Stream: t-compiler/wg-llvm

Topic: A bug related to x32 codegen


Charles Lew (Mar 28 2019 at 16:04, on Zulip):

There was this PR that seems code finished but triggering a suspected LLVM bug. It occurs on the gnux32 target. I wonder if any one's able to give it a look and find a way to fix it or work around it...

Charles Lew (Mar 28 2019 at 16:04, on Zulip):

The output is: LLVM ERROR: Cannot emit physreg copy instruction

Nikita Popov (Mar 28 2019 at 17:28, on Zulip):

There's a similar issue here: https://github.com/rust-lang/rust/issues/45417 That one is apparently resolved. What LLVM version were we at when the PR encountered this issue?

Charles Lew (Mar 28 2019 at 18:13, on Zulip):

Definitely before the llvm 8 update: https://github.com/rust-lang/llvm-project/commits/683d3522690b7a9d0163e7e7e6586f2b1364ed02

Charles Lew (Mar 29 2019 at 02:13, on Zulip):

Rebased the PR to master. It seems the tests pass now.

Nikita Popov (Mar 29 2019 at 08:32, on Zulip):

The try build only tests a single configuration, while the previous failure was on dist-various-2, so this doesn't really tell us whether the issue is resolved or not.

Charles Lew (Mar 29 2019 at 15:51, on Zulip):

oh!! sorry i'm not familiar with this, but if there any way to ask bors to test it on gnux32?

Charles Lew (Apr 02 2019 at 07:49, on Zulip):

A dist-various-2 run reveals that the problem is still there :(

Charles Lew (Apr 04 2019 at 03:12, on Zulip):

Minimized the case to https://github.com/rust-lang/rust/issues/59674

Nikita Popov (Apr 19 2019 at 19:00, on Zulip):

Submitted https://reviews.llvm.org/D60909 to fix this issue.

Last update: Nov 15 2019 at 09:40UTC