Thanks to Jordon Rose <jordan_rose@apple.com> for pointing this out. llvm-svn: 190310
We already have a working mul_hi, and the spec gives us the implementation as: Returns mul_hi(a,b)+c. Signed-off-by: Aaron Watry <awatry@gmail.com> Reviewed-by: Tom Stellard <thomas.stellard@amd.com> llvm-svn: 190211