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       1              : /* Header file for gimple range phi analysis.
       2              :    Copyright (C) 2023-2026 Free Software Foundation, Inc.
       3              :    Contributed by Andrew MacLeod <amacleod@redhat.com>.
       4              : 
       5              : This file is part of GCC.
       6              : 
       7              : GCC is free software; you can redistribute it and/or modify it under
       8              : the terms of the GNU General Public License as published by the Free
       9              : Software Foundation; either version 3, or (at your option) any later
      10              : version.
      11              : 
      12              : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
      13              : WARRANTY; without even the implied warranty of MERCHANTABILITY or
      14              : FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      15              :  for more details.
      16              : 
      17              : You should have received a copy of the GNU General Public License
      18              : along with GCC; see the file COPYING3.  If not see
      19              : <http://www.gnu.org/licenses/>.  */
      20              : 
      21              : #ifndef GCC_SSA_RANGE_PHI_H
      22              : #define GCC_SSA_RANGE_PHI_H
      23              : 
      24              : // -------------------------------------------------------------------------
      25              : 
      26              : // A PHI_GROUP consists of a set of SSA_NAMES which are all PHI_DEFS, and
      27              : // their arguemnts contain nothing but other PHI defintions, with at most
      28              : // 2 exceptions:
      29              : //  1 - An initial value.  This is either a constant, or another non-phi name
      30              : //      with a single incoming edge to the cycle group
      31              : //  2 - A modifier statement which adjusts the value.  ie, name2 = phi_name + 1
      32              : //  The initial range is used to create one bound and the modifier is examined
      33              : //  to determine the other bound.
      34              : //  All members of the PHI cycle will be given the same range.
      35              : //
      36              : // For example, given the follwoing sequences:
      37              : // qa_20 = qa_10 + 1;
      38              : // qa_9 = PHI <qa_10(3), qa_20(4)>
      39              : // qa_10 = PHI <0(2), qa_9(5)>
      40              : //
      41              : // We can determine the following group:
      42              : //
      43              : // PHI cycle members qa_9, qa_10
      44              : // Initial value : 0
      45              : // modifier stmt: qa_20 = qa_10 + 1;
      46              : //
      47              : // Based on just this analysis, We can project that qa_9 and qa_10 will have
      48              : // a range of [0, +INF].
      49              : 
      50      1792164 : class phi_group
      51              : {
      52              : public:
      53              :   phi_group (bitmap bm, irange &init_range, gimple *mod, range_query *q);
      54              :   phi_group (const phi_group &g);
      55            0 :   const_bitmap group () const { return m_group; }
      56       834978 :   const vrange &range () const { return m_vr; }
      57              :   gimple *modifier_stmt () const { return m_modifier; }
      58              :   void dump (FILE *);
      59              : protected:
      60              :   bool calculate_using_modifier (range_query *q);
      61              :   bool refine_using_relation (relation_kind k);
      62              :   static unsigned is_modifier_p (gimple *s, const bitmap bm, tree *op = NULL);
      63              :   bitmap m_group;
      64              :   gimple *m_modifier;     // Single stmt which modifies phi group.
      65              :   unsigned m_modifier_op; // Operand of group member in modifier stmt.
      66              :   tree m_modifier_name;   // Name of modifier operand ssa-name.
      67              :   int_range_max m_vr;
      68              :   friend class phi_analyzer;
      69              : };
      70              : 
      71              : // The phi anlyzer will return the group that name belongs to.
      72              : // If inforamtion is not known about a name yet, analysis is conducted by
      73              : // looking at the arguments to PHIS and following them to their defs to
      74              : // determine whether the conditions are met to form a new group.
      75              : 
      76              : class phi_analyzer
      77              : {
      78              : public:
      79              :   phi_analyzer (range_query &);
      80              :   ~phi_analyzer ();
      81              :   phi_group *operator[] (tree name);
      82              :   void dump (FILE *f);
      83              : protected:
      84              :   phi_group *group (tree name) const;
      85              :   void process_phi (gphi *phi, range_query &query);
      86              :   vec<tree> m_work;
      87              : 
      88              :   bitmap m_simple;       // Processed, not part of a group.
      89              :   bitmap m_current;      // Potential group currently being analyzed.
      90              :   vec<phi_group *> m_phi_groups;
      91              :   vec<phi_group *> m_tab;
      92              :   bitmap_obstack m_bitmaps;
      93              : };
      94              : 
      95              : // Invoke a phi analyzer.  It will process all the current PHI nodes and try
      96              : // to form groups with initial values. Then export any ranges found
      97              : // to set_range_info.  When finished, it will simply dispose of itself.
      98              : 
      99              : void phi_analysis (range_query &q);
     100              : 
     101              : #endif // GCC_SSA_RANGE_PHI_H