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Auto merge of rust-lang#117783 - tmiasko:inline-ret, r=cjgillot
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 Fix insertion of statements to be executed along return edge in inlining

Inlining creates additional statements to be executed along the return
edge: an assignment to the destination, storage end for temporaries.

Previously those statements where inserted directly into a call target,
but this is incorrect when the target has other predecessors.

Avoid the issue by creating a new dedicated block for those statements.
When the block happens to be redundant it will be removed by CFG
simplification that follows inlining.

Fixes rust-lang#117355
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@bors
bors committed Nov 20, 2023
2 parents 19079cf + 1be1c2e commit 79e961f
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Showing 13 changed files with 356 additions and 725 deletions.
297 changes: 163 additions & 134 deletions compiler/rustc_mir_transform/src/inline.rs
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Large diffs are not rendered by default.

44 changes: 22 additions & 22 deletions tests/mir-opt/inline/exponential_runtime.main.Inline.panic-abort.diff
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Original file line number Diff line number Diff line change
Expand Up @@ -69,66 +69,66 @@
+ }
+
+ bb2: {
+ _4 = <() as F>::call() -> [return: bb1, unwind unreachable];
+ }
+
+ bb3: {
+ StorageDead(_7);
+ StorageDead(_6);
+ StorageDead(_5);
+ _3 = <() as F>::call() -> [return: bb3, unwind unreachable];
+ _3 = <() as F>::call() -> [return: bb2, unwind unreachable];
+ }
+
+ bb3: {
+ _4 = <() as F>::call() -> [return: bb1, unwind unreachable];
+ bb4: {
+ _7 = <() as E>::call() -> [return: bb3, unwind unreachable];
+ }
+
+ bb4: {
+ bb5: {
+ StorageDead(_10);
+ StorageDead(_9);
+ StorageDead(_8);
+ _6 = <() as E>::call() -> [return: bb5, unwind unreachable];
+ _6 = <() as E>::call() -> [return: bb4, unwind unreachable];
+ }
+
+ bb5: {
+ _7 = <() as E>::call() -> [return: bb2, unwind unreachable];
+ bb6: {
+ _10 = <() as D>::call() -> [return: bb5, unwind unreachable];
+ }
+
+ bb6: {
+ bb7: {
+ StorageDead(_13);
+ StorageDead(_12);
+ StorageDead(_11);
+ _9 = <() as D>::call() -> [return: bb7, unwind unreachable];
+ _9 = <() as D>::call() -> [return: bb6, unwind unreachable];
+ }
+
+ bb7: {
+ _10 = <() as D>::call() -> [return: bb4, unwind unreachable];
+ bb8: {
+ _13 = <() as C>::call() -> [return: bb7, unwind unreachable];
+ }
+
+ bb8: {
+ bb9: {
+ StorageDead(_16);
+ StorageDead(_15);
+ StorageDead(_14);
+ _12 = <() as C>::call() -> [return: bb9, unwind unreachable];
+ _12 = <() as C>::call() -> [return: bb8, unwind unreachable];
+ }
+
+ bb9: {
+ _13 = <() as C>::call() -> [return: bb6, unwind unreachable];
+ bb10: {
+ _16 = <() as B>::call() -> [return: bb9, unwind unreachable];
+ }
+
+ bb10: {
+ bb11: {
+ StorageDead(_19);
+ StorageDead(_18);
+ StorageDead(_17);
+ _15 = <() as B>::call() -> [return: bb11, unwind unreachable];
+ }
+
+ bb11: {
+ _16 = <() as B>::call() -> [return: bb8, unwind unreachable];
+ _15 = <() as B>::call() -> [return: bb10, unwind unreachable];
+ }
+
+ bb12: {
+ _18 = <() as A>::call() -> [return: bb13, unwind unreachable];
+ }
+
+ bb13: {
+ _19 = <() as A>::call() -> [return: bb10, unwind unreachable];
+ _19 = <() as A>::call() -> [return: bb11, unwind unreachable];
}
}

