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Speculatively revert r112433.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112608 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-08-31 17:56:47 +00:00
parent 19dc7faf25
commit f3bba4c1ae
1 changed files with 21 additions and 24 deletions
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45
lib/Analysis/ScalarEvolution.cpp
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@ -1886,30 +1886,27 @@ const SCEV *ScalarEvolution::getMulExpr(SmallVectorImpl<const SCEV *> &Ops,
// there are multiple AddRec's with the same loop induction variable being
// multiplied together. If so, we can fold them.
for (unsigned OtherIdx = Idx+1;
OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
++OtherIdx)
if (AddRecLoop == cast<SCEVAddRecExpr>(Ops[OtherIdx])->getLoop()) {
// F * G, where F = {A,+,B}<L> and G = {C,+,D}<L> -->
// {A*C,+,F*D + G*B + B*D}<L>
for (; OtherIdx != Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);
++OtherIdx)
if (const SCEVAddRecExpr *OtherAddRec =
dyn_cast<SCEVAddRecExpr>(Ops[OtherIdx]))
if (OtherAddRec->getLoop() == AddRecLoop) {
const SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
const SCEV *NewStart = getMulExpr(F->getStart(), G->getStart());
const SCEV *B = F->getStepRecurrence(*this);
const SCEV *D = G->getStepRecurrence(*this);
const SCEV *NewStep = getAddExpr(getMulExpr(F, D),
getMulExpr(G, B),
getMulExpr(B, D));
const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
F->getLoop());
if (Ops.size() == 2) return NewAddRec;
Ops[Idx] = AddRec = cast<SCEVAddRecExpr>(NewAddRec);
Ops.erase(Ops.begin() + OtherIdx); --OtherIdx;
}
return getMulExpr(Ops);
OtherIdx < Ops.size() && isa<SCEVAddRecExpr>(Ops[OtherIdx]);++OtherIdx)
if (OtherIdx != Idx) {
const SCEVAddRecExpr *OtherAddRec = cast<SCEVAddRecExpr>(Ops[OtherIdx]);
if (AddRecLoop == OtherAddRec->getLoop()) {
// F * G --> {A,+,B} * {C,+,D} --> {A*C,+,F*D + G*B + B*D}
const SCEVAddRecExpr *F = AddRec, *G = OtherAddRec;
const SCEV *NewStart = getMulExpr(F->getStart(), G->getStart());
const SCEV *B = F->getStepRecurrence(*this);
const SCEV *D = G->getStepRecurrence(*this);
const SCEV *NewStep = getAddExpr(getMulExpr(F, D),
getMulExpr(G, B),
getMulExpr(B, D));
const SCEV *NewAddRec = getAddRecExpr(NewStart, NewStep,
F->getLoop());
if (Ops.size() == 2) return NewAddRec;
Ops.erase(Ops.begin()+Idx);
Ops.erase(Ops.begin()+OtherIdx-1);
Ops.push_back(NewAddRec);
return getMulExpr(Ops);
}
}
// Otherwise couldn't fold anything into this recurrence. Move onto the