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delinearization of arrays

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194527 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sebastian Pop
2013-11-12 22:47:20 +00:00
parent b8fc659c8e
commit 5230ad61fd
20 changed files with 1423 additions and 1 deletions
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55
lib/Analysis/DependenceAnalysis.cpp
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@ -61,6 +61,7 @@
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Operator.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/InstIterator.h"
@ -104,6 +105,10 @@ STATISTIC(BanerjeeApplications, "Banerjee applications");
STATISTIC(BanerjeeIndependence, "Banerjee independence");
STATISTIC(BanerjeeSuccesses, "Banerjee successes");
static cl::opt<bool>
Delinearize("da-delinearize", cl::init(false), cl::Hidden, cl::ZeroOrMore,
cl::desc("Try to delinearize array references."));
//===----------------------------------------------------------------------===//
// basics
@ -3171,6 +3176,44 @@ void DependenceAnalysis::updateDirection(Dependence::DVEntry &Level,
llvm_unreachable("constraint has unexpected kind");
}
/// Check if we can delinearize the subscripts. If the SCEVs representing the
/// source and destination array references are recurrences on a nested loop,
/// this function flattens the nested recurrences into seperate recurrences
/// for each loop level.
bool
DependenceAnalysis::tryDelinearize(const SCEV *SrcSCEV, const SCEV *DstSCEV,
SmallVectorImpl<Subscript> &Pair) const {
const SCEVAddRecExpr *SrcAR = dyn_cast<SCEVAddRecExpr>(SrcSCEV);
const SCEVAddRecExpr *DstAR = dyn_cast<SCEVAddRecExpr>(DstSCEV);
if (!SrcAR || !DstAR || !SrcAR->isAffine() || !DstAR->isAffine())
return false;
SmallVector<const SCEV *, 4> SrcSubscripts, DstSubscripts, SrcSizes, DstSizes;
SrcAR->delinearize(*SE, SrcSubscripts, SrcSizes);
DstAR->delinearize(*SE, DstSubscripts, DstSizes);
int size = SrcSubscripts.size();
int dstSize = DstSubscripts.size();
if (size != dstSize || size < 2)
return false;
#ifndef NDEBUG
DEBUG(errs() << "\nSrcSubscripts: ");
for (int i = 0; i < size; i++)
DEBUG(errs() << *SrcSubscripts[i]);
DEBUG(errs() << "\nDstSubscripts: ");
for (int i = 0; i < size; i++)
DEBUG(errs() << *DstSubscripts[i]);
#endif
Pair.resize(size);
for (int i = 0; i < size; ++i) {
Pair[i].Src = SrcSubscripts[i];
Pair[i].Dst = DstSubscripts[i];
}
return true;
}
//===----------------------------------------------------------------------===//
@ -3280,6 +3323,12 @@ Dependence *DependenceAnalysis::depends(Instruction *Src,
Pair[0].Dst = DstSCEV;
}
if (Delinearize && Pairs == 1 && CommonLevels > 1 &&
tryDelinearize(Pair[0].Src, Pair[0].Dst, Pair)) {
DEBUG(dbgs() << " delinerized GEP\n");
Pairs = Pair.size();
}
for (unsigned P = 0; P < Pairs; ++P) {
Pair[P].Loops.resize(MaxLevels + 1);
Pair[P].GroupLoops.resize(MaxLevels + 1);
@ -3698,6 +3747,12 @@ 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)) {
DEBUG(dbgs() << " delinerized GEP\n");
Pairs = Pair.size();
}
for (unsigned P = 0; P < Pairs; ++P) {
Pair[P].Loops.resize(MaxLevels + 1);
Pair[P].GroupLoops.resize(MaxLevels + 1);