Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Disable the SimplifyArmIdentity pass #73262

Merged
merged 1 commit into from
Jun 12, 2020
Merged

Disable the SimplifyArmIdentity pass #73262

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 5 additions & 1 deletion src/librustc_mir/transform/simplify_try.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -306,7 +306,11 @@ fn optimization_applies<'tcx>(
}

impl<'tcx> MirPass<'tcx> for SimplifyArmIdentity {
fn run_pass(&self, _: TyCtxt<'tcx>, source: MirSource<'tcx>, body: &mut Body<'tcx>) {
fn run_pass(&self, tcx: TyCtxt<'tcx>, source: MirSource<'tcx>, body: &mut Body<'tcx>) {
if tcx.sess.opts.debugging_opts.mir_opt_level < 2 {
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Uh, could we maybe not keep buggy passes running at all? I think a -Zmir-opt-level=3 miscompilation is a soundness bug just like it would be at a lower optimization level.

C/C++ programmers seem to associate "high optimization levels" with "creates buggy code", but really that's awful and we shouldn't do it.

Copy link
Member Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

@RalfJung I opened a related MCP: rust-lang/compiler-team#319

If you have thoughts about it, please leave a comment there. Thanks!

return;
}

trace!("running SimplifyArmIdentity on {:?}", source);
let (basic_blocks, local_decls) = body.basic_blocks_and_local_decls_mut();
for bb in basic_blocks {
Expand Down
17 changes: 8 additions & 9 deletions src/test/mir-opt/simplify-arm/rustc.id.SimplifyArmIdentity.diff
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,15 +26,14 @@
}

bb3: {
- StorageLive(_3); // scope 0 at $DIR/simplify-arm.rs:11:14: 11:15
- _3 = ((_1 as Some).0: u8); // scope 0 at $DIR/simplify-arm.rs:11:14: 11:15
- StorageLive(_4); // scope 1 at $DIR/simplify-arm.rs:11:25: 11:26
- _4 = _3; // scope 1 at $DIR/simplify-arm.rs:11:25: 11:26
- ((_0 as Some).0: u8) = move _4; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
- discriminant(_0) = 1; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
- StorageDead(_4); // scope 1 at $DIR/simplify-arm.rs:11:26: 11:27
- StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:11:27: 11:28
+ _0 = move _1; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
StorageLive(_3); // scope 0 at $DIR/simplify-arm.rs:11:14: 11:15
_3 = ((_1 as Some).0: u8); // scope 0 at $DIR/simplify-arm.rs:11:14: 11:15
StorageLive(_4); // scope 1 at $DIR/simplify-arm.rs:11:25: 11:26
_4 = _3; // scope 1 at $DIR/simplify-arm.rs:11:25: 11:26
((_0 as Some).0: u8) = move _4; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
discriminant(_0) = 1; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
StorageDead(_4); // scope 1 at $DIR/simplify-arm.rs:11:26: 11:27
StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:11:27: 11:28
goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:10:5: 13:6
}

Expand Down
9 changes: 8 additions & 1 deletion src/test/mir-opt/simplify-arm/rustc.id.SimplifyBranchSame.diff
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,14 @@
}

bb3: {
_0 = move _1; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
StorageLive(_3); // scope 0 at $DIR/simplify-arm.rs:11:14: 11:15
_3 = ((_1 as Some).0: u8); // scope 0 at $DIR/simplify-arm.rs:11:14: 11:15
StorageLive(_4); // scope 1 at $DIR/simplify-arm.rs:11:25: 11:26
_4 = _3; // scope 1 at $DIR/simplify-arm.rs:11:25: 11:26
((_0 as Some).0: u8) = move _4; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
discriminant(_0) = 1; // scope 1 at $DIR/simplify-arm.rs:11:20: 11:27
StorageDead(_4); // scope 1 at $DIR/simplify-arm.rs:11:26: 11:27
StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:11:27: 11:28
goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:10:5: 13:6
}

