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
+87 −62
Merged

Disable the SimplifyArmIdentity pass #73262

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
Disable the SimplifyArmIdentity pass on beta 
This pass is buggy so I'm disabling it to fix a stable-to-beta
regression.

Related to #73223
@wesleywiser
wesleywiser committed Jun 12, 2020
commit f1605834a568b26bb540e743e9dd7e25d4ad9151
6 changes: 5 additions & 1 deletion src/librustc_mir/transform/simplify_try.rs
View file
Original file line number Diff line number Diff line change
@@ -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 {
17 changes: 8 additions & 9 deletions src/test/mir-opt/simplify-arm/rustc.id.SimplifyArmIdentity.diff
View file
Original file line number Diff line number Diff line change
@@ -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
}

9 changes: 8 additions & 1 deletion src/test/mir-opt/simplify-arm/rustc.id.SimplifyBranchSame.diff
View file
Original file line number Diff line number Diff line change
@@ -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
}

34 changes: 16 additions & 18 deletions src/test/mir-opt/simplify-arm/rustc.id_result.SimplifyArmIdentity.diff
View file
Original file line number Diff line number Diff line change
@@ -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
}

@@ -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
}

43 changes: 27 additions & 16 deletions src/test/mir-opt/simplify-arm/rustc.id_result.SimplifyBranchSame.diff
View file
Original file line number Diff line number Diff line change
@@ -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
}
}
19 changes: 9 additions & 10 deletions src/test/mir-opt/simplify-arm/rustc.id_try.SimplifyArmIdentity.diff
View file
Original file line number Diff line number Diff line change
@@ -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
}
10 changes: 9 additions & 1 deletion src/test/mir-opt/simplify-arm/rustc.id_try.SimplifyBranchSame.diff
View file
Original file line number Diff line number Diff line change
@@ -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
}
11 changes: 5 additions & 6 deletions src/test/mir-opt/simplify_try_if_let/rustc.{{impl}}-append.SimplifyArmIdentity.diff
View file
Original file line number Diff line number Diff line change
@@ -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