gcc/c-family/c-cilkplus.c

   1 /* This file contains routines to construct and validate Cilk Plus
   2    constructs within the C and C++ front ends.
   3
   4    Copyright (C) 2013-2015 Free Software Foundation, Inc.
   5    Contributed by Aldy Hernandez <aldyh@redhat.com>.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it
  10 under the terms of the GNU General Public License as published by
  11 the Free Software Foundation; either version 3, or (at your option)
  12 any later version.
  13
  14 GCC is distributed in the hope that it will be useful, but
  15 WITHOUT ANY WARRANTY; without even the implied warranty of
  16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17 General Public License for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "hash-set.h"
  27 #include "machmode.h"
  28 #include "vec.h"
  29 #include "double-int.h"
  30 #include "input.h"
  31 #include "alias.h"
  32 #include "symtab.h"
  33 #include "options.h"
  34 #include "wide-int.h"
  35 #include "inchash.h"
  36 #include "tree.h"
  37 #include "c-common.h"
  38
  39 /* Validate the body of a _Cilk_for construct or a <#pragma simd> for
  40    loop.
  41
  42    Returns true if there were no errors, false otherwise.  */
  43
  44 bool
  45 c_check_cilk_loop (location_t loc, tree decl)
  46 {
  47   if (TREE_THIS_VOLATILE (decl))
  48     {
  49       error_at (loc, "iteration variable cannot be volatile");
  50       return false;
  51     }
  52   return true;
  53 }
  54
  55 /* Validate and emit code for <#pragma simd> clauses.  */
  56
  57 tree
  58 c_finish_cilk_clauses (tree clauses)
  59 {
  60   for (tree c = clauses; c; c = OMP_CLAUSE_CHAIN (c))
  61     {
  62       tree prev = clauses;
  63
  64       /* If a variable appears in a linear clause it cannot appear in
  65          any other OMP clause.  */
  66       if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LINEAR)
  67         for (tree c2 = clauses; c2; c2 = OMP_CLAUSE_CHAIN (c2))
  68           {
  69             if (c == c2)
  70               continue;
  71             enum omp_clause_code code = OMP_CLAUSE_CODE (c2);
  72
  73             switch (code)
  74               {
  75               case OMP_CLAUSE_LINEAR:
  76               case OMP_CLAUSE_PRIVATE:
  77               case OMP_CLAUSE_FIRSTPRIVATE:
  78               case OMP_CLAUSE_LASTPRIVATE:
  79               case OMP_CLAUSE_REDUCTION:
  80                 break;
  81
  82               case OMP_CLAUSE_SAFELEN:
  83                 goto next;
  84
  85               default:
  86                 gcc_unreachable ();
  87               }
  88
  89             if (OMP_CLAUSE_DECL (c) == OMP_CLAUSE_DECL (c2))
  90               {
  91                 error_at (OMP_CLAUSE_LOCATION (c2),
  92                           "variable appears in more than one clause");
  93                 inform (OMP_CLAUSE_LOCATION (c),
  94                         "other clause defined here");
  95                 // Remove problematic clauses.
  96                 OMP_CLAUSE_CHAIN (prev) = OMP_CLAUSE_CHAIN (c2);
  97               }
  98           next:
  99             prev = c2;
 100           }
 101     }
 102   return clauses;
 103 }
 104
 105 /* Calculate number of iterations of CILK_FOR.  */
 106
 107 tree
 108 cilk_for_number_of_iterations (tree cilk_for)
 109 {
 110   tree t, v, n1, n2, step, type, init, cond, incr, itype;
 111   enum tree_code cond_code;
 112   location_t loc = EXPR_LOCATION (cilk_for);
 113
 114   init = TREE_VEC_ELT (OMP_FOR_INIT (cilk_for), 0);
 115   v = TREE_OPERAND (init, 0);
 116   cond = TREE_VEC_ELT (OMP_FOR_COND (cilk_for), 0);
 117   incr = TREE_VEC_ELT (OMP_FOR_INCR (cilk_for), 0);
 118   type = TREE_TYPE (v);
 119
 120   gcc_assert (TREE_CODE (TREE_TYPE (v)) == INTEGER_TYPE
 121               || TREE_CODE (TREE_TYPE (v)) == POINTER_TYPE);
 122   n1 = TREE_OPERAND (init, 1);
 123   cond_code = TREE_CODE (cond);
 124   n2 = TREE_OPERAND (cond, 1);
 125   switch (cond_code)
 126     {
 127     case LT_EXPR:
 128     case GT_EXPR:
 129     case NE_EXPR:
 130       break;
 131     case LE_EXPR:
 132       if (POINTER_TYPE_P (TREE_TYPE (n2)))
 133         n2 = fold_build_pointer_plus_hwi_loc (loc, n2, 1);
 134       else
 135         n2 = fold_build2_loc (loc, PLUS_EXPR, TREE_TYPE (n2), n2,
