Reuse existing shared Lrc for MatchImpl parent

[Mark-Simulacrum]

This is a small performance win for the hot path, which helps to address this regression: #87244 (comment).

[rust-highfive]

r? @petrochenkov

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[Mark-Simulacrum]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

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

[bors]

⌛ Trying commit 905beab with merge 7673a3aaa9e105ce44a072adc092435bee541800...

[bors]

☀️ Try build successful - checks-actions
Build commit: 7673a3aaa9e105ce44a072adc092435bee541800 (7673a3aaa9e105ce44a072adc092435bee541800)

[rust-timer]

Queued 7673a3aaa9e105ce44a072adc092435bee541800 with parent 4aed1ab, future comparison URL.

[rust-timer]

Finished benchmarking commit (7673a3aaa9e105ce44a072adc092435bee541800): comparison url.

Summary: This change led to very small relevant improvements 🎉 in compiler performance.

• Very small improvement in instruction counts (up to -1.1% on incr-patched: println builds of coercions)

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

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR led to changes in compiler perf.

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

[petrochenkov]

@bors r+

[bors]

📌 Commit 905beab has been approved by petrochenkov

[bors]

⌛ Testing commit 905beab with merge aa8f2d4...

[bors]

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing aa8f2d4 to master...

[rust-timer]

Finished benchmarking commit (aa8f2d4): comparison url.

Summary: This benchmark run did not return any relevant changes.

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

@rustbot label: -perf-regression