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While handling floating point IVs lift restrictions on initial value and increment value.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59471 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2008-11-17 23:27:13 +00:00
parent 84e3515974
commit cd40233429
2 changed files with 91 additions and 26 deletions
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67
lib/Transforms/Scalar/IndVarSimplify.cpp
View File

@ -446,7 +446,6 @@ bool IndVarSimplify::doInitialization(Loop *L, LPPassManager &LPM) {
bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
LI = &getAnalysis<LoopInfo>();
SE = &getAnalysis<ScalarEvolution>();
@ -723,6 +722,19 @@ void IndVarSimplify::OptimizeCanonicalIVType(Loop *L) {
Incr->eraseFromParent();
}
static bool convertToInt(const APFloat &APF, uint64_t *intVal) {
bool isExact = false;
if (APF.convertToInteger(intVal, 32, APF.isNegative(),
APFloat::rmTowardZero, &isExact)
!= APFloat::opOK)
return false;
if (!isExact)
return false;
return true;
}
/// HandleFloatingPointIV - If the loop has floating induction variable
/// then insert corresponding integer induction variable if possible.
/// For example,
@ -739,12 +751,14 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH,
unsigned BackEdge = IncomingEdge^1;
// Check incoming value.
ConstantFP *CZ = dyn_cast<ConstantFP>(PH->getIncomingValue(IncomingEdge));
if (!CZ) return;
APFloat PHInit = CZ->getValueAPF();
if (!PHInit.isPosZero()) return;
// Check IV increment.
ConstantFP *InitValue = dyn_cast<ConstantFP>(PH->getIncomingValue(IncomingEdge));
if (!InitValue) return;
uint64_t newInitValue = Type::Int32Ty->getPrimitiveSizeInBits();
if (!convertToInt(InitValue->getValueAPF(), &newInitValue))
return;
// Check IV increment. Reject this PH if increement operation is not
// an add or increment value can not be represented by an integer.
BinaryOperator *Incr =
dyn_cast<BinaryOperator>(PH->getIncomingValue(BackEdge));
if (!Incr) return;
@ -755,11 +769,12 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH,
IncrVIndex = 0;
IncrValue = dyn_cast<ConstantFP>(Incr->getOperand(IncrVIndex));
if (!IncrValue) return;
APFloat IVAPF = IncrValue->getValueAPF();
APFloat One = APFloat(IVAPF.getSemantics(), 1);
if (!IVAPF.bitwiseIsEqual(One)) return;
uint64_t newIncrValue = Type::Int32Ty->getPrimitiveSizeInBits();
if (!convertToInt(IncrValue->getValueAPF(), &newIncrValue))
return;
// Check Incr uses.
// Check Incr uses. One user is PH and the other users is exit condition used
// by the conditional terminator.
Value::use_iterator IncrUse = Incr->use_begin();
Instruction *U1 = cast<Instruction>(IncrUse++);
if (IncrUse == Incr->use_end()) return;
@ -777,23 +792,17 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH,
if (BI->getCondition() != EC) return;
}
// Find exit value.
// Find exit value. If exit value can not be represented as an interger then
// do not handle this floating point PH.
ConstantFP *EV = NULL;
unsigned EVIndex = 1;
if (EC->getOperand(1) == Incr)
EVIndex = 0;
EV = dyn_cast<ConstantFP>(EC->getOperand(EVIndex));
if (!EV) return;
APFloat EVAPF = EV->getValueAPF();
if (EVAPF.isNegative()) return;
// Find corresponding integer exit value.
uint64_t intEV = Type::Int32Ty->getPrimitiveSizeInBits();
bool isExact = false;
if (EVAPF.convertToInteger(&intEV, 32, false, APFloat::rmTowardZero, &isExact)
!= APFloat::opOK)
if (!convertToInt(EV->getValueAPF(), &intEV))
return;
if (!isExact) return;
// Find new predicate for integer comparison.
CmpInst::Predicate NewPred = CmpInst::BAD_ICMP_PREDICATE;
@ -826,11 +835,12 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH,
// Insert new integer induction variable.
PHINode *NewPHI = PHINode::Create(Type::Int32Ty,
PH->getName()+".int", PH);
NewPHI->addIncoming(Constant::getNullValue(NewPHI->getType()),
NewPHI->addIncoming(ConstantInt::get(Type::Int32Ty, newInitValue),
PH->getIncomingBlock(IncomingEdge));
Value *NewAdd = BinaryOperator::CreateAdd(NewPHI,
ConstantInt::get(Type::Int32Ty, 1),
ConstantInt::get(Type::Int32Ty,
newIncrValue),
Incr->getName()+".int", Incr);
NewPHI->addIncoming(NewAdd, PH->getIncomingBlock(BackEdge));
@ -849,9 +859,16 @@ void IndVarSimplify::HandleFloatingPointIV(Loop *L, PHINode *PH,
DeadInsts.insert(Incr);
// Replace floating induction variable.
UIToFPInst *Conv = new UIToFPInst(NewPHI, PH->getType(), "indvar.conv",
PH->getParent()->getFirstNonPHI());
PH->replaceAllUsesWith(Conv);
if (EV->getValueAPF().isNegative()
|| InitValue->getValueAPF().isNegative()) {
SIToFPInst *Conv = new SIToFPInst(NewPHI, PH->getType(), "indvar.conv",
PH->getParent()->getFirstNonPHI());
PH->replaceAllUsesWith(Conv);
} else {
UIToFPInst *Conv = new UIToFPInst(NewPHI, PH->getType(), "indvar.conv",
PH->getParent()->getFirstNonPHI());
PH->replaceAllUsesWith(Conv);
}
DeadInsts.insert(PH);
}

