GVN: Use a VnIndex in Address projection.

[cjgillot]

The current implementation of address projections is inconsistent. Indexing semantically relies on the index' value, but the implementation uses the index' place. This PR fixes that by using ProjectionElem<VnIndex, Ty<'tcx>> instead of the raw PlaceElem<'tcx>.

[cjgillot]

@bors try @rust-timer queue

[rust-bors]

⌛ Trying commit 783ac7a with merge 413faf3…

To cancel the try build, run the command @bors try cancel.

[rust-bors]

☀️ Try build successful (CI)
Build commit: 413faf3 (413faf3ee16ba890d3a82bfe8255e45c0aa5a4a5, parent: 430d6eddfc6a455ca4a0137c0822a982cccd3b2b)

[rust-timer]

Finished benchmarking commit (413faf3): comparison URL.

Overall result: ❌ regressions - no action needed

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

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

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	1.0%	[0.4%, 1.6%]	2
Regressions ❌ (secondary)	0.8%	[0.0%, 1.6%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.0%	[0.4%, 1.6%]	2

Max RSS (memory usage)

Results (primary 0.1%, secondary -2.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.1%	[0.7%, 3.0%]	4
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-4.0%	[-4.0%, -4.0%]	2
Improvements ✅ (secondary)	-3.5%	[-4.6%, -2.2%]	3
All ❌✅ (primary)	0.1%	[-4.0%, 3.0%]	6

Cycles

Results (primary -3.7%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.7%	[-3.7%, -3.7%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.7%	[-3.7%, -3.7%]	1

Binary size

Results (primary 0.0%, secondary 0.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.0%, 0.2%]	7
Regressions ❌ (secondary)	0.1%	[0.0%, 0.2%]	2
Improvements ✅ (primary)	-0.1%	[-0.2%, -0.0%]	2
Improvements ✅ (secondary)	-0.0%	[-0.0%, -0.0%]	3
All ❌✅ (primary)	0.0%	[-0.2%, 0.2%]	9

Bootstrap: 468.925s -> 469.927s (0.21%)
Artifact size: 374.68 MiB -> 374.75 MiB (0.02%)