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Re: Slowdowns in code generated by GCC>=3.3
>>
>> Nothing stops GCC from folding that asm into the common-ized jump
>> block.
>>
>> zw
>>
>
>I see.
>
>So the practical solution is
>
>- generate asm listing
>- identify appropriate jumps, eg:
>
> ...
> movl 8(%ecx), %eax
> jmp .Lxxxxx
> ...
>.Lxxxxx:
> jmp *%eax
>
>- change "jmp .Lxxxxx" to "jmp *%eax" with your favorite text editor
>- compile the asm source
Wouldn't it be better to make the compiler not do
tail-merging/crossjumping unless the savings makes it
wortwhile; i.e. don't do the jump to save less than N
instructions(where in this case, it actaully *increases* the
instruction count by one)?
--
Peter Barada
peter@the-baradas.com