[PATCH] D111643: [ValueTracking] Let propgatesPoison consider single poison operand.

[Florian Hahn via Phabricator via llvm-commits]

fhahn added inline comments.


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Comment at: llvm/include/llvm/Analysis/ValueTracking.h:609
+  bool propagatesPoison(const Operator *I,
+                        const Value *ValAssumedPoison = nullptr);
 
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nikic wrote:
> fhahn wrote:
> > nikic wrote:
> > > Can we make this function accept (only) a `Use`?
> > I think that should be possible, it just requires updating a few of the users.
> This isn't really what I had in mind. Why do we need both an Operator and a Use? Can't we make this API accept only a (required) Use and dispatch based on `U.getUser()`? Are there any usages that don't work on a specific Use?
That's an option. If we do not want to provide 2 versions of the function this requires updating all users to actually check which operands are poison before calling `propagatesPoison`. I did that in the latest iteration of the patch. It doesn't look too bad, I am not sure if the convenience of having a version that does not require specifying *which* operand may be poison would still be desirable.


Repository:
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  https://reviews.llvm.org/D111643/new/

https://reviews.llvm.org/D111643