Index: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3833,7 +3833,13 @@
 
         for (int64_t Offset : Worklist) {
           Offset -= Step;
-          GenerateOffset(G, Offset);
+          Formula F = Base;
+          F.BaseOffset = (uint64_t)Base.BaseOffset - Offset;
+          // Check that the offset will result in a legal formula and addressing
+          // mode.
+          if (isLegalUse(TTI, LU.MinOffset, LU.MaxOffset, LU.Kind, LU.AccessTy,
+                         F))
+            GenerateOffset(G, Offset);
         }
       }
     }