On Wed, Sep 4, 2024 at 9:25 AM <pan2...@intel.com> wrote:
>
> From: Pan Li <pan2...@intel.com>
>
> The gen_phi_on_cond can only support below control flow for cond
> from day 1. Aka:
>
> +------+
> | def |
> | ... | +-----+
> | cond |------>| def |
> +------+ | ... |
> | +-----+
> | |
> v |
> +-----+ |
> | PHI |<----------+
> +-----+
>
> Unfortunately, there will be more scenarios of control flow on PHI.
> For example as below:
>
> T __attribute__((noinline)) \
> sat_s_add_##T##_fmt_3 (T x, T y) \
> { \
> T sum; \
> bool overflow = __builtin_add_overflow (x, y, &sum); \
> return overflow ? x < 0 ? MIN : MAX : sum; \
> }
>
> DEF_SAT_S_ADD_FMT_3(int8_t, uint8_t, INT8_MIN, INT8_MAX)
>
> With expanded RTL like below.
> 3 │
> 4 │ __attribute__((noinline))
> 5 │ int8_t sat_s_add_int8_t_fmt_3 (int8_t x, int8_t y)
> 6 │ {
> 7 │ signed char _1;
> 8 │ signed char _2;
> 9 │ int8_t _3;
> 10 │ __complex__ signed char _6;
> 11 │ _Bool _8;
> 12 │ signed char _9;
> 13 │ signed char _10;
> 14 │ signed char _11;
> 15 │
> 16 │ ;; basic block 2, loop depth 0
> 17 │ ;; pred: ENTRY
> 18 │ _6 = .ADD_OVERFLOW (x_4(D), y_5(D));
> 19 │ _2 = IMAGPART_EXPR <_6>;
> 20 │ if (_2 != 0)
> 21 │ goto <bb 4>; [50.00%]
> 22 │ else
> 23 │ goto <bb 3>; [50.00%]
> 24 │ ;; succ: 4
> 25 │ ;; 3
> 26 │
> 27 │ ;; basic block 3, loop depth 0
> 28 │ ;; pred: 2
> 29 │ _1 = REALPART_EXPR <_6>;
> 30 │ goto <bb 5>; [100.00%]
> 31 │ ;; succ: 5
> 32 │
> 33 │ ;; basic block 4, loop depth 0
> 34 │ ;; pred: 2
> 35 │ _8 = x_4(D) < 0;
> 36 │ _9 = (signed char) _8;
> 37 │ _10 = -_9;
> 38 │ _11 = _10 ^ 127;
> 39 │ ;; succ: 5
> 40 │
> 41 │ ;; basic block 5, loop depth 0
> 42 │ ;; pred: 3
> 43 │ ;; 4
> 44 │ # _3 = PHI <_1(3), _11(4)>
> 45 │ return _3;
> 46 │ ;; succ: EXIT
> 47 │
> 48 │ }
>
> The above code will have below control flow which is not supported by
> the gen_phi_on_cond.
>
> +------+
> | def |
> | ... | +-----+
> | cond |------>| def |
> +------+ | ... |
> | +-----+
> | |
> v |
> +-----+ |
> | def | |
> | ... | |
> +-----+ |
> | |
> | |
> v |
> +-----+ |
> | PHI |<----------+
> +-----+
>
> This patch would like to add support above control flow for the
> gen_phi_on_cond.
>
> The below testsuites are passed for this patch:
> * The rv64gcv fully regression test.
> * The x86 bootstrap test.
> * The x86 fully regression test.
I'm lazy - can you please quote genmatch generated code for the condition for
one case?
Thanks,
Richard.
> gcc/ChangeLog:
>
> * genmatch.cc (dt_operand::gen_phi_on_cond): Add support for
> a new control flow when gen phi on condition.
