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nora 2022-04-17 22:13:41 +02:00
parent d5d80f79b7
commit 3b8b091406
2 changed files with 19 additions and 11 deletions
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28
rust2/src/mir/opts.rs
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@ -22,7 +22,8 @@ pub fn pass_fill_state_info<'mir>(alloc: &'mir Bump, mir: &mut Mir<'mir>) {
pass_fill_state_info_inner(alloc, mir, empty_state);
}
#[tracing::instrument(skip(alloc, mir))]
// note: this whole thing is unsound because it doesn't consider that stores inside a loop
// could be loaded from after the loop
fn pass_fill_state_info_inner<'mir>(
alloc: &'mir Bump,
mir: &mut Mir<'mir>,
@ -113,7 +114,8 @@ fn pass_dead_store_elimination(mir: &mut Mir<'_>) {
pass_dead_store_elimination_mark_dead_stores(mir)
}
fn pass_dead_store_elimination_mark_dead_stores(mir: &mut Mir<'_>) {
#[tracing::instrument(skip(mir))]
fn pass_dead_store_elimination_mark_dead_stores(mir: &Mir<'_>) {
fn mark_store(
potential_dead_stores: &mut HashMap<Offset, Store>,
offset: Offset,
@ -158,9 +160,17 @@ fn pass_dead_store_elimination_mark_dead_stores(mir: &mut Mir<'_>) {
);
}
StmtKind::PointerMove(offset) => {
current_offset -= offset; // ???
current_offset += offset; // ???
}
StmtKind::Loop(_) | StmtKind::Out => {
StmtKind::Loop(body) => {
let store = potential_dead_stores.get(&current_offset);
if let Some(store) = store {
store.add_load();
}
pass_dead_store_elimination_mark_dead_stores(body);
}
StmtKind::Out => {
let store = potential_dead_stores.get(&current_offset);
if let Some(store) = store {
store.add_load();
@ -173,11 +183,9 @@ fn pass_dead_store_elimination_mark_dead_stores(mir: &mut Mir<'_>) {
if stmt.state.has_forget_delta() {
// they might all have loads now
for store in potential_dead_stores.values_mut() {
// TODO STOP: WE MUTATE THE STATE HERE!!! ALL COOL DEAD STORES WILL BE CLOBBERED
store.clobber();
}
potential_dead_stores.values().for_each(Store::clobber);
}
info!(?potential_dead_stores, ?current_offset, "stores");
}
}
@ -191,12 +199,12 @@ fn pass_const_propagation_inner(mir: &mut Mir<'_>) {
for stmt in &mut mir.stmts {
match &mut stmt.kind {
StmtKind::Out => {
let state = stmt.state.state_for_offset(0);
let _state = stmt.state.state_for_offset(0);
// we could now insert a `SetN` before the `Out`, to mark the previous store
// as dead.
}
StmtKind::Loop(body) => {
let state = stmt.state.state_for_offset(0);
let _state = stmt.state.state_for_offset(0);
// we could now insert a `SetN` before the `Loop`, to mark the previous store
// as dead.
pass_const_propagation_inner(body);