On Mon, Jan 16, 2017 at 09:53:17PM +1030, Alan Modra wrote:
> Commited as obvious.
>
> PR target/79098
> * config/rs6000/rs6000.c (rs6000_legitimate_combined_insn): Don't
> use a switch.
Perhaps it would be useful to write why it can't be written as a switch.
Or, as a switch it could be of the form:
switch (INSN_CODE (insn))
{
#ifdef HAVE_ctrsi_internal1
case CODE_FOR_ctrsi_internal1:
case CODE_FOR_ctrsi_internal2:
case CODE_FOR_ctrsi_internal3:
case CODE_FOR_ctrsi_internal4:
#endif
#ifdef HAVE_ctrdi_internal1
case CODE_FOR_ctrdi_internal1:
case CODE_FOR_ctrdi_internal2:
case CODE_FOR_ctrdi_internal3:
case CODE_FOR_ctrdi_internal4:
#endif
return false;
default:
break;
}
> diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> index 11394b2..f1d5d9d 100644
> --- a/gcc/config/rs6000/rs6000.c
> +++ b/gcc/config/rs6000/rs6000.c
> @@ -9085,40 +9085,41 @@ rs6000_const_not_ok_for_debug_p (rtx x)
> static bool
> rs6000_legitimate_combined_insn (rtx_insn *insn)
> {
> - switch (INSN_CODE (insn))
> - {
> - /* Reject creating doloop insns. Combine should not be allowed
> - to create these for a number of reasons:
> - 1) In a nested loop, if combine creates one of these in an
> - outer loop and the register allocator happens to allocate ctr
> - to the outer loop insn, then the inner loop can't use ctr.
> - Inner loops ought to be more highly optimized.
> - 2) Combine often wants to create one of these from what was
> - originally a three insn sequence, first combining the three
> - insns to two, then to ctrsi/ctrdi. When ctrsi/ctrdi is not
> - allocated ctr, the splitter takes use back to the three insn
> - sequence. It's better to stop combine at the two insn
> - sequence.
> - 3) Faced with not being able to allocate ctr for ctrsi/crtdi
> - insns, the register allocator sometimes uses floating point
> - or vector registers for the pseudo. Since ctrsi/ctrdi is a
> - jump insn and output reloads are not implemented for jumps,
> - the ctrsi/ctrdi splitters need to handle all possible cases.
> - That's a pain, and it gets to be seriously difficult when a
> - splitter that runs after reload needs memory to transfer from
> - a gpr to fpr. See PR70098 and PR71763 which are not fixed
> - for the difficult case. It's better to not create problems
> - in the first place. */
> - case CODE_FOR_ctrsi_internal1:
> - case CODE_FOR_ctrdi_internal1:
> - case CODE_FOR_ctrsi_internal2:
> - case CODE_FOR_ctrdi_internal2:
> - case CODE_FOR_ctrsi_internal3:
> - case CODE_FOR_ctrdi_internal3:
> - case CODE_FOR_ctrsi_internal4:
> - case CODE_FOR_ctrdi_internal4:
> - return false;
> - }
> + int icode = INSN_CODE (insn);
> +
> + /* Reject creating doloop insns. Combine should not be allowed
> + to create these for a number of reasons:
> + 1) In a nested loop, if combine creates one of these in an
> + outer loop and the register allocator happens to allocate ctr
> + to the outer loop insn, then the inner loop can't use ctr.
> + Inner loops ought to be more highly optimized.
> + 2) Combine often wants to create one of these from what was
> + originally a three insn sequence, first combining the three
> + insns to two, then to ctrsi/ctrdi. When ctrsi/ctrdi is not
> + allocated ctr, the splitter takes use back to the three insn
> + sequence. It's better to stop combine at the two insn
> + sequence.
> + 3) Faced with not being able to allocate ctr for ctrsi/crtdi
> + insns, the register allocator sometimes uses floating point
> + or vector registers for the pseudo. Since ctrsi/ctrdi is a
> + jump insn and output reloads are not implemented for jumps,
> + the ctrsi/ctrdi splitters need to handle all possible cases.
> + That's a pain, and it gets to be seriously difficult when a
> + splitter that runs after reload needs memory to transfer from
> + a gpr to fpr. See PR70098 and PR71763 which are not fixed
> + for the difficult case. It's better to not create problems
> + in the first place. */
> + if (icode != CODE_FOR_nothing
> + && (icode == CODE_FOR_ctrsi_internal1
> + || icode == CODE_FOR_ctrdi_internal1
> + || icode == CODE_FOR_ctrsi_internal2
> + || icode == CODE_FOR_ctrdi_internal2
> + || icode == CODE_FOR_ctrsi_internal3
> + || icode == CODE_FOR_ctrdi_internal3
> + || icode == CODE_FOR_ctrsi_internal4
> + || icode == CODE_FOR_ctrdi_internal4))
> + return false;
> +
> return true;
> }
>
>
> --
> Alan Modra
> Australia Development Lab, IBM
Jakub
