bjoernager/rust
bjoernager/rust
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This commit is contained in:
Nicholas Nethercote 2025-02-13 10:46:34 +11:00
parent 13003100f8
commit 23dbff88f6
1 changed files with 9 additions and 2 deletions
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11
compiler/rustc_middle/src/mir/basic_blocks.rs
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@ -20,6 +20,13 @@ pub struct BasicBlocks<'tcx> {
// Typically 95%+ of basic blocks have 4 or fewer predecessors.
type Predecessors = IndexVec<BasicBlock, SmallVec<[BasicBlock; 4]>>;
/// Each `(target, switch)` entry in the map contains a list of switch values
/// that lead to a `target` block from a `switch` block.
///
/// Note: this type is currently never instantiated, because it's only used for
/// `BasicBlocks::switch_sources`, which is only called by backwards analyses
/// that do `SwitchInt` handling, and we don't have any of those, not even in
/// tests. See #95120 and #94576.
type SwitchSources = FxHashMap<(BasicBlock, BasicBlock), SmallVec<[Option<u128>; 1]>>;
#[derive(Clone, Default, Debug)]
@ -70,8 +77,8 @@ impl<'tcx> BasicBlocks<'tcx> {
})
}
/// `switch_sources()[&(target, switch)]` returns a list of switch
/// values that lead to a `target` block from a `switch` block.
/// Returns info about switch values that lead from one block to another
/// block. See `SwitchSources`.
#[inline]
pub fn switch_sources(&self) -> &SwitchSources {
self.cache.switch_sources.get_or_init(|| {