> -----Original Message-----
> From: Richard Biener <rguent...@suse.de>
> Sent: Friday, May 31, 2024 8:41 PM
> To: Hu, Lin1 <lin1...@intel.com>
> Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao....@intel.com>;
> ubiz...@gmail.com
> Subject: RE: [PATCH 1/3] vect: generate suitable convert insn for int -> int,
> float
> -> float and int <-> float.
>
> On Fri, 31 May 2024, Hu, Lin1 wrote:
>
> > > -----Original Message-----
> > > From: Richard Biener <rguent...@suse.de>
> > > Sent: Wednesday, May 29, 2024 5:41 PM
> > > To: Hu, Lin1 <lin1...@intel.com>
> > > Cc: gcc-patches@gcc.gnu.org; Liu, Hongtao <hongtao....@intel.com>;
> > > ubiz...@gmail.com
> > > Subject: Re: [PATCH 1/3] vect: generate suitable convert insn for
> > > int -> int, float
> > > -> float and int <-> float.
> > >
> > > On Thu, 23 May 2024, Hu, Lin1 wrote:
> > >
> > > > gcc/ChangeLog:
> > > >
> > > > PR target/107432
> > > > * tree-vect-generic.cc
> > > > (supportable_indirect_narrowing_operation): New function for
> > > > support indirect narrowing convert.
> > > > (supportable_indirect_widening_operation): New function for
> > > > support indirect widening convert.
> > > > (expand_vector_conversion): Support convert for int -> int,
> > > > float -> float and int <-> float.
> > > >
> > > > gcc/testsuite/ChangeLog:
> > > >
> > > > PR target/107432
> > > > * gcc.target/i386/pr107432-1.c: New test.
> > > > * gcc.target/i386/pr107432-2.c: Ditto.
> > > > * gcc.target/i386/pr107432-3.c: Ditto.
> > > > * gcc.target/i386/pr107432-4.c: Ditto.
> > > > * gcc.target/i386/pr107432-5.c: Ditto.
> > > > * gcc.target/i386/pr107432-6.c: Ditto.
> > > > * gcc.target/i386/pr107432-7.c: Ditto.
> > > > ---
> > > > diff --git a/gcc/tree-vect-generic.cc b/gcc/tree-vect-generic.cc
> > > > index
> > > > ab640096ca2..0bedb53d9f9 100644
> > > > --- a/gcc/tree-vect-generic.cc
> > > > +++ b/gcc/tree-vect-generic.cc
> > > > @@ -45,6 +45,8 @@ along with GCC; see the file COPYING3. If not
> > > > see #include "gimple-match.h"
> > > > #include "recog.h" /* FIXME: for insn_data */
> > > > #include "optabs-libfuncs.h"
> > > > +#include "cfgloop.h"
> > > > +#include "tree-vectorizer.h"
> > > >
> > > >
> > > > /* Build a ternary operation and gimplify it. Emit code before GSI.
