diff --git a/tests/mir-opt/simplify_aggregate_to_copy_miscompile.foo.GVN.diff b/tests/mir-opt/simplify_aggregate_to_copy_miscompile.foo.GVN.diff new file mode 100644 index 00000000000..22d4277ee45 --- /dev/null +++ b/tests/mir-opt/simplify_aggregate_to_copy_miscompile.foo.GVN.diff @@ -0,0 +1,72 @@ +- // MIR for `foo` before GVN ++ // MIR for `foo` after GVN + + fn foo(_1: &mut Option) -> Option { + debug v => _1; + let mut _0: std::option::Option; + let mut _2: &std::option::Option; + let mut _3: &std::option::Option; + let _4: &&mut std::option::Option; + let mut _5: isize; + let mut _7: !; + let mut _8: std::option::Option; + let mut _9: i32; + let mut _10: !; + let mut _11: &mut std::option::Option; + scope 1 { + debug col => _6; + let _6: i32; + } + + bb0: { +- StorageLive(_2); ++ nop; + StorageLive(_3); + StorageLive(_4); + _4 = &_1; +- _11 = deref_copy (*_4); +- _3 = &(*_11); ++ _11 = copy _1; ++ _3 = &(*_1); + _2 = get(move _3) -> [return: bb1, unwind unreachable]; + } + + bb1: { + StorageDead(_3); + _5 = discriminant((*_2)); + switchInt(move _5) -> [1: bb2, otherwise: bb3]; + } + + bb2: { +- StorageLive(_6); ++ nop; + _6 = copy (((*_2) as Some).0: i32); + StorageLive(_8); +- _8 = Option::::None; +- (*_1) = move _8; ++ _8 = const Option::::None; ++ (*_1) = const Option::::None; + StorageDead(_8); + StorageLive(_9); + _9 = copy _6; +- _0 = Option::::Some(move _9); ++ _0 = copy (*_2); + StorageDead(_9); +- StorageDead(_6); ++ nop; + StorageDead(_4); +- StorageDead(_2); ++ nop; + return; + } + + bb3: { + StorageLive(_10); + unreachable; + } ++ } ++ ++ ALLOC0 (size: 8, align: 4) { ++ 00 00 00 00 __ __ __ __ │ ....░░░░ + } + diff --git a/tests/mir-opt/simplify_aggregate_to_copy_miscompile.rs b/tests/mir-opt/simplify_aggregate_to_copy_miscompile.rs new file mode 100644 index 00000000000..47721b768be --- /dev/null +++ b/tests/mir-opt/simplify_aggregate_to_copy_miscompile.rs @@ -0,0 +1,32 @@ +//! The `simplify_aggregate_to_copy` mir-opt introduced in +//! caused a miscompile because the initial +//! implementation +//! +//! > introduce[d] new dereferences without checking for aliasing +//! +//! This test demonstrates the behavior, and should be adjusted or removed when fixing and relanding +//! the mir-opt. +#![crate_type = "lib"] +// skip-filecheck +//@ compile-flags: -O -Zunsound-mir-opts +//@ test-mir-pass: GVN +#![allow(internal_features)] +#![feature(rustc_attrs, core_intrinsics)] + +// EMIT_MIR simplify_aggregate_to_copy_miscompile.foo.GVN.diff +#[no_mangle] +fn foo(v: &mut Option) -> Option { + if let &Some(col) = get(&v) { + *v = None; + return Some(col); + } else { + unsafe { std::intrinsics::unreachable() } + } +} + +#[no_mangle] +#[inline(never)] +#[rustc_nounwind] +fn get(v: &Option) -> &Option { + v +}