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Re: Slowdowns in code generated by GCC>=3.3
On Wed, 20 Oct 2004, Zack Weinberg wrote:
> Földy Lajos <foldy@rmki.kfki.hu> writes:
>
> > and what about adding the real goto (which will be never executed, but
> > gcc will have "almost real" control flow):
> >
> > __asm__("jmp *%0" : : "a" (pc));
> > goto *pc;
>
> 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
:-)
Is there a chance, that the patch for PR15242 (if available) will go into
3.4.3?
regards,
lajos