[Bug middle-end/78977] [7 Regression] g++7 snprintf() of double produces wrong code with -O3

["h2+bugs at fsfe dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78977

--- Comment #8 from Hannes Hauswedell <h2+bugs at fsfe dot org> ---
(In reply to Jakub Jelinek from comment #7)
> (In reply to Hannes Hauswedell from comment #6)
> > (In reply to Martin Sebor from comment #5)
> > > (In reply to Hannes Hauswedell from comment #3)
> > > > 
> > > > Great, let me know if it's merged, then I will try a newer snapshot!
> > > 
> > > The patch has been committed (r244037).  Please give it a try and let us
> > > know how it goes.
> > 
> > Thanks! I have checked out master via git and verified that it includes the
> > fix. I then tried to tie this into the FreeBSD-port (to make use of the
> > local patches and build flags), but unfortunately it still doesn't build.
> > I normally don't build gcc myself so it would likely take me considerable
> > time to track these build problems and fix them. The next weekly snapshot
> > should be built on 20170108 and then land in the FreeBSD-ports very soon
> > after.
> > Can we wait for this, or are we in a hurry -- for when is the GCC7 release
> > scheduled?
> 
> Could you in the mean time attach the preprocessed source + options (and
> confirm whether it is appendNumber in the preprocessed source or something
> else)?
> Then we can easily check if the patch actually changed anything or not.

This is the command line used for building test_random:

cd /home/mi/h4nn3s/devel/seqan_local-build/release/tests/random &&
/usr/local/libexec/ccache/g++7   -DSEQAN_DISABLE_VERSION_CHECK
-DSEQAN_ENABLE_TESTING=1 -DSEQAN_HAS_BZIP2=1 -DSEQAN_HAS_EXECINFO=1
-DSEQAN_HAS_OPENMP=1 -DSEQAN_HAS_ZLIB=1 -D_FILE_OFFSET_BITS=64
-D_GLIBCXX_USE_C99=1 -D_LARGEFILE_SOURCE
-I/home/mi/h4nn3s/devel/seqan_local/include -fdiagnostics-color -W -Wall
-pedantic -fstrict-aliasing -Wstrict-aliasing -fopenmp -O3    
-DSEQAN_GLOBAL_EXCEPTION_HANDLER=1 -o
CMakeFiles/test_random.dir/test_random.cpp.o -c
/home/mi/h4nn3s/devel/seqan_local/tests/random/test_random.cpp
Linking CXX executable ../../bin/test_random
cd /home/mi/h4nn3s/devel/seqan_local-build/release/tests/random &&
/usr/local/bin/cmake -E cmake_link_script CMakeFiles/test_random.dir/link.txt
--verbose=1
/usr/local/libexec/ccache/g++7   -fdiagnostics-color -W -Wall -pedantic
-fstrict-aliasing -Wstrict-aliasing -fopenmp -O3   
CMakeFiles/test_random.dir/test_random.cpp.o  -o ../../bin/test_random 
-lpthread -lexecinfo -lelf -lz -lbz2

I have attached gzipped .ii for both a build with "-O3" and with "-O3
-fno-printf-return-value". Is that what you require or by which other means
would I get the preprocessed source?

Thanks!