Hexagon: Add patterns to generate 'combine' instructions.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181805 91177308-0d34-0410-b5e6-96231b3b80d8
Recognize sparc64 as an alias for sparcv9 triples.

Patch by Brad Smith!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181808 91177308-0d34-0410-b5e6-96231b3b80d8
Subtract isn't commutative, fix this for MMX psub.

Patch by Andrea DiBiagio.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181809 91177308-0d34-0410-b5e6-96231b3b80d8