[Bug middle-end/23401] New: Gimplifier produces too many temporaries

[Bug middle-end/23401] New: Gimplifier produces too many temporaries

[pinskia at gcc dot gnu dot org]

Take the following code:
struct f
{
  struct {
   int i;
  } ff[10];
};

struct f g;
int ffff(int i)
{
  int t1 = 0;
  int i1 = g.ff[t1].i;
  int i2 = g.ff[i].i;
  return i1 + i2;
}

The gimplfiier will produce at -O0:
  int i.0;
  int t1.1;
  int D.1289;
  int t1;
  int i1;
  int i2;

  t1 = 0;
  i.0 = i;
  i1 = g.ff[i.0].i;
  t1.1 = t1;
  i2 = g.ff[t1.1].i;
  D.1289 = i1 + i2;
  return D.1289;

Notice how there is a t1.0 and i.0, there should not be there as i and t1 are already gimple variables.
This might produce a nice speed up for some testcase but I don't know.  at -O0, there will be less 
registers to be allocated so reload should not be as high as before.

-- 
           Summary: Gimplifier produces too many temporaries
           Product: gcc
           Version: 4.1.0
            Status: UNCONFIRMED
          Severity: minor
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23401

[Bug middle-end/23401] Gimplifier produces too many temporaries

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-15 15:21 -------
For PR 8361, there are about 14 places where this happens.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23401

[Bug middle-end/23401] Gimplifier produces too many temporaries

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-15 15:24 -------
In PR15855, there are a lot more, at about 874.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23401

[Bug middle-end/23401] Gimplifier produces too many temporaries

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-15 15:43 -------
Hmm, I think this FIXME has something to do with it:
	  /* Gimplify the dimension.
	     Temporary fix for gcc.c-torture/execute/20040313-1.c.
	     Gimplify non-constant array indices into a temporary
	     variable.
	     FIXME - The real fix is to gimplify post-modify
	     expressions into a minimal gimple lvalue.  However, that
	     exposes bugs in alias analysis.  The alias analyzer does
	     not handle &PTR->FIELD very well.  Will fix after the
	     branch is merged into mainline (dnovillo 2004-05-03).  */

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23401

[Bug middle-end/23401] Gimplifier produces too many temporaries

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-08-31 16:04 -------
Confirmed.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|                            |1
   Last reconfirmed|0000-00-00 00:00:00         |2005-08-31 16:04:05
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23401