[GlobalISel] Make scalar G_SHUFFLE_VECTOR illegal. #140508
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@llvm/pr-subscribers-llvm-globalisel @llvm/pr-subscribers-backend-amdgpu Author: David Green (davemgreen) ChangesI'm not sure if this is the best way forward or not, but we have a lot of issues with forgetting that shuffle_vectors can be scalar again and again. (There is another example from the recent known-bits code added recently). As a scalar-dst shuffle vector is just an extract, and a scalar-source shuffle vector is just a build vector, this patch makes scalar shuffle vector illegal and adjusts the irbuilder to create the correct node as required. Most targets do this already through lowering or combines. Making scalar shuffles illegal simplifies gisel as a whole, it just requires that transforms that create shuffles of new sizes to account for the scalar shuffle being illegal (mostly IRBuilder and LessElements). Patch is 32.57 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/140508.diff 20 Files Affected:
diff --git a/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h b/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
index c15263e0b06f8..fcefcb2452818 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
@@ -262,7 +262,6 @@ class CombinerHelper {
SmallVector<Register> &Ops) const;
/// Replace \p MI with a build_vector.
- bool matchCombineShuffleToBuildVector(MachineInstr &MI) const;
void applyCombineShuffleToBuildVector(MachineInstr &MI) const;
/// Try to combine G_SHUFFLE_VECTOR into G_CONCAT_VECTORS.
@@ -281,8 +280,6 @@ class CombinerHelper {
/// Replace \p MI with a concat_vectors with \p Ops.
void applyCombineShuffleVector(MachineInstr &MI,
const ArrayRef<Register> Ops) const;
- bool matchShuffleToExtract(MachineInstr &MI) const;
- void applyShuffleToExtract(MachineInstr &MI) const;
/// Optimize memcpy intrinsics et al, e.g. constant len calls.
/// /p MaxLen if non-zero specifies the max length of a mem libcall to inline.
diff --git a/llvm/include/llvm/Target/GlobalISel/Combine.td b/llvm/include/llvm/Target/GlobalISel/Combine.td
index efd88524a159e..49b49bba8e17a 100644
--- a/llvm/include/llvm/Target/GlobalISel/Combine.td
+++ b/llvm/include/llvm/Target/GlobalISel/Combine.td
@@ -471,13 +471,6 @@ def propagate_undef_shuffle_mask: GICombineRule<
[{ return Helper.matchUndefShuffleVectorMask(*${root}); }]),
(apply [{ Helper.replaceInstWithUndef(*${root}); }])>;
-// Replace a G_SHUFFLE_VECTOR with a G_EXTRACT_VECTOR_ELT.
-def shuffle_to_extract: GICombineRule<
- (defs root:$root),
- (match (wip_match_opcode G_SHUFFLE_VECTOR):$root,
- [{ return Helper.matchShuffleToExtract(*${root}); }]),
- (apply [{ Helper.applyShuffleToExtract(*${root}); }])>;
-
// Replace an insert/extract element of an out of bounds index with undef.
