R600: Implement 64bit SHL

v2: Use c++ style comment

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211157 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Implement 64bit SRL

v2: use C++ style comment

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211158 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Implement 64bit SRA

v2: Use capitalized variable name

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211159 91177308-0d34-0410-b5e6-96231b3b80d8