[RFC/PATCH v2][PR89245] Check REG_CALL_DECL note during the tail-merging

[Dragan Mladjenovic]

On 01.10.2019. 21:35, Jeff Law wrote:
> On 9/6/19 4:23 AM, Dragan Mladjenovic wrote:
>> On 24.07.2019. 20:57, Jeff Law wrote:
>>> On 7/17/19 2:29 AM, Dragan Mladjenovic wrote:
>>>>
>>>>
>>>> On 09.07.2019. 23:21, Jeff Law wrote:
>>>>> On 7/9/19 2:06 PM, Dragan Mladjenovic wrote:
>>>>>> This patch prevents merging of CALL instructions that that have different
>>>>>> REG_CALL_DECL notes attached to them.
>>>>>>
>>>>>> On most architectures this is not an important distinction. Usually instruction patterns
>>>>>> for calls to different functions reference different SYMBOL_REF-s, so they won't match.
>>>>>> On MIPS PIC calls get split into an got_load/*call_internal pair where the latter represents
>>>>>> indirect register call w/o SYMBOL_REF attached (until machine_reorg pass). The bugzilla issue
>>>>>> had such two internal_call-s merged despite the fact that they had different register usage
>>>>>> information assigned by ipa-ra.
>>>>>>
>>>>>> As per comment form Richard Sandiford, this version compares reg usage for both call
>>>>>> instruction instead of shallow comparing the notes. Tests updated accordingly.
>>>>>>
>>>>>> gcc/ChangeLog:
>>>>>>
>>>>>> 2019-07-09  Dragan Mladjenovic  <dmladjenovic@wavecomp.com>
>>>>>>
>>>>>> 	* cfgcleanup.c (old_insns_match_p): Check if used hard regs set is equal
>>>>>> 	for both call instructions.
>>>>>>
>>>>>> gcc/testsuite/ChangeLog:
>>>>>>
>>>>>> 2019-07-09  Dragan Mladjenovic  <dmladjenovic@wavecomp.com>
>>>>>>
>>>>>> 	* gcc.target/mips/cfgcleanup-jalr1.c: New test.
>>>>>> 	* gcc.target/mips/cfgcleanup-jalr2.c: New test.
>>>>>> 	* gcc.target/mips/cfgcleanup-jalr3.c: New test.
>>>>> THanks.  I've installed this on the trunk.
>>>>>
>>>>> jeff
>>>> Thanks. Can this be back-ported to active branches also. This issue
>>>> seems to be there > since gcc6 if not gcc5.
>>> I've asked Matthew to handle the backport.  I'm going to be on PTO the
>>> next couple weeks.
>>>
>>> jeff
>>>
>>
>> Hi,
>>
>> Sorry, I forgot to check up on this patch. Is it still ok for me to try
>> to backport it to gcc 9 and gcc 8 branches?
> Yes, this would be fine to backport to gcc-8 and gcc-9 branches.  I'd
> expect it to be pretty easy as I don't think old_insns_match_p has
> changed much.

Thanks and sorry for the delay.
Backported as r277625 and r277626 to gcc-9 and gcc-8 branch respectively.

Best regards,
Dragan