Expand Down
34 changes: 16 additions & 18 deletions src/test/mir-opt/simplify-arm/rustc.id_result.SimplifyArmIdentity.diff
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -22,15 +22,14 @@
}

bb1: {
- StorageLive(_5); // scope 0 at $DIR/simplify-arm.rs:19:13: 19:14
- _5 = ((_1 as Err).0: i32); // scope 0 at $DIR/simplify-arm.rs:19:13: 19:14
- StorageLive(_6); // scope 2 at $DIR/simplify-arm.rs:19:23: 19:24
- _6 = _5; // scope 2 at $DIR/simplify-arm.rs:19:23: 19:24
- ((_0 as Err).0: i32) = move _6; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
- discriminant(_0) = 1; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
- StorageDead(_6); // scope 2 at $DIR/simplify-arm.rs:19:24: 19:25
- StorageDead(_5); // scope 0 at $DIR/simplify-arm.rs:19:25: 19:26
+ _0 = move _1; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
StorageLive(_5); // scope 0 at $DIR/simplify-arm.rs:19:13: 19:14
_5 = ((_1 as Err).0: i32); // scope 0 at $DIR/simplify-arm.rs:19:13: 19:14
StorageLive(_6); // scope 2 at $DIR/simplify-arm.rs:19:23: 19:24
_6 = _5; // scope 2 at $DIR/simplify-arm.rs:19:23: 19:24
((_0 as Err).0: i32) = move _6; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
discriminant(_0) = 1; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
StorageDead(_6); // scope 2 at $DIR/simplify-arm.rs:19:24: 19:25
StorageDead(_5); // scope 0 at $DIR/simplify-arm.rs:19:25: 19:26
goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:17:5: 20:6
}

Expand All @@ -39,15 +38,14 @@
}

bb3: {
- StorageLive(_3); // scope 0 at $DIR/simplify-arm.rs:18:12: 18:13
- _3 = ((_1 as Ok).0: u8); // scope 0 at $DIR/simplify-arm.rs:18:12: 18:13
- StorageLive(_4); // scope 1 at $DIR/simplify-arm.rs:18:21: 18:22
- _4 = _3; // scope 1 at $DIR/simplify-arm.rs:18:21: 18:22
- ((_0 as Ok).0: u8) = move _4; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
- discriminant(_0) = 0; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
- StorageDead(_4); // scope 1 at $DIR/simplify-arm.rs:18:22: 18:23
- StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:18:23: 18:24
+ _0 = move _1; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
StorageLive(_3); // scope 0 at $DIR/simplify-arm.rs:18:12: 18:13
_3 = ((_1 as Ok).0: u8); // scope 0 at $DIR/simplify-arm.rs:18:12: 18:13
StorageLive(_4); // scope 1 at $DIR/simplify-arm.rs:18:21: 18:22
_4 = _3; // scope 1 at $DIR/simplify-arm.rs:18:21: 18:22
((_0 as Ok).0: u8) = move _4; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
discriminant(_0) = 0; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
StorageDead(_4); // scope 1 at $DIR/simplify-arm.rs:18:22: 18:23
StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:18:23: 18:24
goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:17:5: 20:6
}

Expand Down
43 changes: 27 additions & 16 deletions src/test/mir-opt/simplify-arm/rustc.id_result.SimplifyBranchSame.diff
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -18,27 +18,38 @@

bb0: {
_2 = discriminant(_1); // scope 0 at $DIR/simplify-arm.rs:18:9: 18:14
- switchInt(move _2) -> [0isize: bb3, 1isize: bb1, otherwise: bb2]; // scope 0 at $DIR/simplify-arm.rs:18:9: 18:14
+ goto -> bb1; // scope 0 at $DIR/simplify-arm.rs:18:9: 18:14
switchInt(move _2) -> [0isize: bb3, 1isize: bb1, otherwise: bb2]; // scope 0 at $DIR/simplify-arm.rs:18:9: 18:14
}

