Why we optimize by time by default for < -O2 case?

[Bruce Evans]

On Mon, 8 Oct 2007, LI Xin wrote:

> I wonder why we want to optimize by time by default and not by space by
> default for the system compiler, does the reasoning still hold true?

-O means optimize for time if possible.

> The commit log said:
>
>  Modified files:
>    contrib/gcc          toplev.c
>  Log:
>  Clarify revision 1.14:
>  Gcc 3.1's -O0 and -O1 actually optimized alignment for space, but we feel
>  it should optimize alignment for time like Gcc 2.95 used to.  Optimization
>  for space should give 1-byte alignment on i386's, but doesn't quite.
>
>  Revision  Changes    Path
>  1.15      +0 -0      src/contrib/gcc/toplev.c

Without this change, -O pessimizes for time.

Bruce