[llvm-commits] [llvm] r55913 - /llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
Devang Patel
dpatel at apple.com
Mon Sep 8 09:13:28 PDT 2008
Author: dpatel
Date: Mon Sep 8 11:13:27 2008
New Revision: 55913
URL: http://llvm.org/viewvc/llvm-project?rev=55913&view=rev
Log:
Remove OptimizeIVType()
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=55913&r1=55912&r2=55913&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Mon Sep 8 11:13:27 2008
@@ -185,10 +185,6 @@
/// inside the loop then try to eliminate the cast opeation.
void OptimizeShadowIV(Loop *L);
- /// OptimizeIVType - If IV is always sext'ed or zext'ed then
- /// change the type of IV, if possible.
- void OptimizeIVType(Loop *L);
-
bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse,
const SCEVHandle *&CondStride);
bool RequiresTypeConversion(const Type *Ty, const Type *NewTy);
@@ -1813,206 +1809,6 @@
}
}
-/// suitableExtInstruction - Helper function used by OptimizeIVType.
-/// If I is a suitable SEXT or ZEXT instruction then return type
-/// to which I is extended to. Otherwise return NULL.
-const Type *suitableExtInstruction(Instruction *I, bool isSigned,
- const Type *ExtType) {
-
- const Type *DestType = NULL;
- if (ZExtInst *ZI = dyn_cast<ZExtInst>(I))
- DestType = ZI->getDestTy();
- else if (SExtInst *SI = dyn_cast<SExtInst>(I)) {
- // If the inital value is signed then this is not suitable for
- // OptimizeIVType transformation.
- if (isSigned)
- return NULL;
- DestType = SI->getDestTy();
- }
-
- if (!DestType) return NULL;
-
- if (!ExtType)
- return DestType;
-
- // If another use of IV extended to some other type then the IV is not
- // suitable for OptimizeIVType transformation.
- if (ExtType != DestType)
- return NULL;
-
- return DestType;
-}
-
-/// suitableIVIncr - Helper function used by OptimizeIVType. If I is
-/// a suitable binary operator whose all uses are either SEXT or ZEXT
-/// then return the type to which all uses are extended to. Otherwise
-/// return NULL.
-const Type *suitableIVIncr(Instruction *I,
- Instruction *PHI, bool isSigned,
- const Type *ExtType) {
-
- BinaryOperator *Incr = dyn_cast<BinaryOperator>(I);
- if (!Incr) return NULL;
-
- if (Incr->getOpcode() != Instruction::Add)
- return NULL;
-
- ConstantInt *C = NULL;
- if (Incr->getOperand(0) == PHI)
- C = dyn_cast<ConstantInt>(Incr->getOperand(1));
- else if (Incr->getOperand(1) == PHI)
- C = dyn_cast<ConstantInt>(Incr->getOperand(0));
-
- if (!C) return NULL;
-
- const Type *RExtType = NULL;
- for (Value::use_iterator IncUI = Incr->use_begin(),
- IncUE = Incr->use_end(); IncUI != IncUE; ++IncUI) {
-
- Instruction *U2 = dyn_cast<Instruction>(*IncUI);
- if (U2 == PHI)
- continue;
- const Type *DestType = suitableExtInstruction(U2, isSigned, ExtType);
- if (!DestType)
- return NULL;
-
- if (!RExtType)
- RExtType = DestType;
-
- if (DestType != RExtType)
- return NULL;
- }
-
- return RExtType;
-
-}
-
-/// getNewPHIIncrement - Create a new increment instruction for newPHI
-/// using type Ty based on increment instruction Incr.
-/// Helper function used by OptimizeIVType.
-BinaryOperator *getNewPHIIncrement(BinaryOperator *Incr, PHINode *PHI,
- PHINode *NewPHI, const Type *Ty) {
- ConstantInt *C = NULL;
- if (Incr->getOperand(0) == PHI)
- C = dyn_cast<ConstantInt>(Incr->getOperand(1));
- else if (Incr->getOperand(1) == PHI)
- C = dyn_cast<ConstantInt>(Incr->getOperand(0));
-
- assert (C && "Unexpected Incr operand!");
- return BinaryOperator::Create(Incr->getOpcode(), NewPHI,
- ConstantInt::get(Ty, C->getZExtValue()),
- "IV.next", Incr);
-}
-
-/// OptimizeIVType - If IV is always sext'ed or zext'ed then
-/// change the type of IV, if possible.
