FW: gcc optimization problems?

[Ivan R. Judson]

I just found this again.

--ivan

> -----Original Message-----
> From: owner-openmash-developers at bmrc.berkeley.edu 
> [mailto:owner-openmash-developers at bmrc.berkeley.edu] On 
> Behalf Of Kun Wei
> Sent: Thursday, July 11, 2002 11:29 AM
> To: Robert Olson
> Cc: Open Mash Developers; VRVS Team
> Subject: Re: gcc optimization problems?
> 
> 
> Following is from VRVS README on compiling VIC. Hope it helps.
> --
> 4) Knowning problems
>  vic can be compiled successfully under Redhat 6.x, which use 
> an old version of gcc. 
>  Under Redhat 7.x, because of gcc2.96 optimization bug, the 
> compiled version will 
>  be very fragile. Thanks for Piers O'Hanlon pointing it out. 
> 
>  To compile under gcc 2.96, you can try to compile without 
> -O2 option. Or you should  upgrade to gcc3.02. It can be 
> download from http://gcc.gnu.org/
> 	
>  To compile under new kernel, some small changes needed here:
> 	# add "#include <time.h>" in common/config_unix.h
> 	# add newline to the end of common/inet_pton.h
> 	# add newline to the end of common/mbus_parser.h
> 	# change function call "tmpnam(...)" to "mkstemp(...)" 
> in tcl8.0/unix/tclUnixPipe.c
> 	# change "#define SIGARGS ..." to  "#define SIGARGS 
> int" in vic/main.cpp
> 	# change "strcasecomp(...)" to "strcasecomp(...) throw 
> ()" in vic/config.h
> 	# change struct JpegEncoder::huffentry from protected 
> to public in
> 	vic/codec/encoder-jpeg.cpp
>  patch is available as vic--kernel2.4.patch.txt.  
>  "patch -p0 -r vic-2.9.1 < vic--kernel2.4.patch.txt"
> 
> Cheers
> Kun
> 
> 
> Robert Olson wrote:
> > 
> > I'm curious if any of you have seen probelms with gcc -O2 
> optimization 
> > and the H261 encoder in mash. I was building the UCL/AG vic on 
> > RH7.2/7.3 with gcc-2.96. When building with -O2, I got 
> funky distorted 
> > video with the h261 encoder and crashes after 10-20 sec of capture.
> > 
> > This didn't show up with the stock compiler on RH6.2 (looks 
> like egcs 
> > 2.91.66).
> > 
> > thanks,
> > --bob
> 
> -- 
> -----------------------------
>  Kun Wei
>  Email:   weikun at caltech.edu
>  Address: MC 256-48, Caltech
>           Pasadena, CA 91125
>  Phone:   1-626-395-8767
> -----------------------------
>