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Auto merge of #117359 - tmiasko:call-def, r=cjgillot

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Fix def-use check for call terminators

Fixes #117331.
This commit is contained in:
bors 2023-11-15 01:31:46 +00:00
commit 6d069a0ac7
4 changed files with 93 additions and 30 deletions
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19
compiler/rustc_middle/src/mir/mod.rs
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@ -1611,14 +1611,29 @@ impl Location {
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum DefLocation {
Argument,
Body(Location),
Assignment(Location),
CallReturn { call: BasicBlock, target: Option<BasicBlock> },
}
impl DefLocation {
pub fn dominates(self, location: Location, dominators: &Dominators<BasicBlock>) -> bool {
match self {
DefLocation::Argument => true,
DefLocation::Body(def) => def.successor_within_block().dominates(location, dominators),
DefLocation::Assignment(def) => {
def.successor_within_block().dominates(location, dominators)
}
DefLocation::CallReturn { target: None, .. } => false,
DefLocation::CallReturn { call, target: Some(target) } => {
// The definition occurs on the call -> target edge. The definition dominates a use
// if and only if the edge is on all paths from the entry to the use.
//
// Note that a call terminator has only one edge that can reach the target, so when
// the call strongly dominates the target, all paths from the entry to the target
// go through the call -> target edge.
call != target
&& dominators.dominates(call, target)
&& dominators.dominates(target, location.block)
}
}
}
}