diff options
Diffstat (limited to 'tests/mir-opt/dataflow-const-prop/sibling_ptr.rs')
| -rw-r--r-- | tests/mir-opt/dataflow-const-prop/sibling_ptr.rs | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/tests/mir-opt/dataflow-const-prop/sibling_ptr.rs b/tests/mir-opt/dataflow-const-prop/sibling_ptr.rs index 87ef00d18..6dfb3a4ed 100644 --- a/tests/mir-opt/dataflow-const-prop/sibling_ptr.rs +++ b/tests/mir-opt/dataflow-const-prop/sibling_ptr.rs @@ -1,3 +1,10 @@ +// This attempts to modify `x.1` via a pointer derived from `addr_of_mut!(x.0)`. +// According to Miri, that is UB. However, T-opsem has not finalized that +// decision and as such we cannot rely on it in optimizations. Consequently, +// DataflowConstProp must treat the `addr_of_mut!(x.0)` as potentially being +// used to modify `x.1` - if it did not, then it might incorrectly assume that it +// can infer the value of `x.1` at the end of this function. + // unit-test: DataflowConstProp // EMIT_MIR sibling_ptr.main.DataflowConstProp.diff @@ -7,5 +14,5 @@ fn main() { let p = std::ptr::addr_of_mut!(x.0); *p.add(1) = 1; } - let x1 = x.1; // should not be propagated + let x1 = x.1; // should not be propagated } |