, 2025
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10 changes: 5 additions & 5 deletions clang/include/clang/Basic/BuiltinsX86.td
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Expand Up @@ -1072,24 +1072,24 @@ let Features = "avx512f", Attributes = [NoThrow, RequiredVectorWidth<512>] in {
def storeaps512_mask : X86Builtin<"void(_Vector<16, float *>, _Vector<16, float>, unsigned short)">;
}

let Features = "avx512f", Attributes = [NoThrow, Const, RequiredVectorWidth<512>] in {
let Features = "avx512f", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<512>] in {
def alignq512 : X86Builtin<"_Vector<8, long long int>(_Vector<8, long long int>, _Vector<8, long long int>, _Constant int)">;
def alignd512 : X86Builtin<"_Vector<16, int>(_Vector<16, int>, _Vector<16, int>, _Constant int)">;
}

let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
def alignd128 : X86Builtin<"_Vector<4, int>(_Vector<4, int>, _Vector<4, int>, _Constant int)">;
}

let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
def alignd256 : X86Builtin<"_Vector<8, int>(_Vector<8, int>, _Vector<8, int>, _Constant int)">;
}

let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<128>] in {
let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<128>] in {
def alignq128 : X86Builtin<"_Vector<2, long long int>(_Vector<2, long long int>, _Vector<2, long long int>, _Constant int)">;
}

let Features = "avx512vl", Attributes = [NoThrow, Const, RequiredVectorWidth<256>] in {
let Features = "avx512vl", Attributes = [NoThrow, Const, Constexpr, RequiredVectorWidth<256>] in {
def alignq256 : X86Builtin<"_Vector<4, long long int>(_Vector<4, long long int>, _Vector<4, long long int>, _Constant int)">;
}

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20 changes: 20 additions & 0 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Expand Up @@ -4774,6 +4774,26 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const CallExpr *Call,
return std::pair<unsigned, int>{VecIdx, ElemIdx};
});

case X86::BI__builtin_ia32_alignd128:
case X86::BI__builtin_ia32_alignd256:
case X86::BI__builtin_ia32_alignd512:
case X86::BI__builtin_ia32_alignq128:
case X86::BI__builtin_ia32_alignq256:
case X86::BI__builtin_ia32_alignq512: {
unsigned NumElems =
Call->getType()->castAs<VectorType>()->getNumElements();
return interp__builtin_ia32_shuffle_generic(
S, OpPC, Call, [NumElems](unsigned DstIdx, unsigned Shift) {
unsigned Imm = Shift & 0xFF;
unsigned EffectiveShift = Imm & (NumElems - 1);
unsigned SourcePos = DstIdx + EffectiveShift;
unsigned VecIdx = SourcePos < NumElems ? 1u : 0u;
unsigned ElemIdx =
SourcePos < NumElems ? SourcePos : SourcePos - NumElems;
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@RKSimon RKSimon Nov 17, 2025

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Suggested change
SourcePos < NumElems ? SourcePos : SourcePos - NumElems;
unsigned ElemIdx = SourcePos & (NumElems - 1);

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@0xzre 0xzre Nov 19, 2025

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oh nice, fixed

return std::pair<unsigned, int>{VecIdx, static_cast<int>(ElemIdx)};
});
}

default:
S.FFDiag(S.Current->getLocation(OpPC),
diag::note_invalid_subexpr_in_const_expr)
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24 changes: 24 additions & 0 deletions clang/lib/AST/ExprConstant.cpp
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Expand Up @@ -13551,6 +13551,30 @@ bool VectorExprEvaluator::VisitCallExpr(const CallExpr *E) {
return false;
return Success(R, E);
}
case X86::BI__builtin_ia32_alignd128:
case X86::BI__builtin_ia32_alignd256:
case X86::BI__builtin_ia32_alignd512:
case X86::BI__builtin_ia32_alignq128:
case X86::BI__builtin_ia32_alignq256:
case X86::BI__builtin_ia32_alignq512: {
APValue R;
const unsigned NumElts =
E->getType()->castAs<VectorType>()->getNumElements();
if (!evalShuffleGeneric(
Info, E, R, [NumElts](unsigned DstIdx, unsigned Shift) {
unsigned Imm = Shift & 0xFF;
unsigned EffectiveShift = Imm & (NumElts - 1);
unsigned SourcePos = DstIdx + EffectiveShift;
unsigned VecIdx = SourcePos < NumElts ? 1 : 0;
unsigned ElemIdx =
SourcePos < NumElts ? SourcePos : SourcePos - NumElts;
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@RKSimon RKSimon Nov 17, 2025

