Fix how DependenceAnalysis calls delinearization

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!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245408 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hal Finkel 2015-08-19 02:56:36 +00:00
parent d5369c945d
commit dd7ef64b29
3 changed files with 43 additions and 27 deletions

View File

@ -926,9 +926,8 @@ namespace llvm {
void updateDirection(Dependence::DVEntry &Level,
const Constraint &CurConstraint) const;
bool tryDelinearize(const SCEV *SrcSCEV, const SCEV *DstSCEV,
SmallVectorImpl<Subscript> &Pair,
const SCEV *ElementSize);
bool tryDelinearize(Instruction *Src, Instruction *Dst,
SmallVectorImpl<Subscript> &Pair);
public:
static char ID; // Class identification, replacement for typeinfo

View File

@ -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) {

View File

@ -269,10 +269,10 @@ entry:
; CHECK: da analyze - none!
; DELIN: 'Dependence Analysis' for function 'gcd4'
; DELIN: da analyze - output [* *]!
; DELIN: da analyze - none!
; DELIN: da analyze - none!
; DELIN: da analyze - confused!
; DELIN: da analyze - input [* *]!
; DELIN: da analyze - none!
; DELIN: da analyze - confused!
; DELIN: da analyze - none!
@ -339,10 +339,10 @@ entry:
; CHECK: da analyze - none!
; DELIN: 'Dependence Analysis' for function 'gcd5'
; DELIN: da analyze - output [* *]!
; DELIN: da analyze - flow [<> *]!
; DELIN: da analyze - none!
; DELIN: da analyze - flow [> *]!
; DELIN: da analyze - confused!
; DELIN: da analyze - input [* *]!
; DELIN: da analyze - none!
; DELIN: da analyze - confused!
; DELIN: da analyze - none!
@ -410,10 +410,10 @@ entry:
; CHECK: da analyze - output [* *]!
; DELIN: 'Dependence Analysis' for function 'gcd6'
; DELIN: da analyze - output [* *]!
; DELIN: da analyze - none!
; DELIN: da analyze - none!
; DELIN: da analyze - confused!
; DELIN: da analyze - input [* *]!
; DELIN: da analyze - none!
; DELIN: da analyze - confused!
; DELIN: da analyze - output [* *]!