Revert "Prototype: Add unstable -Z reference-niches option"

[dtolnay]

Clean revert of #113166. I confirmed this fixes #113941.

[rustbot]

r? @oli-obk

(rustbot has picked a reviewer for you, use r? to override)

[rustbot]

Some changes occurred in compiler/rustc_codegen_gcc

cc @antoyo

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

Some changes occurred to the CTFE / Miri engine

cc @rust-lang/miri

The Miri subtree was changed

cc @rust-lang/miri

Some changes occurred to the core trait solver

cc @rust-lang/initiative-trait-system-refactor

[oli-obk]

Please revert only the merge commit of that PR, not all individual commits.

r=me on that

[oli-obk]

@bors p=1

[dtolnay]

👍 generated by git revert 557359f9251 -m1

@bors r=oli-obk

[bors]

📌 Commit 5bbf0a8 has been approved by oli-obk

It is now in the queue for this repository.

[bors]

⌛ Testing commit 5bbf0a8 with merge a876552...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing a876552 to master...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing a876552 to master...

[rust-timer]

Finished benchmarking commit (a876552): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -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)	-0.8%	[-1.1%, -0.3%]	13
Improvements ✅ (secondary)	-1.1%	[-1.3%, -0.7%]	4
All ❌✅ (primary)	-0.8%	[-1.1%, -0.3%]	13

Max RSS (memory usage)

Results

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)	3.6%	[2.2%, 5.8%]	3
Improvements ✅ (primary)	-2.1%	[-4.0%, -0.7%]	10
Improvements ✅ (secondary)	-1.9%	[-1.9%, -1.9%]	1
All ❌✅ (primary)	-2.1%	[-4.0%, -0.7%]	10

Cycles

Results

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)	-4.1%	[-5.0%, -2.1%]	7
Improvements ✅ (secondary)	-2.3%	[-2.6%, -2.1%]	2
All ❌✅ (primary)	-4.1%	[-5.0%, -2.1%]	7

Binary size

Results

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)	0.2%	[0.2%, 0.2%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.2%	[0.2%, 0.2%]	1

Bootstrap: 657.715s -> 652.6s (-0.78%)