[EXPERIMENT] GVN: Track known value ranges through assert and switchInt.

[dianqk]

r? ghost (for perf)

[dianqk]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: f2bc50f (f2bc50f4689333c80bcd074203a0a387187d19d8, parent: d3f16d2f35d8d4b25bb15a85ae869eee70ffb4cd)

[rust-timer]

Finished benchmarking commit (f2bc50f): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

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.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@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)	0.3%	[0.1%, 0.4%]	3
Regressions ❌ (secondary)	0.5%	[0.5%, 0.5%]	1
Improvements ✅ (primary)	-0.4%	[-0.9%, -0.2%]	9
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.2%	[-0.9%, 0.4%]	12

Max RSS (memory usage)

Results (primary -1.1%, secondary 0.8%)

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

	mean	range	count
Regressions ❌ (primary)	2.5%	[1.9%, 3.1%]	2
Regressions ❌ (secondary)	2.4%	[2.4%, 2.4%]	1
Improvements ✅ (primary)	-2.9%	[-4.2%, -1.4%]	4
Improvements ✅ (secondary)	-0.7%	[-0.7%, -0.7%]	1
All ❌✅ (primary)	-1.1%	[-4.2%, 3.1%]	6

Cycles

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

Binary size

Results (primary -0.0%, secondary -0.1%)

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

	mean	range	count
Regressions ❌ (primary)	0.3%	[0.1%, 0.4%]	5
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.1%	[-0.8%, -0.0%]	16
Improvements ✅ (secondary)	-0.1%	[-0.8%, -0.0%]	19
All ❌✅ (primary)	-0.0%	[-0.8%, 0.4%]	21

Bootstrap: 481.777s -> 483.166s (0.29%)
Artifact size: 390.59 MiB -> 390.61 MiB (0.01%)

[bors]

☔ The latest upstream changes (presumably #150231) made this pull request unmergeable. Please resolve the merge conflicts.

[dianqk]

I don't think GVN is required here. A new pass with SSA locals may make sense. @cjgillot What do you think?