[PATCH] D36656: [SCCP] Propagate integer range information in IPSCCP (WIP).

[Florian Hahn via Phabricator via llvm-commits]

fhahn added a comment.

Thanks for all the feedback! I'll update the patch soon.

In https://reviews.llvm.org/D36656#843034, @davide wrote:

> Thanks for your work!
>  FWIW, I agree with Eli/Sanjoy that we shouldn't rely on assumptions.
>  Another comment that I have is: instead of using a single lattice for constants and ranges [and *], have you considered looking at something akin to what GCC does? https://github.com/gcc-mirror/gcc/blob/master/gcc/ipa-cp.c#L307
>  They have different lattices for constants/aggregates/bits/ranges. I find their code easier to read/reason about than LLVM's.


Thanks for pointing me to that. I'll look into adding a separate range lattice.

re using assume: It shouldn't be to hard to use the range lattice to eliminate compare instructions in the IPSCCP pass.


https://reviews.llvm.org/D36656