50
test/Transforms/IndVarsSimplify/2008-11-03-Floating.ll
View File

@ -1,4 +1,4 @@
; RUN: llvm-as < %s | opt -indvars | llvm-dis | grep icmp | count 1
; RUN: llvm-as < %s | opt -indvars | llvm-dis | grep icmp | count 4
define void @bar() nounwind {
entry:
br label %bb
@ -15,3 +15,51 @@ return: ; preds = %bb
}
declare i32 @foo(double)
define void @bar2() nounwind {
entry:
br label %bb
bb: ; preds = %bb, %entry
%x.0.reg2mem.0 = phi double [ -10.000000e+00, %entry ], [ %1, %bb ] ; <double> [#uses=2]
%0 = tail call i32 @foo(double %x.0.reg2mem.0) nounwind ; <i32> [#uses=0]
%1 = add double %x.0.reg2mem.0, 2.000000e+00 ; <double> [#uses=2]
%2 = fcmp olt double %1, -1.000000e+00 ; <i1> [#uses=1]
br i1 %2, label %bb, label %return
return: ; preds = %bb
ret void
}
define void @bar3() nounwind {
entry:
br label %bb
bb: ; preds = %bb, %entry
%x.0.reg2mem.0 = phi double [ 0.000000e+00, %entry ], [ %1, %bb ] ; <double> [#uses=2]
%0 = tail call i32 @foo(double %x.0.reg2mem.0) nounwind ; <i32> [#uses=0]
%1 = add double %x.0.reg2mem.0, 1.000000e+00 ; <double> [#uses=2]
%2 = fcmp olt double %1, -1.000000e+00 ; <i1> [#uses=1]
br i1 %2, label %bb, label %return
return: ; preds = %bb
ret void
}
define void @bar4() nounwind {
entry:
br label %bb
bb: ; preds = %bb, %entry
%x.0.reg2mem.0 = phi double [ 40.000000e+00, %entry ], [ %1, %bb ] ; <double> [#uses=2]
%0 = tail call i32 @foo(double %x.0.reg2mem.0) nounwind ; <i32> [#uses=0]
%1 = add double %x.0.reg2mem.0, -1.000000e+00 ; <double> [#uses=2]
%2 = fcmp olt double %1, 1.000000e+00 ; <i1> [#uses=1]
br i1 %2, label %bb, label %return
return: ; preds = %bb
ret void
}