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[GISel][CombinerHelper] Add concat_vectors(build_vector, build_vector) => build_vector
Teach the combiner helper how to flatten concat_vectors of build_vectors into a build_vector. Add this combine as part of AArch64 pre-legalizer combiner. Differential Revision: https://reviews.llvm.org/D69071 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375066 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Quentin Colombet
parent
8e00d5acbc
commit
17cdb7fdd5
@ -89,6 +89,29 @@ public:
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void applyElideBrByInvertingCond(MachineInstr &MI);
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bool tryElideBrByInvertingCond(MachineInstr &MI);
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/// If \p MI is G_CONCAT_VECTORS, try to combine it.
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/// Returns true if MI changed.
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/// Right now, we support:
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/// - concat_vector(undef, undef) => undef
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/// - concat_vector(build_vector(A, B), build_vector(C, D)) =>
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/// build_vector(A, B, C, D)
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///
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/// \pre MI.getOpcode() == G_CONCAT_VECTORS.
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bool tryCombineConcatVectors(MachineInstr &MI);
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/// Check if the G_CONCAT_VECTORS \p MI is undef or if it
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/// can be flattened into a build_vector.
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/// In the first case \p IsUndef will be true.
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/// In the second case \p Ops will contain the operands needed
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/// to produce the flattened build_vector.
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///
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/// \pre MI.getOpcode() == G_CONCAT_VECTORS.
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bool matchCombineConcatVectors(MachineInstr &MI, bool &IsUndef,
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SmallVectorImpl<Register> &Ops);
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/// Replace \p MI with a flattened build_vector with \p Ops or an
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/// implicit_def if IsUndef is true.
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void applyCombineConcatVectors(MachineInstr &MI, bool IsUndef,
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const ArrayRef<Register> Ops);
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/// Optimize memcpy intrinsics et al, e.g. constant len calls.
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/// /p MaxLen if non-zero specifies the max length of a mem libcall to inline.
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///
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@ -89,6 +89,90 @@ void CombinerHelper::applyCombineCopy(MachineInstr &MI) {
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replaceRegWith(MRI, DstReg, SrcReg);
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}
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bool CombinerHelper::tryCombineConcatVectors(MachineInstr &MI) {
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bool IsUndef = false;
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SmallVector<Register, 4> Ops;
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if (matchCombineConcatVectors(MI, IsUndef, Ops)) {
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applyCombineConcatVectors(MI, IsUndef, Ops);
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return true;
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}
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return false;
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}
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bool CombinerHelper::matchCombineConcatVectors(MachineInstr &MI, bool &IsUndef,
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SmallVectorImpl<Register> &Ops) {
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assert(MI.getOpcode() == TargetOpcode::G_CONCAT_VECTORS &&
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"Invalid instruction");
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IsUndef = true;
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MachineInstr *Undef = nullptr;
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// Walk over all the operands of concat vectors and check if they are
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// build_vector themselves or undef.
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// Then collect their operands in Ops.
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for (const MachineOperand &MO : MI.operands()) {
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// Skip the instruction definition.
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if (MO.isDef())
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continue;
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Register Reg = MO.getReg();
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MachineInstr *Def = MRI.getVRegDef(Reg);
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assert(Def && "Operand not defined");
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switch (Def->getOpcode()) {
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case TargetOpcode::G_BUILD_VECTOR:
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IsUndef = false;
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// Remember the operands of the build_vector to fold
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// them into the yet-to-build flattened concat vectors.
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for (const MachineOperand &BuildVecMO : Def->operands()) {
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// Skip the definition.
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if (BuildVecMO.isDef())
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continue;
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Ops.push_back(BuildVecMO.getReg());
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}
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break;
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case TargetOpcode::G_IMPLICIT_DEF: {
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LLT OpType = MRI.getType(Reg);
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// Keep one undef value for all the undef operands.
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if (!Undef) {
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Builder.setInsertPt(*MI.getParent(), MI);
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Undef = Builder.buildUndef(OpType.getScalarType());
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}
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LLT UndefType = MRI.getType(Undef->getOperand(0).getReg());
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assert(UndefType == OpType.getScalarType() &&
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"All undefs should have the same type");
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// Break the undef vector in as many scalar elements as needed
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// for the flattening.
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for (unsigned EltIdx = 0, EltEnd = OpType.getNumElements();
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EltIdx != EltEnd; ++EltIdx)
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Ops.push_back(Undef->getOperand(0).getReg());
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break;
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}
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default:
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return false;
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}
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}
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return true;
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}
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void CombinerHelper::applyCombineConcatVectors(
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MachineInstr &MI, bool IsUndef, const ArrayRef<Register> Ops) {
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// We determined that the concat_vectors can be flatten.
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// Generate the flattened build_vector.
