Optimisation options turned on at a certain level

[Ian Lance Taylor]

jgrant@reflectionsinteractive.com writes:

> Could this be added the documentation? so its clear exactly what is being
> done by which options are being passed.

My two comments are:

1) Documentation patches are always welcome.

2) But note that the precise meaning of the optimization levels
   changes for different architectures.  See the OPTIMIZATION_OPTIONS
   macro as defined in various gcc/config/*/*.h files.

Ian