diff --git a/llvm/lib/CodeGen/TypePromotion.cpp b/llvm/lib/CodeGen/TypePromotion.cpp
--- a/llvm/lib/CodeGen/TypePromotion.cpp
+++ b/llvm/lib/CodeGen/TypePromotion.cpp
@@ -359,11 +359,8 @@
     return false;
 
   // Now check that the result can't wrap on itself.
-  APInt Total = ICmpConst->getValue().getBitWidth() < 32 ?
-    ICmpConst->getValue().zext(32) : ICmpConst->getValue();
-
-  Total += OverflowConst->getValue().getBitWidth() < 32 ?
-    OverflowConst->getValue().abs().zext(32) : OverflowConst->getValue().abs();
+  APInt Total = ICmpConst->getValue().zextOrSelf(RegisterBitWidth);
+  Total += OverflowConst->getValue().abs().zextOrSelf(RegisterBitWidth);
 
   APInt Max = APInt::getAllOnes(TypePromotion::TypeSize);