Re: [avr-gcc-list] -O vs. -O2

[Russell Shaw]

Nathan Cooprider wrote:
> Russell Shaw wrote:
> > What are you trying to do? Any autoconf package can be set for -02 with:
> > ./configure CFLAGS="-g -O2"
>
> I am using avr-gcc as part of the TinyOS package, along with a bunch of 
> other non-TinyOS tools. The non-TinyOS tools do something to the TinyOS 
> applications so that they compile fine with avr-gcc -O, but then break 
> with -Os or -O2. My understanding is that -O2 is just -O with some extra 
> command options. I looked through the manual and found what options 
> those were, but adding them to -O did not trigger the error. So I was at 
> a loss.

Which manual did you look at?

Look under "Optimize Options" in "info gcc".

> Unfortunately, I believe I am stuck using an older version of gcc. Which 
> sort of makes my problem irrelevant for this list. Also, I probably just 
> have to look at the actual command line options in the source and find 
> out which ones -O turns on and which ones -O2 turns on. Anyway, thanks 
> for the concern.

The individual options are listed under the section "Optimize Options"
in "info gcc".

More specifically, i'm currently looking at: File: gcc-4.0.info,
"3.10 Options That Control Optimization". Your gcc may have a different
section number.