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Refactor how SwitchInt stores jump targets

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This commit is contained in:
Jonas Schievink 2020-10-10 17:36:04 +02:00
parent cae8bc1f23
commit 432535da2b
22 changed files with 247 additions and 206 deletions
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14
compiler/rustc_mir/src/transform/simplify_try.rs
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@ -576,15 +576,13 @@ impl<'a, 'tcx> SimplifyBranchSameOptimizationFinder<'a, 'tcx> {
.iter_enumerated()
.filter_map(|(bb_idx, bb)| {
let (discr_switched_on, targets_and_values) = match &bb.terminator().kind {
TerminatorKind::SwitchInt { targets, discr, values, .. } => {
// if values.len() == targets.len() - 1, we need to include None where no value is present
// such that the zip does not throw away targets. If no `otherwise` case is in targets, the zip will simply throw away the added None
let values_extended = values.iter().map(|x|Some(*x)).chain(once(None));
let targets_and_values:Vec<_> = targets.iter().zip(values_extended)
.map(|(target, value)| SwitchTargetAndValue{target:*target, value})
TerminatorKind::SwitchInt { targets, discr, .. } => {
let targets_and_values: Vec<_> = targets.iter()
.map(|(val, target)| SwitchTargetAndValue { target, value: Some(val) })
.chain(once(SwitchTargetAndValue { target: targets.otherwise(), value: None }))
.collect();
assert_eq!(targets.len(), targets_and_values.len());
(discr, targets_and_values)},
(discr, targets_and_values)
},
_ => return None,
};