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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
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@ -45,7 +45,6 @@ STATISTIC(NumReduced , "Number of GEPs strength reduced");
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STATISTIC(NumInserted, "Number of PHIs inserted");
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STATISTIC(NumVariable, "Number of PHIs with variable strides");
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STATISTIC(NumEliminated , "Number of strides eliminated");
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STATISTIC(NumShadow , "Number of Shdow IVs optimized");
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namespace {
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@ -178,10 +177,6 @@ private:
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IVStrideUse* &CondUse,
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const SCEVHandle* &CondStride);
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void OptimizeIndvars(Loop *L);
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/// OptimizeShadowIV - If IV is used in a int-to-float cast
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/// inside the loop then try to eliminate the cast opeation.
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void OptimizeShadowIV(Loop *L);
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bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse,
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const SCEVHandle *&CondStride);
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bool RequiresTypeConversion(const Type *Ty, const Type *NewTy);
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@ -1694,108 +1689,12 @@ ICmpInst *LoopStrengthReduce::ChangeCompareStride(Loop *L, ICmpInst *Cond,
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return Cond;
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}
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/// OptimizeShadowIV - If IV is used in a int-to-float cast
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/// inside the loop then try to eliminate the cast opeation.
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void LoopStrengthReduce::OptimizeShadowIV(Loop *L) {
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for (unsigned Stride = 0, e = StrideOrder.size(); Stride != e;
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++Stride) {
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std::map<SCEVHandle, IVUsersOfOneStride>::iterator SI =
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IVUsesByStride.find(StrideOrder[Stride]);
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assert(SI != IVUsesByStride.end() && "Stride doesn't exist!");
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for (std::vector<IVStrideUse>::iterator UI = SI->second.Users.begin(),
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E = SI->second.Users.end(); UI != E; /* empty */) {
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std::vector<IVStrideUse>::iterator CandidateUI = UI;
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UI++;
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Instruction *ShadowUse = CandidateUI->User;
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const Type *DestTy = NULL;
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/* If shadow use is a int->float cast then insert a second IV
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to elminate this cast.
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for (unsigned i = 0; i < n; ++i)
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foo((double)i);
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is trnasformed into
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double d = 0.0;
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for (unsigned i = 0; i < n; ++i, ++d)
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foo(d);
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*/
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UIToFPInst *UCast = dyn_cast<UIToFPInst>(CandidateUI->User);
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if (UCast)
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DestTy = UCast->getDestTy();
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else {
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SIToFPInst *SCast = dyn_cast<SIToFPInst>(CandidateUI->User);
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if (!SCast) continue;
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DestTy = SCast->getDestTy();
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}
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PHINode *PH = dyn_cast<PHINode>(ShadowUse->getOperand(0));
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if (!PH) continue;
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if (PH->getNumIncomingValues() != 2) continue;
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unsigned Entry, Latch;
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if (PH->getIncomingBlock(0) == L->getLoopPreheader()) {
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Entry = 0;
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Latch = 1;
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} else {
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Entry = 1;
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Latch = 0;
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}
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ConstantInt *Init = dyn_cast<ConstantInt>(PH->getIncomingValue(Entry));
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if (!Init) continue;
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ConstantFP *NewInit = ConstantFP::get(DestTy, Init->getZExtValue());
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BinaryOperator *Incr =
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dyn_cast<BinaryOperator>(PH->getIncomingValue(Latch));
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if (!Incr) continue;
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if (Incr->getOpcode() != Instruction::Add
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&& Incr->getOpcode() != Instruction::Sub)
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continue;
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/* Initialize new IV, double d = 0.0 in above example. */
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ConstantInt *C = NULL;
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if (Incr->getOperand(0) == PH)
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C = dyn_cast<ConstantInt>(Incr->getOperand(1));
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else if (Incr->getOperand(1) == PH)
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C = dyn_cast<ConstantInt>(Incr->getOperand(0));
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else
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continue;
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if (!C) continue;
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/* create new icnrement. '++d' in above example. */
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ConstantFP *CFP = ConstantFP::get(DestTy, C->getZExtValue());
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BinaryOperator *NewIncr =
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BinaryOperator::Create(Incr->getOpcode(),
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NewInit, CFP, "IV.S.next.", Incr);
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/* Add new PHINode. */
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PHINode *NewPH = PHINode::Create(DestTy, "IV.S.", PH);
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NewPH->addIncoming(NewInit, PH->getIncomingBlock(Entry));
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NewPH->addIncoming(NewIncr, PH->getIncomingBlock(Latch));
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/* Remove cast operation */
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ShadowUse->replaceAllUsesWith(NewPH);
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ShadowUse->eraseFromParent();
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SI->second.Users.erase(CandidateUI);
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NumShadow++;
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break;
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}
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}
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}
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// OptimizeIndvars - Now that IVUsesByStride is set up with all of the indvar
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// uses in the loop, look to see if we can eliminate some, in favor of using
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// common indvars for the different uses.
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void LoopStrengthReduce::OptimizeIndvars(Loop *L) {
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// TODO: implement optzns here.
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OptimizeShadowIV(L);
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// Finally, get the terminating condition for the loop if possible. If we
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// can, we want to change it to use a post-incremented version of its
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// induction variable, to allow coalescing the live ranges for the IV into
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@ -1,27 +0,0 @@
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; RUN: llvm-as < %s | opt -loop-reduce | llvm-dis | grep "phi double"
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define void @foobar(i32 %n) nounwind {
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entry:
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icmp eq i32 %n, 0 ; <i1>:0 [#uses=2]
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br i1 %0, label %return, label %bb.nph
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bb.nph: ; preds = %entry
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%umax = select i1 %0, i32 1, i32 %n ; <i32> [#uses=1]
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br label %bb
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bb: ; preds = %bb, %bb.nph
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%i.03 = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb ] ; <i32> [#uses=3]
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tail call void @bar( i32 %i.03 ) nounwind
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uitofp i32 %i.03 to double ; <double>:1 [#uses=1]
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tail call void @foo( double %1 ) nounwind
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%indvar.next = add i32 %i.03, 1 ; <i32> [#uses=2]
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%exitcond = icmp eq i32 %indvar.next, %umax ; <i1> [#uses=1]
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br i1 %exitcond, label %return, label %bb
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return: ; preds = %bb, %entry
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ret void
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}
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declare void @bar(i32)
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declare void @foo(double)
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