[PATCH,ARM] Improve peepholes for LDM with commutative operators
Ramana Radhakrishnan
ramana.radhakrishnan@linaro.org
Wed Feb 29 03:12:00 GMT 2012
[Sorry about the duplicate mail. My mailer seems to have eaten up the
original reply I sent. ]
On Tue, Feb 28, 2012 at 05:09:05PM -0000, Greta Yorsh wrote:
> Is it OK for GCC 4.7 Stage 4 ?
This is stage4 - I'd like to hear what the RM's think. Technically
it's fixing a regression and is low risk to me.
In any case there are a couple of changes that I'd like done
as explained below.
>
> Thank you,
>
> Greta
>
> gcc/ChangeLog
>
> 2012-02-28 Greta Yorsh <Greta.Yorsh@arm.com>
>
> * config/arm/arm-ldmstm.ml: Improved conditions of peepholes that
> generate
> LDM followed by a commutative operator.
> * config/arm/ldmstm.md: Regenerated.
Can you mention which 2 peepholes are changed in some way.
> diff --git a/gcc/config/arm/arm-ldmstm.ml b/gcc/config/arm/arm-ldmstm.ml
> index 221edd2..5f5a5e0 100644
> --- a/gcc/config/arm/arm-ldmstm.ml
> +++ b/gcc/config/arm/arm-ldmstm.ml
> @@ -216,9 +216,10 @@ let write_ldm_commutative_peephole thumb =
> Printf.printf "%s (match_operand:SI %d \"s_register_operand\" \"\")]))\n" indent (nregs * 2 + 3);
> Printf.printf "%s (clobber (reg:CC CC_REGNUM))])]\n" indent
> end;
> - Printf.printf " \"(((operands[%d] == operands[0] && operands[%d] == operands[1])\n" (nregs * 2 + 2) (nregs * 2 + 3);
> - Printf.printf " || (operands[%d] == operands[0] && operands[%d] == operands[1]))\n" (nregs * 2 + 3) (nregs * 2 + 2);
> - Printf.printf " && peep2_reg_dead_p (%d, operands[0]) && peep2_reg_dead_p (%d, operands[1]))\"\n" (nregs + 1) (nregs + 1);
> + Printf.printf " \"(((rtx_equal_p (operands[%d], operands[0]) && rtx_equal_p (operands[%d], operands[1]))\n" (nregs * 2 + 2) (nregs * 2 + 3);
> + Printf.printf " || (rtx_equal_p (operands[%d], operands[0]) && rtx_equal_p (operands[%d], operands[1])))\n" (nregs * 2 + 3) (nregs * 2 + 2);
> + Printf.printf " && (peep2_reg_dead_p (%d, operands[0]) || rtx_equal_p (operands[0], operands[%d]))\n" (nregs + 1) (nregs * 2);
> + Printf.printf " && (peep2_reg_dead_p (%d, operands[1]) || rtx_equal_p (operands[1], operands[%d])))\"\n" (nregs + 1) (nregs * 2);
> begin
> if thumb then
> Printf.printf " [(set (match_dup %d) (match_op_dup %d [(match_dup %d) (match_dup %d)]))]\n"
> diff --git a/gcc/config/arm/ldmstm.md b/gcc/config/arm/ldmstm.md
> index 5db4a32..5db3d57 100644
> --- a/gcc/config/arm/ldmstm.md
> +++ b/gcc/config/arm/ldmstm.md
> @@ -1160,9 +1160,10 @@
> [(match_operand:SI 6 "s_register_operand" "")
> (match_operand:SI 7 "s_register_operand" "")]))
> (clobber (reg:CC CC_REGNUM))])]
> - "(((operands[6] == operands[0] && operands[7] == operands[1])
> - || (operands[7] == operands[0] && operands[6] == operands[1]))
> - && peep2_reg_dead_p (3, operands[0]) && peep2_reg_dead_p (3, operands[1]))"
> + "(((rtx_equal_p (operands[6], operands[0]) && rtx_equal_p (operands[7], operands[1]))
> + || (rtx_equal_p (operands[7], operands[0]) && rtx_equal_p (operands[6], operands[1])))
> + && (peep2_reg_dead_p (3, operands[0]) || rtx_equal_p (operands[0], operands[4]))
> + && (peep2_reg_dead_p (3, operands[1]) || rtx_equal_p (operands[1], operands[4])))"
Line > 80 characters -
> [(parallel
> [(set (match_dup 4) (match_op_dup 5 [(match_dup 6) (match_dup 7)]))
> (clobber (reg:CC CC_REGNUM))])]
> @@ -1180,9 +1181,10 @@
> (match_operator:SI 5 "commutative_binary_operator"
> [(match_operand:SI 6 "s_register_operand" "")
> (match_operand:SI 7 "s_register_operand" "")]))]
> - "(((operands[6] == operands[0] && operands[7] == operands[1])
> - || (operands[7] == operands[0] && operands[6] == operands[1]))
> - && peep2_reg_dead_p (3, operands[0]) && peep2_reg_dead_p (3, operands[1]))"
> + "(((rtx_equal_p (operands[6], operands[0]) && rtx_equal_p (operands[7], operands[1]))
> + || (rtx_equal_p (operands[7], operands[0]) && rtx_equal_p (operands[6], operands[1])))
Again line > 80 characters.
Instead of rtx_equal_p, check that the REGNOs are equal.
That will be cheaper: we know these are register_operands.
For bonus points you use peep2_regno_dead_p with REGNO (operands[n])
instead of peep2_reg_dead_p. If we are accessing REGNO might as well
reuse it :).
regards
Ramana
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