> > > > @@ -1834,6 +1836,142 @@ do_vec_narrow_conversion
> > > (gimple_stmt_iterator *gsi, tree inner_type, tree a,
> > > > return gimplify_build2 (gsi, code, outer_type, b, c); }
> > > >
> > > > +/* A subroutine of expand_vector_conversion, support indirect
> > > > +conversion
> > > for
> > > > + float <-> int, like double -> char. */ bool
> > > > +supportable_indirect_narrowing_operation (gimple_stmt_iterator *gsi,
> > > > + enum tree_code code,
> > > > + tree lhs,
> > > > + tree arg)
> > > > +{
> > > > + gimple *g;
> > > > + tree ret_type = TREE_TYPE (lhs);
> > > > + tree arg_type = TREE_TYPE (arg);
> > > > + tree new_rhs;
> > > > +
> > > > + unsigned int ret_elt_bits = vector_element_bits (ret_type);
> > > > + unsigned int arg_elt_bits = vector_element_bits (arg_type); if
> > > > + (code != FIX_TRUNC_EXPR || flag_trapping_math || ret_elt_bits >=
> > > arg_elt_bits)
> > > > + return false;
> > > > +
> > > > + unsigned short target_size;
> > > > + scalar_mode tmp_cvt_mode;
> > > > + scalar_mode lhs_mode = GET_MODE_INNER (TYPE_MODE (ret_type));
> > > > + scalar_mode rhs_mode = GET_MODE_INNER (TYPE_MODE (arg_type));
> > > > + tree cvt_type = NULL_TREE; tmp_cvt_mode = lhs_mode;
> > > > + target_size = GET_MODE_SIZE (rhs_mode);
> > > > +
> > > > + opt_scalar_mode mode_iter;
> > > > + enum tree_code tc1, tc2;
> > > > + unsigned HOST_WIDE_INT nelts
> > > > + = constant_lower_bound (TYPE_VECTOR_SUBPARTS (arg_type));
> > > > +
> > > > + FOR_EACH_2XWIDER_MODE (mode_iter, tmp_cvt_mode)
> > > > + {
> > > > + tmp_cvt_mode = mode_iter.require ();
> > > > +
> > > > + if (GET_MODE_SIZE (tmp_cvt_mode) > target_size)
> > > > + break;
> > > > +
> > > > + scalar_mode cvt_mode;
> > > > + int tmp_cvt_size = GET_MODE_BITSIZE (tmp_cvt_mode);
> > > > + if (!int_mode_for_size (tmp_cvt_size, 0).exists (&cvt_mode))
> > > > + break;
> > > > +
> > > > + int cvt_size = GET_MODE_BITSIZE (cvt_mode);
> > > > + bool isUnsigned = TYPE_UNSIGNED (ret_type) || TYPE_UNSIGNED
> > > (arg_type);
> > > > + cvt_type = build_nonstandard_integer_type (cvt_size,
> > > > + isUnsigned);
> > > > +
> > > > + cvt_type = build_vector_type (cvt_type, nelts);
> > > > + if (cvt_type == NULL_TREE
> > > > + || !supportable_convert_operation ((tree_code) NOP_EXPR,
> > > > + ret_type,
> > > > + cvt_type, &tc1)
> > > > + || !supportable_convert_operation ((tree_code) code,
> > > > + cvt_type,
> > > > + arg_type, &tc2))
> > > > + continue;
> > > > +
> > > > + new_rhs = make_ssa_name (cvt_type);
> > > > + g = vect_gimple_build (new_rhs, tc2, arg);
> > > > + gsi_insert_before (gsi, g, GSI_SAME_STMT);
> > > > + g = gimple_build_assign (lhs, tc1, new_rhs);
> > > > + gsi_replace (gsi, g, false);
> > > > + return true;
> > > > + }
> > > > + return false;
> > > > +}
> > > > +
> > > > +/* A subroutine of expand_vector_conversion, support indirect
> > > > +conversion
> > > for
> > > > + float <-> int, like char -> double. */ bool
> > > > +supportable_indirect_widening_operation (gimple_stmt_iterator *gsi,
> > > > + enum tree_code code,
> > > > + tree lhs,
> > > > + tree arg)
> > > > +{
> > > > + gimple *g;
> > > > + tree ret_type = TREE_TYPE (lhs);
> > > > + tree arg_type = TREE_TYPE (arg);
> > > > + tree new_rhs;
> > > > +
> > > > + unsigned int ret_elt_bits = vector_element_bits (ret_type);
> > > > + unsigned int arg_elt_bits = vector_element_bits (arg_type); if
> > > > + (ret_elt_bits <= arg_elt_bits || code != FLOAT_EXPR)
> > > > + return false;
> > > > +
> > > > + unsigned short target_size;
> > > > + scalar_mode tmp_cvt_mode;
