On Mon, Sep 4, 2017 at 1:36 PM, Richard Sandiford
<richard.sandif...@linaro.org> wrote:
> There are at least a few places that want to create an integer vector
> with a specified element size and element count, or to create the
> integer equivalent of an existing mode. This patch adds helpers
> for doing that.
>
> The require ()s are all used in functions that go on to emit
> instructions that use the result as a vector mode.
>
> 2017-09-04 Richard Sandiford <richard.sandif...@linaro.org>
>
> gcc/
> * machmode.h (mode_for_int_vector): New function.
> * stor-layout.c (mode_for_int_vector): Likewise.
> * config/aarch64/aarch64.c (aarch64_emit_approx_sqrt): Use it.
> * config/powerpcspe/powerpcspe.c (rs6000_do_expand_vec_perm):
> Likewise.
> * config/rs6000/rs6000.c (rs6000_do_expand_vec_perm): Likewise.
> * config/s390/s390.c (s390_expand_vec_compare_cc): Likewise.
> (s390_expand_vcond): Likewise.
>
> Index: gcc/machmode.h
> ===================================================================
> --- gcc/machmode.h 2017-09-04 12:18:50.674859598 +0100
> +++ gcc/machmode.h 2017-09-04 12:18:53.153306182 +0100
> @@ -706,6 +706,21 @@ extern machine_mode bitwise_mode_for_mod
>
> extern machine_mode mode_for_vector (scalar_mode, unsigned);
>
> +extern opt_machine_mode mode_for_int_vector (unsigned int, unsigned int);
> +
> +/* Return the integer vector equivalent of MODE, if one exists. In other
> + words, return the mode for an integer vector that has the same number
> + of bits as MODE and the same number of elements as MODE, with the
> + latter being 1 if MODE is scalar. The returned mode can be either
> + an integer mode or a vector mode. */
> +
> +inline opt_machine_mode
> +mode_for_int_vector (machine_mode mode)
So this is similar to int_mode_for_mode which means...
int_vector_mode_for_vector_mode?
> +{
Nothing prevents use with non-vector MODE here, can we place an assert here?
> + return mode_for_int_vector (GET_MODE_UNIT_BITSIZE (mode),
> + GET_MODE_NUNITS (mode));
> +}
> +
> /* A class for iterating through possible bitfield modes. */
> class bit_field_mode_iterator
> {
> Index: gcc/stor-layout.c
> ===================================================================
> --- gcc/stor-layout.c 2017-09-04 12:18:50.675762071 +0100
> +++ gcc/stor-layout.c 2017-09-04 12:18:53.153306182 +0100
> @@ -517,6 +517,23 @@ mode_for_vector (scalar_mode innermode,
> return mode;
> }
>
> +/* Return the mode for a vector that has NUNITS integer elements of
> + INT_BITS bits each, if such a mode exists. The mode can be either
> + an integer mode or a vector mode. */
> +
> +opt_machine_mode
> +mode_for_int_vector (unsigned int int_bits, unsigned int nunits)
That's more vector_int_mode_for_size (...), no? Similar to int_mode_for_size
or mode_for_size.
Ok with those renamings. I wonder if int_vector_mode_for_vector_mode
is necessary -- is calling vector_int_mode_for_size
(GET_MODE_UNIT_BITSIZE (mode),
GET_MODE_NUNITS (mode)) too cumbersome?
> +{
> + scalar_int_mode int_mode;
> + if (int_mode_for_size (int_bits, 0).exists (&int_mode))
> + {
> + machine_mode vec_mode = mode_for_vector (int_mode, nunits);
Uh, so we _do_ have an existing badly named 'mode_for_vector' ...
