Auto merge of #88839 - nbdd0121:alignof, r=nagisa

Introduce NullOp::AlignOf

This PR introduces `Rvalue::NullaryOp(NullOp::AlignOf, ty)`, which will be lowered from `align_of`, similar to `size_of` lowering to `Rvalue::NullaryOp(NullOp::SizeOf, ty)`.

The changes are originally part of #88700 but since it's not dependent on other changes and could have performance impact on its own, it's separated into its own PR.
This commit is contained in:
bors 2021-09-12 23:49:24 +00:00
commit 02d3c132ae
2 changed files with 9 additions and 4 deletions

View File

@ -726,15 +726,20 @@ fn is_fat_ptr<'tcx>(fx: &FunctionCx<'_, '_, 'tcx>, ty: Ty<'tcx>) -> bool {
let ptr = fx.bcx.inst_results(call)[0];
lval.write_cvalue(fx, CValue::by_val(ptr, box_layout));
}
Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
Rvalue::NullaryOp(null_op, ty) => {
assert!(
lval.layout()
.ty
.is_sized(fx.tcx.at(stmt.source_info.span), ParamEnv::reveal_all())
);
let ty_size = fx.layout_of(fx.monomorphize(ty)).size.bytes();
let layout = fx.layout_of(fx.monomorphize(ty));
let val = match null_op {
NullOp::SizeOf => layout.size.bytes(),
NullOp::AlignOf => layout.align.abi.bytes(),
NullOp::Box => unreachable!(),
};
let val =
CValue::const_val(fx, fx.layout_of(fx.tcx.types.usize), ty_size.into());
CValue::const_val(fx, fx.layout_of(fx.tcx.types.usize), val.into());
lval.write_cvalue(fx, val);
}
Rvalue::Aggregate(ref kind, ref operands) => match kind.as_ref() {

View File

@ -823,7 +823,7 @@ fn swap(bcx: &mut FunctionBuilder<'_>, v: Value) -> Value {
dest.write_cvalue(fx, val);
};
pref_align_of | min_align_of | needs_drop | type_id | type_name | variant_count, () {
pref_align_of | needs_drop | type_id | type_name | variant_count, () {
let const_val =
fx.tcx.const_eval_instance(ParamEnv::reveal_all(), instance, None).unwrap();
let val = crate::constant::codegen_const_value(