-void LoopStrengthReduce::OptimizeIVType(Loop *L) {
-
- SCEVHandle IterationCount = SE->getIterationCount(L);
- if (isa<SCEVCouldNotCompute>(IterationCount))
- return;
-
- BasicBlock *LPH = L->getLoopPreheader();
- BasicBlock *LatchBB = L->getLoopLatch();
- SmallVector<PHINode *, 4> PHIs;
- for (BasicBlock::iterator BI = L->getHeader()->begin(),
- BE = L->getHeader()->end(); BI != BE; ++BI) {
- if (PHINode *PHI = dyn_cast<PHINode>(BI))
- PHIs.push_back(PHI);
- else
- break;
- }
-
- while(!PHIs.empty()) {
- PHINode *PHI = PHIs.back(); PHIs.pop_back();
- if (PHI->getNumIncomingValues() != 2) continue;
-
- unsigned Entry = 0, Latch = 1;
- if (PHI->getIncomingBlock(0) != LPH) {
- Entry = 1;
- Latch = 0;
- }
-
- ConstantInt *CInit = dyn_cast<ConstantInt>(PHI->getIncomingValue(Entry));
- if (!CInit) return;
- if (!CInit->isZero()) return;
-
- bool signedInit = CInit->getValue().isNegative();
-
- bool TransformPhi = true;
- const Type *ExtType = NULL;
- BinaryOperator *Incr = NULL;
- SmallVector<Instruction *, 4> PHIUses;
-
- // Collect all IV uses.
- for (Value::use_iterator UI = PHI->use_begin(),
- UE = PHI->use_end(); UI != UE; ++UI) {
- Instruction *Use = dyn_cast<Instruction>(*UI);
- if (!Use) {
- TransformPhi = false;
- break;
- }
-
- ExtType = suitableIVIncr(Use, PHI, signedInit, ExtType);
- if (ExtType) {
- Incr = cast<BinaryOperator>(Use);
- continue;
- }
- ExtType = suitableExtInstruction(Use, signedInit, ExtType);
- if (ExtType) {
- PHIUses.push_back(Use);
- continue;
- }
-
- TransformPhi = false;
- break;
- }
-
- if (!TransformPhi || Incr == false || PHIUses.empty())
- continue;
-
- // Apply transformation. Extend IV type and eliminate SEXT or ZEXT
- // instructions.
- NumIVType++;
-
- PHINode *NewPH = PHINode::Create(ExtType, "IV", PHI);
- ConstantInt *NewCInit = ConstantInt::get(ExtType, CInit->getZExtValue());
- BinaryOperator *NewIncr = getNewPHIIncrement(Incr, PHI, NewPH, ExtType);
-
- NewPH->addIncoming(NewCInit, PHI->getIncomingBlock(Entry));
- NewPH->addIncoming(NewIncr, PHI->getIncomingBlock(Latch));
-
- // Replace all SEXT or ZEXT uses with new IV directly.
- while (!PHIUses.empty()) {
- Instruction *Use = PHIUses.back(); PHIUses.pop_back();
- SE->deleteValueFromRecords(Use);
- Use->replaceAllUsesWith(NewPH);
- Use->eraseFromParent();
- }
-
- // Replace all uses of IV increment with new increment.
- SmallVector<Instruction *, 2> IncrUses;
- for (Value::use_iterator UI2 = Incr->use_begin(),
- UE2 = Incr->use_end(); UI2 != UE2; ++UI2)
- IncrUses.push_back(cast<Instruction>(*UI2));
-
- while (!IncrUses.empty()) {
- Instruction *Use = IncrUses.back(); IncrUses.pop_back();
- if (Use == PHI) continue;
- SE->deleteValueFromRecords(Use);
- Use->replaceAllUsesWith(NewIncr);
- Use->eraseFromParent();
- }
-
- // Remove old PHI and increment instruction.
- SE->deleteValueFromRecords(PHI);
- PHI->removeIncomingValue(LatchBB);
- PHI->removeIncomingValue(LPH);
- SE->deleteValueFromRecords(Incr);
- Incr->eraseFromParent();
- }
-}
-
// OptimizeIndvars - Now that IVUsesByStride is set up with all of the indvar
// uses in the loop, look to see if we can eliminate some, in favor of using
// common indvars for the different uses.
@@ -2082,8 +1878,6 @@
UIntPtrTy = TD->getIntPtrType();
Changed = false;
- OptimizeIVType(L);
-
// Find all uses of induction variables in this loop, and catagorize
// them by stride. Start by finding all of the PHI nodes in the header for
// this loop. If they are induction variables, inspect their uses.
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