[Bug rtl-optimization/38449] New: delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[Bug rtl-optimization/38449] New: delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[amylaar at gcc dot gnu dot org]

I see an assemble failure for gcc.dg/tree-prof/bb-reorg.c; compare-and-branch
instructions are modified to jump to another section.

Some jumps simply can't be made cross-section; one for the ones that can, it
is essential that the REG_CROSSING_JUMP note is added.

I have this patch:

        * hooks.c (hook_bool_const_rtx_const_rtx_true): New function.
        * hooks.h (hook_bool_const_rtx_const_rtx_true): Declare.
        * target.h (can_follow_jump): New hook.
        * target-def.h (TARGET_CAN_FOLLOW_JUMP): Define.
        (TARGET_INITIALIZER): Include it.
        * reorg.c (follow_jumps): New parameters jump and cp.
        Changed all callers.
        * config/arc/arc.c (arc_can_follow_jump): New function.
        (TARGET_CAN_FOLLOW_JUMP): Override.
        * config/arc/arc.md (jump_i): If a REG_CROSSING_JUMP is present,
        length is 4.

Which I can post with a tm.texi patch once our Copyright assignment has been
acknowledged.


-- 
           Summary: delay branch scheduling follows REG_CROSSING_JUMP jumps
                    indiscriminately
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: assemble-failure
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: amylaar at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

[Bug rtl-optimization/38449] delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[steven at gcc dot gnu dot org]

------- Comment #1 from steven at gcc dot gnu dot org  2008-12-08 20:06 -------
What is target dependent about this, that you need a target hook for it?


-- 

steven at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-12-08 20:06:02
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

[Bug rtl-optimization/38449] delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[amylaar at gcc dot gnu dot org]

------- Comment #2 from amylaar at gcc dot gnu dot org  2008-12-08 20:36 -------
(In reply to comment #1)
> What is target dependent about this, that you need a target hook for it?

Some jumps are OK to be made section crossing, while others are not.
And which ones are OK also depends on target options - the ARCompact
architecture has branches with 21 and 25 bit offset range.  These may cross
section
boundaries if the binary is not too large.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

[Bug rtl-optimization/38449] delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[amylaar at gcc dot gnu dot org]

-- 

amylaar at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|39302                       |
OtherBugsDependingO|                            |39363
              nThis|                            |
         AssignedTo|unassigned at gcc dot gnu   |amylaar at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
           Keywords|                            |patch
   Last reconfirmed|2008-12-08 20:06:02         |2009-03-04 22:38:47
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

[Bug rtl-optimization/38449] delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[amylaar at gcc dot gnu dot org]

------- Comment #3 from amylaar at gcc dot gnu dot org  2009-03-05 00:30 -------
The patch is here:
http://gcc.gnu.org/ml/gcc-patches/2009-03/msg00249.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

[Bug rtl-optimization/38449] delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[amylaar at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

--- Comment #4 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> 2012-09-30 19:25:53 UTC ---
Author: amylaar
Date: Sun Sep 30 19:25:49 2012
New Revision: 191878

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191878
Log:
        PR rtl-optimization/38449:
        * hooks.c (hook_bool_const_rtx_const_rtx_true): New function.
        * hooks.h (hook_bool_const_rtx_const_rtx_true): Declare.
        * target.def: Merge in definitions and documentation for
        TARGET_CAN_FOLLOW_JUMP.
        * doc/tm.texi.in: Add documentation locations for the above.
        * doc/tm.texi: Regenerate.
        * reorg.c (follow_jumps): New parameters jump and crossing.
        Changed all callers.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/doc/tm.texi
    trunk/gcc/doc/tm.texi.in
    trunk/gcc/hooks.c
    trunk/gcc/hooks.h
    trunk/gcc/reorg.c
    trunk/gcc/target.def

[Bug rtl-optimization/38449] delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

--- Comment #5 from Steven Bosscher <steven at gcc dot gnu.org> 2013-04-18 21:49:14 UTC ---
Can this new hook replace MD_CAN_REDIRECT_BRANCH?

[Bug rtl-optimization/38449] delay branch scheduling follows REG_CROSSING_JUMP jumps indiscriminately

[amylaar at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38449

--- Comment #6 from Jorn Wolfgang Rennecke <amylaar at gcc dot gnu.org> 2013-04-22 14:10:02 UTC ---
(In reply to comment #5)
> Can this new hook replace MD_CAN_REDIRECT_BRANCH?

I think so.  I'll look into making a patch for that.