Re: ira.c update_equiv_regs patch causes gcc/testsuite/gcc.target/arm/pr43920-2.c regression

[Alex Velenko <Alex dot Velenko at arm dot com>]

On 31/07/15 12:04, Alex Velenko wrote:
> On 29/07/15 23:14, Jeff Law wrote:
> > On 07/28/2015 12:18 PM, Alex Velenko wrote:
> > > On 21/04/15 06:27, Jeff Law wrote:
> > > > On 04/20/2015 01:09 AM, Shiva Chen wrote:
> > > > > Hi, Jeff
> > > > >
> > > > > Thanks for your advice.
> > > > >
> > > > > can_replace_by.patch is the new patch to handle both cases.
> > > > >
> > > > > pr43920-2.c.244r.jump2.ori is the original  jump2 rtl dump
> > > > >
> > > > > pr43920-2.c.244r.jump2.patch_can_replace_by is the jump2 rtl dump
> > > > > after patch  can_replace_by.patch
> > > > >
> > > > > Could you help me to review the patch?
> > > > Thanks.  This looks pretty good.
> > > >
> > > > I expanded the comment for the new function a bit and renamed the
> > > > function in an effort to clarify its purpose.  From reviewing
> > > > can_replace_by, it seems it should have been handling this case, but
> > > > clearly wasn't due to implementation details.
> > > >
> > > > I then bootstrapped and regression tested the patch on 
> > > > x86_64-linux-gnu
> > > > where it passed.  I also instrumented that compiler to see how often
> > > > this code triggers.  During a bootstrap it triggers a couple hundred
> > > > times (which is obviously a proxy for cross jumping improvements).  So
> > > > it's triggering regularly on x86_64, which is good.
> > > >
> > > > I also verified that this fixes BZ64916 for an arm-non-eabi toolchain
> > > > configured with --with-arch=armv7.
> > > >
> > > > Installed on the trunk.  No new testcase as it's covered by existing
> > > > tests.
> > > >
> > > > Thanks,,
> > > > jeff
> > >
> > > Hi,
> > > I see this patch been committed in r222256 on trunk. Is it okay to port
> > > this to fsf-5?
> > It's not a regression, so backporting it would be generally frowned
> > upon.  If you feel strongly about it, you should ask Jakub, Joseph or
> > Richi (the release managers) for an exception to the general policy.
> >
> > jeff
> Hi Jakub,
> Can this commit be ported to fsf-5? It fixed gcc.target/arm/pr43920-2.c
> at the time, so I think it is a good idea to port. Please, see
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64916
> Kind regards,
> Alex

Ping!

Currently this test is passed on fsf-trunk, but not passed on fsf-5, so 
I think it is a regression on fsf-5:

arm-none-eabi fsf-5:
PASS: gcc.target/arm/pr43920-2.c (test for excess errors)
FAIL: gcc.target/arm/pr43920-2.c scan-assembler-times pop 2
PASS: gcc.target/arm/pr43920-2.c scan-assembler-times beq 3
Executing on host: arm-none-eabi-size pr43920-2.o   (timeout = 300)
spawn arm-none-eabi-size pr43920-2.o
   text       data        bss        dec        hex    filename
     58          0          0         58         3a    pr43920-2.o
text size is 58
FAIL: gcc.target/arm/pr43920-2.c object-size text <= 54

arm-none-eabi fsf-trunk:

PASS: gcc.target/arm/pr43920-2.c (test for excess errors)
PASS: gcc.target/arm/pr43920-2.c scan-assembler-times pop 2
PASS: gcc.target/arm/pr43920-2.c scan-assembler-times beq 3
size is arm-none-eabi-size
Executing on host: arm-none-eabi-size pr43920-2.o   (timeout = 300)
spawn arm-none-eabi-size pr43920-2.o
   text       data        bss        dec        hex    filename
     54          0          0         54         36    pr43920-2.o
text size is 54
PASS: gcc.target/arm/pr43920-2.c object-size text <= 54

Can this, please, be ported?
Kind regards,
Alex