bb1: {
- _0 = move _1; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
- goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:17:5: 20:6
- }
-
- bb2: {
- unreachable; // scope 0 at $DIR/simplify-arm.rs:17:11: 17:12
- }
-
- bb3: {
_0 = move _1; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
- goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:17:5: 20:6
+ goto -> bb2; // scope 0 at $DIR/simplify-arm.rs:17:5: 20:6
StorageLive(_5); // scope 0 at $DIR/simplify-arm.rs:19:13: 19:14
_5 = ((_1 as Err).0: i32); // scope 0 at $DIR/simplify-arm.rs:19:13: 19:14
StorageLive(_6); // scope 2 at $DIR/simplify-arm.rs:19:23: 19:24
_6 = _5; // scope 2 at $DIR/simplify-arm.rs:19:23: 19:24
((_0 as Err).0: i32) = move _6; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
discriminant(_0) = 1; // scope 2 at $DIR/simplify-arm.rs:19:19: 19:25
StorageDead(_6); // scope 2 at $DIR/simplify-arm.rs:19:24: 19:25
StorageDead(_5); // scope 0 at $DIR/simplify-arm.rs:19:25: 19:26
goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:17:5: 20:6
}

- bb4: {
+ bb2: {
bb2: {
unreachable; // scope 0 at $DIR/simplify-arm.rs:17:11: 17:12
}

bb3: {
StorageLive(_3); // scope 0 at $DIR/simplify-arm.rs:18:12: 18:13
_3 = ((_1 as Ok).0: u8); // scope 0 at $DIR/simplify-arm.rs:18:12: 18:13
StorageLive(_4); // scope 1 at $DIR/simplify-arm.rs:18:21: 18:22
_4 = _3; // scope 1 at $DIR/simplify-arm.rs:18:21: 18:22
((_0 as Ok).0: u8) = move _4; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
discriminant(_0) = 0; // scope 1 at $DIR/simplify-arm.rs:18:18: 18:23
StorageDead(_4); // scope 1 at $DIR/simplify-arm.rs:18:22: 18:23
StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:18:23: 18:24
goto -> bb4; // scope 0 at $DIR/simplify-arm.rs:17:5: 20:6
}

bb4: {
return; // scope 0 at $DIR/simplify-arm.rs:21:2: 21:2
}
}
Expand Down
19 changes: 9 additions & 10 deletions src/test/mir-opt/simplify-arm/rustc.id_try.SimplifyArmIdentity.diff
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,17 +49,16 @@
}

bb2: {
- StorageLive(_10); // scope 0 at $DIR/simplify-arm.rs:24:13: 24:15
- _10 = ((_3 as Ok).0: u8); // scope 0 at $DIR/simplify-arm.rs:24:13: 24:15
- _2 = _10; // scope 5 at $DIR/simplify-arm.rs:24:13: 24:15
- StorageDead(_10); // scope 0 at $DIR/simplify-arm.rs:24:14: 24:15
+ _0 = move _3; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
StorageLive(_10); // scope 0 at $DIR/simplify-arm.rs:24:13: 24:15
_10 = ((_3 as Ok).0: u8); // scope 0 at $DIR/simplify-arm.rs:24:13: 24:15
_2 = _10; // scope 5 at $DIR/simplify-arm.rs:24:13: 24:15
StorageDead(_10); // scope 0 at $DIR/simplify-arm.rs:24:14: 24:15
StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:24:15: 24:16
- StorageLive(_11); // scope 1 at $DIR/simplify-arm.rs:25:8: 25:9
- _11 = _2; // scope 1 at $DIR/simplify-arm.rs:25:8: 25:9
- ((_0 as Ok).0: u8) = move _11; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
- discriminant(_0) = 0; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
- StorageDead(_11); // scope 1 at $DIR/simplify-arm.rs:25:9: 25:10
StorageLive(_11); // scope 1 at $DIR/simplify-arm.rs:25:8: 25:9
_11 = _2; // scope 1 at $DIR/simplify-arm.rs:25:8: 25:9
((_0 as Ok).0: u8) = move _11; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
discriminant(_0) = 0; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
StorageDead(_11); // scope 1 at $DIR/simplify-arm.rs:25:9: 25:10
StorageDead(_2); // scope 0 at $DIR/simplify-arm.rs:26:1: 26:2
goto -> bb5; // scope 0 at $DIR/simplify-arm.rs:26:2: 26:2
}
Expand Down
10 changes: 9 additions & 1 deletion src/test/mir-opt/simplify-arm/rustc.id_try.SimplifyBranchSame.diff
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -49,8 +49,16 @@
}

