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

[Jeff Law <law@redhat.com>]

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