> > > > + scalar_mode lhs_mode = GET_MODE_INNER (TYPE_MODE (ret_type));
> > > > + scalar_mode rhs_mode = GET_MODE_INNER (TYPE_MODE (arg_type));
> > > > + tree cvt_type = NULL_TREE; target_size = GET_MODE_SIZE
> > > > + (lhs_mode); int rhs_size = GET_MODE_BITSIZE (rhs_mode); if
> > > > + (!int_mode_for_size (rhs_size, 0).exists (&tmp_cvt_mode))
> > > > + return false;
> > > > +
> > > > + opt_scalar_mode mode_iter;
> > > > + enum tree_code tc1, tc2;
> > > > + unsigned HOST_WIDE_INT nelts
> > > > + = constant_lower_bound (TYPE_VECTOR_SUBPARTS (arg_type));
> > > > +
> > > > + FOR_EACH_2XWIDER_MODE (mode_iter, tmp_cvt_mode)
> > > > + {
> > > > + tmp_cvt_mode = mode_iter.require ();
> > > > +
> > > > + if (GET_MODE_SIZE (tmp_cvt_mode) > target_size)
> > > > + break;
> > > > +
> > > > + scalar_mode cvt_mode;
> > > > + int tmp_cvt_size = GET_MODE_BITSIZE (tmp_cvt_mode);
> > > > + if (!int_mode_for_size (tmp_cvt_size, 0).exists (&cvt_mode))
> > > > + break;
> > > > +
> > > > + int cvt_size = GET_MODE_BITSIZE (cvt_mode);
> > > > + bool isUnsigned = TYPE_UNSIGNED (ret_type) || TYPE_UNSIGNED
> > > (arg_type);
> > > > + cvt_type = build_nonstandard_integer_type (cvt_size,
> > > > + isUnsigned);
> > > > +
> > > > + cvt_type = build_vector_type (cvt_type, nelts);
> > > > + if (cvt_type == NULL_TREE
> > > > + || !supportable_convert_operation ((tree_code) code,
> > > > + ret_type,
> > > > + cvt_type, &tc1)
> > > > + || !supportable_convert_operation ((tree_code) NOP_EXPR,
> > > > + cvt_type,
> > > > + arg_type, &tc2))
> > > > + continue;
> > > > +
> > > > + new_rhs = make_ssa_name (cvt_type);
> > > > + g = vect_gimple_build (new_rhs, tc2, arg);
> > > > + gsi_insert_before (gsi, g, GSI_SAME_STMT);
> > > > + g = gimple_build_assign (lhs, tc1, new_rhs);
> > > > + gsi_replace (gsi, g, false);
> > > > + return true;
> > > > + }
> > > > + return false;
> > > > +}
> > > > +
> > >
> > > So the above improve the situation where the target can handle the
> > > two-step conversion. It doesn't really allow this to work for too
> > > large vectors AFAICS (nor does it try pack/unpack for any of the
> > > conversions). It also still duplicates code that's in the
> > > vectorizer. I think you should be able to use
> > > supportable_narrowing_operation and possibly even
> > > supportable_widening_operation (though that needs refatoring to
> > > avoid the vectorizer internal stmt_vec_info type - possibly simply by
> > > gating
> the respective code on a non-NULL vinfo). Both support multi-step
> conversions.
> > >
> >
> > I tried to use supportable_narrowing_operation and I met two questions:
> >
> > 1) supportable_narrowing_operation support v2df->v16qi, but I don't know
> > which optab can help me convert v16qi to v2qi.
>
> It's API is a bit tricky but for v2df -> v2qi (I expect you'll have an equal
> number of
> lanes in/out for .CONVERT_VECTOR) it likely outputs a multi-step conversion
> where you have to look into *INTERM_TYPES and second-guess the operation
> code to use for the intermediate steps (IIRC the intermediate steps all use
> either
> PACK/UNPACK or CONVERT, never FLOAT/FIX).
>
I made a mistake in what I said before. I think supportable_narrowing_operation
doesn't support v2df->v2qi, it only use VEC_PACK_TRUNC_EXPRT in its
intermediate steps. This makes it require that vectype_in and vectype_out have
the same size to return true. I want to make sure I'm doing the right thing, I
can build a tmp_type by build_nonstandard_integer_type and
get_same_sized_vectype. And use tree_vec_extract to extract v2qi from v16qi
after supportable_narrowing_operation.
