diff options
| -rw-r--r-- | compiler/rustc_mir/src/transform/instcombine.rs | 5 | ||||
| -rw-r--r-- | src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff | 2 | ||||
| -rw-r--r-- | src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff | 2 | ||||
| -rw-r--r-- | src/test/mir-opt/inst_combine_deref.rs | 2 | ||||
| -rw-r--r-- | src/test/ui/issues/issue-78192.rs | 17 |
5 files changed, 25 insertions, 3 deletions
diff --git a/compiler/rustc_mir/src/transform/instcombine.rs b/compiler/rustc_mir/src/transform/instcombine.rs index c5c14ca7cae..59b7db24319 100644 --- a/compiler/rustc_mir/src/transform/instcombine.rs +++ b/compiler/rustc_mir/src/transform/instcombine.rs @@ -119,6 +119,11 @@ impl OptimizationFinder<'b, 'tcx> { } fn find_deref_of_address(&mut self, rvalue: &Rvalue<'tcx>, location: Location) -> Option<()> { + // FIXME(#78192): This optimization can result in unsoundness. + if !self.tcx.sess.opts.debugging_opts.unsound_mir_opts { + return None; + } + // Look for the sequence // // _2 = &_1; diff --git a/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff b/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff index feef65f52eb..4fd1b8b2276 100644 --- a/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff +++ b/src/test/mir-opt/const_prop/ref_deref.main.ConstProp.diff @@ -19,7 +19,7 @@ // + span: $DIR/ref_deref.rs:5:6: 5:10 // + literal: Const { ty: &i32, val: Unevaluated(WithOptConstParam { did: DefId(0:3 ~ ref_deref[317d]::main), const_param_did: None }, [], Some(promoted[0])) } _2 = _4; // scope 0 at $DIR/ref_deref.rs:5:6: 5:10 -- _1 = (*_4); // scope 0 at $DIR/ref_deref.rs:5:5: 5:10 +- _1 = (*_2); // scope 0 at $DIR/ref_deref.rs:5:5: 5:10 + _1 = const 4_i32; // scope 0 at $DIR/ref_deref.rs:5:5: 5:10 StorageDead(_2); // scope 0 at $DIR/ref_deref.rs:5:10: 5:11 StorageDead(_1); // scope 0 at $DIR/ref_deref.rs:5:10: 5:11 diff --git a/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff b/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff index 7ec0751263f..812c7c97718 100644 --- a/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff +++ b/src/test/mir-opt/const_prop/ref_deref_project.main.ConstProp.diff @@ -19,7 +19,7 @@ // + span: $DIR/ref_deref_project.rs:5:6: 5:17 // + literal: Const { ty: &(i32, i32), val: Unevaluated(WithOptConstParam { did: DefId(0:3 ~ ref_deref_project[317d]::main), const_param_did: None }, [], Some(promoted[0])) } _2 = &((*_4).1: i32); // scope 0 at $DIR/ref_deref_project.rs:5:6: 5:17 - _1 = ((*_4).1: i32); // scope 0 at $DIR/ref_deref_project.rs:5:5: 5:17 + _1 = (*_2); // scope 0 at $DIR/ref_deref_project.rs:5:5: 5:17 StorageDead(_2); // scope 0 at $DIR/ref_deref_project.rs:5:17: 5:18 StorageDead(_1); // scope 0 at $DIR/ref_deref_project.rs:5:17: 5:18 _0 = const (); // scope 0 at $DIR/ref_deref_project.rs:4:11: 6:2 diff --git a/src/test/mir-opt/inst_combine_deref.rs b/src/test/mir-opt/inst_combine_deref.rs index 3be8c2f3ac7..78361c33660 100644 --- a/src/test/mir-opt/inst_combine_deref.rs +++ b/src/test/mir-opt/inst_combine_deref.rs @@ -1,4 +1,4 @@ -// compile-flags: -O +// compile-flags: -O -Zunsound-mir-opts // EMIT_MIR inst_combine_deref.simple_opt.InstCombine.diff fn simple_opt() -> u64 { let x = 5; diff --git a/src/test/ui/issues/issue-78192.rs b/src/test/ui/issues/issue-78192.rs new file mode 100644 index 00000000000..b5c3001599a --- /dev/null +++ b/src/test/ui/issues/issue-78192.rs @@ -0,0 +1,17 @@ +// run-pass + +#![allow(unused_assignments)] + +fn main() { + let a = 1u32; + let b = 2u32; + + let mut c: *const u32 = &a; + let d: &u32 = &b; + + let x = unsafe { &*c }; + c = d; + let z = *x; + + assert_eq!(1, z); +} |