[PATCH] D39417: InstCombine: Preserve nuw when reassociating nuw ops [1/3]

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri accepted this revision.
lebedev.ri added a comment.
This revision is now accepted and ready to land.

Okay, this looks good to me.
Thanks!



================
Comment at: lib/Transforms/InstCombine/InstructionCombining.cpp:338-344
+          bool IsNUW = hasNoUnsignedWrap(I);
+          bool IsNSW = MaintainNoSignedWrap(I, B, C);
+
+          ClearSubclassDataAfterReassociation(I);
+
+          if (IsNUW && hasNoUnsignedWrap(*Op0))
+            I.setHasNoUnsignedWrap(true);
----------------
I would still recomment
```
          bool IsNUW = hasNoUnsignedWrap(I) && hasNoUnsignedWrap(*Op0);
          bool IsNSW = MaintainNoSignedWrap(I, B, C);

          ClearSubclassDataAfterReassociation(I);

          if (IsNUW)
            I.setHasNoUnsignedWrap(true);
```


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D39417/new/

https://reviews.llvm.org/D39417