>
> Signed-off-by: Pan Li <pan2...@intel.com>
> ---
> gcc/genmatch.cc | 85 +++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 76 insertions(+), 9 deletions(-)
>
> diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc
> index a56bd90cb2c..f538df1be62 100644
> --- a/gcc/genmatch.cc
> +++ b/gcc/genmatch.cc
> @@ -3529,28 +3529,95 @@ dt_operand::gen_phi_on_cond (FILE *f, int indent, int
> depth)
> "basic_block _pb_0_%d = EDGE_PRED (_b%d, 0)->src;\n", depth, depth);
> fprintf_indent (f, indent,
> "basic_block _pb_1_%d = EDGE_PRED (_b%d, 1)->src;\n", depth, depth);
> +
> fprintf_indent (f, indent,
> - "basic_block _db_%d = safe_dyn_cast <gcond *> (*gsi_last_bb (_pb_0_%d))
> ? "
> - "_pb_0_%d : _pb_1_%d;\n", depth, depth, depth, depth);
> + "gcond *_ct_0_%d = safe_dyn_cast <gcond *> (*gsi_last_bb (_pb_0_%d));\n",
> + depth, depth);
> fprintf_indent (f, indent,
> - "basic_block _other_db_%d = safe_dyn_cast <gcond *> "
> - "(*gsi_last_bb (_pb_0_%d)) ? _pb_1_%d : _pb_0_%d;\n",
> + "gcond *_ct_1_%d = safe_dyn_cast <gcond *> (*gsi_last_bb (_pb_1_%d));\n",
> + depth, depth);
> + fprintf_indent (f, indent,
> + "gcond *_ct_a_%d = _ct_0_%d ? _ct_0_%d : _ct_1_%d;\n",
> + depth, depth, depth, depth);
> + fprintf_indent (f, indent,
> + "basic_block _db_%d = _ct_0_%d ? _pb_0_%d : _pb_1_%d;\n",
> + depth, depth, depth, depth);
> + fprintf_indent (f, indent,
> + "basic_block _other_db_%d = _ct_0_%d ? _pb_1_%d : _pb_0_%d;\n",
> depth, depth, depth, depth);
>
> fprintf_indent (f, indent,
> - "gcond *_ct_%d = safe_dyn_cast <gcond *> (*gsi_last_bb (_db_%d));\n",
> - depth, depth);
> - fprintf_indent (f, indent, "if (_ct_%d"
> + "edge _e_00_%d = _pb_0_%d->preds ? EDGE_PRED (_pb_0_%d, 0) : NULL;\n",
> + depth, depth, depth);
> + fprintf_indent (f, indent,
> + "basic_block _pb_00_%d = _e_00_%d ? _e_00_%d->src : NULL;\n",
> + depth, depth, depth);
> + fprintf_indent (f, indent,
> + "gcond *_ct_b_%d = _pb_00_%d ? "
> + "safe_dyn_cast <gcond *> (*gsi_last_bb (_pb_00_%d)) : NULL;\n",
> + depth, depth, depth);
> +
> + /* Case 1 flow for PHI.
> + * +------+
> + * | def |
> + * | ... | +-----+
> + * | cond |------>| def |
> + * +------+ | ... |
> + * | +-----+
> + * | |
> + * v |
> + * +-----+ |
> + * | PHI |<----------+
> + * +-----+
> + */
> + fprintf_indent (f, indent, "if ((_ct_a_%d"
> " && EDGE_COUNT (_other_db_%d->preds) == 1\n", depth, depth);
> fprintf_indent (f, indent,
> - " && EDGE_COUNT (_other_db_%d->succs) == 1\n", depth);
> + " && EDGE_COUNT (_other_db_%d->succs) == 1\n", depth);
> + fprintf_indent (f, indent,
> + " && EDGE_PRED (_other_db_%d, 0)->src == _db_%d)\n", depth, depth);
> +
> + fprintf_indent (f, indent, " ||\n");
> +
> + /* Case 2 flow for PHI.
> + * +------+
> + * | def |
> + * | ... | +-----+
> + * | cond |------>| def |
> + * +------+ | ... |
> + * | +-----+
> + * | |
> + * v |
> + * +-----+ |
> + * | def | |
> + * | ... | |
> + * +-----+ |
> + * | |
> + * | |
> + * v |
> + * +-----+ |
> + * | PHI |<----------+
> + * +-----+
> + */
> + fprintf_indent (f, indent,
> + " (_ct_b_%d && _pb_00_%d && EDGE_COUNT (_pb_0_%d->succs) == 1\n",
> + depth, depth, depth);
> + fprintf_indent (f, indent,
> + " && EDGE_COUNT (_pb_0_%d->preds) == 1\n", depth);
> fprintf_indent (f, indent,
> - " && EDGE_PRED (_other_db_%d, 0)->src == _db_%d)\n", depth, depth);
> + " && EDGE_COUNT (_other_db_%d->preds) == 1\n", depth);
> + fprintf_indent (f, indent,
> + " && EDGE_COUNT (_other_db_%d->succs) == 1\n", depth);
> + fprintf_indent (f, indent,
> + " && EDGE_PRED (_other_db_%d, 0)->src == _pb_00_%d))\n", depth,
> depth);
>
> indent += 2;
> fprintf_indent (f, indent, "{\n");
> indent += 2;
>
> + fprintf_indent (f, indent,
> + "gcond *_ct_%d = _ct_a_%d ? _ct_a_%d : _ct_b_%d;\n",
> + depth, depth, depth, depth);
> fprintf_indent (f, indent,
> "tree _cond_lhs_%d = gimple_cond_lhs (_ct_%d);\n", depth, depth);
> fprintf_indent (f, indent,
> --
> 2.43.0
>
