[Bug rtl-optimization/69567] PowerPC64: cstore optimisation produces bad code

["segher at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69567

--- Comment #9 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Fri Feb 12 18:32:21 2016
New Revision: 233384

URL: https://gcc.gnu.org/viewcvs?rev=233384&root=gcc&view=rev
Log:
combine: More distribute_notes trouble (PR69737)

PR64682 is a problem in distribute_notes, where it has trouble putting
a REG_DEAD note for a reg that is set twice in the right spot.  My fix
for that did the wrong thing for PR69567.  And then my attempted fix
for that one made PR64682 fail again.

Instead, let's just lose the note in such complicated cases, like we
already do in certain similar cases.


        Backport from mainline
        2016-02-11  Segher Boessenkool  <segher@kernel.crashing.org>

        PR rtl-optimization/64682
        PR rtl-optimization/69567
        PR rtl-optimization/69737
        * combine.c (distribute_notes) <REG_DEAD>: If the register is set
        in I2 as well, just lose it.

Modified:
    branches/gcc-5-branch/gcc/ChangeLog
    branches/gcc-5-branch/gcc/combine.c