Stream: t-compiler/wg-mir-opt

Topic: copy prop is slow


oli (Dec 29 2019 at 00:31, on Zulip):

No idea if copy prop is still slow, but I found this gem: https://github.com/rust-lang/rust/issues/36673

oli (Dec 29 2019 at 00:31, on Zulip):

in MIR terms this issue is ancient

Björn Steinbrink (Jan 14 2020 at 09:54, on Zulip):

Yeah, looking at the code, it's still slow. I tried improving that sometime last year, adding a rather crude hack to update the def-use chains instead of recreating them (which is what makes this pass so slow). But it's also limited in the cases it can handle which made the gains from running the pass rather marginal and I didn't have the time to finish the work I started in a way that's suitable for a PR.

Last update: Jan 28 2020 at 00:35UTC