On Fri, Oct 11, 2024 at 8:24 AM <pan2...@intel.com> wrote:
>
> From: Pan Li <pan2...@intel.com>
>
> Almost the same as vector unsigned integer SAT_SUB, try to match
> the signed version during the vector pattern matching.
>
> The below test suites are passed for this patch.
> * The rv64gcv fully regression test.
> * The x86 bootstrap test.
> * The x86 fully regression test.
OK.
> gcc/ChangeLog:
>
> * tree-vect-patterns.cc (gimple_signed_integer_sat_sub): Add new
> func decl for signed SAT_SUB.
> (vect_recog_sat_sub_pattern_transform): Update comments.
> (vect_recog_sat_sub_pattern): Try the vector signed SAT_SUB
> pattern.
>
> Signed-off-by: Pan Li <pan2...@intel.com>
> ---
> gcc/tree-vect-patterns.cc | 26 +++++++++++++++++++++++++-
> 1 file changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc
> index 9bf8526ac99..746f100a084 100644
> --- a/gcc/tree-vect-patterns.cc
> +++ b/gcc/tree-vect-patterns.cc
> @@ -4538,6 +4538,7 @@ extern bool gimple_unsigned_integer_sat_sub (tree,
> tree*, tree (*)(tree));
> extern bool gimple_unsigned_integer_sat_trunc (tree, tree*, tree (*)(tree));
>
> extern bool gimple_signed_integer_sat_add (tree, tree*, tree (*)(tree));
> +extern bool gimple_signed_integer_sat_sub (tree, tree*, tree (*)(tree));
>
> static gimple *
> vect_recog_build_binary_gimple_stmt (vec_info *vinfo, stmt_vec_info
> stmt_info,
> @@ -4684,6 +4685,7 @@ vect_recog_sat_sub_pattern_transform (vec_info *vinfo,
>
> /*
> * Try to detect saturation sub pattern (SAT_ADD), aka below gimple:
> + * Unsigned:
> * _7 = _1 >= _2;
> * _8 = _1 - _2;
> * _10 = (long unsigned int) _7;
> @@ -4691,6 +4693,27 @@ vect_recog_sat_sub_pattern_transform (vec_info *vinfo,
> *
> * And then simplied to
> * _9 = .SAT_SUB (_1, _2);
> + *
> + * Signed:
> + * x.0_4 = (unsigned char) x_16;
> + * y.1_5 = (unsigned char) y_18;
> + * _6 = x.0_4 - y.1_5;
> + * minus_19 = (int8_t) _6;
> + * _7 = x_16 ^ y_18;
> + * _8 = x_16 ^ minus_19;
> + * _44 = _7 < 0;
> + * _23 = x_16 < 0;
> + * _24 = (signed char) _23;
> + * _58 = (unsigned char) _24;
> + * _59 = -_58;
> + * _25 = (signed char) _59;
> + * _26 = _25 ^ 127;
> + * _42 = _8 < 0;
> + * _41 = _42 & _44;
> + * iftmp.2_11 = _41 ? _26 : minus_19;
> + *
> + * And then simplied to
> + * iftmp.2_11 = .SAT_SUB (x_16, y_18);
> */
>
> static gimple *
> @@ -4705,7 +4728,8 @@ vect_recog_sat_sub_pattern (vec_info *vinfo,
> stmt_vec_info stmt_vinfo,
> tree ops[2];
> tree lhs = gimple_assign_lhs (last_stmt);
>
> - if (gimple_unsigned_integer_sat_sub (lhs, ops, NULL))
> + if (gimple_unsigned_integer_sat_sub (lhs, ops, NULL)
> + || gimple_signed_integer_sat_sub (lhs, ops, NULL))
> {
> vect_recog_sat_sub_pattern_transform (vinfo, stmt_vinfo, lhs, ops);
> gimple *stmt = vect_recog_build_binary_gimple_stmt (vinfo, stmt_vinfo,
> --
> 2.43.0
>