 136                               build_int_cst (TREE_TYPE (n2), 1));
 137       cond_code = LT_EXPR;
 138       break;
 139     case GE_EXPR:
 140       if (POINTER_TYPE_P (TREE_TYPE (n2)))
 141         n2 = fold_build_pointer_plus_hwi_loc (loc, n2, -1);
 142       else
 143         n2 = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (n2), n2,
 144                               build_int_cst (TREE_TYPE (n2), 1));
 145       cond_code = GT_EXPR;
 146       break;
 147     default:
 148       gcc_unreachable ();
 149     }
 150
 151   step = NULL_TREE;
 152   switch (TREE_CODE (incr))
 153     {
 154     case PREINCREMENT_EXPR:
 155     case POSTINCREMENT_EXPR:
 156       step = build_int_cst (TREE_TYPE (v), 1);
 157       break;
 158     case PREDECREMENT_EXPR:
 159     case POSTDECREMENT_EXPR:
 160       step = build_int_cst (TREE_TYPE (v), -1);
 161       break;
 162     case MODIFY_EXPR:
 163       t = TREE_OPERAND (incr, 1);
 164       gcc_assert (TREE_OPERAND (t, 0) == v);
 165       switch (TREE_CODE (t))
 166         {
 167         case PLUS_EXPR:
 168           step = TREE_OPERAND (t, 1);
 169           break;
 170         case POINTER_PLUS_EXPR:
 171           step = fold_convert (ssizetype, TREE_OPERAND (t, 1));
 172           break;
 173         case MINUS_EXPR:
 174           step = TREE_OPERAND (t, 1);
 175           step = fold_build1_loc (loc, NEGATE_EXPR, TREE_TYPE (step), step);
 176           break;
 177         default:
 178           gcc_unreachable ();
 179         }
 180       break;
 181     default:
 182       gcc_unreachable ();
 183     }
 184
 185   itype = type;
 186   if (POINTER_TYPE_P (itype))
 187     itype = signed_type_for (itype);
 188   if (cond_code == NE_EXPR)
 189     {
 190       /* For NE_EXPR, we need to find out if the iterator increases
 191          or decreases from whether step is positive or negative.  */
 192       tree stype = itype;
 193       if (TYPE_UNSIGNED (stype))
 194         stype = signed_type_for (stype);
 195       cond = fold_build2_loc (loc, GE_EXPR, boolean_type_node,
 196                               fold_convert_loc (loc, stype, step),
 197                               build_int_cst (stype, 0));
 198       t = fold_build3_loc (loc, COND_EXPR, itype, cond,
 199                            build_int_cst (itype, -1),
 200                            build_int_cst (itype, 1));
 201     }
 202   else
 203     t = build_int_cst (itype, (cond_code == LT_EXPR ? -1 : 1));
 204   t = fold_build2_loc (loc, PLUS_EXPR, itype,
 205                        fold_convert_loc (loc, itype, step), t);
 206   t = fold_build2_loc (loc, PLUS_EXPR, itype, t,
 207                        fold_convert_loc (loc, itype, n2));
 208   t = fold_build2_loc (loc, MINUS_EXPR, itype, t,
 209                        fold_convert_loc (loc, itype, n1));
 210   if (TYPE_UNSIGNED (itype) && cond_code == GT_EXPR)
 211     t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype,
 212                          fold_build1_loc (loc, NEGATE_EXPR, itype, t),
 213                          fold_build1_loc (loc, NEGATE_EXPR, itype,
 214                                           fold_convert_loc (loc, itype,
 215                                                             step)));
 216   else if (TYPE_UNSIGNED (itype) && cond_code == NE_EXPR)
 217     {
 218       tree t1
 219         = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype, t,
 220                            fold_convert_loc (loc, itype, step));
 221       tree t2
 222         = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype,
 223                            fold_build1_loc (loc, NEGATE_EXPR, itype, t),
 224                            fold_build1_loc (loc, NEGATE_EXPR, itype,
 225                                             fold_convert_loc (loc, itype,
 226                                                               step)));
 227       t = fold_build3_loc (loc, COND_EXPR, itype, cond, t1, t2);
 228     }
 229   else
 230     t = fold_build2_loc (loc, TRUNC_DIV_EXPR, itype, t,
 231                          fold_convert_loc (loc, itype, step));
 232   cond = fold_build2_loc (loc, cond_code, boolean_type_node, n1, n2);
 233   t = fold_build3_loc (loc, COND_EXPR, itype, cond, t,
 234                        build_int_cst (itype, 0));
 235   return t;
 236 }