[Bug optimization/13169] New: asm using r30 or r31 confuses global_alloc

[Bug optimization/13169] New: asm using r30 or r31 confuses global_alloc

[amodra at gcc dot gnu dot org]

This testcase demonstrates a problem with global_alloc of registers
   that are mentioned as a "from" register in ELIMINATE_REGS.
   When compiled with -O0 -fomit-frame-pointer, this testcase returns a
   zero status.  When compiled with -O1 or higher, it returns 1.

   Notes: rs6000.h mentions both r31 and r30 as a "from" register in
   ELIMINATE_REGS.

   global.c:global_alloc does

  for (i = 0; i < ARRAY_SIZE (eliminables); i++)
    {
      SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from);

      if (! CAN_ELIMINATE (eliminables[i].from, eliminables[i].to)
	  || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp))
	SET_HARD_REG_BIT (no_global_alloc_regs, eliminables[i].from);
    }

   resulting in both r30 and r31 being set in eliminable_regset,
   and *not* in no_global_alloc_regs.  Later we have

      /* Eliminate conflicts between pseudos and eliminable registers.  If
	 the register is not eliminated, the pseudo won't really be able to
	 live in the eliminable register, so the conflict doesn't matter.
	 If we do eliminate the register, the conflict will no longer exist.
	 So in either case, we can ignore the conflict.  Likewise for
	 preferences.  */

      for (i = 0; i < (size_t) max_allocno; i++)
	{
	  AND_COMPL_HARD_REG_SET (allocno[i].hard_reg_conflicts,
				  eliminable_regset);
	  AND_COMPL_HARD_REG_SET (allocno[i].hard_reg_copy_preferences,
				  eliminable_regset);
	  AND_COMPL_HARD_REG_SET (allocno[i].hard_reg_preferences,
				  eliminable_regset);
	}

    Removing r30 and r31 from hard_reg_conflicts allows them to be used
    willy nilly as global regs, when really they should remain as
    conflicts because they're used by the asm.  :-(

-- 
           Summary: asm using r30 or r31 confuses global_alloc
           Product: gcc
           Version: 3.4
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P2
         Component: optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: amodra at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169

[Bug optimization/13169] asm using r30 or r31 confuses global_alloc

[amodra at gcc dot gnu dot org]

------- Additional Comments From amodra at gcc dot gnu dot org  2003-11-24 03:29 -------
Created an attachment (id=5197)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5197&action=view)
testcase


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169

[Bug optimization/13169] asm using r30 or r31 confuses global_alloc

[amodra at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |amodra at gcc dot gnu dot
                   |dot org                     |org
             Status|UNCONFIRMED                 |ASSIGNED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169

[Bug optimization/13169] asm using r30 or r31 confuses global_alloc

[amodra at gcc dot gnu dot org]

------- Additional Comments From amodra at gcc dot gnu dot org  2003-11-24 15:22 -------
Proposed fix http://gcc.gnu.org/ml/gcc-patches/2003-11/msg01924.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169

[Bug optimization/13169] asm using r30 or r31 confuses global_alloc

[pinskia at gcc dot gnu dot org]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
   Target Milestone|---                         |3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169

[Bug optimization/13169] asm using r30 or r31 confuses global_alloc

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2003-12-06 12:22 -------
Subject: Bug 13169

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	amodra@gcc.gnu.org	2003-12-06 12:22:31

Modified files:
	gcc            : ChangeLog basic-block.h final.c flow.c global.c 
	                 regs.h 

Log message:
	PR 13169
	* basic-block.h (PROP_ASM_SCAN): Define.
	* final.c (regs_asm_clobbered): New array.
	* regs.h (regs_asm_clobbered): Declare.
	* flow.c (life_analysis): Init it.
	(mark_set_regs): Set PROP_ASM_SCAN for asms.
	(mark_set_1): Set regs_asm_clobbered.
	* global.c (global_alloc): Don't set eliminable_regset when
	regs_asm_clobbered.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.1938&r2=2.1939
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/basic-block.h.diff?cvsroot=gcc&r1=1.183&r2=1.184
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/final.c.diff?cvsroot=gcc&r1=1.297&r2=1.298
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/flow.c.diff?cvsroot=gcc&r1=1.566&r2=1.567
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/global.c.diff?cvsroot=gcc&r1=1.94&r2=1.95
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/regs.h.diff?cvsroot=gcc&r1=1.30&r2=1.31



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169

[Bug optimization/13169] asm using r30 or r31 confuses global_alloc

[amodra at gcc dot gnu dot org]

------- Additional Comments From amodra at gcc dot gnu dot org  2003-12-06 12:30 -------
Fixed for gcc-3.4

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169

[Bug optimization/13169] asm using r30 or r31 confuses global_alloc

[cvs-commit at gcc dot gnu dot org]

------- Additional Comments From cvs-commit at gcc dot gnu dot org  2004-01-31 12:46 -------
Subject: Bug 13169

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	hammer-3_3-branch
Changes by:	amodra@gcc.gnu.org	2004-01-31 12:46:04

Modified files:
	gcc            : ChangeLog.hammer basic-block.h regs.h final.c 
	                 flow.c global.c 

Log message:
	Backport from mainline.
	2003-12-19  James E Wilson  <wilson@specifixinc.com>
	* flow.c (mark_set_regs, case PARALLEL): Scan loop forwards.
	Add case for ASM_OPERANDS.
	* global.c (global_alloc): Set regs_ever_live for regs_asm_clobbered
	registers.
	
	2003-12-06  Alan Modra  <amodra@bigpond.net.au>
	PR 13169
	* basic-block.h (PROP_ASM_SCAN): Define.
	* final.c (regs_asm_clobbered): New array.
	* regs.h (regs_asm_clobbered): Declare.
	* flow.c (life_analysis): Init it.
	(mark_set_regs): Set PROP_ASM_SCAN for asms.
	(mark_set_1): Set regs_asm_clobbered.
	* global.c (global_alloc): Don't set eliminable_regset when
	regs_asm_clobbered.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.hammer.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.1.2.301&r2=1.1.2.302
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/basic-block.h.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.161.2.11&r2=1.161.2.12
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/regs.h.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.26.2.1&r2=1.26.2.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/final.c.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.270.2.7&r2=1.270.2.8
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/flow.c.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.540.2.8&r2=1.540.2.9
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/global.c.diff?cvsroot=gcc&only_with_tag=hammer-3_3-branch&r1=1.86.2.2&r2=1.86.2.3



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13169