Don't treat values as signed when looking at loop steppings in HowForToNonZero.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51560 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 26010eb..e01cf51 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -2548,9 +2548,9 @@
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);
}
}
diff --git a/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll b/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll
new file mode 100644
index 0000000..922d9a9
--- /dev/null
+++ b/test/Analysis/ScalarEvolution/2008-05-25-NegativeStepToZero.ll
@@ -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
+}