Re: very different compilation times [no optimisation]

[Dave Korn <dave dot korn dot cygwin at googlemail dot com>]

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?

    cheers,
      DaveK