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Register DstReg = MI.getOperand(0).getReg();
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Builder.setInsertPt(*MI.getParent(), MI);
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Register NewDstReg = MRI.cloneVirtualRegister(DstReg);
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// Note: IsUndef is sort of redundant. We could have determine it by
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// checking that at all Ops are undef. Alternatively, we could have
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// generate a build_vector of undefs and rely on another combine to
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// clean that up. For now, given we already gather this information
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// in tryCombineConcatVectors, just save compile time and issue the
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// right thing.
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if (IsUndef)
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Builder.buildUndef(NewDstReg);
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else
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Builder.buildBuildVector(NewDstReg, Ops);
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MI.eraseFromParent();
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replaceRegWith(MRI, DstReg, NewDstReg);
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}
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namespace {
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/// Select a preference between two uses. CurrentUse is the current preference
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@ -58,6 +58,8 @@ bool AArch64PreLegalizerCombinerInfo::combine(GISelChangeObserver &Observer,
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CombinerHelper Helper(Observer, B, KB, MDT);
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switch (MI.getOpcode()) {
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case TargetOpcode::G_CONCAT_VECTORS:
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return Helper.tryCombineConcatVectors(MI);
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case TargetOpcode::G_LOAD:
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case TargetOpcode::G_SEXTLOAD:
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case TargetOpcode::G_ZEXTLOAD: {
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@ -0,0 +1,141 @@
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# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
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# RUN: llc -mtriple aarch64-apple-ios -run-pass=aarch64-prelegalizer-combiner %s -o - | FileCheck %s
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# Check that we canonicalize concat_vectors(build_vector, build_vector)
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# into build_vector.
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---
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name: concat_to_build_vector
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tracksRegLiveness: true
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body: |
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bb.1:
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liveins: $x0, $x1, $x2, $x3
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; CHECK-LABEL: name: concat_to_build_vector
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; CHECK: liveins: $x0, $x1, $x2, $x3
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; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
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; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY $x1
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; CHECK: [[COPY2:%[0-9]+]]:_(s64) = COPY $x2
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; CHECK: [[COPY3:%[0-9]+]]:_(s64) = COPY $x3
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; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s64>) = G_BUILD_VECTOR [[COPY]](s64), [[COPY1]](s64), [[COPY2]](s64), [[COPY3]](s64)
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; CHECK: RET_ReallyLR implicit [[BUILD_VECTOR]](<4 x s64>)
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%0:_(s64) = COPY $x0
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%1:_(s64) = COPY $x1
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%2:_(s64) = COPY $x2
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%3:_(s64) = COPY $x3
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%4:_(<2 x s64>) = G_BUILD_VECTOR %0(s64), %1
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%5:_(<2 x s64>) = G_BUILD_VECTOR %2(s64), %3
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%6:_(<4 x s64>) = G_CONCAT_VECTORS %4(<2 x s64>), %5
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RET_ReallyLR implicit %6
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...
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# Same test as concat_to_build_vector but with pointer types.
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---
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name: concat_to_build_vector_ptr
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tracksRegLiveness: true
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body: |
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bb.1:
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liveins: $x0, $x1, $x2, $x3
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; CHECK-LABEL: name: concat_to_build_vector_ptr
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; CHECK: liveins: $x0, $x1, $x2, $x3
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; CHECK: [[COPY:%[0-9]+]]:_(p0) = COPY $x0
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; CHECK: [[COPY1:%[0-9]+]]:_(p0) = COPY $x1
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; CHECK: [[COPY2:%[0-9]+]]:_(p0) = COPY $x2
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; CHECK: [[COPY3:%[0-9]+]]:_(p0) = COPY $x3
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; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x p0>) = G_BUILD_VECTOR [[COPY]](p0), [[COPY1]](p0), [[COPY2]](p0), [[COPY3]](p0)
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; CHECK: RET_ReallyLR implicit [[BUILD_VECTOR]](<4 x p0>)
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%0:_(p0) = COPY $x0
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%1:_(p0) = COPY $x1
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%2:_(p0) = COPY $x2
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%3:_(p0) = COPY $x3
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%4:_(<2 x p0>) = G_BUILD_VECTOR %0(p0), %1
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%5:_(<2 x p0>) = G_BUILD_VECTOR %2(p0), %3
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%6:_(<4 x p0>) = G_CONCAT_VECTORS %4(<2 x p0>), %5
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RET_ReallyLR implicit %6
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...
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# Check that we canonicalize concat_vectors(undef, undef) into undef.
