gcc/config/epiphany/resolve-sw-modes.c

   1 /* Mode switching cleanup pass for the EPIPHANY cpu.
   2    Copyright (C) 2000, 2011 Free Software Foundation, Inc.
   3    Contributed by Embecosm on behalf of Adapteva, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License 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 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "machmode.h"
  25 #include "tm.h"
  26 #include "hard-reg-set.h"
  27 #include "tm_p.h"
  28 #include "vec.h"
  29 #include "sbitmap.h"
  30 #include "basic-block.h"
  31 #include "df.h"
  32 #include "rtl.h"
  33 #include "insn-config.h"
  34 #include "insn-codes.h"
  35 #include "emit-rtl.h"
  36 #include "recog.h"
  37 #include "function.h"
  38 #include "insn-attr-common.h"
  39 #include "tree-pass.h"
  40
  41 /* Clean-up after mode switching:
  42    Check for mode setting insns that have FP_MODE_ROUND_UNKNOWN.
  43    If only one rounding mode is required, select that one.
  44    Else we have to choose one to use in this mode setting insn and
  45    insert new mode setting insns on the edges where the other mode
  46    becomes unambigous.  */
  47
  48 static bool
  49 gate_resolve_sw_modes (void)
  50 {
  51   return optimize;
  52 }
  53
  54 static unsigned
  55 resolve_sw_modes (void)
  56 {
  57   basic_block bb;
  58   rtx insn, src;
  59   vec<basic_block> todo;
  60   sbitmap pushed;
  61   bool need_commit = false;
  62   bool finalize_fp_sets = (MACHINE_FUNCTION (cfun)->unknown_mode_sets == 0);
  63
  64   todo.create (last_basic_block);
  65   pushed = sbitmap_alloc (last_basic_block);
  66   bitmap_clear (pushed);
  67   if (!finalize_fp_sets)
  68     {
  69       df_note_add_problem ();
  70       df_analyze ();
  71     }
  72   FOR_EACH_BB (bb)
  73     FOR_BB_INSNS (bb, insn)
  74       {
  75         enum attr_fp_mode selected_mode;
  76
  77         if (!NONJUMP_INSN_P (insn)
  78             || recog_memoized (insn) != CODE_FOR_set_fp_mode)
  79           continue;
  80         src = SET_SRC (XVECEXP (PATTERN (insn), 0, 0));
  81         if (finalize_fp_sets)
  82           {
  83             SET_SRC (XVECEXP (PATTERN (insn), 0, 2)) = copy_rtx (src);
  84             if (REG_P (src))
  85               df_insn_rescan (insn);
  86             continue;
  87           }
  88         if (REG_P (src)
  89             || XINT (XVECEXP (XEXP (src, 0), 0, 0), 0) != FP_MODE_ROUND_UNKNOWN)
  90           continue;
  91         if (find_regno_note (insn, REG_UNUSED, FP_TRUNCATE_REGNUM))
  92           selected_mode = FP_MODE_ROUND_NEAREST;
  93         else if (find_regno_note (insn, REG_UNUSED, FP_NEAREST_REGNUM))
  94           selected_mode = FP_MODE_ROUND_TRUNC;
  95         else
  96           {
  97             /* We could get more fancy in the selection of the mode by
  98                checking the total frequency of the affected edges.  */
  99             selected_mode = (enum attr_fp_mode) epiphany_normal_fp_rounding;
 100
 101             todo.quick_push (bb);
 102             bitmap_set_bit (pushed, bb->index);
 103           }
 104         XVECEXP (XEXP (src, 0), 0, 0) = GEN_INT (selected_mode);
 105         SET_SRC (XVECEXP (PATTERN (insn), 0, 1)) = copy_rtx (src);
 106         SET_SRC (XVECEXP (PATTERN (insn), 0, 2)) = copy_rtx (src);
 107         df_insn_rescan (insn);
 108       }
 109   while (todo.length ())
 110     {
 111       basic_block bb = todo.pop ();
 112       int selected_reg, jilted_reg;
 113       enum attr_fp_mode jilted_mode;
 114       edge e;
 115       edge_iterator ei;
 116
 117       bitmap_set_bit (pushed, bb->index);
 118       bitmap_set_bit (pushed, bb->index);
 119
 120       if (epiphany_normal_fp_rounding == FP_MODE_ROUND_NEAREST)
 121         {
 122           selected_reg = FP_NEAREST_REGNUM;
 123           jilted_reg = FP_TRUNCATE_REGNUM;
 124           jilted_mode = FP_MODE_ROUND_TRUNC;
 125         }
 126       else
 127         {
 128           selected_reg = FP_TRUNCATE_REGNUM;
 129           jilted_reg = FP_NEAREST_REGNUM;
 130           jilted_mode = FP_MODE_ROUND_NEAREST;
 131         }
 132
 133       FOR_EACH_EDGE (e, ei, bb->succs)
 134         {
 135           basic_block succ = e->dest;
 136           rtx seq;
 137
 138           if (!REGNO_REG_SET_P (DF_LIVE_IN (succ), jilted_reg))
 139             continue;
 140           if (REGNO_REG_SET_P (DF_LIVE_IN (succ), selected_reg))
 141             {
 142               if (bitmap_bit_p (pushed, succ->index))
 143                 continue;
 144               todo.quick_push (succ);
 145               bitmap_set_bit (pushed, bb->index);
 146               continue;
 147             }
 148           start_sequence ();
 149           emit_set_fp_mode (EPIPHANY_MSW_ENTITY_ROUND_UNKNOWN,
 150                             jilted_mode, NULL);
 151           seq = get_insns ();
 152           end_sequence ();
 153           need_commit = true;
 154           insert_insn_on_edge (seq, e);
 155         }
 156     }
 157   todo.release ();
 158   sbitmap_free (pushed);
 159   if (need_commit)
 160     commit_edge_insertions ();
 161   return 0;
 162 }
 163
 164 struct rtl_opt_pass pass_resolve_sw_modes =
 165 {
 166  {
 167   RTL_PASS,
 168   "resolve_sw_modes",                   /* name */
 169   OPTGROUP_NONE,                        /* optinfo_flags */
 170   gate_resolve_sw_modes,                /* gate */
 171   resolve_sw_modes,                     /* execute */
 172   NULL,                                 /* sub */
 173   NULL,                                 /* next */
 174   0,                                    /* static_pass_number */
 175   TV_MODE_SWITCH,                       /* tv_id */
 176   0,                                    /* properties_required */
 177   0,                                    /* properties_provided */
 178   0,                                    /* properties_destroyed */
 179   0,                                    /* todo_flags_start */
 180   TODO_df_finish | TODO_verify_rtl_sharing |
 181   0                                     /* todo_flags_finish */
 182  }
 183 };