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match lowering: Remove hacky branch in sort_candidate #121706

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Merged
merged 2 commits into from
Mar 2, 2024
Merged

match lowering: Remove hacky branch in sort_candidate #121706

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5e11a99
Remove hacky branch in `sort_candidate`
Nadrieril Feb 15, 2024
f363c1a
Group default cases in `sort_candidate`
Nadrieril Feb 20, 2024
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51 changes: 17 additions & 34 deletions compiler/rustc_mir_build/src/build/matches/test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -575,10 +575,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
fully_matched = true;
Some(variant_index.as_usize())
}
(&TestKind::Switch { .. }, _) => {
fully_matched = false;
None
}

// If we are performing a switch over integers, then this informs integer
// equality, but nothing else.
Expand All @@ -603,10 +599,6 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
options.len()
})
}
(&TestKind::SwitchInt { .. }, _) => {
fully_matched = false;
None
}

(
&TestKind::Len { len: test_len, op: BinOp::Eq },
Expand Down Expand Up @@ -695,34 +687,25 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
None
}
}
(&TestKind::Range { .. }, _) => {
fully_matched = false;
None
}

(&TestKind::Eq { .. } | &TestKind::Len { .. }, _) => {
// The call to `self.test(&match_pair)` below is not actually used to generate any
// MIR. Instead, we just want to compare with `test` (the parameter of the method)
// to see if it is the same.
//
// However, at this point we can still encounter or-patterns that were extracted
// from previous calls to `sort_candidate`, so we need to manually address that
// case to avoid panicking in `self.test()`.
if let TestCase::Or { .. } = &match_pair.test_case {
return None;
}
// FIXME(#29623): return `Some(1)` when the values are different.
(TestKind::Eq { value: test_val, .. }, TestCase::Constant { value: case_val })
if test_val == case_val =>
{
fully_matched = true;
Some(0)
}

// These are all binary tests.
//
// FIXME(#29623) we can be more clever here
let pattern_test = self.test(match_pair);
if pattern_test.kind == test.kind {
fully_matched = true;
Some(0)
} else {
fully_matched = false;
None
}
(
TestKind::Switch { .. }
| TestKind::SwitchInt { .. }
| TestKind::Len { .. }
| TestKind::Range { .. }
| TestKind::Eq { .. },
_,
) => {
fully_matched = false;
None
}
};

Expand Down