Disable indvars on loops when LoopSimplify form is not available.
This fixes PR7333.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106267 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 36bea67..84e393f 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -467,6 +467,17 @@
}
bool IndVarSimplify::runOnLoop(Loop *L, LPPassManager &LPM) {
+ // If LoopSimplify form is not available, stay out of trouble. Some notes:
+ // - LSR currently only supports LoopSimplify-form loops. Indvars'
+ // canonicalization can be a pessimization without LSR to "clean up"
+ // afterwards.
+ // - We depend on having a preheader; in particular,
+ // Loop::getCanonicalInductionVariable only supports loops with preheaders,
+ // and we're in trouble if we can't find the induction variable even when
+ // we've manually inserted one.
+ if (!L->isLoopSimplifyForm())
+ return false;
+
IU = &getAnalysis<IVUsers>();
LI = &getAnalysis<LoopInfo>();
SE = &getAnalysis<ScalarEvolution>();