[PATCH] [GCC] Don't use section anchors for declarations that don't fit in a single anchor range

[Richard Biener]

On Tue, Aug 16, 2016 at 6:06 PM, Jeff Law <law@redhat.com> wrote:
> On 08/16/2016 08:01 AM, Tamar Christina wrote:
>>
>>
>> Hi All,
>>
>> This patch turns off the usage of section anchors for
>> declarations that do not fit in a single anchor range.
>> A large enough object will use the full anchor range
>> and also force the use of another anchor pointer.
>>
>> By not using an anchor for large objects more globals
>> can share the same anchor.
>>
>> The patch has been benchmarked using Spec2000 and
>> the impact on performance is negligible, however some files
>> using large arrays showed a appreciable reduction in amount of
>> instructions in the assembly file.
>>
>> Regression tests were run on aarch64-none-elf and no regressions.
>>
>> Ok for trunk?
>>
>> 2016-08-16  Tamar Christina  <tamar.christina@arm.com>
>>         Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
>>
>>     * gcc/varasm.c
>>     (default_use_anchors_for_symbol_p): Reject too large decls.
>
> Do you have to worry about DECL_SIZE being non-constant here or are those
> filtered out earlier?

Globals can't have variable size.

Richard.

> jeff