Re: [PATCH][AArch64] Implement ALU_BRANCH fusion

[Wilco Dijkstra]

Hi,

I think the patch isn't quite complete yet. You will also need changes in
generic code. Currently sched_macro_fuse_insns() does:

  if (any_condjump_p (insn))
    {
      unsigned int condreg1, condreg2;
      rtx cc_reg_1;
      targetm.fixed_condition_code_regs (&condreg1, &condreg2);
      cc_reg_1 = gen_rtx_REG (CCmode, condreg1);
      prev = prev_nonnote_nondebug_insn (insn);
      if (!reg_referenced_p (cc_reg_1, PATTERN (insn))
          || !prev
          || !modified_in_p (cc_reg_1, prev))
        return;
    }

Ie. it explicitly looks for a flag-setting ALU instruction whose condition is
used by a conditional branch, so none of the cases in your patch can match.

Note this code also excludes all CBZ type branches as fusion candidates,
is that intended too?

Wilco