[Bug target/32623] New: m68k: Inaccurate multiply cost on some V2 ColdFire CPUs.

["betheking at spray dot se" <gcc-bugzilla at gcc dot gnu dot org>]

When building for a ColdFire V2 CPU, GCC will prefer using shift-and-add over
multiply, even if multiply would generate code that is smaller and as fast, if
not faster, on the target CPU in question. This happens because the multiply
cost is based on ColdFire version rather than the capabilities. Basing the
multiply cost on the presence of a MAC (or EMAC) unit on the target CPU would
be more accurate, at least on ColdFire V2.

See the definitions of MULL_COST and MULW_COST in gcc/config/m68k/m68k.c, at
about line 2138.


-- 
           Summary: m68k: Inaccurate multiply cost on some V2 ColdFire CPUs.
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: betheking at spray dot se


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32623