bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #109247 - saethlin:inline-without-inline, r=oli-obk

Browse source 
Permit MIR inlining without #[inline]

I noticed that there are at least a handful of portable-simd functions that have no `#[inline]` but compile to an assign + return.

I locally benchmarked inlining thresholds between 0 and 50 in increments of 5, and 50 seems to be the best. Interesting. That didn't include check builds though, ~maybe perf will have something to say about that~.

Perf has little useful to say about this. We generally regress all the check builds, as best as I can tell, due to a number of small codegen changes in a particular hot function in the compiler. Probably this is because we've nudged the inlining outcomes all over, and uses of `#[inline(always)]`/`#[inline(never)]` might need to be adjusted.
This commit is contained in:
bors 2023-04-17 02:36:38 +00:00
commit 5546cb64f6
13 changed files with 16 additions and 22 deletions
Download patch file Download diff file Expand all files Collapse all files

10
compiler/rustc_mir_transform/src/inline.rs
View file

@ -350,14 +350,8 @@ impl<'tcx> Inliner<'tcx> {
callsite: &CallSite<'tcx>,
callee_attrs: &CodegenFnAttrs,
) -> Result<(), &'static str> {
match callee_attrs.inline {
InlineAttr::Never => return Err("never inline hint"),
InlineAttr::Always | InlineAttr::Hint => {}
InlineAttr::None => {
if self.tcx.sess.mir_opt_level() <= 2 {
return Err("at mir-opt-level=2, only #[inline] is inlined");
}
}
if let InlineAttr::Never = callee_attrs.inline {
return Err("never inline hint");
}
// Only inline local functions if they would be eligible for cross-crate