tce-load -i libffi-dev

cd llvm-3.7.0.src

mkdir build
cd build

CC="gcc -flto -fuse-linker-plugin -mtune=generic -Os -pipe" CXX="g++ -flto -fuse-linker-plugin -mtune=generic -Os -pipe -fno-exceptions -fno-rtti" ../configure --prefix=/usr/local -disable-static --localstatedir=/var --datarootdir=/usr/local/share --enable-libffi --enable-optimized --enable-shared --enable-targets=host,r600,amdgpu --disable-assertions --docdir=/usr/local/share/doc/llvm-3.7.0

find . -name Makefile.config -type f -exec sed -i 's/-O3//g' {} \;

make [real 40m 8.38s]
make install

sudo chmod 644 /usr/local/lib/libLLVM*.a
sudo chmod 644 /usr/local/lib/libLTO*.a