Gentoo's Bugzilla –
Attachment 385466 Details for
Bug 523744www-client/chromium-38.0.2125.66 - In file included from ../../third_party/skia/src/opts/SkBlurImage_opts_SSE4.cpp:19: /usr/lib/gcc/i686-pc-linux-gnu/4.8.3/include/pmmintrin.h:50:68: error: ‘__builtin_ia32_addsubps’ was not declared in this scope