On Mon, May 19, 2025 at 10:41 AM Li Xu <xu...@eswincomputing.com> wrote:
>
> From: xuli <xu...@eswincomputing.com>
>
> This patch would like to support .SAT_ADD when IMM=-1.
>
> Form1:
> T __attribute__((noinline)) \
> sat_s_add_imm_##T##_fmt_1##_##INDEX (T x) \
> { \
> T sum = (UT)x + (UT)IMM; \
> return (x ^ IMM) < 0 \
> ? sum \
> : (sum ^ x) >= 0 \
> ? sum \
> : x < 0 ? MIN : MAX; \
> }
>
> Take below form1 as example:
> DEF_SAT_S_ADD_IMM_FMT_1(0, int8_t, uint8_t, -1, INT8_MIN, INT8_MAX)
>
> Before this patch:
> __attribute__((noinline))
> int8_t sat_s_add_imm_int8_t_fmt_1_0 (int8_t x)
> {
> unsigned char x.0_1;
> unsigned char _2;
> unsigned char _3;
> int8_t iftmp.1_4;
> signed char _8;
> unsigned char _9;
> signed char _10;
>
> <bb 2> [local count: 1073741824]:
> x.0_1 = (unsigned char) x_5(D);
> _3 = -x.0_1;
> _10 = (signed char) _3;
> _8 = x_5(D) & _10;
> if (_8 < 0)
> goto <bb 4>; [1.40%]
> else
> goto <bb 3>; [98.60%]
>
> <bb 3> [local count: 434070867]:
> _2 = x.0_1 + 255;
>
> <bb 4> [local count: 1073741824]:
> # _9 = PHI <_2(3), 128(2)>
> iftmp.1_4 = (int8_t) _9;
> return iftmp.1_4;
>
> }
>
> After this patch:
> __attribute__((noinline))
> int8_t sat_s_add_imm_int8_t_fmt_1_0 (int8_t x)
> {
> int8_t _4;
>
> <bb 2> [local count: 1073741824]:
> gimple_call <.SAT_ADD, _4, x_5(D), 255> [tail call]
> gimple_return <_4>
>
> }
>
> The below test suites are passed for this patch:
> 1. The rv64gcv fully regression tests.
> 2. The x86 bootstrap tests.
> 3. The x86 fully regression tests.
OK.
Richard.
> Signed-off-by: Li Xu <xu...@eswincomputing.com>
>
> gcc/ChangeLog:
>
> * match.pd: Add signed scalar SAT_ADD IMM form1 with IMM=-1 matching.
> * tree-ssa-math-opts.cc (match_unsigned_saturation_add): Adapt
> function name.
> (match_saturation_add_with_assign): Match signed and unsigned SAT_ADD
> with assign.
> (math_opts_dom_walker::after_dom_children): Match imm=-1 signed
> SAT_ADD with NOP_EXPR case.