def insert_extract_vec_elt_out_of_bounds : GICombineRule<
(defs root:$root),
@@ -1575,8 +1568,7 @@ def combine_shuffle_concat : GICombineRule<
// Combines shuffles of vector into build_vector
def combine_shuffle_vector_to_build_vector : GICombineRule<
(defs root:$root),
- (match (G_SHUFFLE_VECTOR $dst, $src1, $src2, $mask):$root,
- [{ return Helper.matchCombineShuffleToBuildVector(*${root}); }]),
+ (match (G_SHUFFLE_VECTOR $dst, $src1, $src2, $mask):$root),
(apply [{ Helper.applyCombineShuffleToBuildVector(*${root}); }])>;
def insert_vector_element_idx_undef : GICombineRule<
diff --git a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
index 5191360c7718a..e0bfeb0c35a59 100644
--- a/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
@@ -386,19 +386,6 @@ void CombinerHelper::applyCombineConcatVectors(
MI.eraseFromParent();
}
-bool CombinerHelper::matchCombineShuffleToBuildVector(MachineInstr &MI) const {
- assert(MI.getOpcode() == TargetOpcode::G_SHUFFLE_VECTOR &&
- "Invalid instruction");
- auto &Shuffle = cast<GShuffleVector>(MI);
-
- Register SrcVec1 = Shuffle.getSrc1Reg();
- Register SrcVec2 = Shuffle.getSrc2Reg();
-
- LLT SrcVec1Type = MRI.getType(SrcVec1);
- LLT SrcVec2Type = MRI.getType(SrcVec2);
- return SrcVec1Type.isVector() && SrcVec2Type.isVector();
-}
-
void CombinerHelper::applyCombineShuffleToBuildVector(MachineInstr &MI) const {
auto &Shuffle = cast<GShuffleVector>(MI);
@@ -527,11 +514,9 @@ bool CombinerHelper::matchCombineShuffleVector(
LLT DstType = MRI.getType(MI.getOperand(0).getReg());
Register Src1 = MI.getOperand(1).getReg();
LLT SrcType = MRI.getType(Src1);
- // As bizarre as it may look, shuffle vector can actually produce
- // scalar! This is because at the IR level a <1 x ty> shuffle
- // vector is perfectly valid.
- unsigned DstNumElts = DstType.isVector() ? DstType.getNumElements() : 1;
- unsigned SrcNumElts = SrcType.isVector() ? SrcType.getNumElements() : 1;
+
+ unsigned DstNumElts = DstType.getNumElements();
+ unsigned SrcNumElts = SrcType.getNumElements();
// If the resulting vector is smaller than the size of the source
// vectors being concatenated, we won't be able to replace the
@@ -548,7 +533,7 @@ bool CombinerHelper::matchCombineShuffleVector(
//
// TODO: If the size between the source and destination don't match
// we could still emit an extract vector element in that case.
- if (DstNumElts < 2 * SrcNumElts && DstNumElts != 1)
+ if (DstNumElts < 2 * SrcNumElts)
return false;
// Check that the shuffle mask can be broken evenly between the
@@ -611,39 +596,6 @@ void CombinerHelper::applyCombineShuffleVector(
MI.eraseFromParent();
}
-bool CombinerHelper::matchShuffleToExtract(MachineInstr &MI) const {
- assert(MI.getOpcode() == TargetOpcode::G_SHUFFLE_VECTOR &&
- "Invalid instruction kind");
-
- ArrayRef<int> Mask = MI.getOperand(3).getShuffleMask();
- return Mask.size() == 1;
-}
-
-void CombinerHelper::applyShuffleToExtract(MachineInstr &MI) const {
- Register DstReg = MI.getOperand(0).getReg();
- Builder.setInsertPt(*MI.getParent(), MI);
-
- int I = MI.getOperand(3).getShuffleMask()[0];
- Register Src1 = MI.getOperand(1).getReg();
- LLT Src1Ty = MRI.getType(Src1);
- int Src1NumElts = Src1Ty.isVector() ? Src1Ty.getNumElements() : 1;
- Register SrcReg;
- if (I >= Src1NumElts) {
- SrcReg = MI.getOperand(2).getReg();
- I -= Src1NumElts;
- } else if (I >= 0)
- SrcReg = Src1;
-
- if (I < 0)
- Builder.buildUndef(DstReg);
- else if (!MRI.getType(SrcReg).isVector())
- Builder.buildCopy(DstReg, SrcReg);
- else
- Builder.buildExtractVectorElementConstant(DstReg, SrcReg, I);
-
- MI.eraseFromParent();
-}
-
namespace {
/// Select a preference between two uses. CurrentUse is the current preference
@@ -7942,7 +7894,7 @@ bool CombinerHelper::matchShuffleDisjointMask(MachineInstr &MI,
return false;
ArrayRef<int> Mask = Shuffle.getMask();
- const unsigned NumSrcElems = Src1Ty.isVector() ? Src1Ty.getNumElements() : 1;
+ const unsigned NumSrcElems = Src1Ty.getNumElements();
bool TouchesSrc1 = false;
bool TouchesSrc2 = false;
diff --git a/llvm/lib/CodeGen/GlobalISel/GISelValueTracking.cpp b/llvm/lib/CodeGen/GlobalISel/GISelValueTracking.cpp
index 748ecbd767c3e..e51a2fd92f770 100644
--- a/llvm/lib/CodeGen/GlobalISel/GISelValueTracking.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/GISelValueTracking.cpp
@@ -591,6 +591,8 @@ void GISelValueTracking::computeKnownBitsImpl(Register R, KnownBits &Known,
Depth + 1);
computeKnownBitsImpl(MI.getOperand(3).getReg(), WidthKnown, DemandedElts,
Depth + 1);
+ OffsetKnown = OffsetKnown.sext(BitWidth);
+ WidthKnown = WidthKnown.sext(BitWidth);
Known = extractBits(BitWidth, SrcOpKnown, OffsetKnown, WidthKnown);
// Sign extend the extracted value using shift left and arithmetic shift
// right.