>
> > 2) I tried a testcase (https://godbolt.org/z/z88xYW85e), this result is
> > not what I expected, because it only use vec_pack_trunc. I expect it
> > can use vcvttpd2dq + vpmovdw.
>
> With -O3 -fno-tree-loop-vectorize that's what you get. What you see is
> because
> of the restriction of the loop vectorizer to work on a single vector size
> only.
>
Yes, it works, but the program runs the NONE part (tree-vect-stmts.cc:5357)
instead of the NARROW_DST part (tree-vect-stmts.cc:5545). I think maybe we can
wrap the part of the code from line:5373 to line:5455 as a function. This
avoids duplicating the wheel, and I get the results I'm looking for.
In addition to wrapping the function. If you are motivated by the fact that our
modifications are not generalized enough, I think we can add
supportable_narrowing/widening_operation after the current single step
VEC_CONVERT (line 1972 and line 2078). It should try to use a single step and
then use multiple steps. If you agree, I'd like to remove my changes about
indirect conversions for now, and keep only the direct conversions, so that I
can merge the three current patches into the trunk first, and then add the
change about indirect conversions later.
BRs,
Lin
>
> > If I can solve the first question and the function be better (maybe
> > support trunc<vectype_in><vectype_out>), I'd be happy to use it
> > directly. I prefer my scheme for now. My functions is more like
> > supportable_convert_operation. Perhaps, we can modify
> > supportable_narrowing_operation, but I think it should be another
> > patch, it will influence vectorizer.
>
> But since you are doing a multi-step conversion this is really what
> supportable_narrowing_operation is about. I don't think we want to re-invent
> the wheel here. Likewise your approach won't get you to use
> VEC_[UN]PACK_HI/LO/EVEN/ODD either (supported by the current single-
> step .CONVERT_VECTOR lowering).
> supportable_narrowing_operation also checks for this.
>
> Richard.
>
>
> > BRs,
> > Lin
> >
> > >
> > > > /* Expand VEC_CONVERT ifn call. */
> > > >
> > > > static void
> > > > @@ -1871,14 +2009,21 @@ expand_vector_conversion
> > > (gimple_stmt_iterator *gsi)
> > > > else if (ret_elt_bits > arg_elt_bits)
> > > > modifier = WIDEN;
> > > >
> > > > + if (supportable_convert_operation (code, ret_type, arg_type, &code1))
> > > > + {
> > > > + g = gimple_build_assign (lhs, code1, arg);
> > > > + gsi_replace (gsi, g, false);
> > > > + return;
> > > > + }
> > > > +
> > > > + if (supportable_indirect_narrowing_operation(gsi, code, lhs, arg))
> > > > + return;
> > > > +
> > > > + if (supportable_indirect_widening_operation(gsi, code, lhs, arg))
> > > > + return;
> > > > +
> > > > if (modifier == NONE && (code == FIX_TRUNC_EXPR || code ==
> > > FLOAT_EXPR))
> > > > {
> > > > - if (supportable_convert_operation (code, ret_type, arg_type,
> > > > &code1))
> > > > - {
> > > > - g = gimple_build_assign (lhs, code1, arg);
> > > > - gsi_replace (gsi, g, false);
> > > > - return;
> > > > - }
> > > > /* Can't use get_compute_type here, as
> supportable_convert_operation
> > > > doesn't necessarily use an optab and needs two arguments. */
> > > > tree vec_compute_type
> > > >
> > >
> > > --
> > > Richard Biener <rguent...@suse.de>
> > > SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461
> > > Nuernberg, Germany;
> > > GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG
> > > Nuernberg)
> >
>
> --
> Richard Biener <rguent...@suse.de>
> SUSE Software Solutions Germany GmbH,
> Frankenstrasse 146, 90461 Nuernberg, Germany;
> GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
