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compiler: Don't mark SingleUseConsts MIR pass as "required for soundness"

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Because:
* Something like it did not exist before PR 107404
* That it is not run our mir-opt-level 0 indicates that it is not
  required for soundness
* Its `MirPass::can_be_overridden()` is unchanged and thus returns true,
  indicating that it is not a required MIR pass.
* No test fails in PR 151426 that stops enabling by default in non-optimized builds

As can be seen from the updated test `tests/mir-opt/optimize_none.rs`,
this means that `#[optimize(none)]` functions become even less
optimized. As expected and as desired.
This commit is contained in:
Martin Nordholts 2026-02-16 20:56:23 +01:00
parent 47611e1604
commit 52b19f7dda
2 changed files with 5 additions and 4 deletions
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2
compiler/rustc_mir_transform/src/single_use_consts.rs
View file

@ -85,7 +85,7 @@ impl<'tcx> crate::MirPass<'tcx> for SingleUseConsts {
}
fn is_required(&self) -> bool {
true
false
}
}

7
tests/mir-opt/optimize_none.rs
View file

@ -15,13 +15,14 @@ pub fn add_noopt() -> i32 {
#[optimize(none)]
pub fn const_branch() -> i32 {
// CHECK-LABEL: fn const_branch(
// CHECK: switchInt(const true) -> [0: [[FALSE:bb[0-9]+]], otherwise: [[TRUE:bb[0-9]+]]];
// CHECK: [[BOOL:_[0-9]+]] = const true;
// CHECK: switchInt(move [[BOOL]]) -> [0: [[BB_FALSE:bb[0-9]+]], otherwise: [[BB_TRUE:bb[0-9]+]]];
// CHECK-NEXT: }
// CHECK: [[FALSE]]: {
// CHECK: [[BB_FALSE]]: {
// CHECK-NEXT: _0 = const 0
// CHECK-NEXT: goto
// CHECK-NEXT: }
// CHECK: [[TRUE]]: {
// CHECK: [[BB_TRUE]]: {
// CHECK-NEXT: _0 = const 1
// CHECK-NEXT: goto
// CHECK-NEXT: }