mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

remove unnecessary and ineffective caching

Browse Source
This commit is contained in:
Erik Desjardins 2021-03-17 20:24:29 -04:00
parent b6d5b728b3
commit 1205e82578
1 changed files with 9 additions and 22 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
compiler/rustc_mir/src/transform/remove_zsts.rs
View File

@ -1,7 +1,6 @@
//! Removes assignments to ZST places.
use crate::transform::MirPass;
use rustc_data_structures::fx::FxHashMap;
use rustc_middle::mir::{Body, StatementKind};
use rustc_middle::ty::TyCtxt;
@ -10,27 +9,14 @@
impl<'tcx> MirPass<'tcx> for RemoveZsts {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let param_env = tcx.param_env(body.source.def_id());
let (basic_blocks, local_decls) = body.basic_blocks_and_local_decls_mut();
let mut is_zst_cache = FxHashMap::default();
for block in basic_blocks.iter_mut() {
for statement in block.statements.iter_mut() {
match statement.kind {
StatementKind::Assign(box (place, _)) => {
let place_ty = place.ty(local_decls, tcx).ty;
let is_inhabited_zst = *is_zst_cache.entry(place_ty).or_insert_with(|| {
if let Ok(layout) = tcx.layout_of(param_env.and(place_ty)) {
if layout.is_zst() && !layout.abi.is_uninhabited() {
return true;
}
}
false
});
if is_inhabited_zst {
if tcx.consider_optimizing(|| {
format!(
"RemoveZsts - Place: {:?} SourceInfo: {:?}",
@ -41,6 +27,7 @@ fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
}
}
}
}
_ => {}
}
}