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 8ab2533afc15f..fceca20745c95 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -3330,6 +3330,53 @@ bool IRTranslator::translateShuffleVector(const User &U,
Mask = SVI->getShuffleMask();
else
Mask = cast<ConstantExpr>(U).getShuffleMask();
+
+ unsigned DstElts = cast<FixedVectorType>(U.getType())->getNumElements();
+ unsigned SrcElts =
+ cast<FixedVectorType>(U.getOperand(0)->getType())->getNumElements();
+ if (DstElts == 1) {
+ int M = Mask[0];
+ if (SrcElts == 1) {
+ if (M == 0 || M == 1) {
+ return translateCopy(U, *U.getOperand(M), MIRBuilder);
+ }
+ MIRBuilder.buildUndef(getOrCreateVReg(U));
+ return true;
+ } else {
+ if (M < SrcElts) {
+ MIRBuilder.buildExtractVectorElementConstant(
+ getOrCreateVReg(U), getOrCreateVReg(*U.getOperand(0)), M);
+ }
+ else if (M < SrcElts * 2) {
+ MIRBuilder.buildExtractVectorElementConstant(
+ getOrCreateVReg(U), getOrCreateVReg(*U.getOperand(1)), M - SrcElts);
+ }
+ else {
+ MIRBuilder.buildUndef(getOrCreateVReg(U));
+ }
+ return true;
+ }
+ }
+
+ if (SrcElts == 1) {
+ SmallVector<Register> Ops;
+ for (int M : Mask) {
+ Register Undef = 0;
+ LLT SrcTy = getLLTForType(*U.getOperand(0)->getType(), *DL);
+ if (M == 0 || M == 1) {
+ Ops.push_back(getOrCreateVReg(*U.getOperand(M)));
+ } else {
+ if (Undef.isValid()) {
+ Undef = MRI->createGenericVirtualRegister(SrcTy);
+ MIRBuilder.buildUndef(Undef);
+ }
+ Ops.push_back(Undef);
+ }
+ }
+ MIRBuilder.buildBuildVector(getOrCreateVReg(U), Ops);
+ return true;
+ }
+
ArrayRef<int> MaskAlloc = MF->allocateShuffleMask(Mask);
MIRBuilder
.buildInstr(TargetOpcode::G_SHUFFLE_VECTOR, {getOrCreateVReg(U)},
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 72f2ba75c927e..0138f625d0c68 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -5626,6 +5626,8 @@ LegalizerHelper::LegalizeResult LegalizerHelper::fewerElementsVectorShuffle(
} else if (InputUsed[0] == -1U) {
// No input vectors were used! The result is undefined.
Output = MIRBuilder.buildUndef(NarrowTy).getReg(0);
+ } else if (NewElts == 1) {
+ Output = MIRBuilder.buildCopy(NarrowTy, Inputs[InputUsed[0]]).getReg(0);
} else {
Register Op0 = Inputs[InputUsed[0]];
// If only one input was used, use an undefined vector for the other.
