Use successor location for dominator check.

cjgillot · cjgillot · commit 263da251af6b · 2023-01-27T18:22:45.000Z
The assignment is complete only after the statement.
This marks self-assignments `x = x + 1` as non-sSA.
diff --git a/compiler/rustc_mir_transform/src/ssa.rs b/compiler/rustc_mir_transform/src/ssa.rs
@@ -162,7 +162,7 @@ impl<'tcx> Visitor<'tcx> for SsaVisitor {
                     Set1::Empty | Set1::Many => false,
                     Set1::One(LocationExtended::Arg) => true,
                     Set1::One(LocationExtended::Plain(assign)) => {
-                        assign.dominates(loc, &self.dominators)
+                        assign.successor_within_block().dominates(loc, &self.dominators)
                     }
                 };
                 // We are visiting a use that is not dominated by an assignment.

Original file line number	Diff line number	Diff line change
`@@ -162,7 +162,7 @@ impl<'tcx> Visitor<'tcx> for SsaVisitor {`
`162`	`162`	`Set1::Empty \| Set1::Many => false,`
`163`	`163`	`Set1::One(LocationExtended::Arg) => true,`
`164`	`164`	`Set1::One(LocationExtended::Plain(assign)) => {`
`165`		`- assign.dominates(loc, &self.dominators)`
	`165`	`+ assign.successor_within_block().dominates(loc, &self.dominators)`
`166`	`166`	`}`
`167`	`167`	`};`
`168`	`168`	`// We are visiting a use that is not dominated by an assignment.`