[PATCH] D157187: [InstCombine] Propagate the nuw/nsw for instruction neg-sub

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp:2069
+        if (I.hasNoSignedWrap() && Op1Inst->hasNoSignedWrap())
+          InstOp1->setHasNoSignedWrap();
+      }
----------------
I don't think its okay to modify NegOp1 inplace like this. the flag propagation works in the context of the transform at hand but might not be applicable to all users.

Also this desperately needs some comments.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D157187/new/

https://reviews.llvm.org/D157187