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Auto merge of #123444 - saethlin:const-eval-inline-cycles, r=tmiasko

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Teach MIR inliner query cycle avoidance about const_eval_select

Fixes https://github.com/rust-lang/rust/issues/122659

r? tmiasko
This commit is contained in:
bors 2024-04-05 04:34:05 +00:00
commit c0ddaef075
2 changed files with 32 additions and 4 deletions
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18
compiler/rustc_mir_transform/src/inline/cycle.rs
View file

@ -5,6 +5,7 @@ use rustc_middle::mir::TerminatorKind;
use rustc_middle::ty::TypeVisitableExt; use rustc_middle::ty::TypeVisitableExt;
use rustc_middle::ty::{self, GenericArgsRef, InstanceDef, TyCtxt}; use rustc_middle::ty::{self, GenericArgsRef, InstanceDef, TyCtxt};
use rustc_session::Limit; use rustc_session::Limit;
use rustc_span::sym;
// FIXME: check whether it is cheaper to precompute the entire call graph instead of invoking // FIXME: check whether it is cheaper to precompute the entire call graph instead of invoking
// this query ridiculously often. // this query ridiculously often.
@ -164,11 +165,20 @@ pub(crate) fn mir_inliner_callees<'tcx>(
let mut calls = FxIndexSet::default(); let mut calls = FxIndexSet::default();
for bb_data in body.basic_blocks.iter() { for bb_data in body.basic_blocks.iter() {
let terminator = bb_data.terminator(); let terminator = bb_data.terminator();
if let TerminatorKind::Call { func, .. } = &terminator.kind { if let TerminatorKind::Call { func, args: call_args, .. } = &terminator.kind {
let ty = func.ty(&body.local_decls, tcx); let ty = func.ty(&body.local_decls, tcx);
let call = match ty.kind() { let ty::FnDef(def_id, generic_args) = ty.kind() else {
ty::FnDef(def_id, args) => (*def_id, *args), continue;
_ => continue, };
let call = if tcx.is_intrinsic(*def_id, sym::const_eval_select) {
let func = &call_args[2].node;
let ty = func.ty(&body.local_decls, tcx);
let ty::FnDef(def_id, generic_args) = ty.kind() else {
continue;
};
(*def_id, *generic_args)
} else {
(*def_id, *generic_args)
}; };
calls.insert(call); calls.insert(call);
} }

18
tests/ui/mir/const_eval_select_cycle.rs Normal file
View file

@ -0,0 +1,18 @@
// Regression test for #122659
//@ build-pass
//@ compile-flags: -O --crate-type=lib
#![feature(core_intrinsics)]
#![feature(const_eval_select)]
use std::intrinsics::const_eval_select;
#[inline]
pub const fn f() {
const_eval_select((), g, g)
}
#[inline]
pub const fn g() {
const_eval_select((), f, f)
}