Test failure, documentation bugs?

[James E Wilson]

Luca Benini wrote:
> O0 -fcprop-registers -fdefer-pop -fguess-branch-probability 
> -fif-conversion -fif-conversion2 -floop-optimize -fmerge-constants 
> -fthread-jumps -fmerge-constants -fdelayed-branch -fthread-jumps 
> -funit-at-a-time -fexceptions -fnon-call-exception
> ...Using all -O1 flag in documentation work.

-O0 means no optimization at all.  If you say "-O0 -feverything" then 
you still get no optimization, because you used -O0.

What you want to do here is use "-O1 -fno-cprop-registers ...".  You can 
selectively disable optimizations to try to determine which one is 
causing trouble.

However, keep in mind that not all optimizations can be explicitly 
enabled or disabled.  When you use -O1, you will get some basic 
optimizations always.  There is no -fno-combine or -fno-cse option for 
instance.  It is highly likely that if you do "-O1 -fno-everything" that 
the testcase will still fail.  This trick of trying -f flags is mainly 
useful when something works at -O1 but does not work at -O2, or vice versa.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com