OpenImageIO: i686 builds failing

[Richard Shaw]

I could use some help figuring out the best fix for the following problem
where only the i686 builds fail:

cd /builddir/build/BUILD/oiio-Release-1.7.7/build/linux/src/libutil &&
/usr/bin/cmake -E cmake_link_script CMakeFiles/fmath_test.dir/link.txt
--verbose=1
/usr/bin/c++   -O2 -g -pipe -Wall -Werror=format-security
-Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong
--param=ssp-buffer-size=4 -grecord-gcc-switches
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -m32 -march=i686 -mtune=atom
-fasynchronous-unwind-tables  -O2 -g -DNDEBUG   -Wl,-z,relro
-specs=/usr/lib/rpm/redhat/redhat-hardened-ld
CMakeFiles/fmath_test.dir/fmath_test.cpp.o  -o fmath_test -rdynamic
libOpenImageIO_Util.so.1.7.7 -lboost_filesystem -lboost_regex
-lboost_system -lboost_thread -lboost_chrono -lboost_date_time
-lboost_atomic -lrt -ldl -lImath -lIex -lHalf -lIlmThread -lpthread
-Wl,-rpath,/builddir/build/BUILD/oiio-Release-1.7.7/build/linux/src/libutil
make[2]: Leaving directory
'/builddir/build/BUILD/oiio-Release-1.7.7/build/linux'
[ 72%] Built target fmath_test
In file included from
/builddir/build/BUILD/oiio-Release-1.7.7/src/include/OpenImageIO/fmath.h:64:0,
                 from
/builddir/build/BUILD/oiio-Release-1.7.7/src/include/OpenImageIO/hash.h:50,
                 from
/builddir/build/BUILD/oiio-Release-1.7.7/src/include/OpenImageIO/strutil.h:54,
                 from
/builddir/build/BUILD/oiio-Release-1.7.7/src/include/OpenImageIO/ustring.h:137,
                 from
/builddir/build/BUILD/oiio-Release-1.7.7/src/libtexture/texturesys.cpp:44:
/builddir/build/BUILD/oiio-Release-1.7.7/src/include/OpenImageIO/simd.h: In
member function 'bool
OpenImageIO::v1_7::pvt::TextureSystemImpl::sample_bicubic(int, const
float*, const float*, int,
OpenImageIO::v1_7::pvt::TextureSystemImpl::TextureFile&,
OpenImageIO::v1_7::pvt::TextureSystemImpl::PerThreadInfo*,
OpenImageIO::v1_7::TextureOpt&, int, int, const float*,
OpenImageIO::v1_7::simd::float4*, OpenImageIO::v1_7::simd::float4*,
OpenImageIO::v1_7::simd::float4*)':
/builddir/build/BUILD/oiio-Release-1.7.7/src/include/OpenImageIO/simd.h:308:71:
error: '*((void*)& dwy +12)' may be used uninitialized in this function
[-Werror=maybe-uninitialized]
 #define SIMD_CONSTRUCT(x) for (int i = 0; i < elements; ++i) m_val[i] = (x)
                                                                       ^
/builddir/build/BUILD/oiio-Release-1.7.7/src/libtexture/texturesys.cpp:2473:20:
note: '*((void*)& dwy +12)' was declared here
         float4 wy, dwy;

Full build logs here:
https://kojipkgs.fedoraproject.org//work/tasks/2540/15912540/build.log

Upstream does not test or use 32bit builds in production...

The following workaround was suggested by upstream and seemed to do the
trick but upstream doesn't want to perform needless initialization on
platforms/arches that don't require it.

Ok, in texturesys.cpp, circa line 2472, please add the following two lines
(bold):

        float4 wx, dwx;
        float4 wy, dwy;
        if (daccumds_) {
            evalBSplineWeights_and_derivs (&wx, sfrac, &dwx);
            evalBSplineWeights_and_derivs (&wy, tfrac, &dwy);
        } else {
            wx = evalBSplineWeights (float4(sfrac));
            wy = evalBSplineWeights (float4(tfrac));
*            dwx = float4::Zero();*
*            dwy = float4::Zero();*
        }

Any suggestions?

Thanks,
Richard