@@ -8407,22 +8409,18 @@ LegalizerHelper::lowerShuffleVector(MachineInstr &MI) {
continue;
}
- if (Src0Ty.isScalar()) {
- BuildVec.push_back(Idx == 0 ? Src0Reg : Src1Reg);
- } else {
- int NumElts = Src0Ty.getNumElements();
- Register SrcVec = Idx < NumElts ? Src0Reg : Src1Reg;
- int ExtractIdx = Idx < NumElts ? Idx : Idx - NumElts;
- auto IdxK = MIRBuilder.buildConstant(IdxTy, ExtractIdx);
- auto Extract = MIRBuilder.buildExtractVectorElement(EltTy, SrcVec, IdxK);
- BuildVec.push_back(Extract.getReg(0));
- }
+ assert(!Src0Ty.isScalar() && "Unexpected scalar G_SHUFFLE_VECTOR");
+
+ int NumElts = Src0Ty.getNumElements();
+ Register SrcVec = Idx < NumElts ? Src0Reg : Src1Reg;
+ int ExtractIdx = Idx < NumElts ? Idx : Idx - NumElts;
+ auto IdxK = MIRBuilder.buildConstant(IdxTy, ExtractIdx);
+ auto Extract = MIRBuilder.buildExtractVectorElement(EltTy, SrcVec, IdxK);
+ BuildVec.push_back(Extract.getReg(0));
}
- if (DstTy.isScalar())
- MIRBuilder.buildCopy(DstReg, BuildVec[0]);
- else
- MIRBuilder.buildBuildVector(DstReg, BuildVec);
+ assert(!DstTy.isScalar() && "Unexpected scalar G_SHUFFLE_VECTOR");
+ MIRBuilder.buildBuildVector(DstReg, BuildVec);
MI.eraseFromParent();
return Legalized;
}
diff --git a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index 121d7e80251c7..4961a96b9ca48 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -784,9 +784,9 @@ MachineInstrBuilder MachineIRBuilder::buildShuffleVector(const DstOp &Res,
LLT DstTy = Res.getLLTTy(*getMRI());
LLT Src1Ty = Src1.getLLTTy(*getMRI());
LLT Src2Ty = Src2.getLLTTy(*getMRI());
- const LLT DstElemTy = DstTy.isVector() ? DstTy.getElementType() : DstTy;
- const LLT ElemTy1 = Src1Ty.isVector() ? Src1Ty.getElementType() : Src1Ty;
- const LLT ElemTy2 = Src2Ty.isVector() ? Src2Ty.getElementType() : Src2Ty;
+ const LLT DstElemTy = DstTy.getScalarType();
+ const LLT ElemTy1 = Src1Ty.getScalarType();
+ const LLT ElemTy2 = Src2Ty.getScalarType();
assert(DstElemTy == ElemTy1 && DstElemTy == ElemTy2);
(void)DstElemTy;
(void)ElemTy1;
diff --git a/llvm/lib/CodeGen/MachineVerifier.cpp b/llvm/lib/CodeGen/MachineVerifier.cpp
index a7dbceb88c4c8..f2e19a9c62b4a 100644
--- a/llvm/lib/CodeGen/MachineVerifier.cpp
+++ b/llvm/lib/CodeGen/MachineVerifier.cpp
@@ -1926,13 +1926,23 @@ void MachineVerifier::verifyPreISelGenericInstruction(const MachineInstr *MI) {
if (Src0Ty != Src1Ty)
report("Source operands must be the same type", MI);
- if (Src0Ty.getScalarType() != DstTy.getScalarType())
+ if (Src0Ty.getScalarType() != DstTy.getScalarType()) {
report("G_SHUFFLE_VECTOR cannot change element type", MI);
+ break;
+ }
+ if (!Src0Ty.isVector()) {
+ report("G_SHUFFLE_VECTOR must have vector src", MI);
+ break;
+ }
+ if (!DstTy.isVector()) {
+ report("G_SHUFFLE_VECTOR must have vector dst", MI);
+ break;
+ }
// Don't check that all operands are vector because scalars are used in
// place of 1 element vectors.