> + if (vec_mode != BLKmode)
> + return vec_mode;
> + }
> + return opt_machine_mode ();
> +}
> +
> /* Return the alignment of MODE. This will be bounded by 1 and
> BIGGEST_ALIGNMENT. */
>
> Index: gcc/config/aarch64/aarch64.c
> ===================================================================
> --- gcc/config/aarch64/aarch64.c 2017-09-04 12:18:44.874165502 +0100
> +++ gcc/config/aarch64/aarch64.c 2017-09-04 12:18:53.144272229 +0100
> @@ -8282,9 +8282,6 @@ aarch64_emit_approx_sqrt (rtx dst, rtx s
> return false;
> }
>
> - machine_mode mmsk
> - = mode_for_vector (int_mode_for_mode (GET_MODE_INNER (mode)).require (),
> - GET_MODE_NUNITS (mode));
> if (!recp)
> {
> if (!(flag_mlow_precision_sqrt
> @@ -8302,7 +8299,7 @@ aarch64_emit_approx_sqrt (rtx dst, rtx s
> /* Caller assumes we cannot fail. */
> gcc_assert (use_rsqrt_p (mode));
>
> -
> + machine_mode mmsk = mode_for_int_vector (mode).require ();
> rtx xmsk = gen_reg_rtx (mmsk);
> if (!recp)
> /* When calculating the approximate square root, compare the
> Index: gcc/config/powerpcspe/powerpcspe.c
> ===================================================================
> --- gcc/config/powerpcspe/powerpcspe.c 2017-09-04 12:18:44.919414816 +0100
> +++ gcc/config/powerpcspe/powerpcspe.c 2017-09-04 12:18:53.148287319 +0100
> @@ -38739,8 +38739,7 @@ rs6000_do_expand_vec_perm (rtx target, r
>
> imode = vmode;
> if (GET_MODE_CLASS (vmode) != MODE_VECTOR_INT)
> - imode = mode_for_vector
> - (int_mode_for_mode (GET_MODE_INNER (vmode)).require (), nelt);
> + imode = mode_for_int_vector (vmode).require ();
>
> x = gen_rtx_CONST_VECTOR (imode, gen_rtvec_v (nelt, perm));
> x = expand_vec_perm (vmode, op0, op1, x, target);
> Index: gcc/config/rs6000/rs6000.c
> ===================================================================
> --- gcc/config/rs6000/rs6000.c 2017-09-04 12:18:44.929470219 +0100
> +++ gcc/config/rs6000/rs6000.c 2017-09-04 12:18:53.151298637 +0100
> @@ -35584,8 +35584,7 @@ rs6000_do_expand_vec_perm (rtx target, r
>
> imode = vmode;
> if (GET_MODE_CLASS (vmode) != MODE_VECTOR_INT)
> - imode = mode_for_vector
> - (int_mode_for_mode (GET_MODE_INNER (vmode)).require (), nelt);
> + imode = mode_for_int_vector (vmode).require ();
>
> x = gen_rtx_CONST_VECTOR (imode, gen_rtvec_v (nelt, perm));
> x = expand_vec_perm (vmode, op0, op1, x, target);
> Index: gcc/config/s390/s390.c
> ===================================================================
> --- gcc/config/s390/s390.c 2017-09-04 11:50:24.561571751 +0100
> +++ gcc/config/s390/s390.c 2017-09-04 12:18:53.153306182 +0100
> @@ -6472,10 +6472,7 @@ s390_expand_vec_compare_cc (rtx target,
> case LE: cc_producer_mode = CCVFHEmode; code = GE; swap_p = true;
> break;
> default: gcc_unreachable ();
> }
> - scratch_mode = mode_for_vector
> - (int_mode_for_mode (GET_MODE_INNER (GET_MODE (cmp1))).require (),
> - GET_MODE_NUNITS (GET_MODE (cmp1)));
> - gcc_assert (scratch_mode != BLKmode);
> + scratch_mode = mode_for_int_vector (GET_MODE (cmp1)).require ();
>
> if (inv_p)
> all_p = !all_p;
> @@ -6581,9 +6578,7 @@ s390_expand_vcond (rtx target, rtx then,
>
> /* We always use an integral type vector to hold the comparison
> result. */
> - result_mode = mode_for_vector
> - (int_mode_for_mode (GET_MODE_INNER (cmp_mode)).require (),
> - GET_MODE_NUNITS (cmp_mode));
> + result_mode = mode_for_int_vector (cmp_mode).require ();
> result_target = gen_reg_rtx (result_mode);
>
> /* We allow vector immediates as comparison operands that
