[do not merge] fmt::Arguments experiment

[m-ou-se]

Just testing some incomplete idea.

[m-ou-se]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit 3259ba1 with merge f585107e5e534511ae54ad991ac429aef3b99ebd...

[bors]

💔 Test failed - checks-actions

[m-ou-se]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit e89626f with merge 9d649c160c564fa8820680f3132796f90912466b...

[rust-log-analyzer]

The job mingw-check failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

configure: rust.channel         := nightly
configure: rust.debug-assertions := True
configure: llvm.assertions      := True
configure: dist.missing-tools   := True
configure: build.configure-args := ['--enable-sccache', '--disable-manage-submodu ...
configure: writing `config.toml` in current directory
configure: 
configure: run `python /checkout/x.py --help`
configure: 
---
tidy error: /checkout/library/core/src/fmt/mod.rs:1266: undocumented unsafe
Found 515 error codes
Found 0 error codes with no tests
Done!
tidy error: /checkout/compiler/rustc_builtin_macros/src/format.rs:63: XXX is deprecated; use FIXME
tidy error: /checkout/compiler/rustc_builtin_macros/src/format.rs:365: XXX is deprecated; use FIXME
tidy error: /checkout/compiler/rustc_builtin_macros/src/format.rs:428: XXX is deprecated; use FIXME
some tidy checks failed



command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/rust-tidy" "/checkout" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "/checkout/obj/build" "16"


failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test --stage 2 src/tools/tidy
Build completed unsuccessfully in 0:00:12

[bors]

☀️ Try build successful - checks-actions
Build commit: 9d649c160c564fa8820680f3132796f90912466b (9d649c160c564fa8820680f3132796f90912466b)

[rust-timer]

Queued 9d649c160c564fa8820680f3132796f90912466b with parent 89ebad5, future comparison URL.

[rust-timer]

Finished benchmarking try commit (9d649c160c564fa8820680f3132796f90912466b): comparison url.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. Please note that if the perf results are neutral, you should likely undo the rollup=never given below by specifying rollup- to bors.

Importantly, though, if the results of this run are non-neutral do not roll this PR up -- it will mask other regressions or improvements in the roll up.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf

[bjorn3]

Up to 9.3% improvement for helloworld-opt incr-patched and up to 8.4% regression for webrender-wrench-check incr-patched. For full builds many regressions up to 6.8% and some improvements up to 2.0%.

[m-ou-se]

Yeah these results are all over the place. Not sure why.

fmt::Arguments was reduced from 6 pointers to 2 pointers in size, and the output of format_args!() didn't really change much in complexity.

[Mark-Simulacrum]

Going to go ahead and close this since it seems like it's not likely to receive much further attention.