- int SrcNumElts = Src0Ty.isVector() ? Src0Ty.getNumElements() : 1;
- int DstNumElts = DstTy.isVector() ? DstTy.getNumElements() : 1;
+ int SrcNumElts = Src0Ty.getNumElements();
+ int DstNumElts = DstTy.getNumElements();
ArrayRef<int> MaskIdxes = MaskOp.getShuffleMask();
diff --git a/llvm/lib/Target/AArch64/AArch64Combine.td b/llvm/lib/Target/AArch64/AArch64Combine.td
index f84e83816bf33..492441d1aebee 100644
--- a/llvm/lib/Target/AArch64/AArch64Combine.td
+++ b/llvm/lib/Target/AArch64/AArch64Combine.td
@@ -70,7 +70,6 @@ def AArch64PreLegalizerCombiner: GICombiner<
fconstant_to_constant,
icmp_redundant_trunc,
fold_global_offset,
- shuffle_to_extract,
ext_addv_to_udot_addv,
ext_uaddv_to_uaddlv,
push_sub_through_zext,
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
index e0c693bff3c0a..389a3fb500bbd 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp
@@ -5191,23 +5191,13 @@ bool AArch64InstructionSelector::selectShuffleVector(
MachineInstr &I, MachineRegisterInfo &MRI) {
const LLT DstTy = MRI.getType(I.getOperand(0).getReg());
Register Src1Reg = I.getOperand(1).getReg();
- const LLT Src1Ty = MRI.getType(Src1Reg);
Register Src2Reg = I.getOperand(2).getReg();
- const LLT Src2Ty = MRI.getType(Src2Reg);
ArrayRef<int> Mask = I.getOperand(3).getShuffleMask();
MachineBasicBlock &MBB = *I.getParent();
MachineFunction &MF = *MBB.getParent();
LLVMContext &Ctx = MF.getFunction().getContext();
- // G_SHUFFLE_VECTOR is weird in that the source operands can be scalars, if
- // it's originated from a <1 x T> type. Those should have been lowered into
- // G_BUILD_VECTOR earlier.
- if (!Src1Ty.isVector() || !Src2Ty.isVector()) {
- LLVM_DEBUG(dbgs() << "Could not select a \"scalar\" G_SHUFFLE_VECTOR\n");
- return false;
- }
-
unsigned BytesPerElt = DstTy.getElementType().getSizeInBits() / 8;
SmallVector<Constant *, 64> CstIdxs;
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
index 7ff2e55e802c5..fe5022b71ccb6 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
@@ -1175,24 +1175,16 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
return llvm::is_contained(
{v8s8, v16s8, v4s16, v8s16, v2s32, v4s32, v2s64}, DstTy);
})
- // G_SHUFFLE_VECTOR can have scalar sources (from 1 x s vectors) or scalar
- // destinations, we just want those lowered into G_BUILD_VECTOR or
- // G_EXTRACT_ELEMENT.
