[Bug target/57708] New: function clobbers callee saved register on ARM

[Bug target/57708] New: function clobbers callee saved register on ARM

[mikulas at artax dot karlin.mff.cuni.cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

            Bug ID: 57708
           Summary: function clobbers callee saved register on ARM
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mikulas at artax dot karlin.mff.cuni.cz

Compile the attached code with -O3 -mcpu=cortex-a15 -marm on ARM EABI (the bug
happens with hardfp or without). The functions html_h3, html_h4, html_h5,
html_h6 clobber the register r5 and do not save it. They save only r4. The bug
is present in gcc-4.8 and gcc-4.8.1

[Bug target/57708] function clobbers callee saved register on ARM

[mikulas at artax dot karlin.mff.cuni.cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

mikulas at artax dot karlin.mff.cuni.cz changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mikulas at artax dot karlin.mff.cu
                   |                            |ni.cz

--- Comment #1 from mikulas at artax dot karlin.mff.cuni.cz ---
Created attachment 30361
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30361&action=edit
a code that reproduces the bug

[Bug target/57708] function clobbers callee saved register on ARM

[mikulas at artax dot karlin.mff.cuni.cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

--- Comment #2 from mikulas at artax dot karlin.mff.cuni.cz ---
Created attachment 30362
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30362&action=edit
another reproduction code

The code in the first attachment actually did some out-of-memory accesses
because I simplified it too much. This is the second attachment that should be
correct.

[Bug rtl-optimization/57708] [4.8 regression] function clobbers callee saved register on ARM

[rearnsha at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-08-02
          Component|target                      |rtl-optimization
            Summary|function clobbers callee    |[4.8 regression] function
                   |saved register on ARM       |clobbers callee saved
                   |                            |register on ARM
     Ever confirmed|0                           |1

--- Comment #3 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
This is a bug in peep2_find_free_register() which fails to correctly validate
that second and subsequent registers in a multi-register mode are available for
use.

Marked as a regression since this code would have worked correctly on older
compilers.

[Bug rtl-optimization/57708] [4.8 regression] function clobbers callee saved register on ARM

[rearnsha at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rearnsha at gcc dot gnu.org

[Bug rtl-optimization/57708] [4.8 regression] function clobbers callee saved register on ARM

[rearnsha at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

--- Comment #4 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Proposed patch posted here:

http://gcc.gnu.org/ml/gcc-patches/2013-08/msg00194.html

[Bug rtl-optimization/57708] [4.8 regression] function clobbers callee saved register on ARM

[rearnsha at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

Richard Earnshaw <rearnsha at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |4.8.2

--- Comment #5 from Richard Earnshaw <rearnsha at gcc dot gnu.org> ---
Fixed with:

    PR rtl-optimization/57708
    * recog.c (peep2_find_free_register): Validate all regs in a
    multi-reg mode.

Trunk revision: r201501.
gcc-4.8 revision: r201510.

[Bug rtl-optimization/57708] [4.8 regression] function clobbers callee saved register on ARM

[clyon at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57708

--- Comment #6 from clyon at gcc dot gnu.org ---
Author: clyon
Date: Mon Sep  2 14:59:09 2013
New Revision: 202176

URL: http://gcc.gnu.org/viewcvs?rev=202176&root=gcc&view=rev
Log:
2013-08-26  Kugan Vivekanandarajah  <kuganv@linaro.org>

    Backport from trunk r201501.
    2013-08-05  Richard Earnshaw  <rearnsha@arm.com>

    PR rtl-optimization/57708
    * recog.c (peep2_find_free_register): Validate all regs in a
    multi-reg mode.



Modified:
    branches/linaro/gcc-4_8-branch/gcc/ChangeLog.linaro
    branches/linaro/gcc-4_8-branch/gcc/recog.c