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Re: Test failure, documentation bugs?
- From: James E Wilson <wilson at specifixinc dot com>
- To: Luca Benini <lbenini at csr dot unibo dot it>
- Cc: gcc at gcc dot gnu dot org
- Date: Fri, 14 Jan 2005 17:53:49 -0800
- Subject: Re: Test failure, documentation bugs?
- References: <41E56CE8.9060104@csr.unibo.it>
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