[Bug rtl-optimization/18233] extraneous inc/dec pair

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-10-30 19:28 -------
On PPC, we get:
        cmpwi cr0,r3,0
        li r2,0
        neg r0,r3
        and r0,r3,r0
        bne- cr0,L7
        mr r3,r2
        blr
L7:
        cntlzw r0,r0
        subfic r2,r0,31
        mr r3,r2
        blr
which is good and there is no extra subfic and also ffs has definition to return 0 for 0 so the extran 
subtraction on the ffs causes this to be good code on PPC.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |enhancement
          Component|tree-optimization           |rtl-optimization
           Keywords|                            |missed-optimization


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18233