bjoernager/rust
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Auto merge of #88242 - bonega:allocation_range, r=oli-obk

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Use custom wrap-around type instead of RangeInclusive

Two reasons:

1. More memory is allocated than necessary for `valid_range` in `Scalar`. The range is not used as an iterator and `exhausted` is never used.
2. `contains`, `count` etc. methods in `RangeInclusive` are doing very unhelpful(and dangerous!) things when used as a wrap-around range. - In general this PR wants to limit potentially confusing methods, that have a low probability of working.

Doing a local perf run, every metric shows improvement except for instructions.
Max-rss seem to have a very consistent improvement.

Sorry - newbie here, probably doing something wrong.
This commit is contained in:
bors 2021-08-25 02:17:41 +00:00
commit e5484cec0e
8 changed files with 115 additions and 81 deletions
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8
compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs
View file

@ -406,11 +406,11 @@ fn push_debuginfo_type_name<'tcx>(
let dataful_discriminant_range =
&dataful_variant_layout.largest_niche.as_ref().unwrap().scalar.valid_range;
let min = dataful_discriminant_range.start();
let min = tag.value.size(&tcx).truncate(*min);
let min = dataful_discriminant_range.start;
let min = tag.value.size(&tcx).truncate(min);
let max = dataful_discriminant_range.end();
let max = tag.value.size(&tcx).truncate(*max);
let max = dataful_discriminant_range.end;
let max = tag.value.size(&tcx).truncate(max);
let dataful_variant_name = def.variants[*dataful_variant].ident.as_str();

8
compiler/rustc_codegen_ssa/src/mir/rvalue.rs
View file

@ -310,15 +310,15 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let er = scalar.valid_range_exclusive(bx.cx());
if er.end != er.start
&& scalar.valid_range.end() >= scalar.valid_range.start()
&& scalar.valid_range.end >= scalar.valid_range.start
{
// We want `table[e as usize ± k]` to not
// have bound checks, and this is the most
// convenient place to put the `assume`s.
if *scalar.valid_range.start() > 0 {
if scalar.valid_range.start > 0 {
let enum_value_lower_bound = bx
.cx()
.const_uint_big(ll_t_in, *scalar.valid_range.start());
.const_uint_big(ll_t_in, scalar.valid_range.start);
let cmp_start = bx.icmp(
IntPredicate::IntUGE,
llval,
@ -328,7 +328,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
}
let enum_value_upper_bound =
bx.cx().const_uint_big(ll_t_in, *scalar.valid_range.end());
bx.cx().const_uint_big(ll_t_in, scalar.valid_range.end);
let cmp_end = bx.icmp(
IntPredicate::IntULE,
llval,