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Don't treat values as signed when looking at loop steppings in HowForToNonZero.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51560 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2008-05-25 23:43:32 +00:00
parent 3dfd7bf511
commit 04b35e8532
2 changed files with 22 additions and 2 deletions
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4
lib/Analysis/ScalarEvolution.cpp
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@ -2548,9 +2548,9 @@ SCEVHandle ScalarEvolutionsImpl::HowFarToZero(SCEV *V, const Loop *L) {
if (SCEVConstant *StartC = dyn_cast<SCEVConstant>(Start)) {
ConstantInt *StartCC = StartC->getValue();
Constant *StartNegC = ConstantExpr::getNeg(StartCC);
Constant *Rem = ConstantExpr::getSRem(StartNegC, StepC->getValue());
Constant *Rem = ConstantExpr::getURem(StartNegC, StepC->getValue());
if (Rem->isNullValue()) {
Constant *Result =ConstantExpr::getSDiv(StartNegC,StepC->getValue());
Constant *Result = ConstantExpr::getUDiv(StartNegC,StepC->getValue());
return SE.getUnknown(Result);
}
}

20
test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll Normal file
View File

@ -0,0 +1,20 @@
; RUN: llvm-as < %s | opt -analyze -scalar-evolution | grep {61 iterations}
define i32 @func_6() nounwind {
entry:
br label %bb5
bb: ; preds = %bb5
%tmp2 = add i32 %i.0, 1 ; <i32> [#uses=1]
%tmp4 = add i8 %x.0, -4 ; <i8> [#uses=1]
br label %bb5
bb5: ; preds = %bb, %entry
%x.0 = phi i8 [ 0, %entry ], [ %tmp4, %bb ] ; <i8> [#uses=2]
%i.0 = phi i32 [ 0, %entry ], [ %tmp2, %bb ] ; <i32> [#uses=2]
%tmp7 = icmp eq i8 %x.0, 12 ; <i1> [#uses=1]
br i1 %tmp7, label %return, label %bb
return: ; preds = %bb5
ret i32 %i.0
}