diff options
| -rw-r--r-- | lib/Transforms/Scalar/LoopStrengthReduce.cpp | 48 |
1 files changed, 15 insertions, 33 deletions
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 859da1a..7951298 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -97,11 +97,9 @@ namespace { SCEVHandle Stride; SCEVHandle Base; PHINode *PHI; - Value *IncV; - IVExpr(const SCEVHandle &stride, const SCEVHandle &base, PHINode *phi, - Value *incv) - : Stride(stride), Base(base), PHI(phi), IncV(incv) {} + IVExpr(const SCEVHandle &stride, const SCEVHandle &base, PHINode *phi) + : Stride(stride), Base(base), PHI(phi) {} }; /// IVsOfOneStride - This structure keeps track of all IV expression inserted @@ -109,9 +107,8 @@ namespace { struct VISIBILITY_HIDDEN IVsOfOneStride { std::vector<IVExpr> IVs; - void addIV(const SCEVHandle &Stride, const SCEVHandle &Base, PHINode *PHI, - Value *IncV) { - IVs.push_back(IVExpr(Stride, Base, PHI, IncV)); + void addIV(const SCEVHandle &Stride, const SCEVHandle &Base, PHINode *PHI) { + IVs.push_back(IVExpr(Stride, Base, PHI)); } }; @@ -695,10 +692,7 @@ namespace { /// Phi - The induction variable that performs the striding that /// should be used for this user. - Value *Phi; - - /// IncV - The post-incremented value of Phi. - Value *IncV; + PHINode *Phi; // isUseOfPostIncrementedValue - True if this should use the // post-incremented version of this IV, not the preincremented version. @@ -1587,13 +1581,11 @@ bool LoopStrengthReduce::ShouldUseFullStrengthReductionMode( /// If NegateStride is true, the stride should be negated by using a /// subtract instead of an add. /// -/// Return the created phi node, and return the step instruction by -/// reference in IncV. +/// Return the created phi node. /// static PHINode *InsertAffinePhi(SCEVHandle Start, SCEVHandle Step, const Loop *L, - SCEVExpander &Rewriter, - Value *&IncV) { + SCEVExpander &Rewriter) { assert(Start->isLoopInvariant(L) && "New PHI start is not loop invariant!"); assert(Step->isLoopInvariant(L) && "New PHI stride is not loop invariant!"); @@ -1615,6 +1607,7 @@ static PHINode *InsertAffinePhi(SCEVHandle Start, SCEVHandle Step, // Insert an add instruction right before the terminator corresponding // to the back-edge. Value *StepV = Rewriter.expandCodeFor(IncAmount, Preheader->getTerminator()); + Instruction *IncV; if (isNegative) { IncV = BinaryOperator::CreateSub(PN, StepV, "lsr.iv.next", LatchBlock->getTerminator()); @@ -1684,16 +1677,13 @@ LoopStrengthReduce::PrepareToStrengthReduceFully( SCEVHandle Imm = UsersToProcess[i].Imm; SCEVHandle Base = UsersToProcess[i].Base; SCEVHandle Start = SE->getAddExpr(CommonExprs, Base, Imm); - Value *IncV; PHINode *Phi = InsertAffinePhi(Start, Stride, L, - PreheaderRewriter, - IncV); + PreheaderRewriter); // Loop over all the users with the same base. do { UsersToProcess[i].Base = SE->getIntegerSCEV(0, Stride->getType()); UsersToProcess[i].Imm = SE->getMinusSCEV(UsersToProcess[i].Imm, Imm); UsersToProcess[i].Phi = Phi; - UsersToProcess[i].IncV = IncV; assert(UsersToProcess[i].Imm->isLoopInvariant(L) && "ShouldUseFullStrengthReductionMode should reject this!"); } while (++i != e && Base == UsersToProcess[i].Base); @@ -1713,25 +1703,19 @@ LoopStrengthReduce::PrepareToStrengthReduceWithNewPhi( SCEVExpander &PreheaderRewriter) { DOUT << " Inserting new PHI:\n"; - Value *IncV; PHINode *Phi = InsertAffinePhi(SE->getUnknown(CommonBaseV), Stride, L, - PreheaderRewriter, - IncV); + PreheaderRewriter); // Remember this in case a later stride is multiple of this. - IVsByStride[Stride].addIV(Stride, CommonExprs, Phi, IncV); + IVsByStride[Stride].addIV(Stride, CommonExprs, Phi); // All the users will share this new IV. - for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i) { + for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i) UsersToProcess[i].Phi = Phi; - UsersToProcess[i].IncV = IncV; - } DOUT << " IV="; DEBUG(WriteAsOperand(*DOUT, Phi, /*PrintType=*/false)); - DOUT << ", INC="; - DEBUG(WriteAsOperand(*DOUT, IncV, /*PrintType=*/false)); DOUT << "\n"; } @@ -1749,10 +1733,8 @@ LoopStrengthReduce::PrepareToStrengthReduceFromSmallerStride( << " and BASE " << *ReuseIV.Base << "\n"; // All the users will share the reused IV. - for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i) { + for (unsigned i = 0, e = UsersToProcess.size(); i != e; ++i) UsersToProcess[i].Phi = ReuseIV.PHI; - UsersToProcess[i].IncV = ReuseIV.IncV; - } Constant *C = dyn_cast<Constant>(CommonBaseV); if (C && @@ -1884,7 +1866,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride, SCEVHandle RewriteFactor = SE->getIntegerSCEV(0, ReplacedTy); IVExpr ReuseIV(SE->getIntegerSCEV(0, Type::Int32Ty), SE->getIntegerSCEV(0, Type::Int32Ty), - 0, 0); + 0); /// Choose a strength-reduction strategy and prepare for it by creating /// the necessary PHIs and adjusting the bookkeeping. @@ -1957,7 +1939,7 @@ void LoopStrengthReduce::StrengthReduceStridedIVUsers(const SCEVHandle &Stride, // after the post-inc and use its value instead of the PHI. Value *RewriteOp = User.Phi; if (User.isUseOfPostIncrementedValue) { - RewriteOp = User.IncV; + RewriteOp = User.Phi->getIncomingValueForBlock(LatchBlock); // If this user is in the loop, make sure it is the last thing in the // loop to ensure it is dominated by the increment. |