forked from OSchip/llvm-project
first half of a pass through IndVarSimplify::HandleFloatingPointIV,
this cleans up a bunch of code and also fixes several crashes and miscompiles. More to come unfortunately, this optimization is quite broken. llvm-svn: 100270
This commit is contained in:
Chris Lattner
parent
2e23e5284c
commit
c558b49f14
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@ -625,10 +625,10 @@ void IndVarSimplify::SinkUnusedInvariants(Loop *L) {
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/// Return true if it is OK to use SIToFPInst for an induction variable
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/// with given initial and exit values.
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static bool useSIToFPInst(ConstantFP &InitV, ConstantFP &ExitV,
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static bool useSIToFPInst(ConstantFP *InitV, ConstantFP *ExitV,
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uint64_t intIV, uint64_t intEV) {
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if (InitV.getValueAPF().isNegative() || ExitV.getValueAPF().isNegative())
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if (InitV->getValueAPF().isNegative() || ExitV->getValueAPF().isNegative())
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return true;
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// If the iteration range can be handled by SIToFPInst then use it.
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@ -640,19 +640,16 @@ static bool useSIToFPInst(ConstantFP &InitV, ConstantFP &ExitV,
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}
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/// convertToInt - Convert APF to an integer, if possible.
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static bool convertToInt(const APFloat &APF, uint64_t *intVal) {
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static bool convertToInt(const APFloat &APF, uint64_t &intVal) {
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bool isExact = false;
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if (&APF.getSemantics() == &APFloat::PPCDoubleDouble)
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return false;
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if (APF.convertToInteger(intVal, 32, APF.isNegative(),
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APFloat::rmTowardZero, &isExact)
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!= APFloat::opOK)
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if (APF.convertToInteger(&intVal, 32, APF.isNegative(),
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APFloat::rmTowardZero, &isExact) != APFloat::opOK)
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return false;
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if (!isExact)
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return false;
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return true;
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}
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/// HandleFloatingPointIV - If the loop has floating induction variable
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@ -665,64 +662,53 @@ static bool convertToInt(const APFloat &APF, uint64_t *intVal) {
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/// bar((double)i);
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///
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void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH) {
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unsigned IncomingEdge = L->contains(PH->getIncomingBlock(0));
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unsigned BackEdge = IncomingEdge^1;
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// Check incoming value.
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ConstantFP *InitValue = dyn_cast<ConstantFP>(PH->getIncomingValue(IncomingEdge));
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ConstantFP *InitValue =
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dyn_cast<ConstantFP>(PH->getIncomingValue(IncomingEdge));
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if (!InitValue) return;
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uint64_t newInitValue =
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Type::getInt32Ty(PH->getContext())->getPrimitiveSizeInBits();
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if (!convertToInt(InitValue->getValueAPF(), &newInitValue))
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uint64_t newInitValue;
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if (!convertToInt(InitValue->getValueAPF(), newInitValue))
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return;
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// Check IV increment. Reject this PH if increment operation is not
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// an add or increment value can not be represented by an integer.
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BinaryOperator *Incr =
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dyn_cast<BinaryOperator>(PH->getIncomingValue(BackEdge));
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if (!Incr) return;
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if (Incr->getOpcode() != Instruction::FAdd) return;
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ConstantFP *IncrValue = NULL;
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unsigned IncrVIndex = 1;
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if (Incr->getOperand(1) == PH)
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IncrVIndex = 0;
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IncrValue = dyn_cast<ConstantFP>(Incr->getOperand(IncrVIndex));
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if (!IncrValue) return;
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uint64_t newIncrValue =
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Type::getInt32Ty(PH->getContext())->getPrimitiveSizeInBits();
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if (!convertToInt(IncrValue->getValueAPF(), &newIncrValue))
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if (Incr == 0 || Incr->getOpcode() != Instruction::FAdd) return;
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// If this is not an add of the PHI with a constantfp, or if the constant fp
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// is not an integer, bail out.
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ConstantFP *IncrValue = dyn_cast<ConstantFP>(Incr->getOperand(1));
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uint64_t newIncrValue;
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if (IncrValue == 0 || Incr->getOperand(0) != PH ||
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!convertToInt(IncrValue->getValueAPF(), newIncrValue))
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return;
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// Check Incr uses. One user is PH and the other users is exit condition used
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// by the conditional terminator.
