[SCEV] Fix PR36974.

The patch changes the usage of dominate to properlyDominate
to satisfy the condition !(a < a) while using std::max.

It is actually NFC due to set data structure is used to keep
the Loops and no two identical loops can be in collection.
So in reality there is no difference between usage of
dominate and properlyDominate in this particular case.
However it might be changed so it is better to fix it.

llvm-svn: 329051

1 files changed, 6 insertions, 5 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index d8a41944acb..fad31cb31e0 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -8668,11 +8668,12 @@ bool ScalarEvolution::isKnownViaInduction(ICmpInst::Predicate Pred,
               DT.dominates(L2->getHeader(), L1->getHeader())) &&
              "Domination relationship is not a linear order");
 #endif
-  
-  const Loop *MDL = *std::max_element(LoopsUsed.begin(), LoopsUsed.end(),
-                                        [&](const Loop *L1, const Loop *L2) {
-                         return DT.dominates(L1->getHeader(), L2->getHeader());
-                       });
+
+  const Loop *MDL =
+      *std::max_element(LoopsUsed.begin(), LoopsUsed.end(),
+                        [&](const Loop *L1, const Loop *L2) {
+         return DT.properlyDominates(L1->getHeader(), L2->getHeader());
+       });
 
   // Get init and post increment value for LHS.
   auto SplitLHS = SplitIntoInitAndPostInc(MDL, LHS);