[Bug c/41366] Very inefficient code generated

[ramana at gcc dot gnu dot org]

------- Comment #1 from ramana at gcc dot gnu dot org  2009-09-16 07:08 -------
The problem occurs with 4.4.x branch r 151319. The problem is evident if you
have -march=armv5te or earlier, but not with -march=armv6 or later. 

This is the code I get with armv6 

foo:
        @ args = 0, pretend = 0, frame = 0
        @ frame_needed = 0, uses_anonymous_args = 0
        @ link register save eliminated.
        mov     r2, #0
        orr     r2, r2, r0
        mov     r0, r2
        bx      lr

Conversely with -mthumb any option less than -march=armv6 gives the following
code. 

foo:
        @ sp needed for prologue
        bx      lr


and a -mcpu=cortex-a8 gives the following code. 

        movs    r2, #0
        orrs    r2, r2, r0
        mov     r0, r2
        bx      lr


The same problem occurs on trunk.


-- 

ramana 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         |2009-09-16 07:08:53
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41366