[AlignmentFromAssumptions] Don't divide by zero for unknown starting alignment

[oota-llvm.git] / lib / Transforms / Scalar / AlignmentFromAssumptions.cpp

diff --git a/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp b/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
index a662accf69fbe7d54a8148f14fc03149359b99cb..7ab16f13811ffdbaefca905b09291674227d64ef 100644 (file)
--- a/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
+++ b/lib/Transforms/Scalar/AlignmentFromAssumptions.cpp
@@ -179,7 +179,9 @@ static unsigned getNewAlignment(const SCEV *AASCEV, const SCEV *AlignSCEV,
     DEBUG(dbgs() << "\tnew start alignment: " << NewAlignment << "\n");
     DEBUG(dbgs() << "\tnew inc alignment: " << NewIncAlignment << "\n");
 
-    if (NewAlignment > NewIncAlignment) {
+    if (!NewAlignment || !NewIncAlignment) {
+      return 0;
+    } else if (NewAlignment > NewIncAlignment) {
       if (NewAlignment % NewIncAlignment == 0) {
         DEBUG(dbgs() << "\tnew start/inc alignment: " <<
                         NewIncAlignment << "\n");
@@ -191,7 +193,7 @@ static unsigned getNewAlignment(const SCEV *AASCEV, const SCEV *AlignSCEV,
                         NewAlignment << "\n");
         return NewAlignment;
       }
-    } else if (NewIncAlignment == NewAlignment && NewIncAlignment) {
+    } else if (NewIncAlignment == NewAlignment) {
       DEBUG(dbgs() << "\tnew start/inc alignment: " <<
                       NewAlignment << "\n");
       return NewAlignment;