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Micro-optimize InstSimplify's simplify_primitive_clone

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This commit is contained in:
Yotam Ofek 2025-04-10 18:06:32 +00:00
parent 69b3959afe
commit 0069cadb9a
1 changed files with 8 additions and 17 deletions
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25
compiler/rustc_mir_transform/src/instsimplify.rs
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@ -10,7 +10,6 @@ use rustc_middle::ty::{self, GenericArgsRef, Ty, TyCtxt, layout};
use rustc_span::{DUMMY_SP, Symbol, sym}; use rustc_span::{DUMMY_SP, Symbol, sym};
use crate::simplify::simplify_duplicate_switch_targets; use crate::simplify::simplify_duplicate_switch_targets;
use crate::take_array;
pub(super) enum InstSimplify { pub(super) enum InstSimplify {
BeforeInline, BeforeInline,
@ -229,7 +228,9 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
terminator: &mut Terminator<'tcx>, terminator: &mut Terminator<'tcx>,
statements: &mut Vec<Statement<'tcx>>, statements: &mut Vec<Statement<'tcx>>,
) { ) {
let TerminatorKind::Call { func, args, destination, target, .. } = &mut terminator.kind let TerminatorKind::Call {
func, args, destination, target: Some(destination_block), ..
} = &terminator.kind
else { else {
return; return;
}; };
@ -237,15 +238,8 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
// It's definitely not a clone if there are multiple arguments // It's definitely not a clone if there are multiple arguments
let [arg] = &args[..] else { return }; let [arg] = &args[..] else { return };
let Some(destination_block) = *target else { return };
// Only bother looking more if it's easy to know what we're calling // Only bother looking more if it's easy to know what we're calling
let Some((fn_def_id, fn_args)) = func.const_fn_def() else { return }; let Some((fn_def_id, ..)) = func.const_fn_def() else { return };
// Clone needs one arg, so we can cheaply rule out other stuff
if fn_args.len() != 1 {
return;
}
// These types are easily available from locals, so check that before // These types are easily available from locals, so check that before
// doing DefId lookups to figure out what we're actually calling. // doing DefId lookups to figure out what we're actually calling.
@ -253,15 +247,12 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
let ty::Ref(_region, inner_ty, Mutability::Not) = *arg_ty.kind() else { return }; let ty::Ref(_region, inner_ty, Mutability::Not) = *arg_ty.kind() else { return };
if !inner_ty.is_trivially_pure_clone_copy() { if !self.tcx.is_lang_item(fn_def_id, LangItem::CloneFn)
|| !inner_ty.is_trivially_pure_clone_copy()
{
return; return;
} }
if !self.tcx.is_lang_item(fn_def_id, LangItem::CloneFn) {
return;
}
let Ok([arg]) = take_array(args) else { return };
let Some(arg_place) = arg.node.place() else { return }; let Some(arg_place) = arg.node.place() else { return };
statements.push(Statement { statements.push(Statement {
@ -273,7 +264,7 @@ impl<'tcx> InstSimplifyContext<'_, 'tcx> {
)), )),
))), ))),
}); });
terminator.kind = TerminatorKind::Goto { target: destination_block }; terminator.kind = TerminatorKind::Goto { target: *destination_block };
} }
fn simplify_nounwind_call(&self, terminator: &mut Terminator<'tcx>) { fn simplify_nounwind_call(&self, terminator: &mut Terminator<'tcx>) {