On 4/16/19 6:55 AM, Richard Biener wrote:
>
> The following makes the C++ FEs heavy use of build_qualified_type
> cheaper. When looking at a tramp3d -fsyntax-only compile you can
> see that for 470.000 build_qualified_type calls we end up
> with 9.492.205 calls to check_qualified_type (thus we visit around
> 20 variant type candidates) ending up finding it in all but
> 15.300 cases that end up in build_variant_type_copy.
>
> That's of course because the FE uses this machinery to do things like
>
> bool
> same_type_ignoring_top_level_qualifiers_p (tree type1, tree type2)
> {
> if (type1 == error_mark_node || type2 == error_mark_node)
> return false;
>
> type1 = cp_build_qualified_type (type1, TYPE_UNQUALIFIED);
> type2 = cp_build_qualified_type (type2, TYPE_UNQUALIFIED);
> return same_type_p (type1, type2);
>
> but so it be. The improvement is to re-organize get_qualified_type
> to put found type variants on the head of the variant list. This
> improves the number of calls to check_qualified_type to 1.215.030
> thus around 2.5 candidates.
>
> Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
>
> Comments? OK?
>
> Richard.
>
> 2019-04-16 Richard Biener <rguent...@suse.de>
>
> * tree.c (get_qualified_type): Put found type variants at the
> head of the variant list.
Seems quite reasonable to me. I just hope we don't find a case where
this is the exact worst case behavior ;-)
jeff
