• Keith Randall's avatar
    cmd/compile: get rid of most byte and word insns for amd64 · 9e3c68f1
    Keith Randall authored
    Now that we're using 32-bit ops for 8/16-bit logical operations
    (to avoid partial register stalls), there's really no need to
    keep track of the 8/16-bit ops at all.  Convert everything we
    can to 32-bit ops.
    
    This CL is the obvious stuff.  I might think a bit more about
    whether we can get rid of weirder stuff like HMULWU.
    
    The only downside to this CL is that we lose some information
    about constants.  If we had source like:
      var a byte = ...
      a += 128
      a += 128
    We will convert that to a += 256, when we could get rid of the
    add altogether.  This seems like a fairly unusual scenario and
    I'm happy with forgoing that optimization.
    
    Change-Id: Ia7c1e5203d0d110807da69ed646535194a3efba1
    Reviewed-on: https://go-review.googlesource.com/22382Reviewed-by: 's avatarTodd Neal <todd@tneal.org>
    9e3c68f1
ssa.go 31.3 KB