If loop induction variable's start value is less then its exit value then do not split the loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53265 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopIndexSplit.cpp b/lib/Transforms/Scalar/LoopIndexSplit.cpp
index 45d4900..135ce33 100644
--- a/lib/Transforms/Scalar/LoopIndexSplit.cpp
+++ b/lib/Transforms/Scalar/LoopIndexSplit.cpp
@@ -384,6 +384,19 @@
BasicBlock *Preheader = L->getLoopPreheader();
StartValue = IndVar->getIncomingValueForBlock(Preheader);
}
+
+ // If start value is more then exit value where induction variable
+ // increments by 1 then we are potentially dealing with an infinite loop.
+ // Do not index split this loop.
+ if (ExitCondition) {
+ ConstantInt *SV = dyn_cast<ConstantInt>(StartValue);
+ ConstantInt *EV =
+ dyn_cast<ConstantInt>(ExitCondition->getOperand(ExitValueNum));
+ if (SV && EV && SV->getSExtValue() > EV->getSExtValue())
+ ExitCondition = NULL;
+ else if (EV && EV->isZero())
+ ExitCondition = NULL;
+ }
}
/// Find condition inside a loop that is suitable candidate for index split.