[PATCH] D106668: [DAG] Add initial SelectionDAG::isGuaranteedNotToBeUndefOrPoison framework (PR51129)

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp:4279
+    return false; // Limit search depth.
+
+  if (isIntOrFPConstant(Op))
----------------
aqjune wrote:
> Probably relying on `noundef` attributes from library functions' return values will be helpful.
> Does SelDag allow getting the function declaration from a call?
> 
> Also, a pointer that is dereferenced by load/store is also noundef.
Yes all of that should be viable - I just don't want to clog this initial version. Should I add specific TODO comments?

e.g. I'm intending to look at whether this can help with some of the regressions in D106675 - which would mean start adding vector coverage.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D106668/new/

https://reviews.llvm.org/D106668