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Date: Sat, 07 Feb 2004 06:25:00 -0000
From: "kazu at cs dot umass dot edu" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20040207062512.14060.kazu@cs.umass.edu>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug middle-end/14060] New: An unused register is saved to the stack.
X-Bugzilla-Reason: CC
X-SW-Source: 2004-02/txt/msg00855.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

/* Use ./cc1 -mh -O2 -fomit-frame-pointer.  */

extern long bar (long, long *);

void
foo (long z)
{
  long a[2];

  a[0] = z;

  while (1)
    {
      if (bar (z, a))
	return;
    }
}

Note that er5 is saved but not used anywhere in the function.

_foo:
	mov.l	er4,@-er7
	mov.l	er5,@-er7
	subs	#4,er7
	subs	#4,er7
	mov.l	er0,er4
	mov.l	er0,@er7
.L2:
	mov.l	er7,er1
	mov.l	er4,er0
	jsr	@_bar
	mov.l	er0,er0
	beq	.L2
	adds	#4,er7
	adds	#4,er7
	mov.l	@er7+,er5
	mov.l	@er7+,er4
	rts

-- 
           Summary: An unused register is saved to the stack.
           Product: gcc
           Version: 3.5.0
            Status: UNCONFIRMED
          Keywords: pessimizes-code
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kazu at cs dot umass dot edu
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: h8300-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14060