>
> ---
> gcc/match.pd | 19 ++++++++++++++++++-
> gcc/tree-ssa-math-opts.cc | 30 +++++++++++++++++++++++++-----
> 2 files changed, 43 insertions(+), 6 deletions(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 98411af3940..a07dbb808d2 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3403,7 +3403,24 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (bit_xor:c @0 INTEGER_CST@3)) integer_zerop)
> (signed_integer_sat_val @0)
> @2)
> - (if (wi::bit_and (wi::to_wide (@1), wi::to_wide (@3)) == 0))))
> + (if (wi::bit_and (wi::to_wide (@1), wi::to_wide (@3)) == 0)))
> +
> +(match (signed_integer_sat_add @0 @1)
> + /* T SUM = (T)((UT)X + (UT)-1);
> + SAT_S_ADD = (X ^ -1) < 0 ? SUM : (X ^ SUM) >= 0 ? SUM
> + : (x < 0) ? MIN : MAX
> */
> + (convert (cond^ (lt (bit_and:c @0 (nop_convert (negate (nop_convert @0))))
> + integer_zerop)
> + INTEGER_CST@2
> + (plus (nop_convert @0) integer_all_onesp@1)))
> + (with
> + {
> + unsigned precision = TYPE_PRECISION (type);
> + wide_int c1 = wi::to_wide (@1);
> + wide_int c2 = wi::to_wide (@2);
> + wide_int sum = wi::add (c1, c2);
> + }
> + (if (wi::eq_p (sum, wi::max_value (precision, SIGNED)))))))
>
> /* Saturation sub for signed integer. */
> (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type))
> diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
> index 292eb852f2d..f6a1bea2002 100644
> --- a/gcc/tree-ssa-math-opts.cc
> +++ b/gcc/tree-ssa-math-opts.cc
> @@ -4064,15 +4064,34 @@ build_saturation_binary_arith_call_and_insert
> (gimple_stmt_iterator *gsi,
> * _10 = -_9;
> * _12 = _7 | _10;
> * =>
> - * _12 = .SAT_ADD (_4, _6); */
> + * _12 = .SAT_ADD (_4, _6);
> + *
> + * Try to match IMM=-1 saturation signed add with assign.
> + * <bb 2> [local count: 1073741824]:
> + * x.0_1 = (unsigned char) x_5(D);
> + * _3 = -x.0_1;
> + * _10 = (signed char) _3;
> + * _8 = x_5(D) & _10;
> + * if (_8 < 0)
> + * goto <bb 4>; [1.40%]
> + * else
> + * goto <bb 3>; [98.60%]
> + * <bb 3> [local count: 434070867]:
> + * _2 = x.0_1 + 255;
> + * <bb 4> [local count: 1073741824]:
> + * # _9 = PHI <_2(3), 128(2)>
> + * _4 = (int8_t) _9;
> + * =>
> + * _4 = .SAT_ADD (x_5, -1); */
>
> static void
> -match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
> +match_saturation_add_with_assign (gimple_stmt_iterator *gsi, gassign *stmt)
> {
> tree ops[2];
> tree lhs = gimple_assign_lhs (stmt);
>
> - if (gimple_unsigned_integer_sat_add (lhs, ops, NULL))
> + if (gimple_unsigned_integer_sat_add (lhs, ops, NULL)
> + || gimple_signed_integer_sat_add (lhs, ops, NULL))
> build_saturation_binary_arith_call_and_replace (gsi, IFN_SAT_ADD, lhs,
> ops[0], ops[1]);
> }
> @@ -6363,7 +6382,7 @@ math_opts_dom_walker::after_dom_children (basic_block
> bb)
> break;
>
> case PLUS_EXPR:
> - match_unsigned_saturation_add (&gsi, as_a<gassign *> (stmt));
> + match_saturation_add_with_assign (&gsi, as_a<gassign *> (stmt));
> match_unsigned_saturation_sub (&gsi, as_a<gassign *> (stmt));
> /* fall-through */
> case MINUS_EXPR:
> @@ -6389,7 +6408,7 @@ math_opts_dom_walker::after_dom_children (basic_block
> bb)
> break;
>
> case BIT_IOR_EXPR:
> - match_unsigned_saturation_add (&gsi, as_a<gassign *> (stmt));
> + match_saturation_add_with_assign (&gsi, as_a<gassign *> (stmt));
> match_unsigned_saturation_trunc (&gsi, as_a<gassign *> (stmt));
> /* fall-through */
> case BIT_XOR_EXPR:
> @@ -6410,6 +6429,7 @@ math_opts_dom_walker::after_dom_children (basic_block
> bb)
>
> case NOP_EXPR:
> match_unsigned_saturation_trunc (&gsi, as_a<gassign *> (stmt));
> + match_saturation_add_with_assign (&gsi, as_a<gassign *> (stmt));
> break;
>
> default:;
> --
> 2.17.1
>
