[Bug target/53949] New: [SH] Add support for mac.w / mac.l instructions

["olegendo at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53949

             Bug #: 53949
           Summary: [SH] Add support for mac.w / mac.l instructions
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: olegendo@gcc.gnu.org
                CC: chrbr@gcc.gnu.org
            Target: sh*-*-*


So far, GCC does not utilize the integer multiply-add instructions.
On SH1 only the mac.w instruction is supported.
On SH2 and above the mac.w and mac.l instructions are available.

Carry over from PR 39423 comment #20

> On a related thread, for further work, I'm thinking on adding support for the
> MAC instruction, now that was have the multiply and add. But this requires
> exposing the MACLH registers to reload. Had anyone had a thought on this ? I'd
> like to give this a try pretty soon.