1  /* Header file for SSA loop optimizations.
       2     Copyright (C) 2013-2023 Free Software Foundation, Inc.
       3  
       4  This file is part of GCC.
       5  
       6  GCC is free software; you can redistribute it and/or modify it under
       7  the terms of the GNU General Public License as published by the Free
       8  Software Foundation; either version 3, or (at your option) any later
       9  version.
      10  
      11  GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      12  WARRANTY; without even the implied warranty of MERCHANTABILITY or
      13  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      14   for more details.
      15  
      16  You should have received a copy of the GNU General Public License
      17  along with GCC; see the file COPYING3.  If not see
      18  <http://www.gnu.org/licenses/>.  */
      19  
      20  #ifndef GCC_TREE_SSA_LOOP_H
      21  #define GCC_TREE_SSA_LOOP_H
      22  
      23  
      24  /* Affine iv.  */
      25  
      26  struct affine_iv
      27  {
      28    /* Iv = BASE + STEP * i.  */
      29    tree base, step;
      30  
      31    /* True if this iv does not overflow.  */
      32    bool no_overflow;
      33  };
      34  
      35  /* Description of number of iterations of a loop.  All the expressions inside
      36     the structure can be evaluated at the end of the loop's preheader
      37     (and due to ssa form, also anywhere inside the body of the loop).  */
      38  
      39  class tree_niter_desc
      40  {
      41  public:
      42    tree assumptions;	/* The boolean expression.  If this expression evaluates
      43  			   to false, then the other fields in this structure
      44  			   should not be used; there is no guarantee that they
      45  			   will be correct.  */
      46    tree may_be_zero;	/* The boolean expression.  If it evaluates to true,
      47  			   the loop will exit in the first iteration (i.e.
      48  			   its latch will not be executed), even if the niter
      49  			   field says otherwise.  */
      50    tree niter;		/* The expression giving the number of iterations of
      51  			   a loop (provided that assumptions == true and
      52  			   may_be_zero == false), more precisely the number
      53  			   of executions of the latch of the loop.  */
      54    widest_int max;	/* The upper bound on the number of iterations of
      55  			   the loop.  If niter is constant, then these values
      56  			   must agree.  */
      57  
      58    /* The simplified shape of the exit condition.  This information is used by
      59       loop unrolling.  If CMP is ERROR_MARK, then the loop cannot be unrolled.
      60       Otherwise, the loop exits if CONTROL CMP BOUND is false, where CMP is one
      61       of NE_EXPR, LT_EXPR, or GT_EXPR, and CONTROL.STEP is positive if CMP is
      62       LT_EXPR and negative if CMP is GT_EXPR.  */
      63    affine_iv control;
      64    tree bound;
      65    enum tree_code cmp;
      66  };
      67  
      68  extern bool for_each_index (tree *, bool (*) (tree, tree *, void *), void *);
      69  extern char *get_lsm_tmp_name (tree ref, unsigned n, const char *suffix = NULL);
      70  extern unsigned tree_num_loop_insns (class loop *, struct eni_weights *);
      71  
      72  /* Returns the loop of the statement STMT.  */
      73  
      74  inline class loop *
      75  loop_containing_stmt (gimple *stmt)
      76  {
      77    basic_block bb = gimple_bb (stmt);
      78    if (!bb)
      79      return NULL;
      80  
      81    return bb->loop_father;
      82  }
      83  
      84  #endif /* GCC_TREE_SSA_LOOP_H */