[Bug middle-end/31528] Inlining with -Os increases code size

["rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Comment #8 from rguenth at gcc dot gnu dot org  2007-11-22 22:00 -------
Same results on current trunk.  Early inlining is already doing it because we
think putchs size (4 insns) when inlined will reduce the compilation units
size by 4 insns (the out-of-line copy of putch).

putchs IL before inlining looks like

<bb 2>:

<bb 4>:
  D.1182_2 ={v} *43B;
  D.1183_3 = (int) D.1182_2;
  D.1184_4 = D.1183_3 & 32;
  if (D.1184_4 == 0)
    goto <bb 4>;
  else
    goto <bb 3>;

<bb 3>:
  ch.0_7 = (volatile unsigned char) ch_6(D);
  *44B ={v} ch.0_7;
  return;

we count INDIRECT_REFs as having no cost, the only thing what counts
is the BIT_AND_EXPR and the comparison.  Constants and registers also
have no cost.

Considering the (currently) recursive structure of estimate_num_insns_1
it is non-trivial to adjust the container-like reference trees (but
the INDIREC_REF ones).


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
 GCC target triplet|*-*-*                       |
           Keywords|                            |missed-optimization
      Known to fail|4.1.2                       |4.1.2 4.3.0
   Last reconfirmed|0000-00-00 00:00:00         |2007-11-22 22:00:55
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31528