• Linus Torvalds's avatar
    Give up on pushing CC_OPTIMIZE_FOR_SIZE · 281dc5c5
    Linus Torvalds authored
    I still happen to believe that I$ miss costs are a major thing, but
    sadly, -Os doesn't seem to be the solution.  With or without it, gcc
    will miss some obvious code size improvements, and with it enabled gcc
    will sometimes make choices that aren't good even with high I$ miss
    ratios.
    
    For example, with -Os, gcc on x86 will turn a 20-byte constant memcpy
    into a "rep movsl".  While I sincerely hope that x86 CPU's will some day
    do a good job at that, they certainly don't do it yet, and the cost is
    higher than a L1 I$ miss would be.
    
    Some day I hope we can re-enable this.
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    281dc5c5
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