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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96688 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index a0700ba..66c4517 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -1973,6 +1973,12 @@
return getAddRecExpr(Operands, L, HasNUW, HasNSW); // {X,+,0} --> X
}
+ // It's tempting to want to call getMaxBackedgeTakenCount count here and
+ // use that information to infer NUW and NSW flags. However, computing a
+ // BE count requires calling getAddRecExpr, so we may not yet have a
+ // meaningful BE count at this point (and if we don't, we'd be stuck
+ // with a SCEVCouldNotCompute as the cached BE count).
+
// If HasNSW is true and all the operands are non-negative, infer HasNUW.
if (!HasNUW && HasNSW) {
bool All = true;