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Do not visit rvalues twice.

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This commit is contained in:
Camille GILLOT 2023-09-23 15:08:41 +00:00
parent d28405972f
commit afd631cc0c
1 changed files with 11 additions and 8 deletions
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19
compiler/rustc_mir_transform/src/gvn.rs
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@ -484,20 +484,23 @@ fn visit_operand(&mut self, operand: &mut Operand<'tcx>, location: Location) {
}
fn visit_statement(&mut self, stmt: &mut Statement<'tcx>, location: Location) {
self.super_statement(stmt, location);
if let StatementKind::Assign(box (_, ref mut rvalue)) = stmt.kind
// Do not try to simplify a constant, it's already in canonical shape.
&& !matches!(rvalue, Rvalue::Use(Operand::Constant(_)))
&& let Some(value) = self.simplify_rvalue(rvalue, location)
{
if let Some(const_) = self.try_as_constant(value) {
*rvalue = Rvalue::Use(Operand::Constant(Box::new(const_)));
} else if let Some(local) = self.try_as_local(value, location)
&& *rvalue != Rvalue::Use(Operand::Move(local.into()))
if let Some(value) = self.simplify_rvalue(rvalue, location)
{
*rvalue = Rvalue::Use(Operand::Copy(local.into()));
self.reused_locals.insert(local);
if let Some(const_) = self.try_as_constant(value) {
*rvalue = Rvalue::Use(Operand::Constant(Box::new(const_)));
} else if let Some(local) = self.try_as_local(value, location)
&& *rvalue != Rvalue::Use(Operand::Move(local.into()))
{
*rvalue = Rvalue::Use(Operand::Copy(local.into()));
self.reused_locals.insert(local);
}
}
} else {
self.super_statement(stmt, location);
}
}
}