• Anton Blanchard's avatar
    [PATCH] ppc64: remove -fno-omit-frame-pointer · 89e09f5e
    Anton Blanchard authored
    During some code inspection using gcc 4.0 I noticed a stack frame was being
    created for a number of functions that didnt require it.  For example:
    
    c0000000000df944 <._spin_unlock>:
    c0000000000df944:       fb e1 ff f0     std     r31,-16(r1)
    c0000000000df948:       f8 21 ff c1     stdu    r1,-64(r1)
    c0000000000df94c:       7c 3f 0b 78     mr      r31,r1
    c0000000000df950:       7c 20 04 ac     lwsync
    c0000000000df954:       e8 21 00 00     ld      r1,0(r1)
    c0000000000df958:       38 00 00 00     li      r0,0
    c0000000000df95c:       90 03 00 00     stw     r0,0(r3)
    c0000000000df960:       eb e1 ff f0     ld      r31,-16(r1)
    c0000000000df964:       4e 80 00 20     blr
    
    It turns out we are adding -fno-omit-frame-pointer to ppc64 which is
    causing the above behaviour.  Removing that flag results in much better
    code:
    
    c0000000000d5b30 <._spin_unlock>:
    c0000000000d5b30:       7c 20 04 ac     lwsync
    c0000000000d5b34:       38 00 00 00     li      r0,0
    c0000000000d5b38:       90 03 00 00     stw     r0,0(r3)
    c0000000000d5b3c:       4e 80 00 20     blr
    
    We dont require a frame pointer to debug on ppc64, so remove it.
    Signed-off-by: default avatarAnton Blanchard <anton@samba.org>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    89e09f5e
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