[PATCH] D107872: [SimplifyLibCalls] propagate tail/musttail/notail flags on CallInsts

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers added inline comments.


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Comment at: llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp:630
   return Dst;
 }
 
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xbolva00 wrote:
> nickdesaulniers wrote:
> > jdoerfert wrote:
> > > Mostly this makes sense but doesn't this violate tail properties now? The old call result was return but it is not anymore.
> > perhaps we should be avoiding libcall transforms that don't return the new `CallInst` if the `CallInst` to be replaced is marked `musttail`? Let me add `musttail` tests.
> You mean eg musttail on strncpy?
> 
> Well yeah, but anyway there are many other libcall simplifications which break “musttail” contract (so if CI is musttail, we should not perform some simplifications).
> 
> But yeah, now with propagated tail kind, some IR verifier or backend may fail.
> 
> Nick, can you try it please?
Yeah, there's 11 cases that I'm updating from Diff 377048.  I will write 11 new tests, too.


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https://reviews.llvm.org/D107872