the GEP faq says that only inbounds geps are guaranteed to not overflow.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123218 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 922751f..8deade3 100644 (file)
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -2722,11 +2722,12 @@ const SCEV *ScalarEvolution::createNodeForPHI(PHINode *PN) {
                   HasNUW = true;
                 if (OBO->hasNoSignedWrap())
                   HasNSW = true;
-              } else if (isa<GEPOperator>(BEValueV)) {
+              } else if (const GEPOperator *GEP = 
+                            dyn_cast<GEPOperator>(BEValueV)) {
                 // If the increment is a GEP, then we know it won't perform an
                 // unsigned overflow, because the address space cannot be
                 // wrapped around.
-                HasNUW = true;
+                HasNUW |= GEP->isInBounds();
               }
 
               const SCEV *StartVal = getSCEV(StartValueV);