[Bug rtl-optimization/27469] zero extension not eliminated

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2006-05-07 18:59 -------
Confirmed.
It does try to do it:
(insn 18 16 19 2 (set (reg:DI 79 [ x.25 ])
        (zero_extend:DI (subreg/s:SI (reg/v:DI 71 [ x.25 ]) 0))) 52
{zero_extendsidi2} (insn_list:REG_DEP_TRUE 16 (nil))
    (nil))

into;
(insn 56 16 54 2 (set (subreg:SI (reg:DI 79 [ x.25 ]) 0)
        (subreg/s:SI (reg/v:DI 71 [ x.25 ]) 0)) -1 (nil)
    (nil))

(insn 54 56 19 2 (set (reg:DI 79 [ x.25 ])
        (zero_extend:DI (subreg:SI (reg:DI 79 [ x.25 ]) 0))) 52
{zero_extendsidi2} (nil)
    (nil))


-- 

pinskia 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         |2006-05-07 18:59:35
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27469