[dianqk]

Fixes #164069.
Add assume_variant to the downcast projection. This allows GVN to know the active variant of the place.

LLM disclosure: I applied some naming suggestions from LLMs.

[rust-log-analyzer]

The job test-aarch64-gnu-llvm-22-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

test result: FAILED. 0 passed; 1 failed; 7 ignored; 0 measured; 0 filtered out; finished in 37.46ms

all doctests ran in 0.48s; merged doctests compilation took 0.43s
error: doctest failed, to rerun pass `-p rustc_mir_transform --doc`
Bootstrap failed while executing `--stage 2 test --skip tidy --skip tests --skip library --skip tidyselftest`
Currently active steps:
test::CrateLibrustc { build_compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu, crates: ["rustc-main", "rustc_abi", "rustc_arena", "rustc_ast", "rustc_ast_ir", "rustc_ast_lowering", "rustc_ast_passes", "rustc_ast_pretty", "rustc_attr_ir", "rustc_attr_parsing", "rustc_baked_icu_data", "rustc_borrowck", "rustc_builtin_macros", "rustc_codegen_llvm", "rustc_codegen_ssa", "rustc_const_eval", "rustc_crate_store", "rustc_data_structures", "rustc_driver", "rustc_driver_impl", "rustc_error_codes", "rustc_error_messages", "rustc_errors", "rustc_expand", "rustc_expand_queries", "rustc_feature", "rustc_fs_util", "rustc_graphviz", "rustc_hashes", "rustc_hir", "rustc_hir_analysis", "rustc_hir_id", "rustc_hir_pretty", "rustc_hir_typeck", "rustc_incremental", "rustc_index", "rustc_index_macros", "rustc_infer", "rustc_interface", "rustc_lexer", "rustc_lint", "rustc_lint_defs", "rustc_llvm", "rustc_log", "rustc_macros", "rustc_metadata", "rustc_middle", "rustc_mir_build", "rustc_mir_dataflow", "rustc_mir_transform", "rustc_monomorphize", "rustc_next_trait_solver", "rustc_parse", "rustc_parse_format", "rustc_passes", "rustc_pattern_analysis", "rustc_privacy", "rustc_proc_macro", "rustc_public", "rustc_public_bridge", "rustc_query_impl", "rustc_resolve", "rustc_sanitizers", "rustc_serialize", "rustc_session", "rustc_span", "rustc_structures", "rustc_symbol_mangling", "rustc_target", "rustc_thread_pool", "rustc_trait_selection", "rustc_traits", "rustc_transmute", "rustc_ty_utils", "rustc_ty_walk", "rustc_type_ir", "rustc_type_ir_macros", "rustc_windows_rc"] } at src/bootstrap/src/core/build_steps/test.rs:3444
test::Crate { build_compiler: Compiler { stage: 1, host: aarch64-unknown-linux-gnu, forced_compiler: false }, target: aarch64-unknown-linux-gnu, mode: Rustc, crates: ["rustc-main", "rustc_abi", "rustc_arena", "rustc_ast", "rustc_ast_ir", "rustc_ast_lowering", "rustc_ast_passes", "rustc_ast_pretty", "rustc_attr_ir", "rustc_attr_parsing", "rustc_baked_icu_data", "rustc_borrowck", "rustc_builtin_macros", "rustc_codegen_llvm", "rustc_codegen_ssa", "rustc_const_eval", "rustc_crate_store", "rustc_data_structures", "rustc_driver", "rustc_driver_impl", "rustc_error_codes", "rustc_error_messages", "rustc_errors", "rustc_expand", "rustc_expand_queries", "rustc_feature", "rustc_fs_util", "rustc_graphviz", "rustc_hashes", "rustc_hir", "rustc_hir_analysis", "rustc_hir_id", "rustc_hir_pretty", "rustc_hir_typeck", "rustc_incremental", "rustc_index", "rustc_index_macros", "rustc_infer", "rustc_interface", "rustc_lexer", "rustc_lint", "rustc_lint_defs", "rustc_llvm", "rustc_log", "rustc_macros", "rustc_metadata", "rustc_middle", "rustc_mir_build", "rustc_mir_dataflow", "rustc_mir_transform", "rustc_monomorphize", "rustc_next_trait_solver", "rustc_parse", "rustc_parse_format", "rustc_passes", "rustc_pattern_analysis", "rustc_privacy", "rustc_proc_macro", "rustc_public", "rustc_public_bridge", "rustc_query_impl", "rustc_resolve", "rustc_sanitizers", "rustc_serialize", "rustc_session", "rustc_span", "rustc_structures", "rustc_symbol_mangling", "rustc_target", "rustc_thread_pool", "rustc_trait_selection", "rustc_traits", "rustc_transmute", "rustc_ty_utils", "rustc_ty_walk", "rustc_type_ir", "rustc_type_ir_macros", "rustc_windows_rc"] } at src/bootstrap/src/core/build_steps/test.rs:3451
Build completed unsuccessfully in 0:30:18

[dianqk]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 791dd00 (791dd000e7362e3e8061ee6c8be9a794b3548bc3)
Base parent: 12433c3 (12433c307b5a497388ffe2f4e49dbf1ab8c71fa0)

[rust-timer]

Finished benchmarking commit (791dd00): comparison URL.

Overall result: ❌ regressions - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never rustc-perf
@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%	[0.2%, 0.4%]	12
Regressions ❌ (secondary)	0.3%	[0.2%, 0.4%]	9
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.2%, 0.4%]	12

Max RSS (memory usage)

Results (primary 0.4%, secondary 0.7%)

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

	mean	range	count
Regressions ❌ (primary)	0.6%	[0.5%, 0.9%]	9
Regressions ❌ (secondary)	0.7%	[0.4%, 1.1%]	3
Improvements ✅ (primary)	-0.6%	[-0.7%, -0.6%]	2
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.4%	[-0.7%, 0.9%]	11

Cycles

Results (primary 0.1%, 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)	1.2%	[0.4%, 2.6%]	7
Regressions ❌ (secondary)	1.0%	[0.6%, 1.4%]	2
Improvements ✅ (primary)	-0.7%	[-0.9%, -0.4%]	9
Improvements ✅ (secondary)	-0.8%	[-0.8%, -0.7%]	2
All ❌✅ (primary)	0.1%	[-0.9%, 2.6%]	16

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 488.652s -> 489.239s (0.12%)
Artifact size: 405.92 MiB -> 406.01 MiB (0.02%)

[rust-bors]

☔ The latest upstream changes (presumably #165244) made this pull request unmergeable. Please resolve the merge conflicts by rebasing.