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Re-apply 70645, converting ScalarEvolution to use

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CallbackVH, with fixes. allUsesReplacedWith need to
walk the def-use chains and invalidate all users of a
value that is replaced. SCEVs of users need to be
recalcualted even if the new value is equivalent. Also,
make forgetLoopPHIs walk def-use chains, since any
SCEV that depends on a PHI should be recalculated when
more information about that PHI becomes available.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70927 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2009-05-04 22:30:44 +00:00
parent bf2176a000
commit 35738ac150
9 changed files with 157 additions and 182 deletions
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25
lib/Transforms/Scalar/LoopStrengthReduce.cpp
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@@ -253,8 +253,6 @@ void LoopStrengthReduce::DeleteTriviallyDeadInstructions() {
if (I == 0 || !isInstructionTriviallyDead(I))
continue;
SE->deleteValueFromRecords(I);
for (User::op_iterator OI = I->op_begin(), E = I->op_end(); OI != E; ++OI) {
if (Instruction *U = dyn_cast<Instruction>(*OI)) {
*OI = 0;
@@ -2130,7 +2128,6 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
// Remove the old compare instruction. The old indvar is probably dead too.
DeadInsts.push_back(cast<Instruction>(CondUse->OperandValToReplace));
SE->deleteValueFromRecords(OldCond);
OldCond->replaceAllUsesWith(Cond);
OldCond->eraseFromParent();
@@ -2214,7 +2211,7 @@ ICmpInst *LoopStrengthReduce::OptimizeSMax(Loop *L, ICmpInst *Cond,
SCEVHandle IterationCount = SE->getAddExpr(BackedgeTakenCount, One);
// Check for a max calculation that matches the pattern.
SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(IterationCount);
const SCEVSMaxExpr *SMax = dyn_cast<SCEVSMaxExpr>(IterationCount);
if (!SMax || SMax != SE->getSCEV(Sel)) return Cond;
SCEVHandle SMaxLHS = SMax->getOperand(0);
@@ -2251,16 +2248,12 @@ ICmpInst *LoopStrengthReduce::OptimizeSMax(Loop *L, ICmpInst *Cond,
Cond->getOperand(0), NewRHS, "scmp", Cond);
// Delete the max calculation instructions.
SE->deleteValueFromRecords(Cond);
Cond->replaceAllUsesWith(NewCond);
Cond->eraseFromParent();
Instruction *Cmp = cast<Instruction>(Sel->getOperand(0));
SE->deleteValueFromRecords(Sel);
Sel->eraseFromParent();
if (Cmp->use_empty()) {
SE->deleteValueFromRecords(Cmp);
if (Cmp->use_empty())
Cmp->eraseFromParent();
}
CondUse->User = NewCond;
return NewCond;
}
@@ -2367,7 +2360,6 @@ void LoopStrengthReduce::OptimizeShadowIV(Loop *L) {
NewPH->addIncoming(NewIncr, PH->getIncomingBlock(Latch));
/* Remove cast operation */
SE->deleteValueFromRecords(ShadowUse);
ShadowUse->replaceAllUsesWith(NewPH);
ShadowUse->eraseFromParent();
SI->second.Users.erase(CandidateUI);
@@ -2507,17 +2499,8 @@ bool LoopStrengthReduce::runOnLoop(Loop *L, LPPassManager &LPM) {
DeleteTriviallyDeadInstructions();
// At this point, it is worth checking to see if any recurrence PHIs are also
// dead, so that we can remove them as well. To keep ScalarEvolution
// current, use a ValueDeletionListener class.
struct LSRListener : public ValueDeletionListener {
ScalarEvolution &SE;
explicit LSRListener(ScalarEvolution &se) : SE(se) {}
virtual void ValueWillBeDeleted(Value *V) {
SE.deleteValueFromRecords(V);
}
} VDL(*SE);
DeleteDeadPHIs(L->getHeader(), &VDL);
// dead, so that we can remove them as well.
DeleteDeadPHIs(L->getHeader());
return Changed;
}