Change 'while' loop to 'do' loop.
Add a safety measure. It isn't safe to assume in ScalarEvolutionExpander that
all loops are in canonical form (but it should be safe for loops that have
AddRecs).
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52275 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index e249421..a241960 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -185,14 +185,21 @@
Loop *InsertPtLoop = LI.getLoopFor(MulInsertPt->getParent());
if (InsertPtLoop != L && InsertPtLoop &&
L->contains(InsertPtLoop->getHeader())) {
- while (InsertPtLoop != L) {
+ do {
// If we cannot hoist the multiply out of this loop, don't.
if (!InsertPtLoop->isLoopInvariant(F)) break;
- // Otherwise, move the insert point to the preheader of the loop.
- MulInsertPt = InsertPtLoop->getLoopPreheader()->getTerminator();
+ BasicBlock *InsertPtLoopPH = InsertPtLoop->getLoopPreheader();
+
+ // If this loop hasn't got a preheader, we aren't able to hoist the
+ // multiply.
+ if (!InsertPtLoopPH)
+ break;
+
+ // Otherwise, move the insert point to the preheader.
+ MulInsertPt = InsertPtLoopPH->getTerminator();
InsertPtLoop = InsertPtLoop->getParentLoop();
- }
+ } while (InsertPtLoop != L);
}
return InsertBinop(Instruction::Mul, I, F, MulInsertPt);