[llvm-commits] [llvm] r54813 - in /llvm/trunk: lib/Transforms/Scalar/LoopStrengthReduce.cpp test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll
Evan Cheng
evan.cheng at apple.com
Fri Aug 15 01:12:13 PDT 2008
Author: evancheng
Date: Fri Aug 15 03:12:11 2008
New Revision: 54813
URL: http://llvm.org/viewvc/llvm-project?rev=54813&view=rev
Log:
Revert 54786. It's not checking for overflows, etc.
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll
Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=54813&r1=54812&r2=54813&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Fri Aug 15 03:12:11 2008
@@ -45,7 +45,6 @@
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 @@
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 @@
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<SCEVHandle, IVUsersOfOneStride>::iterator SI =
- IVUsesByStride.find(StrideOrder[Stride]);
- assert(SI != IVUsesByStride.end() && "Stride doesn't exist!");
-
- for (std::vector<IVStrideUse>::iterator UI = SI->second.Users.begin(),
- E = SI->second.Users.end(); UI != E; /* empty */) {
- std::vector<IVStrideUse>::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<UIToFPInst>(CandidateUI->User);
- if (UCast)
- DestTy = UCast->getDestTy();
- else {
- SIToFPInst *SCast = dyn_cast<SIToFPInst>(CandidateUI->User);
- if (!SCast) continue;
- DestTy = SCast->getDestTy();
- }
-
- PHINode *PH = dyn_cast<PHINode>(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<ConstantInt>(PH->getIncomingValue(Entry));
- if (!Init) continue;
- ConstantFP *NewInit = ConstantFP::get(DestTy, Init->getZExtValue());
-
- BinaryOperator *Incr =
- dyn_cast<BinaryOperator>(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<ConstantInt>(Incr->getOperand(1));
- else if (Incr->getOperand(1) == PH)
- C = dyn_cast<ConstantInt>(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
Modified: llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll?rev=54813&r1=54812&r2=54813&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll (original)
+++ llvm/trunk/test/Transforms/LoopStrengthReduce/2008-08-14-ShadowIV.ll Fri Aug 15 03:12:11 2008
@@ -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 ; <i1>:0 [#uses=2]
- br i1 %0, label %return, label %bb.nph
-
-bb.nph: ; preds = %entry
- %umax = select i1 %0, i32 1, i32 %n ; <i32> [#uses=1]
- br label %bb
-
-bb: ; preds = %bb, %bb.nph
- %i.03 = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb ] ; <i32> [#uses=3]
- tail call void @bar( i32 %i.03 ) nounwind
- uitofp i32 %i.03 to double ; <double>:1 [#uses=1]
- tail call void @foo( double %1 ) nounwind
- %indvar.next = add i32 %i.03, 1 ; <i32> [#uses=2]
- %exitcond = icmp eq i32 %indvar.next, %umax ; <i1> [#uses=1]
- br i1 %exitcond, label %return, label %bb
-
-return: ; preds = %bb, %entry
- ret void
-}
-
-declare void @bar(i32)
-
-declare void @foo(double)
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