rust-lang/rust
1
0
Fork 0
Code Issues Pull Requests Actions 1 Packages Projects Releases Wiki Activity

Avoid constructing switch sources unless necessary

Browse Source 
Switch sources are used by backward analysis with a custom switch int
edge effects, but are otherwise unnecessarily computed.

Delay the computation until we know that switch sources are indeed
required and avoid the computation otherwise.
This commit is contained in:
Tomasz Miąsko
2022-05-08 00:00:00 +00:00
parent 83322c557f
commit fbc3cc18be
2 changed files with 6 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
compiler/rustc_mir_dataflow/src/framework/direction.rs
View File

@@ -269,9 +269,9 @@ impl Direction for Backward {
mir::TerminatorKind::SwitchInt { targets: _, ref discr, switch_ty: _ } => {
let mut applier = BackwardSwitchIntEdgeEffectsApplier {
body,
pred,
exit_state,
values: &body.switch_sources()[bb][pred],
bb,
propagate: &mut propagate,
effects_applied: false,
@@ -305,9 +305,9 @@ impl Direction for Backward {
}
struct BackwardSwitchIntEdgeEffectsApplier<'a, D, F> {
body: &'a mir::Body<'a>,
pred: BasicBlock,
exit_state: &'a mut D,
values: &'a [Option<u128>],
bb: BasicBlock,
propagate: &'a mut F,
@@ -322,7 +322,8 @@ where
fn apply(&mut self, mut apply_edge_effect: impl FnMut(&mut D, SwitchIntTarget)) {
assert!(!self.effects_applied);
let targets = self.values.iter().map(|&value| SwitchIntTarget { value, target: self.bb });
let values = &self.body.switch_sources()[self.bb][self.pred];
let targets = values.iter().map(|&value| SwitchIntTarget { value, target: self.bb });
let mut tmp = None;
for target in targets {