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Suggested change
SourcePos < NumElts ? SourcePos : SourcePos - NumElts;
unsigned ElemIdx = SourcePos & (NumElems - 1);


return std::pair<unsigned, int>{VecIdx,
static_cast<int>(ElemIdx)};
}))
return false;
return Success(R, E);
}
case X86::BI__builtin_ia32_permvarsi256:
case X86::BI__builtin_ia32_permvarsf256:
case X86::BI__builtin_ia32_permvardf512:
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34 changes: 34 additions & 0 deletions clang/test/CodeGen/X86/avx512f-builtins.c
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Expand Up @@ -519,6 +519,40 @@ __m512i test_mm512_maskz_alignr_epi64( __mmask8 u, __m512i a, __m512i b)
return _mm512_maskz_alignr_epi64(u, a, b, 2);
}

TEST_CONSTEXPR(match_v16si(_mm512_alignr_epi32(((__m512i)(__v16si){100, 200, 300, 400, 500, 600, 700, 800,
900, 1000, 1100, 1200, 1300, 1400, 1500, 1600}),
((__m512i)(__v16si){0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15}), 19),
3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 100, 200, 300));
TEST_CONSTEXPR(match_v16si(_mm512_mask_alignr_epi32(((__m512i)(__v16si){1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000,
9000, 10000, 11000, 12000, 13000, 14000, 15000, 16000}),
0xA5A5,
((__m512i)(__v16si){100, 200, 300, 400, 500, 600, 700, 800,
900, 1000, 1100, 1200, 1300, 1400, 1500, 1600}),
((__m512i)(__v16si){0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15}), 19),
3, 2000, 5, 4000, 5000, 8, 7000, 10,
11, 10000, 13, 12000, 13000, 100, 15000, 300));
TEST_CONSTEXPR(match_v16si(_mm512_maskz_alignr_epi32(0x0F0F,
((__m512i)(__v16si){100, 200, 300, 400, 500, 600, 700, 800,
900, 1000, 1100, 1200, 1300, 1400, 1500, 1600}),
((__m512i)(__v16si){0, 1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15}), 19),
3, 4, 5, 6, 0, 0, 0, 0, 11, 12, 13, 14, 0, 0, 0, 0));

TEST_CONSTEXPR(match_v8di(_mm512_alignr_epi64(((__m512i)(__v8di){10, 11, 12, 13, 14, 15, 16, 17}),
((__m512i)(__v8di){1, 2, 3, 4, 5, 6, 7, 8}), 11),
4, 5, 6, 7, 8, 10, 11, 12));
TEST_CONSTEXPR(match_v8di(_mm512_mask_alignr_epi64(((__m512i)(__v8di){1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000}),
0xA5,
((__m512i)(__v8di){10, 11, 12, 13, 14, 15, 16, 17}),
((__m512i)(__v8di){1, 2, 3, 4, 5, 6, 7, 8}), 11),
4, 2000, 6, 4000, 5000, 10, 7000, 12));
TEST_CONSTEXPR(match_v8di(_mm512_maskz_alignr_epi64(0x33,
((__m512i)(__v8di){10, 11, 12, 13, 14, 15, 16, 17}),
((__m512i)(__v8di){1, 2, 3, 4, 5, 6, 7, 8}), 11),
4, 5, 0, 0, 8, 10, 0, 0));

__m512d test_mm512_fmadd_round_pd(__m512d __A, __m512d __B, __m512d __C) {
// CHECK-LABEL: test_mm512_fmadd_round_pd
// CHECK: @llvm.x86.avx512.vfmadd.pd.512
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47 changes: 47 additions & 0 deletions clang/test/CodeGen/X86/avx512vl-builtins.c
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Expand Up @@ -10518,6 +10518,53 @@ __m256i test_mm256_maskz_alignr_epi64(__mmask8 __U, __m256i __A, __m256i __B) {
return _mm256_maskz_alignr_epi64(__U, __A, __B, 1);
}

