Re: [PATCH] constexprify some tree variables

[Jeff Law <jeffreyalaw@gmail.com>]

On 11/18/22 19:53, Andrew Pinski wrote:
> On Fri, Nov 18, 2022 at 12:06 PM Jeff Law via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>>
>> On 11/18/22 11:05, apinski--- via Gcc-patches wrote:
>>> From: Andrew Pinski <apinski@marvell.com>
>>>
>>> Since we use C++11 by default now, we can
>>> use constexpr for some const decls in tree-core.h.
>>>
>>> This patch does that and it allows for better optimizations
>>> of GCC code with checking enabled and without LTO.
>>>
>>> For an example generic-match.cc compiling is speed up due
>>> to the less number of basic blocks and less debugging info
>>> produced. I did not check the speed of compiling the same source
>>> but rather the speed of compiling the old vs new sources here
>>> (but with the same compiler base).
>>>
>>> The small slow down in the parsing of the arrays in each TU
>>> is migrated by a speed up in how much code/debugging info
>>> is produced in the end.
>>>
>>> Note I looked at generic-match.cc since it is one of the
>>> compiling sources which causes parallel building to stall and
>>> I wanted to speed it up.
>>>
>>> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
>>> Or should this wait until GCC 13 branches off?
>>>
>>> gcc/ChangeLog:
>>>
>>>        PR middle-end/14840
>>>        * tree-core.h (tree_code_type): Constexprify
>>>        by including all-tree.def.
>>>        (tree_code_length): Likewise.
>>>        * tree.cc (tree_code_type): Remove.
>>>        (tree_code_length): Remove.
>> I would have preferred this a week ago :-)   And if it was just
>> const-ifying, I'd ACK it without hesitation.
> Yes I know which is why I am ok with waiting for GCC 14 really. I
> decided to try to clear out some of the old bug reports assigned to
> myself and this one was one of the oldest and also one of the easiest
> to do.

Let's go ahead.  It addresses a bug and should be quite safe.


Jeff