[perf] skip normalizing param env if it is already normalized

[lukas-code]

If the param env is already normalized after elaboration, then we can skip a bunch of expensive operations.

Note

This makes it so that outlives predicates are no longer sorted after non-outlives predicates. Surely this won't make a semantic difference.

r? ghost

[lukas-code]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 1999d06 with merge 8670a07...

[bors]

☀️ Try build successful - checks-actions
Build commit: 8670a07 (8670a07576d5dc11f39d1fa1990bd183ae638b3a)

[rust-timer]

Finished benchmarking commit (8670a07): comparison URL.

Overall result: ✅ improvements - no action needed

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 may lead to changes in compiler perf.

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

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.1%	[-5.5%, -0.1%]	79
Improvements ✅ (secondary)	-2.7%	[-6.5%, -0.2%]	58
All ❌✅ (primary)	-1.1%	[-5.5%, -0.1%]	79

Max RSS (memory usage)

Results (primary -1.2%, secondary -0.2%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.1%	[0.4%, 2.8%]	5
Improvements ✅ (primary)	-1.2%	[-1.2%, -1.2%]	1
Improvements ✅ (secondary)	-2.5%	[-3.2%, -2.1%]	3
All ❌✅ (primary)	-1.2%	[-1.2%, -1.2%]	1

Cycles

Results (primary -2.3%, secondary -3.8%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-2.3%	[-4.4%, -0.8%]	17
Improvements ✅ (secondary)	-3.8%	[-6.9%, -1.3%]	30
All ❌✅ (primary)	-2.3%	[-4.4%, -0.8%]	17

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 769.526s -> 768.035s (-0.19%)
Artifact size: 341.30 MiB -> 341.26 MiB (-0.01%)

[compiler-errors]

👍

AFAICT, we should not have order dependence for our type outlives obligations at least; I double checked lexical region resolution and MIR borrowck and nothing seemed suspicious there. Or at least, we certainly don't have any order dependence between type-outlives and other predicates.

@bors r+

[bors]

📌 Commit 1999d06 has been approved by compiler-errors

It is now in the queue for this repository.