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Only emit != assumptions if the otherwise target is reachable.

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This commit is contained in:
Camille GILLOT
2023-09-24 08:27:42 +00:00
parent 096196d5b0
commit cb918904fe
11 changed files with 148 additions and 58 deletions
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13
compiler/rustc_mir_transform/src/unreachable_prop.rs
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@@ -116,22 +116,21 @@ fn remove_successors_from_switch<'tcx>(
patch.add_statement(location, StatementKind::Intrinsic(Box::new(assume)));
};
let otherwise = targets.otherwise();
let otherwise_unreachable = is_unreachable(otherwise);
let reachable_iter = targets.iter().filter(|&(value, bb)| {
let is_unreachable = is_unreachable(bb);
if is_unreachable {
// We remove this target from the switch, so record the inequality using `Assume`.
// We remove this target from the switch, so record the inequality using `Assume`.
if is_unreachable && !otherwise_unreachable {
add_assumption(BinOp::Ne, value);
false
} else {
true
}
!is_unreachable
});
let otherwise = targets.otherwise();
let new_targets = SwitchTargets::new(reachable_iter, otherwise);
let num_targets = new_targets.all_targets().len();
let otherwise_unreachable = is_unreachable(otherwise);
let fully_unreachable = num_targets == 1 && otherwise_unreachable;
let terminator = match (num_targets, otherwise_unreachable) {