rust/compiler/rustc_query_system/src
bors 495322d776 Auto merge of #90361 - Mark-Simulacrum:always-verify, r=michaelwoerister
Enable verification for 1/32th of queries loaded from disk

This is a limited enabling of incremental verification for query results loaded from disk, which previously did not run without -Zincremental-verify-ich. If enabled for all queries, we see a probably unacceptable hit of ~50% in the worst case, so this pairs back the verification to a more limited set based on the hash key.

Per collected [perf results](https://github.com/rust-lang/rust/pull/84227#issuecomment-953350582), this is a regression of at most 7% on coercions opt incr-unchanged, and typically less than 0.5% on other benchmarks (largely limited to incr-unchanged). I believe this is acceptable performance to land, and we can either ratchet it up or down fairly easily.

We have no real sense of whether this will lead to a large amount of assertions in the wild, but since those assertions may lead to miscompilations today, it seems potentially warranted. We have a good bit of lead time until the next stable release, though the holiday season will also start soon; we may wish to discuss the timing of enabling this and weigh the desire to prevent (possible) miscompilations against assertions.

cc `@rust-lang/wg-incr-comp`
2021-11-08 13:38:08 +00:00
..
dep_graph Inline DepNodeParams methods. 2021-10-20 18:46:25 +02:00
ich Use SortedMap in HIR. 2021-10-21 23:08:57 +02:00
query Enable verification for 1/32th of queries loaded from disk 2021-10-28 09:57:31 -04:00
cache.rs Remove (lots of) dead code 2021-03-27 22:16:33 -04:00
lib.rs Revert "Add rustc lint, warning when iterating over hashmaps" 2021-10-28 11:01:42 -04:00