Add description of -opt-bisect-limit LLVM option #1182
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rylev
approved these changes
Aug 6, 2021
| If you are seeing incorrect behavior due to an optimization pass, a very handy | ||
| LLVM option is `-opt-bisect-limit`, which takes an integer denoting the index | ||
| value of the highest pass to run. Index values for taken passes are stable | ||
| from run to run; by coupling this with software that automates bisecting the |
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Should we mention software that can be used for this?
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Sorry -- I missed this comment! Yeah, the "software that automates bisecting" is really a euphemism for: "the gnarly script that you, dear reader, are about to write." ;) Happy to spell that out, if with slightly less punchy language..
spastorino
approved these changes
Aug 6, 2021
JohnTitor
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Aug 11, 2021
Update books ## nomicon 2 commits in f51734eb5566c826b471977747ea3d7d6915bbe9..0c7e5bd1428e7838252bb57b7f0fbfda4ec82f02 2021-07-23 18:24:35 +0900 to 2021-08-04 10:18:22 -0700 - Document lifetime elision for fn types, Fn*, impl (rust-lang/nomicon#298) - Remove unnecessary `extern crate`s (rust-lang/nomicon#297) ## reference 3 commits in 3b7be075af5d6e402a18efff672a8a265b4596fd..4884fe45c14f8b22121760fb117181bb4da8dfe0 2021-07-26 13:20:11 -0700 to 2021-07-28 21:31:28 -0700 - Mention "function item type to `fn pointer`" coercion (rust-lang/reference#1079) - example for bindings after at (rust-lang/reference#1027) - array-expr.md: fix typo; 'polish' sentence (rust-lang/reference#1080) ## book 10 commits in a07036f864b37896b31eb996cd7aedb489f69a1f..7e49659102f0977d9142190e1ba23345c0f00eb1 2021-07-26 20:19:46 -0400 to 2021-08-03 21:41:35 -0400 - Make explicit that enum variant construction is a function - Clarify why None means we have to annotate the type - Make the convert quotes script able to do one chapter - Snapshot of chapter 5 - (rust-lang/book#2811) - (rust-lang/book#2809) - Ugh quote script, that's not right - Introduce the dbg macro. Connects to rust-lang/book#1658 - Add an example of declaring and instantiating unit-like structs. Fixes rust-lang/book#2442. - Remove authors field from all the manifests (rust-lang/book#2805) ## rustc-dev-guide 5 commits in 09343d6..c4644b4 2021-07-26 00:37:28 +0200 to 2021-08-10 20:41:44 +0900 - Remove a dead link in `new-target.md` + other nits (rust-lang/rustc-dev-guide#1186) - Add description of -opt-bisect-limit LLVM option (rust-lang/rustc-dev-guide#1182) - Fixed team responsible for stabilization (rust-lang/rustc-dev-guide#1181) - Add S-Inactive PRs as another source of things contributors could work on (rust-lang/rustc-dev-guide#1177) - git.md: Fix No-Merge Policy link ## embedded-book 1 commits in 09986cd352404eb4659db44613b27cac9aa652fc..4f9fcaa30d11ba52b641e6fd5206536d65838af9 2021-07-18 19:26:46 +0000 to 2021-08-06 17:43:12 +0000 - Fix typo in 'Memory Mapped Registers' (rust-embedded/book#298)
JohnTitor
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Aug 11, 2021
Update books ## nomicon 2 commits in f51734eb5566c826b471977747ea3d7d6915bbe9..0c7e5bd1428e7838252bb57b7f0fbfda4ec82f02 2021-07-23 18:24:35 +0900 to 2021-08-04 10:18:22 -0700 - Document lifetime elision for fn types, Fn*, impl (rust-lang/nomicon#298) - Remove unnecessary `extern crate`s (rust-lang/nomicon#297) ## reference 3 commits in 3b7be075af5d6e402a18efff672a8a265b4596fd..4884fe45c14f8b22121760fb117181bb4da8dfe0 2021-07-26 13:20:11 -0700 to 2021-07-28 21:31:28 -0700 - Mention "function item type to `fn pointer`" coercion (rust-lang/reference#1079) - example for bindings after at (rust-lang/reference#1027) - array-expr.md: fix typo; 'polish' sentence (rust-lang/reference#1080) ## book 10 commits