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Re: very different compilation times [no optimisation]
Dave Korn <dave.korn.cygwin@googlemail.com> writes:
> Basile STARYNKEVITCH wrote:
>
>>>> Notice that gcc 4.4 is running four times slower that gcc-4.3!
>
>> glinka ~/tmp 16:39 % gcc-4.3 -ftime-report -O0 -g -fPIC
>> warmelt-normal-1.i -c -o warmelt-normal-1-gcc-4.3.o
>>
>> Execution times (seconds)
>> TOTAL : 33.13 3.33
>> 36.64 363506 kB
>
>> glinka ~/tmp 16:40 % gcc-4.4 -ftime-report -O0 -g -fPIC
>> warmelt-normal-1.i -c -o warmelt-normal-1-gcc-4.4.o
>> TOTAL : 10.83 3.03
>> 13.90 429820 kB
>> glinka ~/tmp 16:41 %
>
> Wait, what? :-P
>
>
> Assuming you got those results swapped round, I see it's mostly expand and
> global alloc. Side effect of IRA on functions with loooong unbroken sequences
> of initialisations maybe?
He didn't swap them--you can tell by the presence of "integrated RA"
rather than "global".
Basile, you posted the time for the wrong file, or you got something
else wrong.
Ian