[PATCH] D45867: [InstCombine] Unfold masked merge with constant mask

[Dávid Bolvanský via Phabricator via llvm-commits]

xbolva00 added a comment.

In https://reviews.llvm.org/D45867#1082081, @lebedev.ri wrote:

> In https://reviews.llvm.org/D45867#1082079, @xbolva00 wrote:
>
> > Not related to this patch exactly but since you work in this area... maybe you can check this too?
> >  https://godbolt.org/g/wksfqb
>
>
> That particular example should be handled by dead code elimination pass i guess,
>  because it is literally optimized down to `return 0;`,
>  since it only reads global `uint32_t b;` once, and ultimately does nothing with that.
>
> But, i have zero clues how it should be done.


It is interesting, since even if we dont use "b", just leave it as "uint32_t a = 5;", code is not eliminated since compiler may think it could be infinite loop (?)


Repository:
  rL LLVM

https://reviews.llvm.org/D45867