search for: inscombin

...somehow combined, not unlike the usual optimization pipelines. The second problem is the size/complexity of the instcombine pass. I do acknowledge that D46336 / D46595 (both in instcombine) is an improvement, which results in more folds that didn't happen before. But it makes the already-large inscombine even more complex, and i'm not sure how it affects the performance. Then there is D45842. That code is pretty simple, and takes ~one page. It does not do any change unless that opens the road for further simplification. (I hope that is what the D46336 / D46595 do, but i don't know.) As s...

I'm looking at the output of memcmp() expansion (D34904), and I noticed that there are many ways to produce the common positive/zero/negative comparison result in IR. For the following 6 functionally equivalent C source functions, we produce 6 different versions of IR which leads to 6 different asm outputs for x86. Which of these should we choose as canonical IR form? 1. Two selects int

> On May 8, 2018, at 9:50 AM, Daniel Berlin via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > 1. The reassociate pass that exists right now was *originally* (AFAIK) written to enable CSE/GVN to do better. Agreed. The original mindset included a (naive) belief that going with a canonical form was better than teaching redundancy elimination to handle abstractions (as a matter