- .lowerIf([=](const LegalityQuery &Query) {
- return !Query.Types[0].isVector() || !Query.Types[1].isVector();
- })
.moreElementsIf(
[](const LegalityQuery &Query) {
- return Query.Types[0].isVector() && Query.Types[1].isVector() &&
- Query.Types[0].getNumElements() >
+ return Query.Types[0].getNumElements() >
Query.Types[1].getNumElements();
},
changeTo(1, 0))
.moreElementsToNextPow2(0)
.moreElementsIf(
[](const LegalityQuery &Query) {
- return Query.Types[0].isVector() && Query.Types[1].isVector() &&
- Query.Types[0].getNumElements() <
+ return Query.Types[0].getNumElements() <
Query.Types[1].getNumElements();
},
changeTo(0, 1))
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
index d457418720f47..1c68812615f65 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/arm64-irtranslator.ll
@@ -1727,8 +1727,7 @@ define float @test_different_call_conv_target(float %x) {
define <2 x i32> @test_shufflevector_s32_v2s32(i32 %arg) {
; CHECK-LABEL: name: test_shufflevector_s32_v2s32
; CHECK: [[ARG:%[0-9]+]]:_(s32) = COPY $w0
-; CHECK-DAG: [[UNDEF:%[0-9]+]]:_(s32) = G_IMPLICIT_DEF
-; CHECK: [[VEC:%[0-9]+]]:_(<2 x s32>) = G_SHUFFLE_VECTOR [[ARG]](s32), [[UNDEF]], shufflemask(0, 0)
+; CHECK: [[VEC:%[0-9]+]]:_(<2 x s32>) = G_BUILD_VECTOR [[ARG]](s32), [[ARG]](s32)
; CHECK: $d0 = COPY [[VEC]](<2 x s32>)
%vec = insertelement <1 x i32> undef, i32 %arg, i32 0
%res = shufflevector <1 x i32> %vec, <1 x i32> undef, <2 x i32> zeroinitializer
@@ -1738,7 +1737,8 @@ define <2 x i32> @test_shufflevector_s32_v2s32(i32 %arg) {
define i32 @test_shufflevector_v2s32_s32(<2 x i32> %arg) {
; CHECK-LABEL: name: test_shufflevector_v2s32_s32
; CHECK: [[ARG:%[0-9]+]]:_(<2 x s32>) = COPY $d0
-; CHECK: [[RES:%[0-9]+]]:_(s32) = G_SHUFFLE_VECTOR [[ARG]](<2 x s32>), [[UNDEF]], shufflemask(1)
+; CHECK: [[IDX:%[0-9]+]]:_(s64) = G_CONSTANT i64 1
+; CHECK: [[RES:%[0-9]+]]:_(s32) = G_EXTRACT_VECTOR_ELT [[ARG]](<2 x s32>), [[IDX]](s64)
; CHECK: $w0 = COPY [[RES]](s32)
%vec = shufflevector <2 x i32> %arg, <2 x i32> undef, <1 x i32> <i32 1>
%res = extractelement <1 x i32> %vec, i32 0
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-shuffle-vector.mir b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-shuffle-vector.mir
index af03a21806982..abd8fd75048f8 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-shuffle-vector.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-shuffle-vector.mir
@@ -117,33 +117,6 @@ body: |
$q0 = COPY %2(<8 x s16>)
RET_ReallyLR implicit $q0
-...
----
-name: shuffle_1elt_mask
-alignment: 4
-tracksRegLiveness: true
-body: |
- bb.1:
- liveins: $d0, $d1
-
- ; CHECK-LABEL: name: shuffle_1elt_mask
- ; CHECK: liveins: $d0, $d1
- ; CHECK-NEXT: {{ $}}
- ; CHECK-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $d0
- ; CHECK-NEXT: [[COPY1:%[0-9]+]]:_(s64) = COPY $d1
- ; CHECK-NEXT: [[COPY2:%[0-9]+]]:_(s64) = COPY [[COPY]](s64)
- ; CHECK-NEXT: [[COPY3:%[0-9]+]]:_(s64) = COPY [[COPY1]](s64)
- ; CHECK-NEXT: $d0 = COPY [[COPY2]](s64)
- ; CHECK-NEXT: $d1 = COPY [[COPY3]](s64)
- ; CHECK-NEXT: RET_ReallyLR implicit $d0, implicit $d1
- %0:_(s64) = COPY $d0
- %1:_(s64) = COPY $d1
- %3:_(s64) = G_SHUFFLE_VECTOR %0:_(s64), %1:_, shufflemask(0)
- %4:_(s64) = G_SHUFFLE_VECTOR %0:_(s64), %1:_, shufflemask(1)
- $d0 = COPY %3(s64)
- $d1 = COPY %4(s64)
- RET_ReallyLR implicit $d0, implicit $d1
-
...
