From 21066541ae22608106fa980bd90f9f6cc7cc8037 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Fri, 15 Aug 2008 08:12:11 +0000 Subject: [PATCH] Revert 54786. It's not checking for overflows, etc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54813 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/LoopStrengthReduce.cpp | 101 ------------------ .../LoopStrengthReduce/2008-08-14-ShadowIV.ll | 27 ----- 2 files changed, 128 deletions(-) diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 37a93e114a0..04faa0aa508 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -45,7 +45,6 @@ STATISTIC(NumReduced , "Number of GEPs strength reduced"); STATISTIC(NumInserted, "Number of PHIs inserted"); STATISTIC(NumVariable, "Number of PHIs with variable strides"); STATISTIC(NumEliminated , "Number of strides eliminated"); -STATISTIC(NumShadow , "Number of Shdow IVs optimized"); namespace { @@ -178,10 +177,6 @@ private: IVStrideUse* &CondUse, const SCEVHandle* &CondStride); void OptimizeIndvars(Loop *L); - - /// OptimizeShadowIV - If IV is used in a int-to-float cast - /// inside the loop then try to eliminate the cast opeation. - void OptimizeShadowIV(Loop *L); bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse, const SCEVHandle *&CondStride); bool RequiresTypeConversion(const Type *Ty, const Type *NewTy); @@ -1694,108 +1689,12 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond, return Cond; } -/// OptimizeShadowIV - If IV is used in a int-to-float cast -/// inside the loop then try to eliminate the cast opeation. -void LoopStrengthReduce::OptimizeShadowIV(Loop *L) { - - for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e; - ++Stride) { - std::map::iterator SI = - IVUsesByStride.find(StrideOrder[Stride]); - assert(SI != IVUsesByStride.end() && "Stride doesn't exist!"); - - for (std::vector::iterator UI = SI->second.Users.begin(), - E = SI->second.Users.end(); UI != E; /* empty */) { - std::vector::iterator CandidateUI = UI; - UI++; - Instruction *ShadowUse = CandidateUI->User; - const Type *DestTy = NULL; - - /* If shadow use is a int->float cast then insert a second IV - to elminate this cast. - - for (unsigned i = 0; i < n; ++i) - foo((double)i); - - is trnasformed into - - double d = 0.0; - for (unsigned i = 0; i < n; ++i, ++d) - foo(d); - */ - UIToFPInst *UCast = dyn_cast(CandidateUI->User); - if (UCast) - DestTy = UCast->getDestTy(); - else { - SIToFPInst *SCast = dyn_cast(CandidateUI->User); - if (!SCast) continue; - DestTy = SCast->getDestTy(); - } - - PHINode *PH = dyn_cast(ShadowUse->getOperand(0)); - if (!PH) continue; - if (PH->getNumIncomingValues() != 2) continue; - - unsigned Entry, Latch; - if (PH->getIncomingBlock(0) == L->getLoopPreheader()) { - Entry = 0; - Latch = 1; - } else { - Entry = 1; - Latch = 0; - } - - ConstantInt *Init = dyn_cast(PH->getIncomingValue(Entry)); - if (!Init) continue; - ConstantFP *NewInit = ConstantFP::get(DestTy, Init->getZExtValue()); - - BinaryOperator *Incr = - dyn_cast(PH->getIncomingValue(Latch)); - if (!Incr) continue; - if (Incr->getOpcode() != Instruction::Add - && Incr->getOpcode() != Instruction::Sub) - continue; - - /* Initialize new IV, double d = 0.0 in above example. */ - ConstantInt *C = NULL; - if (Incr->getOperand(0) == PH) - C = dyn_cast(Incr->getOperand(1)); - else if (Incr->getOperand(1) == PH) - C = dyn_cast(Incr->getOperand(0)); - else - continue; - - if (!C) continue; - - /* create new icnrement. '++d' in above example. */ - ConstantFP *CFP = ConstantFP::get(DestTy, C->getZExtValue()); - BinaryOperator *NewIncr = - BinaryOperator::Create(Incr->getOpcode(), - NewInit, CFP, "IV.S.next.", Incr); - - /* Add new PHINode. */ - PHINode *NewPH = PHINode::Create(DestTy, "IV.S.", PH); - NewPH->addIncoming(NewInit, PH->getIncomingBlock(Entry)); - NewPH->addIncoming(NewIncr, PH->getIncomingBlock(Latch)); - - /* Remove cast operation */ - ShadowUse->replaceAllUsesWith(NewPH); - ShadowUse->eraseFromParent(); - SI->second.Users.erase(CandidateUI); - NumShadow++; - break; - } - } -} - // 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. void LoopStrengthReduce::OptimizeIndvars(Loop *L) { // TODO: implement optzns here. - OptimizeShadowIV(L); - // Finally, get the terminating condition for the loop if possible. If we // can, we want to change it to use a post-incremented version of its // induction variable, to allow coalescing the live ranges for the IV into diff --git a/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll b/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll index 681c9be1675..e69de29bb2d 100644 --- a/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll +++ b/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll @@ -1,27 +0,0 @@ -; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | grep "phi double" - -define void @foobar(i32 %n) nounwind { -entry: - icmp eq i32 %n, 0 ; :0 [#uses=2] - br i1 %0, label %return, label %bb.nph - -bb.nph: ; preds = %entry - %umax = select i1 %0, i32 1, i32 %n ; [#uses=1] - br label %bb - -bb: ; preds = %bb, %bb.nph - %i.03 = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb ] ; [#uses=3] - tail call void @bar( i32 %i.03 ) nounwind - uitofp i32 %i.03 to double ; :1 [#uses=1] - tail call void @foo( double %1 ) nounwind - %indvar.next = add i32 %i.03, 1 ; [#uses=2] - %exitcond = icmp eq i32 %indvar.next, %umax ; [#uses=1] - br i1 %exitcond, label %return, label %bb - -return: ; preds = %bb, %entry - ret void -} - -declare void @bar(i32) - -declare void @foo(double)