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[GlobalISel][AArch64] Gardening: Factor out vector inserts 

Factor out the vector insert code in `selectBuildVector`. Replace part of it
with `emitScalarToVector`, since it was pretty much equivalent.

This will make implementing G_INSERT_VECTOR_ELT easier.

Differential Revision: https://reviews.llvm.org/D59322

llvm-svn: 356106
This commit is contained in:
Jessica Paquette 2019-03-13 23:22:23 +00:00
parent 42bc1e241c
commit 16d67a3e32
1 changed files with 47 additions and 33 deletions
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80
llvm/lib/Target/AArch64/AArch64InstructionSelector.cpp
View File

@ -71,6 +71,17 @@ private:
const TargetRegisterClass *DstRC,
unsigned Scalar,
MachineIRBuilder &MIRBuilder) const;
/// Emit a lane insert into \p DstReg, or a new vector register if None is
/// provided.
///
/// The lane inserted into is defined by \p LaneIdx. The vector source
/// register is given by \p SrcReg. The register containing the element is
/// given by \p EltReg.
MachineInstr *emitLaneInsert(Optional<unsigned> DstReg, unsigned SrcReg,
unsigned EltReg, unsigned LaneIdx,
const RegisterBank &RB,
MachineIRBuilder &MIRBuilder) const;
bool selectBuildVector(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectMergeValues(MachineInstr &I, MachineRegisterInfo &MRI) const;
bool selectUnmergeValues(MachineInstr &I, MachineRegisterInfo &MRI) const;
@ -2304,6 +2315,37 @@ bool AArch64InstructionSelector::selectShuffleVector(
return true;
}
MachineInstr *AArch64InstructionSelector::emitLaneInsert(
Optional<unsigned> DstReg, unsigned SrcReg, unsigned EltReg,
unsigned LaneIdx, const RegisterBank &RB,
MachineIRBuilder &MIRBuilder) const {
MachineInstr *InsElt = nullptr;
const TargetRegisterClass *DstRC = &AArch64::FPR128RegClass;
MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
// Create a register to define with the insert if one wasn't passed in.
if (!DstReg)
DstReg = MRI.createVirtualRegister(DstRC);
unsigned EltSize = MRI.getType(EltReg).getSizeInBits();
unsigned Opc = getInsertVecEltOpInfo(RB, EltSize).first;
if (RB.getID() == AArch64::FPRRegBankID) {
auto InsSub = emitScalarToVector(EltSize, DstRC, EltReg, MIRBuilder);
InsElt = MIRBuilder.buildInstr(Opc, {*DstReg}, {SrcReg})
.addImm(LaneIdx)
.addUse(InsSub->getOperand(0).getReg())
.addImm(0);
} else {
InsElt = MIRBuilder.buildInstr(Opc, {*DstReg}, {SrcReg})
.addImm(LaneIdx)
.addUse(EltReg);
}
constrainSelectedInstRegOperands(*InsElt, TII, TRI, RBI);
return InsElt;
}
bool AArch64InstructionSelector::selectBuildVector(
MachineInstr &I, MachineRegisterInfo &MRI) const {
assert(I.getOpcode() == TargetOpcode::G_BUILD_VECTOR);
@ -2315,11 +2357,6 @@ bool AArch64InstructionSelector::selectBuildVector(
if (EltSize < 16 || EltSize > 64)
return false; // Don't support all element types yet.
const RegisterBank &RB = *RBI.getRegBank(I.getOperand(1).getReg(), MRI, TRI);
unsigned Opc;
unsigned SubregIdx;
std::tie(Opc, SubregIdx) = getInsertVecEltOpInfo(RB, EltSize);
MachineIRBuilder MIRBuilder(I);
const TargetRegisterClass *DstRC = &AArch64::FPR128RegClass;
@ -2336,34 +2373,11 @@ bool AArch64InstructionSelector::selectBuildVector(
// a copy using it.
MachineInstr *PrevMI = nullptr;
for (unsigned i = 2, e = DstSize / EltSize + 1; i < e; ++i) {
// Note that if we don't do a subregister copy, we end up making one more
// of these than we need.
unsigned InsDef = MRI.createVirtualRegister(DstRC);
unsigned LaneIdx = i - 1;
if (RB.getID() == AArch64::FPRRegBankID) {
auto ImpDef =
MIRBuilder.buildInstr(TargetOpcode::IMPLICIT_DEF, {DstRC}, {});
auto InsSub = MIRBuilder
.buildInstr(TargetOpcode::INSERT_SUBREG, {DstRC},
{ImpDef, I.getOperand(i)})
.addImm(SubregIdx);
auto InsElt = MIRBuilder.buildInstr(Opc, {InsDef}, {DstVec})
.addImm(LaneIdx)
.addUse(InsSub.getReg(0))
.addImm(0);
constrainSelectedInstRegOperands(*ImpDef, TII, TRI, RBI);
constrainSelectedInstRegOperands(*InsSub, TII, TRI, RBI);
constrainSelectedInstRegOperands(*InsElt, TII, TRI, RBI);
DstVec = InsDef;
PrevMI = &*InsElt;
} else {
auto Ins = MIRBuilder.buildInstr(Opc, {InsDef}, {DstVec})
.addImm(LaneIdx)
.addUse(I.getOperand(i).getReg());
constrainSelectedInstRegOperands(*Ins, TII, TRI, RBI);
DstVec = InsDef;
PrevMI = &*Ins;
}
// Note that if we don't do a subregister copy, we can end up making an
// extra register.
PrevMI = &*emitLaneInsert(None, DstVec, I.getOperand(i).getReg(), i - 1, RB,
MIRBuilder);
DstVec = PrevMI->getOperand(0).getReg();
}
// If DstTy's size in bits is less than 128, then emit a subregister copy