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---
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name: concat_to_undef
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tracksRegLiveness: true
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body: |
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bb.1:
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; CHECK-LABEL: name: concat_to_undef
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; CHECK: [[DEF:%[0-9]+]]:_(<4 x s64>) = G_IMPLICIT_DEF
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; CHECK: RET_ReallyLR implicit [[DEF]](<4 x s64>)
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%4:_(<2 x s64>) = G_IMPLICIT_DEF
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%5:_(<2 x s64>) = G_IMPLICIT_DEF
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%6:_(<4 x s64>) = G_CONCAT_VECTORS %4(<2 x s64>), %5
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RET_ReallyLR implicit %6
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...
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# Check that when combining concat_vectors(build_vector, undef) into
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# build_vector, we correctly break the undef vector into a sequence
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# of undef scalar.
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---
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name: concat_to_build_vector_with_undef
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tracksRegLiveness: true
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body: |
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bb.1:
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liveins: $x0, $x1
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; CHECK-LABEL: name: concat_to_build_vector_with_undef
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; CHECK: liveins: $x0, $x1
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; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
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; CHECK: [[COPY1:%[0-9]+]]:_(s64) = COPY $x1
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; CHECK: [[DEF:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF
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; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x s64>) = G_BUILD_VECTOR [[COPY]](s64), [[COPY1]](s64), [[DEF]](s64), [[DEF]](s64)
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; CHECK: RET_ReallyLR implicit [[BUILD_VECTOR]](<4 x s64>)
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%0:_(s64) = COPY $x0
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%1:_(s64) = COPY $x1
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%4:_(<2 x s64>) = G_BUILD_VECTOR %0(s64), %1
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%5:_(<2 x s64>) = G_IMPLICIT_DEF
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%6:_(<4 x s64>) = G_CONCAT_VECTORS %4(<2 x s64>), %5
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RET_ReallyLR implicit %6
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...
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# Same as concat_to_build_vector_with_undef but with pointer types.
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---
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name: concat_to_build_vector_with_undef_ptr
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tracksRegLiveness: true
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body: |
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bb.1:
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liveins: $x0, $x1
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; CHECK-LABEL: name: concat_to_build_vector_with_undef_ptr
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; CHECK: liveins: $x0, $x1
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; CHECK: [[COPY:%[0-9]+]]:_(p0) = COPY $x0
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; CHECK: [[COPY1:%[0-9]+]]:_(p0) = COPY $x1
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; CHECK: [[DEF:%[0-9]+]]:_(p0) = G_IMPLICIT_DEF
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; CHECK: [[BUILD_VECTOR:%[0-9]+]]:_(<4 x p0>) = G_BUILD_VECTOR [[COPY]](p0), [[COPY1]](p0), [[DEF]](p0), [[DEF]](p0)
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; CHECK: RET_ReallyLR implicit [[BUILD_VECTOR]](<4 x p0>)
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%0:_(p0) = COPY $x0
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%1:_(p0) = COPY $x1
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%4:_(<2 x p0>) = G_BUILD_VECTOR %0(p0), %1
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%5:_(<2 x p0>) = G_IMPLICIT_DEF
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%6:_(<4 x p0>) = G_CONCAT_VECTORS %4(<2 x p0>), %5
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RET_ReallyLR implicit %6
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...
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# Check that we keep a concat_vectors as soon as one of the operand is
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# not undef or build_vector. I.e., we cannot flatten the concat_vectors.
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---
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name: concat_to_build_vector_negative_test
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tracksRegLiveness: true
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body: |
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bb.1:
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liveins: $x0, $x1
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; CHECK-LABEL: name: concat_to_build_vector_negative_test
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; CHECK: liveins: $x0, $x1
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; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY $x0
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; CHECK: [[DEF:%[0-9]+]]:_(<2 x s64>) = G_IMPLICIT_DEF
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; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 1
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; CHECK: [[IVEC:%[0-9]+]]:_(<2 x s64>) = G_INSERT_VECTOR_ELT [[DEF]], [[COPY]](s64), [[C]](s32)
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; CHECK: [[DEF1:%[0-9]+]]:_(<2 x s64>) = G_IMPLICIT_DEF
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; CHECK: [[CONCAT_VECTORS:%[0-9]+]]:_(<4 x s64>) = G_CONCAT_VECTORS [[IVEC]](<2 x s64>), [[DEF1]](<2 x s64>)
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; CHECK: RET_ReallyLR implicit [[CONCAT_VECTORS]](<4 x s64>)
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%0:_(s64) = COPY $x0
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%1:_(s64) = COPY $x1
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%2:_(<2 x s64>) = G_IMPLICIT_DEF
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%3:_(s32) = G_CONSTANT i32 1
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%4:_(<2 x s64>) = G_INSERT_VECTOR_ELT %2, %0(s64), %3(s32)
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%5:_(<2 x s64>) = G_IMPLICIT_DEF
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%6:_(<4 x s64>) = G_CONCAT_VECTORS %4(<2 x s64>), %5
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RET_ReallyLR implicit %6
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...
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