Don't overwrite CodegenFnAttrs when adding used compiler/linker

[thomcc]

Pointed out by @tmiasko in #93718 (comment). Probably a better fix than #99674 for #99596, assuming it does fix the latter.

I don't have the ability to write a regression test for this at the moment, and am quite surprised this didn't cause other failures. The old code is clearly wrong though, but I'm not picky as to which of these is better to go with.

[rust-highfive]

r? @lcnr

(rust-highfive has picked a reviewer for you, use r? to override)

[tmiasko]

@bors r+

[bors]

📌 Commit 6cfd471 has been approved by tmiasko

It is now in the queue for this repository.

[eddyb]

(oops, the other comments weren't visible at first, was gonna r+ to help out)

[wesleywiser]

@bors p=1

Fixes issues on multiple platforms.

[bors]

⌛ Testing commit 6cfd471 with merge 530c0a8...

[bors]

☀️ Test successful - checks-actions
Approved by: tmiasko
Pushing 530c0a8 to master...

[rust-timer]

Finished benchmarking commit (530c0a8): comparison url.

Instruction count

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: 🎉 relevant improvement found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	-0.3%	-0.3%	1
All 😿🎉 (primary)	N/A	N/A	0

Max RSS (memory usage)

Results

• Primary benchmarks: no relevant changes found
• Secondary benchmarks: 😿 relevant regression found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	2.9%	2.9%	1
Improvements 🎉 (primary)	N/A	N/A	0
Improvements 🎉 (secondary)	N/A	N/A	0
All 😿🎉 (primary)	N/A	N/A	0

Cycles

Results

• Primary benchmarks: 🎉 relevant improvements found
• Secondary benchmarks: 🎉 relevant improvements found

	mean1	max	count2
Regressions 😿 (primary)	N/A	N/A	0
Regressions 😿 (secondary)	N/A	N/A	0
Improvements 🎉 (primary)	-2.1%	-2.4%	2
Improvements 🎉 (secondary)	-2.7%	-3.4%	5
All 😿🎉 (primary)	-2.1%	-2.4%	2

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

@rustbot label: -perf-regression

Footnotes

1. the arithmetic mean of the percent change ↩ ↩² ↩³

2. number of relevant changes ↩ ↩² ↩³