[Bug target/50446] New: [avr] Implement rotate patterns with offset 1

[gjl at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50446

             Bug #: 50446
           Summary: [avr] Implement rotate patterns with offset 1
    Classification: Unclassified
           Product: gcc
           Version: 4.6.1
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: gjl@gcc.gnu.org
                CC: eric.weddington@atmel.com
            Target: avr


GCC tries rotate patterns, e.g. I see combiner try to match against rotate.
Rotate by one is easy to implement on AVR, so add these patterns/insns.