optimizations

Reza Roboubi reza@linisoft.com
Wed Jan 15 06:31:00 GMT 2003


Andrew Pinski wrote:
> 
> On Tuesday, Jan 14, 2003, at 16:49 US/Pacific, Reza Roboubi wrote:
> 
> > Could you please also tell me if 3.3 and 3.4 remove the extra mov's in
> > and out
> > of %eax. Ideally, there should be no more than 4 instructions in the
> > critical
> > loop.
> >
> 
> For some reason it is not (even with -fnew-ra), but on PPC there is no
> extra load/store.

Hmmm. That's interesting. It might be a bug (or overlooked opportunity) on the
PC.


> 
> Thanks,
> Andrew Pinski
> 
> PS here is the asm for the loop of i[3-6]686, pentium4:
> 
> .L2:
>          movl    -4(%ebp), %eax  <== still does the store
>          cmpl    $16, %eax
>          je      .L7
>          incl    %eax
>          movl    %eax, -4(%ebp) <== and load
>          jmp     .L2
> .L7:
> 
> I do not have access to the machine with 3.{3,4} on PPC right now.

I really appreciate your help Andrew.

Reza.



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