bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

InstSimplify from_raw_parts(p, ()) → p as _

Browse source
This commit is contained in:
Scott McMurray 2024-04-14 11:12:32 -07:00
parent de64ff76f8
commit 9520cebfc5
6 changed files with 48 additions and 41 deletions
Download patch file Download diff file Expand all files Collapse all files

36
compiler/rustc_mir_transform/src/instsimplify.rs
View file

@ -36,6 +36,7 @@ impl<'tcx> MirPass<'tcx> for InstSimplify {
ctx.simplify_bool_cmp(&statement.source_info, rvalue);
ctx.simplify_ref_deref(&statement.source_info, rvalue);
ctx.simplify_len(&statement.source_info, rvalue);
ctx.simplify_ptr_aggregate(&statement.source_info, rvalue);
ctx.simplify_cast(rvalue);
}
_ => {}
@ -58,8 +59,17 @@ struct InstSimplifyContext<'tcx, 'a> {
impl<'tcx> InstSimplifyContext<'tcx, '_> {
fn should_simplify(&self, source_info: &SourceInfo, rvalue: &Rvalue<'tcx>) -> bool {
self.should_simplify_custom(source_info, "Rvalue", rvalue)
}
fn should_simplify_custom(
&self,
source_info: &SourceInfo,
label: &str,
value: impl std::fmt::Debug,
) -> bool {
self.tcx.consider_optimizing(|| {
format!("InstSimplify - Rvalue: {rvalue:?} SourceInfo: {source_info:?}")
format!("InstSimplify - {label}: {value:?} SourceInfo: {source_info:?}")
})
}
@ -147,6 +157,30 @@ impl<'tcx> InstSimplifyContext<'tcx, '_> {
}
}
/// Transform "Aggregate(RawPtr, \[p, ()\])" ==> "Cast(PtrToPtr, p)".
fn simplify_ptr_aggregate(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
if let Rvalue::Aggregate(box AggregateKind::RawPtr(pointee_ty, mutability), fields) = rvalue
{
let meta_ty = fields.raw[1].ty(self.local_decls, self.tcx);
if meta_ty.is_unit() {
// The mutable borrows we're holding prevent printing `rvalue` here
if !self.should_simplify_custom(
source_info,
"Aggregate::RawPtr",
(&pointee_ty, *mutability, &fields),
) {
return;
}
let mut fields = std::mem::take(fields);
let _meta = fields.pop().unwrap();
let data = fields.pop().unwrap();
let ptr_ty = Ty::new_ptr(self.tcx, *pointee_ty, *mutability);
*rvalue = Rvalue::Cast(CastKind::PtrToPtr, data, ptr_ty);
}
}
}
fn simplify_ub_check(&self, source_info: &SourceInfo, rvalue: &mut Rvalue<'tcx>) {
if let Rvalue::NullaryOp(NullOp::UbChecks, _) = *rvalue {
let const_ = Const::from_bool(self.tcx, self.tcx.sess.ub_checks());