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insert storageDead for not equal temp

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This commit is contained in:
Simon Vandel Sillesen
2020-09-20 01:09:18 +02:00
parent 2530274023
commit 118aae2af1
5 changed files with 37 additions and 11 deletions
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38
compiler/rustc_mir/src/transform/early_otherwise_branch.rs
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@@ -46,27 +46,32 @@ impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
for opt_to_apply in opts_to_apply {
trace!("SUCCESS: found optimization possibility to apply: {:?}", &opt_to_apply);
// create the patch using MirPatch
let mut patch = MirPatch::new(body);
// create temp to store second discriminant in
let discr_type = opt_to_apply.infos[0].second_switch_info.discr_ty;
let discr_span = opt_to_apply.infos[0].second_switch_info.discr_source_info.span;
let temp = patch.new_temp(discr_type, discr_span);
let statements_before =
body.basic_blocks()[opt_to_apply.basic_block_first_switch].statements.len();
let end_of_block_location = Location {
block: opt_to_apply.basic_block_first_switch,
statement_index: statements_before,
};
patch.add_statement(end_of_block_location, StatementKind::StorageLive(temp));
let mut patch = MirPatch::new(body);
// create temp to store second discriminant in
let discr_type = opt_to_apply.infos[0].second_switch_info.discr_ty;
let discr_span = opt_to_apply.infos[0].second_switch_info.discr_source_info.span;
let second_discriminant_temp = patch.new_temp(discr_type, discr_span);
patch.add_statement(
end_of_block_location,
StatementKind::StorageLive(second_discriminant_temp),
);
// create assignment of discriminant
let place_of_adt_to_get_discriminant_of =
opt_to_apply.infos[0].second_switch_info.place_of_adt_discr_read;
patch.add_assign(
end_of_block_location,
Place::from(temp),
Place::from(second_discriminant_temp),
Rvalue::Discriminant(place_of_adt_to_get_discriminant_of),
);
@@ -81,7 +86,7 @@ impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
opt_to_apply.infos[0].first_switch_info.discr_used_in_switch;
let not_equal_rvalue = Rvalue::BinaryOp(
not_equal,
Operand::Copy(Place::from(temp)),
Operand::Copy(Place::from(second_discriminant_temp)),
Operand::Copy(Place::from(first_descriminant_place)),
);
patch.add_statement(
@@ -126,8 +131,19 @@ impl<'tcx> MirPass<'tcx> for EarlyOtherwiseBranch {
),
);
// generate StorageDead for the temp not in use anymore. We use the not_equal_temp in the switch, so we can't mark that dead
patch.add_statement(end_of_block_location, StatementKind::StorageDead(temp));
// generate StorageDead for the second_discriminant_temp not in use anymore
patch.add_statement(
end_of_block_location,
StatementKind::StorageDead(second_discriminant_temp),
);
// Generate a StorageDead for not_equal_temp in each of the targets, since we moved it into the switch
for bb in [false_case, true_case].iter() {
patch.add_statement(
Location { block: *bb, statement_index: 0 },
StatementKind::StorageDead(not_equal_temp),
);
}
patch.apply(body);
}