[petsc-dev] different compiler behavior in make libfast and make all

[Chetan Jhurani]

Thanks.  I will try it.  An additional question - how does one turn off
optimization for a specific directory?  If I give an argument to
"CFLAGS =" in, say mat/impls/baij/seq/makefile, will it append
or override?  I just want to play with optimization flags.  This will
not turn off optimization for a specific file but will be good to know.

Also, one more observation is that when I turned on procmon (somewhat
similar to strace) when compiling the full tree, then the failure
happened in a different file.  So not quite consistent as I had mentioned
earlier.

Procmon slows down the system and can also lead to differences in clock or
execution speed.  I can't be very sure about this but if the optimizer part
of compilation is time-sensitive (don't optimize for a very long
time, or choose optimization based on some previous time measurements), then
a bug might not be encountered always.  Just a wild guess, especially since
these directories typically take longer to compile because of many manually
unrolled loops in there.

Chetan

> -----Original Message-----
> From: Barry Smith [mailto:bsmith at mcs.anl.gov]
> Sent: Thursday, September 05, 2013 6:53 PM
> To: Chetan Jhurani
> Cc: 'petsc-dev'
> Subject: Re: [petsc-dev] different compiler behavior in make libfast and make all
> 
> 
>   cygwin is a temperamental beast. I don't think the compiler is to blame but rather cygwin mis-
> providing something when many files are being dealt with quickly.
> 
>    make all simply calls make ACTION=libfast tree
> 
>    When make all fails you can go down to the place it crashes and run make ACTION=libfast tree and it
> will finish compiles in all the directories under that current directory. So you can get everything
> compiled with hopefully not too many manual makes needed.  I know this is not particularly
> satisfactory by we still dream about a knight coming along in shining armor with lots of Windows
> experience figuring out a clean and simple way to avoid cygwin completely in the build process.
> 
>    Barry
> 
> 
> On Sep 5, 2013, at 6:16 PM, Chetan Jhurani <chetan.jhurani at gmail.com> wrote:
> 
> > I'm looking for suggestions on how to understand different compiler
> > behavior in make "libfast" in a sub-directory and make "all" in
> > top-level petsc directory.
> >
> > The reason is that make all leads to an internal compiler error, seen
> > in make.log.  But doing make libfast for the same arch in the corresponding
> > subdirectory works fine.  So it is hard to work around the internal
> > compiler error via some simplification.  This is with cygwin and visual
> > studio 2012.  The same petsc code compiles fine with an older visual studio.
> >
> > Here is an example of the error from make.log, which
> > consistently happens here for a particular arch.
> >
> > petsc34\src\mat\impls\sbaij\seq\sbaij2.c(854) : fatal error C1001: An internal error has occurred in
> the compiler.
> > (compiler file 'f:\dd\vctools\compiler\utc\src\p2\main.c', line 211)
> > To work around this problem, try simplifying or changing the program near the locations listed
> above.
> > Please choose the Technical Support command on the Visual C++
> > Help menu, or open the Technical Support help file for more information
> > INTERNAL COMPILER ERROR in 'C:\Program Files (x86)\Microsoft Visual Studio 11.0\VC\BIN\amd64\cl.exe'
> >
> > The error happens in a different location (again consistently)
> > for a different arch.
> >
> > petsc34\src\mat\impls\sbaij\seq\sbstream\sbstrmfact.c(434)
> >
> > Both errors don't get reproduced if I do a make libfast in these
> > directories.  I also invoked the compiler via cl and win32fe
> > and both these ways also work fine and generate object files of
> > non-zero sizes.
> >
> > Thanks,
> >
> > Chetan
> >
> >