---
name: oversize_shuffle_v4i64
@@ -641,7 +614,8 @@ body: |
%0:_(<8 x s1>) = G_TRUNC %2:_(<8 x s8>)
%3:_(<8 x s8>) = COPY $d1
%1:_(<8 x s1>) = G_TRUNC %3:_(<8 x s8>)
- %4:_(s1) = G_SHUFFLE_VECTOR %0:_(<8 x s1>), %1:_, shufflemask(12)
+ %7:_(s64) = G_CONSTANT i64 4
+ %4:_(s1) = G_EXTRACT_VECTOR_ELT %1:_(<8 x s1>), %7(s64)
%5:_(s8) = G_ZEXT %4:_(s1)
%6:_(s32) = G_ANYEXT %5:_(s8)
$w0 = COPY %6:_(s32)
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/prelegalizercombiner-shuffle-vector-disjoint-mask.mir b/llvm/test/CodeGen/AArch64/G...
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✅ With the latest revision this PR passed the C/C++ code formatter. |
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aemerson
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I don't have a problem with this in principle, but let's check with @qcolombet in case there's something we're missing.
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This also came up recently in #139769 |
arsenm
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Sounds good to me. |
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LGTM if nits addressed, after fixing them wait a bit to see if other reviewers have objections too
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I'm not sure if this is the best design or not, but we have a lot of issues with forgetting that shuffle_vectors can be scalar again and again. (There is another example from the recent known-bits code added recently). As a scalar-dst shuffle vector is just an extract, and a scalar-source shuffle vector is just a build vector, this patch makes scalar shuffle vector illegal and adjusts the irbuilder to create the correct node as required.
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Sorry - I lost track of this one. Thanks for the review. Let me know if this runs into any problems. It somewhat just moves where the issues happen, but is hopefully simpler overall. |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/42/builds/6663 Here is the relevant piece of the build log for the reference |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/66/builds/21215 Here is the relevant piece of the build log for the reference |
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LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/129/builds/32106 Here is the relevant piece of the build log for the reference |
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I'm not sure if this is the best way forward or not, but we have a lot of issues with forgetting that shuffle_vectors can be scalar again and again. (There is another example from the recent known-bits code added recently). As a scalar-dst shuffle vector is just an extract, and a scalar-source shuffle vector is just a build vector, this patch makes scalar shuffle vector illegal and adjusts the irbuilder to create the correct node as required. Most targets do this already through lowering or combines. Making scalar shuffles illegal simplifies gisel as a whole, it just requires that transforms that create shuffles of new sizes to account for the scalar shuffle being illegal (mostly IRBuilder and LessElements).
Lukacma
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I'm not sure if this is the best way forward or not, but we have a lot of issues with forgetting that shuffle_vectors can be scalar again and again. (There is another example from the recent known-bits code added recently). As a scalar-dst shuffle vector is just an extract, and a scalar-source shuffle vector is just a build vector, this patch makes scalar shuffle vector illegal and adjusts the irbuilder to create the correct node as required. Most targets do this already through lowering or combines. Making scalar shuffles illegal simplifies gisel as a whole, it just requires that transforms that create shuffles of new sizes to account for the scalar shuffle being illegal (mostly IRBuilder and LessElements).
aokblast
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I'm not sure if this is the best way forward or not, but we have a lot of issues with forgetting that shuffle_vectors can be scalar again and again. (There is another example from the recent known-bits code added recently). As a scalar-dst shuffle vector is just an extract, and a scalar-source shuffle vector is just a build vector, this patch makes scalar shuffle vector illegal and adjusts the irbuilder to create the correct node as required. Most targets do this already through lowering or combines. Making scalar shuffles illegal simplifies gisel as a whole, it just requires that transforms that create shuffles of new sizes to account for the scalar shuffle being illegal (mostly IRBuilder and LessElements).
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I'm not sure if this is the best way forward or not, but we have a lot of issues with forgetting that shuffle_vectors can be scalar again and again. (There is another example from the recent known-bits code added recently). As a scalar-dst shuffle vector is just an extract, and a scalar-source shuffle vector is just a build vector, this patch makes scalar shuffle vector illegal and adjusts the irbuilder to create the correct node as required.
Most targets do this already through lowering or combines. Making scalar shuffles illegal simplifies gisel as a whole, it just requires that transforms that create shuffles of new sizes to account for the scalar shuffle being illegal (mostly IRBuilder and LessElements).