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: [PR80693] drop value of parallel SETs dropped by combine


On May 18, 2017, Alexandre Oliva <aoliva@redhat.com> wrote:

> When an insn used by combine has multiple SETs, only the non-REG_UNUSED
> set is used: others will end up dropped on the floor.  We have to take
> note of the dropped REG_UNUSED SETs, clearing their cached values, so
> that, even if the REGs remain used (e.g. because they were referenced
> in the used SET_SRC), we will not use properties of the latest value
> as if they applied to the earlier one.

> Regstrapped on x86_64-linux-gnu.  Ok to install?

> for  gcc/ChangeLog

> 	PR rtl-optimization/80693
> 	* combine.c (distribute_notes): Add IDEST parameter.  Reset any
> 	REG_UNUSED REGs that are not IDEST, if IDEST is given.  Adjust
> 	all callers.

> for  gcc/testsuite/ChangeLog

> 	PR rtl-optimization/80693
> 	* gcc.dg/pr80693.c: New.

Ping?

https://gcc.gnu.org/ml/gcc-patches/2017-05/msg01444.html

-- 
Alexandre Oliva, freedom fighter    http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer


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