bb2: {
_0 = move _3; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
StorageLive(_10); // scope 0 at $DIR/simplify-arm.rs:24:13: 24:15
_10 = ((_3 as Ok).0: u8); // scope 0 at $DIR/simplify-arm.rs:24:13: 24:15
_2 = _10; // scope 5 at $DIR/simplify-arm.rs:24:13: 24:15
StorageDead(_10); // scope 0 at $DIR/simplify-arm.rs:24:14: 24:15
StorageDead(_3); // scope 0 at $DIR/simplify-arm.rs:24:15: 24:16
StorageLive(_11); // scope 1 at $DIR/simplify-arm.rs:25:8: 25:9
_11 = _2; // scope 1 at $DIR/simplify-arm.rs:25:8: 25:9
((_0 as Ok).0: u8) = move _11; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
discriminant(_0) = 0; // scope 1 at $DIR/simplify-arm.rs:25:5: 25:10
StorageDead(_11); // scope 1 at $DIR/simplify-arm.rs:25:9: 25:10
StorageDead(_2); // scope 0 at $DIR/simplify-arm.rs:26:1: 26:2
goto -> bb5; // scope 0 at $DIR/simplify-arm.rs:26:2: 26:2
}
Expand Down
11 changes: 5 additions & 6 deletions src/test/mir-opt/simplify_try_if_let/rustc.{{impl}}-append.SimplifyArmIdentity.diff
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -80,12 +80,11 @@
StorageLive(_8); // scope 1 at $DIR/simplify_try_if_let.rs:26:29: 26:39
_8 = ((_5 as Some).0: std::ptr::NonNull<Node>); // scope 1 at $DIR/simplify_try_if_let.rs:26:29: 26:39
StorageLive(_9); // scope 3 at $DIR/simplify_try_if_let.rs:28:46: 28:62
- StorageLive(_10); // scope 3 at $DIR/simplify_try_if_let.rs:28:51: 28:61
- _10 = _8; // scope 3 at $DIR/simplify_try_if_let.rs:28:51: 28:61
- ((_9 as Some).0: std::ptr::NonNull<Node>) = move _10; // scope 3 at $DIR/simplify_try_if_let.rs:28:46: 28:62
- discriminant(_9) = 1; // scope 3 at $DIR/simplify_try_if_let.rs:28:46: 28:62
- StorageDead(_10); // scope 3 at $DIR/simplify_try_if_let.rs:28:61: 28:62
+ _9 = move _5; // scope 3 at $DIR/simplify_try_if_let.rs:28:46: 28:62
StorageLive(_10); // scope 3 at $DIR/simplify_try_if_let.rs:28:51: 28:61
_10 = _8; // scope 3 at $DIR/simplify_try_if_let.rs:28:51: 28:61
((_9 as Some).0: std::ptr::NonNull<Node>) = move _10; // scope 3 at $DIR/simplify_try_if_let.rs:28:46: 28:62
discriminant(_9) = 1; // scope 3 at $DIR/simplify_try_if_let.rs:28:46: 28:62
StorageDead(_10); // scope 3 at $DIR/simplify_try_if_let.rs:28:61: 28:62
StorageLive(_11); // scope 3 at $DIR/simplify_try_if_let.rs:28:25: 28:38
StorageLive(_12); // scope 3 at $DIR/simplify_try_if_let.rs:28:25: 28:29
_12 = &mut _4; // scope 3 at $DIR/simplify_try_if_let.rs:28:25: 28:29
Expand Down