44 changes: 22 additions & 22 deletions tests/mir-opt/inline/exponential_runtime.main.Inline.panic-unwind.diff
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Original file line number Diff line number Diff line change
Expand Up @@ -69,66 +69,66 @@
+ }
+
+ bb2: {
+ _4 = <() as F>::call() -> [return: bb1, unwind continue];
+ }
+
+ bb3: {
+ StorageDead(_7);
+ StorageDead(_6);
+ StorageDead(_5);
+ _3 = <() as F>::call() -> [return: bb3, unwind continue];
+ _3 = <() as F>::call() -> [return: bb2, unwind continue];
+ }
+
+ bb3: {
+ _4 = <() as F>::call() -> [return: bb1, unwind continue];
+ bb4: {
+ _7 = <() as E>::call() -> [return: bb3, unwind continue];
+ }
+
+ bb4: {
+ bb5: {
+ StorageDead(_10);
+ StorageDead(_9);
+ StorageDead(_8);
+ _6 = <() as E>::call() -> [return: bb5, unwind continue];
+ _6 = <() as E>::call() -> [return: bb4, unwind continue];
+ }
+
+ bb5: {
+ _7 = <() as E>::call() -> [return: bb2, unwind continue];
+ bb6: {
+ _10 = <() as D>::call() -> [return: bb5, unwind continue];
+ }
+
+ bb6: {
+ bb7: {
+ StorageDead(_13);
+ StorageDead(_12);
+ StorageDead(_11);
+ _9 = <() as D>::call() -> [return: bb7, unwind continue];
+ _9 = <() as D>::call() -> [return: bb6, unwind continue];
+ }
+
+ bb7: {
+ _10 = <() as D>::call() -> [return: bb4, unwind continue];
+ bb8: {
+ _13 = <() as C>::call() -> [return: bb7, unwind continue];
+ }
+
+ bb8: {
+ bb9: {
+ StorageDead(_16);
+ StorageDead(_15);
+ StorageDead(_14);
+ _12 = <() as C>::call() -> [return: bb9, unwind continue];
+ _12 = <() as C>::call() -> [return: bb8, unwind continue];
+ }
+
+ bb9: {
+ _13 = <() as C>::call() -> [return: bb6, unwind continue];
+ bb10: {
+ _16 = <() as B>::call() -> [return: bb9, unwind continue];
+ }
+
+ bb10: {
+ bb11: {
+ StorageDead(_19);
+ StorageDead(_18);
+ StorageDead(_17);
+ _15 = <() as B>::call() -> [return: bb11, unwind continue];
+ }
+
+ bb11: {
+ _16 = <() as B>::call() -> [return: bb8, unwind continue];
+ _15 = <() as B>::call() -> [return: bb10, unwind continue];
+ }
+
+ bb12: {
+ _18 = <() as A>::call() -> [return: bb13, unwind continue];
+ }
+
+ bb13: {
+ _19 = <() as A>::call() -> [return: bb10, unwind continue];
+ _19 = <() as A>::call() -> [return: bb11, unwind continue];
}
}

42 changes: 42 additions & 0 deletions tests/mir-opt/inline/indirect_destination.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,42 @@
// Test for inlining with an indirect destination place.
//
// unit-test: Inline
// edition: 2021
// needs-unwind
#![crate_type = "lib"]
#![feature(custom_mir, core_intrinsics)]
use core::intrinsics::mir::*;

#[custom_mir(dialect = "runtime", phase = "initial")]
// CHECK-LABEL: fn f(
// CHECK: bb1: {
// CHECK-NEXT: StorageLive([[A:.*]]);
// CHECK-NEXT: [[A]] = &mut (*_1);
// CHECK-NEXT: StorageLive([[B:.*]]);
// CHECK-NEXT: [[B]] = const 42_u8;
// CHECK-NEXT: (*[[A]]) = move [[B]];
// CHECK-NEXT: StorageDead([[B]]);
// CHECK-NEXT: StorageDead([[A]]);
// CHECK-NEXT: goto -> bb1;
// CHECK-NEXT: }
pub fn f(a: *mut u8) {
mir! {
{
Goto(bb1)
}
bb1 = {
Call(*a = g(), bb1, UnwindUnreachable())
}
}
}

#[custom_mir(dialect = "runtime", phase = "initial")]
#[inline(always)]
fn g() -> u8 {
mir! {
{
RET = 42;
Return()
}
}
}
22 changes: 11 additions & 11 deletions tests/mir-opt/inline/inline_coroutine.main.Inline.panic-abort.diff
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Original file line number Diff line number Diff line change
Expand Up @@ -50,20 +50,20 @@
bb1: {
- _3 = &mut _4;
- _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}>::new(move _3) -> [return: bb2, unwind unreachable];
+ StorageDead(_7);
+ StorageDead(_6);
+ StorageDead(_5);
+ StorageDead(_2);
+ drop(_4) -> [return: bb2, unwind unreachable];
+ StorageDead(_4);
+ _0 = const ();
+ StorageDead(_1);
+ return;
}

bb2: {
- StorageDead(_3);
- _1 = <{coroutine@$DIR/inline_coroutine.rs:19:5: 19:8} as Coroutine<bool>>::resume(move _2, const false) -> [return: bb3, unwind unreachable];
+ StorageDead(_4);
+ _0 = const ();
+ StorageDead(_1);
+ return;
+ StorageDead(_7);
+ StorageDead(_6);
+ StorageDead(_5);
+ StorageDead(_2);
+ drop(_4) -> [return: bb1, unwind unreachable];
}

