Match: Support more form for scalar unsigned SAT_ADD

After we support one gassign form of the unsigned .SAT_ADD,  we
would like to support more forms including both the branch and
branchless.  There are 5 other forms of .SAT_ADD,  list as below:

Form 1:
  #define SAT_ADD_U_1(T) \
  T sat_add_u_1_##T(T x, T y) \
  { \
    return (T)(x + y) >= x ? (x + y) : -1; \
  }

Form 2:
  #define SAT_ADD_U_2(T) \
  T sat_add_u_2_##T(T x, T y) \
  { \
    T ret; \
    T overflow = __builtin_add_overflow (x, y, &ret); \
    return (T)(-overflow) | ret; \
  }

Form 3:
  #define SAT_ADD_U_3(T) \
  T sat_add_u_3_##T (T x, T y) \
  { \
    T ret; \
    return __builtin_add_overflow (x, y, &ret) ? -1 : ret; \
  }

Form 4:
  #define SAT_ADD_U_4(T) \
  T sat_add_u_4_##T (T x, T y) \
  { \
    T ret; \
    return __builtin_add_overflow (x, y, &ret) == 0 ? ret : -1; \
  }

Form 5:
  #define SAT_ADD_U_5(T) \
  T sat_add_u_5_##T(T x, T y) \
  { \
    return (T)(x + y) < x ? -1 : (x + y); \
  }

Take the forms 3 of above as example:

uint64_t
sat_add (uint64_t x, uint64_t y)
{
  uint64_t ret;
  return __builtin_add_overflow (x, y, &ret) ? -1 : ret;
}

Before this patch:
uint64_t sat_add (uint64_t x, uint64_t y)
{
  long unsigned int _1;
  long unsigned int _2;
  uint64_t _3;
  __complex__ long unsigned int _6;

;;   basic block 2, loop depth 0
;;    pred:       ENTRY
  _6 = .ADD_OVERFLOW (x_4(D), y_5(D));
  _2 = IMAGPART_EXPR <_6>;
  if (_2 != 0)
    goto <bb 4>; [35.00%]
  else
    goto <bb 3>; [65.00%]
;;    succ:       4
;;                3

;;   basic block 3, loop depth 0
;;    pred:       2
  _1 = REALPART_EXPR <_6>;
;;    succ:       4

;;   basic block 4, loop depth 0
;;    pred:       3
;;                2
  # _3 = PHI <_1(3), 18446744073709551615(2)>
  return _3;
;;    succ:       EXIT
}

After this patch:
uint64_t sat_add (uint64_t x, uint64_t y)
{
  long unsigned int _12;

;;   basic block 2, loop depth 0
;;    pred:       ENTRY
  _12 = .SAT_ADD (x_4(D), y_5(D)); [tail call]
  return _12;
;;    succ:       EXIT
}

The flag '^' acts on cond_expr will generate matching code similar as below:

else if (gphi *_a1 = dyn_cast <gphi *> (_d1))
  {
    basic_block _b1 = gimple_bb (_a1);
    if (gimple_phi_num_args (_a1) == 2)
      {
        basic_block _pb_0_1 = EDGE_PRED (_b1, 0)->src;
        basic_block _pb_1_1 = EDGE_PRED (_b1, 1)->src;
        basic_block _db_1 = safe_dyn_cast <gcond *> (*gsi_last_bb (_pb_0_1))
                            ? _pb_0_1 : _pb_1_1;
        basic_block _other_db_1 = safe_dyn_cast <gcond *> (*gsi_last_bb (_pb_0_1))
                                  ? _pb_1_1 : _pb_0_1;
        gcond *_ct_1 = safe_dyn_cast <gcond *> (*gsi_last_bb (_db_1));
        if (_ct_1 && EDGE_COUNT (_other_db_1->preds) == 1
          && EDGE_COUNT (_other_db_1->succs) == 1
          && EDGE_PRED (_other_db_1, 0)->src == _db_1)
          {
            tree _cond_lhs_1 = gimple_cond_lhs (_ct_1);
            tree _cond_rhs_1 = gimple_cond_rhs (_ct_1);
            tree _p0 = build2 (gimple_cond_code (_ct_1), boolean_type_node,
                               _cond_lhs_1, _cond_rhs_1);
            bool _arg_0_is_true_1 = gimple_phi_arg_edge (_a1, 0)->flags & EDGE_TRUE_VALUE;
            tree _p1 = gimple_phi_arg_def (_a1, _arg_0_is_true_1 ? 0 : 1);
            tree _p2 = gimple_phi_arg_def (_a1, _arg_0_is_true_1 ? 1 : 0);
            ....

The below test suites are passed for this patch.
* The x86 bootstrap test.
* The x86 fully regression test.
* The riscv fully regression test.

gcc/ChangeLog:

	* doc/match-and-simplify.texi: Add doc for the matching flag '^'.
	* genmatch.cc (cmp_operand): Add match_phi comparation.
	(dt_node::gen_kids_1): Add cond_expr bool flag for phi match.
	(dt_operand::gen_phi_on_cond): Add new func to gen phi matching
	on cond_expr.
	(parser::parse_expr): Add handling for the expr flag '^'.
	* match.pd: Add more form for unsigned .SAT_ADD.
	* tree-ssa-math-opts.cc (build_saturation_binary_arith_call): Add
	new func impl to build call for phi gimple.
	(match_unsigned_saturation_add): Add new func impl to match the
	.SAT_ADD for phi gimple.
	(math_opts_dom_walker::after_dom_children): Add phi matching
	try for all gimple phi stmt.

Signed-off-by: Pan Li <pan2.li@intel.com>

0 files changed, 0 insertions, 0 deletions