wget https://www.gnuwakes.org/depot/1.1/main/sources/llvm-3.9.1.src.tar.xz

tar -xf llvm-3.9.1.src.tar.xz

wget https://www.gnuwakes.org/depot/1.1/main/sources/llvm.patch
cd llvm-3.9.1.src
patch -p1 < ../llvm.patch 
cd ..

SOURCES_DIR=$PWD/llvm-3.9.1.src
INSTALL_DIR=$PWD/llvm-3.9.1.src-install
BUILD_DIR=$PWD/llvm-3.9.1.src-build

mkdir $INSTALL_DIR $BUILD_DIR
cd $BUILD_DIR

cmake -DCMAKE_BUILD_TYPE=Release        \
  -DCMAKE_INSTALL_PREFIX=/usr           \
  -DLLVM_TARGETS_TO_BUILD='X86;AMDGPU'  \
  -DLLVM_BUILD_LLVM_DYLIB=ON            \
  $SOURCES_DIR &&                       \
make && make DESTDIR=$INSTALL_DIR install