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

[Bruce Evans]

On Mon, 8 Oct 2007, LI Xin wrote:

> Bruce Evans wrote:
>>>  Revision  Changes    Path
>>>  1.15      +0 -0      src/contrib/gcc/toplev.c
>>
>> Without this change, -O pessimizes for time.
>
> Does this affect all platforms or is it i386 only, on the latest GCC
> version?

I don't know, but guess it affects some.  In general, the pessimization
works by breaking lookup of a table that gives the best alignment for
the current target, so it affects all platforms that have such a table.
On platforms with stricter alignment requirements than i386, gcc would
have to adjust any -falign-foo settings that are too small to work.
Then the pessimization might give minimal aligment != 1 and thus have
no effect if the minimal alignment happens to equal the best alignment.

Bruce