This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

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



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.

Thanks in advance,

Dragan

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]