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In simplify_repeated_aggregate, don't test first element against itself

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This commit is contained in:
Yotam Ofek 2025-04-05 13:58:34 +00:00
parent 1e008dd5d8
commit 5b596cd28b
1 changed files with 3 additions and 3 deletions
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6
compiler/rustc_mir_transform/src/instsimplify.rs
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@ -78,20 +78,20 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
/// GVN can also do this optimization, but GVN is only run at mir-opt-level 2 so having this in /// GVN can also do this optimization, but GVN is only run at mir-opt-level 2 so having this in
/// InstSimplify helps unoptimized builds. /// InstSimplify helps unoptimized builds.
fn simplify_repeated_aggregate(&self, rvalue: &mut Rvalue<'tcx>) { fn simplify_repeated_aggregate(&self, rvalue: &mut Rvalue<'tcx>) {
let Rvalue::Aggregate(box AggregateKind::Array(_), fields) = rvalue else { let Rvalue::Aggregate(box AggregateKind::Array(_), fields) = &*rvalue else {
return; return;
}; };
if fields.len() < 5 { if fields.len() < 5 {
return; return;
} }
let first = &fields[rustc_abi::FieldIdx::ZERO]; let (first, rest) = fields[..].split_first().unwrap();
let Operand::Constant(first) = first else { let Operand::Constant(first) = first else {
return; return;
}; };
let Ok(first_val) = first.const_.eval(self.tcx, self.typing_env, first.span) else { let Ok(first_val) = first.const_.eval(self.tcx, self.typing_env, first.span) else {
return; return;
}; };
if fields.iter().all(|field| { if rest.iter().all(|field| {
let Operand::Constant(field) = field else { let Operand::Constant(field) = field else {
return false; return false;
}; };