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From: "macro@linux-mips.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug regression/63150] New: [4.9 regression] FAIL: gcc.target/powerpc/pr53199.c scan-assembler-times *
Date: Wed, 03 Sep 2014 01:16:00 -0000	[thread overview]
Message-ID: <bug-63150-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63150

            Bug ID: 63150
           Summary: [4.9 regression] FAIL: gcc.target/powerpc/pr53199.c
                    scan-assembler-times *
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: regression
          Assignee: unassigned at gcc dot gnu.org
          Reporter: macro@linux-mips.org
            Target: powerpc-linux-gnu
             Build: i686-pc-linux-gnu

I see these failures in Power/Linux testing with 4.9.1 and also trunk
(5.0), so presumably the regression happened sometime between 4.8 and
4.9:

FAIL: gcc.target/powerpc/pr53199.c scan-assembler-times lwbrx 6
FAIL: gcc.target/powerpc/pr53199.c scan-assembler-times stwbrx 6

These tests passed with 4.8.  This is with powerpc-linux-gnu.

I've looked at generated assembly and actually 2 out of 6 cases fail:
load64_reverse_2 and store64_reverse_2, the remaining 4 are fine.  In
all cases code produced looks correct, so this is a missed optimisation
rather a code correctness issue.

Options used to configure the compiler:

--build=i686-pc-linux-gnu
--target=powerpc-linux-gnu
--with-cpu-32=603e
--with-cpu-64=e5500
--with-long-double-128

Actually even with 4.8 code that the test case accepts it looks like
we've got another missed optimisation here because we do:

    lwbrx 8,0,9
    lwbrx 7,0,10
    mr 4,8
    mr 3,7
    blr

while we could do:

    lwbrx 4,0,9
    lwbrx 3,0,10
    blr

instead.  But that's of course a different matter.


             reply	other threads:[~2014-09-03  1:16 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-03  1:16 macro@linux-mips.org [this message]
2014-09-03  8:56 ` [Bug regression/63150] [4.9/5 " rguenth at gcc dot gnu.org
2014-09-03 17:10 ` segher at gcc dot gnu.org
2014-09-03 20:35 ` pthaugen at gcc dot gnu.org
2014-10-30 10:37 ` jakub at gcc dot gnu.org
2014-11-24 13:14 ` rguenth at gcc dot gnu.org
2015-02-20  0:25 ` msebor at gcc dot gnu.org
2015-03-16  3:22 ` amodra at gmail dot com
2015-03-16  3:30 ` amodra at gcc dot gnu.org
2015-03-16  8:50 ` [Bug regression/63150] [4.9 Regression] " jakub at gcc dot gnu.org
2015-03-26  8:56 ` amodra at gcc dot gnu.org
2015-03-26  9:27 ` amodra at gmail dot com

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