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Don't repeatedly simplify already-simplified match pairs

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This commit is contained in:
Nadrieril 2024-02-10 20:46:08 +01:00
parent e86c82296f
commit 308b4824aa
2 changed files with 11 additions and 15 deletions
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18
compiler/rustc_mir_build/src/build/matches/simplify.rs
View File

@ -59,22 +59,17 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
//
// final bindings: [6, 7, 4, 5, 1, 2, 3]
let mut accumulated_bindings = mem::take(candidate_bindings);
// Repeatedly simplify match pairs until fixed point is reached
let mut simplified_match_pairs = Vec::new();
// Repeatedly simplify match pairs until we're left with only unsimplifiable ones.
loop {
let mut changed = false;
for match_pair in mem::take(match_pairs) {
match self.simplify_match_pair(
if let Err(match_pair) = self.simplify_match_pair(
match_pair,
candidate_bindings,
candidate_ascriptions,
match_pairs,
) {
Ok(()) => {
changed = true;
}
Err(match_pair) => {
match_pairs.push(match_pair);
}
simplified_match_pairs.push(match_pair);
}
}
@ -83,14 +78,15 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
mem::swap(candidate_bindings, &mut accumulated_bindings);
candidate_bindings.clear();
if !changed {
// If we were not able to simplify anymore, done.
if match_pairs.is_empty() {
break;
}
}
// Store computed bindings back in `candidate_bindings`.
mem::swap(candidate_bindings, &mut accumulated_bindings);
// Store simplified match pairs back in `match_pairs`.
mem::swap(match_pairs, &mut simplified_match_pairs);
// Move or-patterns to the end, because they can result in us
// creating additional candidates, so we want to test them as

8
tests/mir-opt/exponential_or.match_tuple.SimplifyCfg-initial.after.mir
View File

@ -19,7 +19,8 @@ fn match_tuple(_1: (u32, bool, Option<i32>, u32)) -> u32 {
bb0: {
PlaceMention(_1);
switchInt((_1.0: u32)) -> [1: bb2, 4: bb2, otherwise: bb1];
_2 = discriminant((_1.2: std::option::Option<i32>));
switchInt(move _2) -> [0: bb3, 1: bb2, otherwise: bb1];
}
bb1: {
@ -28,12 +29,11 @@ fn match_tuple(_1: (u32, bool, Option<i32>, u32)) -> u32 {
}
bb2: {
_2 = discriminant((_1.2: std::option::Option<i32>));
switchInt(move _2) -> [0: bb4, 1: bb3, otherwise: bb1];
switchInt((((_1.2: std::option::Option<i32>) as Some).0: i32)) -> [1: bb3, 8: bb3, otherwise: bb1];
}
bb3: {
switchInt((((_1.2: std::option::Option<i32>) as Some).0: i32)) -> [1: bb4, 8: bb4, otherwise: bb1];
switchInt((_1.0: u32)) -> [1: bb4, 4: bb4, otherwise: bb1];
}
bb4: {