in a07036f864b37896b31eb996cd7aedb489f69a1f..7e49659102f0977d9142190e1ba23345c0f00eb1 2021-07-26 20:19:46 -0400 to 2021-08-03 21:41:35 -0400 - Make explicit that enum variant construction is a function - Clarify why None means we have to annotate the type - Make the convert quotes script able to do one chapter - Snapshot of chapter 5 - (rust-lang/book#2811) - (rust-lang/book#2809) - Ugh quote script, that's not right - Introduce the dbg macro. Connects to rust-lang/book#1658 - Add an example of declaring and instantiating unit-like structs. Fixes rust-lang/book#2442. - Remove authors field from all the manifests (rust-lang/book#2805) ## rustc-dev-guide 5 commits in 09343d6..c4644b4 2021-07-26 00:37:28 +0200 to 2021-08-10 20:41:44 +0900 - Remove a dead link in `new-target.md` + other nits (rust-lang/rustc-dev-guide#1186) - Add description of -opt-bisect-limit LLVM option (rust-lang/rustc-dev-guide#1182) - Fixed team responsible for stabilization (rust-lang/rustc-dev-guide#1181) - Add S-Inactive PRs as another source of things contributors could work on (rust-lang/rustc-dev-guide#1177) - git.md: Fix No-Merge Policy link ## embedded-book 1 commits in 09986cd352404eb4659db44613b27cac9aa652fc..4f9fcaa30d11ba52b641e6fd5206536d65838af9 2021-07-18 19:26:46 +0000 to 2021-08-06 17:43:12 +0000 - Fix typo in 'Memory Mapped Registers' (rust-embedded/book#298)
JohnTitor
added a commit
to JohnTitor/rust
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Aug 12, 2021
Update books ## nomicon 2 commits in f51734eb5566c826b471977747ea3d7d6915bbe9..0c7e5bd1428e7838252bb57b7f0fbfda4ec82f02 2021-07-23 18:24:35 +0900 to 2021-08-04 10:18:22 -0700 - Document lifetime elision for fn types, Fn*, impl (rust-lang/nomicon#298) - Remove unnecessary `extern crate`s (rust-lang/nomicon#297) ## reference 3 commits in 3b7be075af5d6e402a18efff672a8a265b4596fd..4884fe45c14f8b22121760fb117181bb4da8dfe0 2021-07-26 13:20:11 -0700 to 2021-07-28 21:31:28 -0700 - Mention "function item type to `fn pointer`" coercion (rust-lang/reference#1079) - example for bindings after at (rust-lang/reference#1027) - array-expr.md: fix typo; 'polish' sentence (rust-lang/reference#1080) ## book 10 commits in a07036f864b37896b31eb996cd7aedb489f69a1f..7e49659102f0977d9142190e1ba23345c0f00eb1 2021-07-26 20:19:46 -0400 to 2021-08-03 21:41:35 -0400 - Make explicit that enum variant construction is a function - Clarify why None means we have to annotate the type - Make the convert quotes script able to do one chapter - Snapshot of chapter 5 - (rust-lang/book#2811) - (rust-lang/book#2809) - Ugh quote script, that's not right - Introduce the dbg macro. Connects to rust-lang/book#1658 - Add an example of declaring and instantiating unit-like structs. Fixes rust-lang/book#2442. - Remove authors field from all the manifests (rust-lang/book#2805) ## rustc-dev-guide 5 commits in 09343d6..c4644b4 2021-07-26 00:37:28 +0200 to 2021-08-10 20:41:44 +0900 - Remove a dead link in `new-target.md` + other nits (rust-lang/rustc-dev-guide#1186) - Add description of -opt-bisect-limit LLVM option (rust-lang/rustc-dev-guide#1182) - Fixed team responsible for stabilization (rust-lang/rustc-dev-guide#1181) - Add S-Inactive PRs as another source of things contributors could work on (rust-lang/rustc-dev-guide#1177) - git.md: Fix No-Merge Policy link ## embedded-book 1 commits in 09986cd352404eb4659db44613b27cac9aa652fc..4f9fcaa30d11ba52b641e6fd5206536d65838af9 2021-07-18 19:26:46 +0000 to 2021-08-06 17:43:12 +0000 - Fix typo in 'Memory Mapped Registers' (rust-embedded/book#298)
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This adds a description of the
-opt-bisect-limitLLVM option to the (very helpful!) doc on debugging LLVM. (We found this option to be essential in honing in on an LLVM optimization issue -- but it's not easy to find if you don't already know about it!)