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Fix how DependenceAnalysis calls delinearization

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Fix how DependenceAnalysis calls delinearization, mirroring what is done in
Delinearization.cpp (mostly by making sure to call getSCEVAtScope before
delinearizing, and by removing the unnecessary 'Pairs == 1' check).

Patch by Vaivaswatha Nagaraj!

llvm-svn: 245408
This commit is contained in:
Hal Finkel
2015-08-19 02:56:36 +00:00
parent 46fc8168c2
commit 0ef2b10f16
3 changed files with 43 additions and 27 deletions
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51
llvm/lib/Analysis/DependenceAnalysis.cpp
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@@ -3245,20 +3245,36 @@ void DependenceAnalysis::updateDirection(Dependence::DVEntry &Level,
/// source and destination array references are recurrences on a nested loop,
/// this function flattens the nested recurrences into separate recurrences
/// for each loop level.
bool DependenceAnalysis::tryDelinearize(const SCEV *SrcSCEV,
const SCEV *DstSCEV,
SmallVectorImpl<Subscript> &Pair,
const SCEV *ElementSize) {
bool DependenceAnalysis::tryDelinearize(Instruction *Src,
Instruction *Dst,
SmallVectorImpl<Subscript> &Pair)
{
Value *SrcPtr = getPointerOperand(Src);
Value *DstPtr = getPointerOperand(Dst);
Loop *SrcLoop = LI->getLoopFor(Src->getParent());
Loop *DstLoop = LI->getLoopFor(Dst->getParent());
// Below code mimics the code in Delinearization.cpp
const SCEV *SrcAccessFn =
SE->getSCEVAtScope(SrcPtr, SrcLoop);
const SCEV *DstAccessFn =
SE->getSCEVAtScope(DstPtr, DstLoop);
const SCEVUnknown *SrcBase =
dyn_cast<SCEVUnknown>(SE->getPointerBase(SrcSCEV));
dyn_cast<SCEVUnknown>(SE->getPointerBase(SrcAccessFn));
const SCEVUnknown *DstBase =
dyn_cast<SCEVUnknown>(SE->getPointerBase(DstSCEV));
dyn_cast<SCEVUnknown>(SE->getPointerBase(DstAccessFn));
if (!SrcBase || !DstBase || SrcBase != DstBase)
return false;
SrcSCEV = SE->getMinusSCEV(SrcSCEV, SrcBase);
DstSCEV = SE->getMinusSCEV(DstSCEV, DstBase);
const SCEV *ElementSize = SE->getElementSize(Src);
if (ElementSize != SE->getElementSize(Dst))
return false;
const SCEV *SrcSCEV = SE->getMinusSCEV(SrcAccessFn, SrcBase);
const SCEV *DstSCEV = SE->getMinusSCEV(DstAccessFn, DstBase);
const SCEVAddRecExpr *SrcAR = dyn_cast<SCEVAddRecExpr>(SrcSCEV);
const SCEVAddRecExpr *DstAR = dyn_cast<SCEVAddRecExpr>(DstSCEV);
@@ -3331,7 +3347,6 @@ static void dumpSmallBitVector(SmallBitVector &BV) {
}
#endif
// depends -
// Returns NULL if there is no dependence.
// Otherwise, return a Dependence with as many details as possible.
@@ -3426,10 +3441,11 @@ DependenceAnalysis::depends(Instruction *Src, Instruction *Dst,
Pair[0].Dst = DstSCEV;
}
if (Delinearize && Pairs == 1 && CommonLevels > 1 &&
tryDelinearize(Pair[0].Src, Pair[0].Dst, Pair, SE->getElementSize(Src))) {
DEBUG(dbgs() << " delinerized GEP\n");
Pairs = Pair.size();
if (Delinearize && CommonLevels > 1) {
if (tryDelinearize(Src, Dst, Pair)) {
DEBUG(dbgs() << " delinerized GEP\n");
Pairs = Pair.size();
}
}
for (unsigned P = 0; P < Pairs; ++P) {
@@ -3851,10 +3867,11 @@ const SCEV *DependenceAnalysis::getSplitIteration(const Dependence &Dep,
Pair[0].Dst = DstSCEV;
}
if (Delinearize && Pairs == 1 && CommonLevels > 1 &&
tryDelinearize(Pair[0].Src, Pair[0].Dst, Pair, SE->getElementSize(Src))) {
DEBUG(dbgs() << " delinerized GEP\n");
Pairs = Pair.size();
if (Delinearize && CommonLevels > 1) {
if (tryDelinearize(Src, Dst, Pair)) {
DEBUG(dbgs() << " delinerized GEP\n");
Pairs = Pair.size();
}
}
for (unsigned P = 0; P < Pairs; ++P) {