bb3: {
Expand All @@ -90,7 +90,7 @@
+ bb6: {
+ _1 = CoroutineState::<i32, bool>::Yielded(move _8);
+ discriminant((*_6)) = 3;
+ goto -> bb1;
+ goto -> bb2;
+ }
+
+ bb7: {
Expand All @@ -102,7 +102,7 @@
+ StorageDead(_8);
+ _1 = CoroutineState::<i32, bool>::Complete(_5);
+ discriminant((*_6)) = 1;
+ goto -> bb1;
+ goto -> bb2;
+ }
+
+ bb9: {
Expand Down
74 changes: 38 additions & 36 deletions tests/mir-opt/inline/inline_coroutine.main.Inline.panic-unwind.diff
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Original file line number Diff line number Diff line change
Expand Up @@ -34,18 +34,10 @@
StorageLive(_3);
StorageLive(_4);
- _4 = g() -> [return: bb1, unwind continue];
- }
-
- bb1: {
+ _4 = {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8 (#0)};
_3 = &mut _4;
- _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}>::new(move _3) -> [return: bb2, unwind: bb5];
- }
-
- bb2: {
+ _3 = &mut _4;
+ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}> { pointer: move _3 };
StorageDead(_3);
- _1 = <{coroutine@$DIR/inline_coroutine.rs:19:5: 19:8} as Coroutine<bool>>::resume(move _2, const false) -> [return: bb3, unwind: bb5];
+ StorageDead(_3);
+ StorageLive(_5);
+ _5 = const false;
+ StorageLive(_6);
Expand All @@ -55,40 +47,50 @@
+ switchInt(move _7) -> [0: bb5, 1: bb9, 3: bb10, otherwise: bb11];
}

bb1: {
- _3 = &mut _4;
- _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}>::new(move _3) -> [return: bb2, unwind: bb5];
+ StorageDead(_4);
+ _0 = const ();
+ StorageDead(_1);
+ return;
}

- bb2: {
- StorageDead(_3);
- _1 = <{coroutine@$DIR/inline_coroutine.rs:19:5: 19:8} as Coroutine<bool>>::resume(move _2, const false) -> [return: bb3, unwind: bb5];
+ bb2 (cleanup): {
+ drop(_4) -> [return: bb3, unwind terminate(cleanup)];
}

- bb3: {
+ bb1: {
+ StorageDead(_7);
+ StorageDead(_6);
+ StorageDead(_5);
StorageDead(_2);
- StorageDead(_2);
- drop(_4) -> [return: bb4, unwind: bb6];
+ drop(_4) -> [return: bb2, unwind: bb4];
+ bb3 (cleanup): {
+ resume;
}

- bb4: {
+ bb2: {
StorageDead(_4);
_0 = const ();
StorageDead(_1);
return;
bb4: {
- StorageDead(_4);
- _0 = const ();
- StorageDead(_1);
- return;
+ StorageDead(_7);
+ StorageDead(_6);
+ StorageDead(_5);
+ StorageDead(_2);
+ drop(_4) -> [return: bb1, unwind: bb3];
}

- bb5 (cleanup): {
- drop(_4) -> [return: bb6, unwind terminate(cleanup)];
+ bb3 (cleanup): {
+ drop(_4) -> [return: bb4, unwind terminate(cleanup)];
}

- bb6 (cleanup): {
+ bb4 (cleanup): {
resume;
+ }
+
+ bb5: {
+ StorageLive(_8);
+ switchInt(_5) -> [0: bb6, otherwise: bb7];
+ }
+
}

- bb6 (cleanup): {
- resume;
+ bb6: {
+ _8 = const 13_i32;
+ goto -> bb8;
Expand All @@ -102,19 +104,19 @@
+ bb8: {
+ _1 = CoroutineState::<i32, bool>::Yielded(move _8);
+ discriminant((*_6)) = 3;
+ goto -> bb1;
+ goto -> bb4;
+ }
+
+ bb9: {
+ assert(const false, "coroutine resumed after completion") -> [success: bb9, unwind: bb3];
+ assert(const false, "coroutine resumed after completion") -> [success: bb9, unwind: bb2];
+ }
+
+ bb10: {
+ StorageLive(_8);
+ StorageDead(_8);
+ _1 = CoroutineState::<i32, bool>::Complete(_5);
+ discriminant((*_6)) = 1;
+ goto -> bb1;
+ goto -> bb4;
+ }
+
+ bb11: {
Expand Down
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