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// Check Incr uses. One user is PH and the other user is an exit condition
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// used by the conditional terminator.
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Value::use_iterator IncrUse = Incr->use_begin();
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Instruction *U1 = cast<Instruction>(IncrUse++);
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if (IncrUse == Incr->use_end()) return;
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Instruction *U2 = cast<Instruction>(IncrUse++);
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if (IncrUse != Incr->use_end()) return;
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// Find exit condition.
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// Find exit condition, which is an fcmp. If it doesn't exist, or if it isn't
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// only used by a branch, we can't transform it.
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FCmpInst *EC = dyn_cast<FCmpInst>(U1);
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if (!EC)
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EC = dyn_cast<FCmpInst>(U2);
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if (!EC) return;
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if (EC == 0 || !EC->hasOneUse() || !isa<BranchInst>(EC->use_back()))
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return;
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if (BranchInst *BI = dyn_cast<BranchInst>(EC->getParent()->getTerminator())) {
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if (!BI->isConditional()) return;
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if (BI->getCondition() != EC) return;
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}
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// Find exit value. If exit value can not be represented as an integer then
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// do not handle this floating point PH.
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ConstantFP *EV = NULL;
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unsigned EVIndex = 1;
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if (EC->getOperand(1) == Incr)
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EVIndex = 0;
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EV = dyn_cast<ConstantFP>(EC->getOperand(EVIndex));
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if (!EV) return;
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uint64_t intEV = Type::getInt32Ty(PH->getContext())->getPrimitiveSizeInBits();
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if (!convertToInt(EV->getValueAPF(), &intEV))
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// If it isn't a comparison with an integer-as-fp (the exit value), we can't
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// transform it.
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ConstantFP *ExitValueVal = dyn_cast<ConstantFP>(EC->getOperand(1));
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uint64_t ExitValue;
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if (ExitValueVal == 0 || !convertToInt(ExitValueVal->getValueAPF(),ExitValue))
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return;
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// Find new predicate for integer comparison.
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@ -769,9 +755,11 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH) {
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// The back edge is edge 1 of newPHI, whatever it may have been in the
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// original PHI.
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ConstantInt *NewEV = ConstantInt::get(Type::getInt32Ty(PH->getContext()),
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intEV);
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Value *LHS = (EVIndex == 1 ? NewPHI->getIncomingValue(1) : NewEV);
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Value *RHS = (EVIndex == 1 ? NewEV : NewPHI->getIncomingValue(1));
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ExitValue);
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// FIXME: This is probably wrong.
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Value *LHS = NewPHI->getIncomingValue(1);
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Value *RHS = NewEV;
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ICmpInst *NewEC = new ICmpInst(EC->getParent()->getTerminator(),
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NewPred, LHS, RHS, EC->getName());
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@ -792,7 +780,7 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH) {
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// Give SIToFPInst preference over UIToFPInst because it is faster on
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// platforms that are widely used.
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if (WeakPH && !PH->use_empty()) {
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if (useSIToFPInst(*InitValue, *EV, newInitValue, intEV)) {
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if (useSIToFPInst(InitValue, ExitValueVal, newInitValue, ExitValue)) {
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SIToFPInst *Conv = new SIToFPInst(NewPHI, PH->getType(), "indvar.conv",
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PH->getParent()->getFirstNonPHI());
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PH->replaceAllUsesWith(Conv);
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@ -0,0 +1,19 @@
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; RUN: opt -indvars %s -disable-output
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declare i32 @putchar(i8) nounwind
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define void @t2(i1* %P) nounwind {
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; <label>:0
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br label %1
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; <label>:1 ; preds = %1, %0
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%2 = phi double [ 9.000000e+00, %0 ], [ %4, %1 ] ; <double> [#uses=1]
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%3 = tail call i32 @putchar(i8 72) ; <i32> [#uses=0]
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%4 = fadd double %2, -1.000000e+00 ; <double> [#uses=2]
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%5 = fcmp ult double %4, 0.000000e+00 ; <i1> [#uses=1]
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store i1 %5, i1* %P
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br i1 %5, label %6, label %1
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; <label>:6 ; preds = %1
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ret void
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}
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