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[Loop vectorizer] Simplified GEP cloning. NFC. 

Simplified GEP cloning in vectorizeMemoryInstruction().
Added an assertion that checks consecutive GEP, which should have only one loop-variant operand.

Differential Revision: https://reviews.llvm.org/D24557

llvm-svn: 281851
This commit is contained in:
Elena Demikhovsky 2016-09-18 09:22:54 +00:00
parent 05ee64e67a
commit a1a0e7ddbe
1 changed files with 25 additions and 34 deletions
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59
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
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@ -2783,44 +2783,35 @@ void InnerLoopVectorizer::vectorizeMemoryInstruction(Instruction *Instr) {
// Handle consecutive loads/stores.
GetElementPtrInst *Gep = getGEPInstruction(Ptr);
if (ConsecutiveStride) {
if (Gep && Legal->isInductionVariable(Gep->getPointerOperand())) {
setDebugLocFromInst(Builder, Gep);
auto *FirstBasePtr = getScalarValue(Gep->getPointerOperand(), 0, 0);
// Create the new GEP with the new induction variable.
GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
Gep2->setOperand(0, FirstBasePtr);
Gep2->setName("gep.indvar.base");
Ptr = Builder.Insert(Gep2);
} else if (Gep) {
setDebugLocFromInst(Builder, Gep);
assert(PSE.getSE()->isLoopInvariant(PSE.getSCEV(Gep->getPointerOperand()),
OrigLoop) &&
"Base ptr must be invariant");
// The last index does not have to be the induction. It can be
// consecutive and be a function of the index. For example A[I+1];
if (Gep) {
unsigned NumOperands = Gep->getNumOperands();
unsigned InductionOperand = getGEPInductionOperand(Gep);
// Create the new GEP with the new induction variable.
#ifndef NDEBUG
// The original GEP that identified as a consecutive memory access
// should have only one loop-variant operand.
unsigned NumOfLoopVariantOps = 0;
for (unsigned i = 0; i < NumOperands; ++i)
if (!PSE.getSE()->isLoopInvariant(PSE.getSCEV(Gep->getOperand(i)),
OrigLoop))
NumOfLoopVariantOps++;
assert(NumOfLoopVariantOps == 1 &&
"Consecutive GEP should have only one loop-variant operand");
#endif
GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
Gep2->setName("gep.indvar");
for (unsigned i = 0; i < NumOperands; ++i) {
Value *GepOperand = Gep->getOperand(i);
Instruction *GepOperandInst = dyn_cast<Instruction>(GepOperand);
// Update last index or loop invariant instruction anchored in loop.
if (i == InductionOperand ||
(GepOperandInst && OrigLoop->contains(GepOperandInst))) {
assert((i == InductionOperand ||
PSE.getSE()->isLoopInvariant(PSE.getSCEV(GepOperandInst),
OrigLoop)) &&
"Must be last index or loop invariant");
Gep2->setOperand(i, getScalarValue(GepOperand, 0, 0));
Gep2->setName("gep.indvar.idx");
}
}
// A new GEP is created for a 0-lane value of the first unroll iteration.
// The GEPs for the rest of the unroll iterations are computed below as an
// offset from this GEP.
for (unsigned i = 0; i < NumOperands; ++i)
// We can apply getScalarValue() for all GEP indices. It returns an
// original value for loop-invariant operand and 0-lane for consecutive
// operand.
Gep2->setOperand(i, getScalarValue(Gep->getOperand(i),
0, /* First unroll iteration */
0 /* 0-lane of the vector */ ));
setDebugLocFromInst(Builder, Gep);
Ptr = Builder.Insert(Gep2);
} else { // No GEP
// Use the induction element ptr.
assert(isa<PHINode>(Ptr) && "Invalid induction ptr");