diff options
| -rw-r--r-- | lib/Transforms/Scalar/LoopStrengthReduce.cpp | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index dc1dc18b89..75a681d98e 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -26,6 +26,7 @@ #include "llvm/Analysis/ScalarEvolutionExpander.h" #include "llvm/Support/CFG.h" #include "llvm/Support/GetElementPtrTypeIterator.h" +#include "llvm/Transforms/Utils/BasicBlockUtils.h" #include "llvm/Transforms/Utils/Local.h" #include "llvm/Target/TargetData.h" #include "llvm/ADT/Statistic.h" @@ -391,7 +392,7 @@ namespace { // operands of Inst to use the new expression 'NewBase', with 'Imm' added // to it. void RewriteInstructionToUseNewBase(const SCEVHandle &NewBase, - SCEVExpander &Rewriter); + SCEVExpander &Rewriter, Pass *P); // Sort by the Base field. bool operator<(const BasedUser &BU) const { return Base < BU.Base; } @@ -413,12 +414,12 @@ void BasedUser::dump() const { // operands of Inst to use the new expression 'NewBase', with 'Imm' added // to it. void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase, - SCEVExpander &Rewriter) { + SCEVExpander &Rewriter, + Pass *P) { if (!isa<PHINode>(Inst)) { SCEVHandle NewValSCEV = SCEVAddExpr::get(NewBase, Imm); Value *NewVal = Rewriter.expandCodeFor(NewValSCEV, Inst, OperandValToReplace->getType()); - // Replace the use of the operand Value with the new Phi we just created. Inst->replaceUsesOfWith(OperandValToReplace, NewVal); DEBUG(std::cerr << " CHANGED: IMM =" << *Imm << " Inst = " << *Inst); @@ -434,7 +435,19 @@ void BasedUser::RewriteInstructionToUseNewBase(const SCEVHandle &NewBase, PHINode *PN = cast<PHINode>(Inst); for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) { if (PN->getIncomingValue(i) == OperandValToReplace) { - // FIXME: this should split any critical edges. + // If this is a critical edge, split the edge so that we do not insert the + // code on all predecessor/successor paths. + if (e != 1 && + PN->getIncomingBlock(i)->getTerminator()->getNumSuccessors() > 1) { + TerminatorInst *PredTI = PN->getIncomingBlock(i)->getTerminator(); + for (unsigned Succ = 0; ; ++Succ) { + assert(Succ != PredTI->getNumSuccessors() &&"Didn't find successor?"); + if (PredTI->getSuccessor(Succ) == PN->getParent()) { + SplitCriticalEdge(PredTI, Succ, P); + break; + } + } + } Value *&Code = InsertedCode[PN->getIncomingBlock(i)]; if (!Code) { @@ -623,7 +636,7 @@ RemoveCommonExpressionsFromUseBases(std::vector<BasedUser> &Uses) { for (unsigned j = 0, e = AE->getNumOperands(); j != e; ++j) if (!SubExpressionUseCounts.count(AE->getOperand(j))) NewOps.push_back(AE->getOperand(j)); - if (NewOps.size() == 0) + if (NewOps.empty()) Uses[i].Base = Zero; else Uses[i].Base = SCEVAddExpr::get(NewOps); @@ -783,7 +796,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride, // Add BaseV to the PHI value if needed. RewriteExpr = SCEVAddExpr::get(RewriteExpr, SCEVUnknown::get(BaseV)); - User.RewriteInstructionToUseNewBase(RewriteExpr, Rewriter); + User.RewriteInstructionToUseNewBase(RewriteExpr, Rewriter, this); // Mark old value we replaced as possibly dead, so that it is elminated // if we just replaced the last use of that value. |