TEST_CONSTEXPR(match_v4si(_mm_alignr_epi32(((__m128i)(__v4si){100, 200, 300, 400}),
((__m128i)(__v4si){10, 20, 30, 40}), 1),
20, 30, 40, 100));
TEST_CONSTEXPR(match_v4si(_mm_mask_alignr_epi32(((__m128i)(__v4si){1000, 2000, 3000, 4000}), 0x5,
((__m128i)(__v4si){100, 200, 300, 400}),
((__m128i)(__v4si){10, 20, 30, 40}), 1),
20, 2000, 40, 4000));
TEST_CONSTEXPR(match_v4si(_mm_maskz_alignr_epi32(0x3,
((__m128i)(__v4si){100, 200, 300, 400}),
((__m128i)(__v4si){10, 20, 30, 40}), 1),
20, 30, 0, 0));

TEST_CONSTEXPR(match_v8si(_mm256_alignr_epi32(((__m256i)(__v8si){100, 200, 300, 400, 500, 600, 700, 800}),
((__m256i)(__v8si){1, 2, 3, 4, 5, 6, 7, 8}), 3),
4, 5, 6, 7, 8, 100, 200, 300));
TEST_CONSTEXPR(match_v8si(_mm256_mask_alignr_epi32(((__m256i)(__v8si){1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000}),
0xA5,
((__m256i)(__v8si){100, 200, 300, 400, 500, 600, 700, 800}),
((__m256i)(__v8si){1, 2, 3, 4, 5, 6, 7, 8}), 3),
4, 2000, 6, 4000, 5000, 100, 7000, 300));
TEST_CONSTEXPR(match_v8si(_mm256_maskz_alignr_epi32(0x33,
((__m256i)(__v8si){100, 200, 300, 400, 500, 600, 700, 800}),
((__m256i)(__v8si){1, 2, 3, 4, 5, 6, 7, 8}), 3),
4, 5, 0, 0, 8, 100, 0, 0));

TEST_CONSTEXPR(match_v2di(_mm_alignr_epi64(((__m128i)(__v2di){10, 11}), ((__m128i)(__v2di){1, 2}), 1), 2, 10));
TEST_CONSTEXPR(match_v2di(_mm_mask_alignr_epi64(((__m128i)(__v2di){1000, 2000}), 0x1,
((__m128i)(__v2di){10, 11}),
((__m128i)(__v2di){1, 2}), 1),
2, 2000));
TEST_CONSTEXPR(match_v2di(_mm_maskz_alignr_epi64(0x2,
((__m128i)(__v2di){10, 11}),
((__m128i)(__v2di){1, 2}), 1),
0, 10));

TEST_CONSTEXPR(match_v4di(_mm256_alignr_epi64(((__m256i)(__v4di){10, 11, 12, 13}),
((__m256i)(__v4di){1, 2, 3, 4}), 2),
3, 4, 10, 11));
TEST_CONSTEXPR(match_v4di(_mm256_mask_alignr_epi64(((__m256i)(__v4di){1000, 2000, 3000, 4000}), 0x5,
((__m256i)(__v4di){10, 11, 12, 13}),
((__m256i)(__v4di){1, 2, 3, 4}), 2),
3, 2000, 10, 4000));
TEST_CONSTEXPR(match_v4di(_mm256_maskz_alignr_epi64(0xA,
((__m256i)(__v4di){10, 11, 12, 13}),
((__m256i)(__v4di){1, 2, 3, 4}), 2),
0, 4, 0, 11));

__m128 test_mm_mask_movehdup_ps(__m128 __W, __mmask8 __U, __m128 __A) {
// CHECK-LABEL: test_mm_mask_movehdup_ps
// CHECK: shufflevector <4 x float> %{{.*}}, <4 x float> %{{.*}}, <4 x i32> <i32 1, i32 1, i32 3, i32 3>
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