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[ARM] Use matchSimpleRecurrence to simplify some code in MVEGatherScatterLowering. NFCI

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Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D105262
This commit is contained in:
Craig Topper 2021-07-08 11:42:53 -07:00
parent ffb982ed74
commit c852776479
1 changed files with 12 additions and 20 deletions
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32
lib/Target/ARM/MVEGatherScatterLowering.cpp
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@ -17,6 +17,7 @@
#include "ARMSubtarget.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
@ -972,30 +973,18 @@ bool MVEGatherScatterLowering::optimiseOffsets(Value *Offsets, BasicBlock *BB,
}
}
// A phi node we want to perform this function on should be from the
// loop header, and shouldn't have more than 2 incoming values
if (Phi->getParent() != L->getHeader() ||
Phi->getNumIncomingValues() != 2)
// loop header.
if (Phi->getParent() != L->getHeader())
return false;
// The phi must be an induction variable
int IncrementingBlock = -1;
for (int i = 0; i < 2; i++)
if (auto *Op = dyn_cast<Instruction>(Phi->getIncomingValue(i)))
if (Op->getOpcode() == Instruction::Add &&
(Op->getOperand(0) == Phi || Op->getOperand(1) == Phi))
IncrementingBlock = i;
if (IncrementingBlock == -1)
// We're looking for a simple add recurrence.
BinaryOperator *IncInstruction;
Value *Start, *IncrementPerRound;
if (!matchSimpleRecurrence(Phi, IncInstruction, Start, IncrementPerRound) ||
IncInstruction->getOpcode() != Instruction::Add)
return false;
Instruction *IncInstruction =
cast<Instruction>(Phi->getIncomingValue(IncrementingBlock));
// If the phi is not used by anything else, we can just adapt it when
// replacing the instruction; if it is, we'll have to duplicate it
PHINode *NewPhi;
Value *IncrementPerRound = IncInstruction->getOperand(
(IncInstruction->getOperand(0) == Phi) ? 1 : 0);
int IncrementingBlock = Phi->getIncomingValue(0) == IncInstruction ? 0 : 1;
// Get the value that is added to/multiplied with the phi
Value *OffsSecondOperand = Offs->getOperand(OffsSecondOp);
@ -1012,6 +1001,9 @@ bool MVEGatherScatterLowering::optimiseOffsets(Value *Offsets, BasicBlock *BB,
!L->contains(cast<Instruction>(IncrementPerRound))))
return false;
// If the phi is not used by anything else, we can just adapt it when
// replacing the instruction; if it is, we'll have to duplicate it
PHINode *NewPhi;
if (Phi->getNumUses() == 2) {
// No other users -> reuse existing phi (One user is the instruction
// we're looking at, the other is the phi increment)