R600/SI: Add double precision fsub pattern for SI

Patch by: Niels Ole Salscheider

Reviewed-by: Tom Stellard <thomas.stellard@amd.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186179 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed