re PR tree-optimization/56210 (invalid -Warray-bounds warning)

2013-03-18  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/56210
	* tree-ssa-structalias.c (find_func_aliases_for_builtin_call):
	Handle string / character search functions.
	* tree-ssa-alias.c (ref_maybe_used_by_call_p_1): Likewise.

From-SVN: r196777

gcc/ChangeLog

 2013-03-18  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/56210
+	* tree-ssa-structalias.c (find_func_aliases_for_builtin_call):
+	Handle string / character search functions.
+	* tree-ssa-alias.c (ref_maybe_used_by_call_p_1): Likewise.
+
+2013-03-18  Richard Biener  <rguenther@suse.de>
+
 	PR middle-end/56483
 	* cfgexpand.c (expand_gimple_cond): Inline gimple_cond_single_var_p
 	and implement properly.

gcc/tree-ssa-alias.c

@@ -1314,6 +1314,43 @@ ref_maybe_used_by_call_p_1 (gimple call, ao_ref *ref)
 					   size);
 	    return refs_may_alias_p_1 (&dref, ref, false);
 	  }
+	/* These read memory pointed to by the first argument.  */
+	case BUILT_IN_INDEX:
+	case BUILT_IN_STRCHR:
+	case BUILT_IN_STRRCHR:
+	  {
+	    ao_ref dref;
+	    ao_ref_init_from_ptr_and_size (&dref,
+					   gimple_call_arg (call, 0),
+					   NULL_TREE);
+	    return refs_may_alias_p_1 (&dref, ref, false);
+	  }
+	/* These read memory pointed to by the first argument with size
+	   in the third argument.  */
+	case BUILT_IN_MEMCHR:
+	  {
+	    ao_ref dref;
+	    ao_ref_init_from_ptr_and_size (&dref,
+					   gimple_call_arg (call, 0),
+					   gimple_call_arg (call, 2));
+	    return refs_may_alias_p_1 (&dref, ref, false);
+	  }
+	/* These read memory pointed to by the first and second arguments.  */
+	case BUILT_IN_STRSTR:
+	case BUILT_IN_STRPBRK:
+	  {
+	    ao_ref dref;
+	    ao_ref_init_from_ptr_and_size (&dref,
+					   gimple_call_arg (call, 0),
+					   NULL_TREE);
+	    if (refs_may_alias_p_1 (&dref, ref, false))
+	      return true;
+	    ao_ref_init_from_ptr_and_size (&dref,
+					   gimple_call_arg (call, 1),
+					   NULL_TREE);
+	    return refs_may_alias_p_1 (&dref, ref, false);
+	  }
+
 	/* The following builtins do not read from memory.  */
 	case BUILT_IN_FREE:
 	case BUILT_IN_MALLOC:

gcc/tree-ssa-structalias.c

@@ -4196,6 +4196,29 @@ find_func_aliases_for_builtin_call (gimple t)
 	    return true;
 	  }
 	break;
+      /* String / character search functions return a pointer into the
+         source string or NULL.  */
+      case BUILT_IN_INDEX:
+      case BUILT_IN_STRCHR:
+      case BUILT_IN_STRRCHR:
+      case BUILT_IN_MEMCHR:
+      case BUILT_IN_STRSTR:
+      case BUILT_IN_STRPBRK:
+	if (gimple_call_lhs (t))
+	  {
+	    tree src = gimple_call_arg (t, 0);
+	    get_constraint_for_ptr_offset (src, NULL_TREE, &rhsc);
+	    constraint_expr nul;
+	    nul.var = nothing_id;
+	    nul.offset = 0;
+	    nul.type = ADDRESSOF;
+	    rhsc.safe_push (nul);
+	    get_constraint_for (gimple_call_lhs (t), &lhsc);
+	    process_all_all_constraints (lhsc, rhsc);
+	    lhsc.release();
+	    rhsc.release();
+	  }
+	return true;
       /* Trampolines are special - they set up passing the static
 	 frame.  */
       case BUILT_IN_INIT_TRAMPOLINE: