semantics.c (end_maybe_infinite_loop): Use fold_non_dependent_expr.

2014-11-14  Paolo Carlini  <paolo.carlini@oracle.com>

	* semantics.c (end_maybe_infinite_loop): Use fold_non_dependent_expr.
	* parser.c (cp_parser_omp_clause_collapse): Likewise.
	(cp_parser_enumerator_definition): Don't call
	instantiate_non_dependent_expr...
	* decl.c (build_enumerator): ... call fold_non_dependent_expr here.
	* typeck2.c (massage_init_elt): Use fold_non_dependent_expr.
	* constexpr.c (maybe_constant_value): Allow VIEW_CONVERT_EXPR in
	the final gcc_assert.

	* constexpr.c (fold_non_dependent_expr): Add.
	* cp-tree.h (fold_non_dependent_expr): Declare it.
	* call.c (null_ptr_cst_p): Use it.
	* pt.c (tsubst_copy_and_build, build_non_dependent_expr): Likewise.
	* semantics.c (begin_maybe_infinite_loop): Likewise.
	* typeck.c (cp_build_binary_op): Likewise.
	* typeck2.c (check_narrowing): Likewise.

	* pt.c (fold_non_dependent_expr): Rename to
	instantiate_non_dependent_expr.
	(fold_non_dependent_expr_sfinae): Rename to
	instantiate_non_dependent_expr_sfinae.
	(convert_nontype_argument, build_non_dependent_expr): Adjust.
	* decl.c (compute_array_index_type): Likewise.
	* parser.c (cp_parser_parenthesized_expression_list,
	cp_parser_enumerator_definition, cp_parser_omp_clause_collapse):
	Likewise.
	* semantics.c (end_maybe_infinite_loop, finish_static_assert):
	Likewise.
	* typeck.c (cxx_alignas_expr): Likewise.
	* typeck2.c (store_init_value, massage_init_elt): Likewise.
	* call.c: Adjust comments.
	* class.c: Likewise.
	* constexpr.c: Likewise.
	* decl2.c: Likewise.
	* tree.c: Likewise.

From-SVN: r217577

gcc/cp/ChangeLog

@@ -1,3 +1,41 @@
+2014-11-14  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	* semantics.c (end_maybe_infinite_loop): Use fold_non_dependent_expr.
+	* parser.c (cp_parser_omp_clause_collapse): Likewise.
+	(cp_parser_enumerator_definition): Don't call
+	instantiate_non_dependent_expr...
+	* decl.c (build_enumerator): ... call fold_non_dependent_expr here.
+	* typeck2.c (massage_init_elt): Use fold_non_dependent_expr.
+	* constexpr.c (maybe_constant_value): Allow VIEW_CONVERT_EXPR in
+	the final gcc_assert.
+
+	* constexpr.c (fold_non_dependent_expr): Add.
+	* cp-tree.h (fold_non_dependent_expr): Declare it.
+	* call.c (null_ptr_cst_p): Use it.
+	* pt.c (tsubst_copy_and_build, build_non_dependent_expr): Likewise.
+	* semantics.c (begin_maybe_infinite_loop): Likewise.
+	* typeck.c (cp_build_binary_op): Likewise.
+	* typeck2.c (check_narrowing): Likewise.
+
+	* pt.c (fold_non_dependent_expr): Rename to
+	instantiate_non_dependent_expr.
+	(fold_non_dependent_expr_sfinae): Rename to
+	instantiate_non_dependent_expr_sfinae.
+	(convert_nontype_argument, build_non_dependent_expr): Adjust.
+	* decl.c (compute_array_index_type): Likewise.
+	* parser.c (cp_parser_parenthesized_expression_list,
+	cp_parser_enumerator_definition, cp_parser_omp_clause_collapse):
+	Likewise.
+	* semantics.c (end_maybe_infinite_loop, finish_static_assert):
+	Likewise.
+	* typeck.c (cxx_alignas_expr): Likewise.
+	* typeck2.c (store_init_value, massage_init_elt): Likewise.
+	* call.c: Adjust comments.
+	* class.c: Likewise.
+	* constexpr.c: Likewise.
+	* decl2.c: Likewise.
+	* tree.c: Likewise.
+
 2014-11-14  Jonathan Wakely  <jwakely@redhat.com>
 
 	* mangle.c (find_substitution): Look for abi_tag on class templates.

gcc/cp/call.c

@@ -572,7 +572,7 @@ null_ptr_cst_p (tree t)
     {
       /* Core issue 903 says only literal 0 is a null pointer constant.  */
       if (cxx_dialect < cxx11)
-	t = maybe_constant_value (fold_non_dependent_expr_sfinae (t, tf_none));
+	t = fold_non_dependent_expr (t);
       STRIP_NOPS (t);
       if (integer_zerop (t) && !TREE_OVERFLOW (t))
 	return true;
@@ -7437,8 +7437,8 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
     return error_mark_node;
 
   if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) == 0
-      /* Don't mess with virtual lookup in fold_non_dependent_expr; virtual
+      /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
-	 functions can't be constexpr.  */
+	 virtual functions can't be constexpr.  */
       && !in_template_function ())
     {
       tree t;
@@ -9361,7 +9361,7 @@ perform_implicit_conversion_flags (tree type, tree expr,
 	 type of non-dependent expressions, so we do not have to
 	 perform the actual conversion.  But for initializers, we
 	 need to be able to perform it at instantiation
-	 (or fold_non_dependent_expr) time.  */
+	 (or instantiate_non_dependent_expr) time.  */
       expr = build1 (IMPLICIT_CONV_EXPR, type, expr);
       if (!(flags & LOOKUP_ONLYCONVERTING))
 	IMPLICIT_CONV_EXPR_DIRECT_INIT (expr) = true;

gcc/cp/class.c

@@ -359,9 +359,9 @@ build_base_path (enum tree_code code,
 
   /* Don't bother with the calculations inside sizeof; they'll ICE if the
      source type is incomplete and the pointer value doesn't matter.  In a
-     template (even in fold_non_dependent_expr), we don't have vtables set
+     template (even in instantiate_non_dependent_expr), we don't have vtables
-     up properly yet, and the value doesn't matter there either; we're just
+     set up properly yet, and the value doesn't matter there either; we're
-     interested in the result of overload resolution.  */
+     just interested in the result of overload resolution.  */
   if (cp_unevaluated_operand != 0
       || in_template_function ())
     {
@@ -6933,7 +6933,8 @@ resolves_to_fixed_type_p (tree instance, int* nonnull)
   tree fixed;
 
   /* processing_template_decl can be false in a template if we're in
-     fold_non_dependent_expr, but we still want to suppress this check.  */
+     instantiate_non_dependent_expr, but we still want to suppress
+     this check.  */
   if (in_template_function ())
     {
       /* In a template we only care about the type of the result.  */

gcc/cp/constexpr.c

@@ -2908,12 +2908,83 @@ maybe_constant_value (tree t, tree decl)
   /* cp_tree_equal looks through NOPs, so allow them.  */
   gcc_assert (r == t
 	      || CONVERT_EXPR_P (t)
+	      || TREE_CODE (t) == VIEW_CONVERT_EXPR
 	      || (TREE_CONSTANT (t) && !TREE_CONSTANT (r))
 	      || !cp_tree_equal (r, t));
 #endif
   return r;
 }
 
+/* Like maybe_constant_value but first fully instantiate the argument.
+
+   Note: this is equivalent to instantiate_non_dependent_expr_sfinae
+   (t, tf_none) followed by maybe_constant_value but is more efficient,
+   because calls instantiation_dependent_expression_p and
+   potential_constant_expression at most once.  */
+
+tree
+fold_non_dependent_expr (tree t)
+{
+  if (t == NULL_TREE)
+    return NULL_TREE;
+
+  /* If we're in a template, but T isn't value dependent, simplify
+     it.  We're supposed to treat:
+
+       template <typename T> void f(T[1 + 1]);
+       template <typename T> void f(T[2]);
+
+     as two declarations of the same function, for example.  */
+  if (processing_template_decl)
+    {
+      if (!instantiation_dependent_expression_p (t)
+	  && potential_constant_expression (t))
+	{
+	  HOST_WIDE_INT saved_processing_template_decl;
+
+	  saved_processing_template_decl = processing_template_decl;
+	  processing_template_decl = 0;
+	  t = tsubst_copy_and_build (t,
+				     /*args=*/NULL_TREE,
+				     tf_none,
+				     /*in_decl=*/NULL_TREE,
+				     /*function_p=*/false,
+				     /*integral_constant_expression_p=*/true);
+	  processing_template_decl = saved_processing_template_decl;
+
+	  if (type_unknown_p (t)
+	      || BRACE_ENCLOSED_INITIALIZER_P (t))
+	    {
+	      if (TREE_OVERFLOW_P (t))
+		{
+		  t = build_nop (TREE_TYPE (t), t);
+		  TREE_CONSTANT (t) = false;
+		}
+	      return t;
+	    }
+
+	  tree r = cxx_eval_outermost_constant_expr (t, true, NULL_TREE);
+#ifdef ENABLE_CHECKING
+	  /* cp_tree_equal looks through NOPs, so allow them.  */
+	  gcc_assert (r == t
+		      || CONVERT_EXPR_P (t)
+		      || TREE_CODE (t) == VIEW_CONVERT_EXPR
+		      || (TREE_CONSTANT (t) && !TREE_CONSTANT (r))
+		      || !cp_tree_equal (r, t));
+#endif
+	  return r;
+	}
+      else if (TREE_OVERFLOW_P (t))
+	{
+	  t = build_nop (TREE_TYPE (t), t);
+	  TREE_CONSTANT (t) = false;
+	}
+      return t;
+    }
+
+  return maybe_constant_value (t);
+}
+
 /* Like maybe_constant_value, but returns a CONSTRUCTOR directly, rather
    than wrapped in a TARGET_EXPR.  */
 
@@ -3386,7 +3457,7 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
 	if (!potential_constant_expression_1 (denom, rval, flags))
 	  return false;
 	/* We can't call cxx_eval_outermost_constant_expr on an expression
-	   that hasn't been through fold_non_dependent_expr yet.  */
+	   that hasn't been through instantiate_non_dependent_expr yet.  */
 	if (!processing_template_decl)
 	  denom = cxx_eval_outermost_constant_expr (denom, true);
 	if (integer_zerop (denom))

gcc/cp/cp-tree.h

@@ -5690,8 +5690,8 @@ extern tree template_for_substitution		(tree);
 extern tree build_non_dependent_expr		(tree);
 extern void make_args_non_dependent		(vec<tree, va_gc> *);
 extern bool reregister_specialization		(tree, tree, tree);
-extern tree fold_non_dependent_expr		(tree);
+extern tree instantiate_non_dependent_expr	(tree);
-extern tree fold_non_dependent_expr_sfinae	(tree, tsubst_flags_t);
+extern tree instantiate_non_dependent_expr_sfinae (tree, tsubst_flags_t);
 extern bool alias_type_or_template_p            (tree);
 extern bool alias_template_specialization_p     (const_tree);
 extern bool dependent_alias_template_spec_p     (const_tree);
@@ -6331,6 +6331,7 @@ extern bool require_potential_rvalue_constant_expression (tree);
 extern tree cxx_constant_value			(tree, tree = NULL_TREE);
 extern tree maybe_constant_value		(tree, tree = NULL_TREE);
 extern tree maybe_constant_init			(tree, tree = NULL_TREE);
+extern tree fold_non_dependent_expr		(tree);
 extern bool is_sub_constant_expr                (tree);
 extern bool reduced_constant_expression_p       (tree);
 extern bool is_instantiation_of_constexpr       (tree);

gcc/cp/decl.c

@@ -8356,7 +8356,7 @@ compute_array_index_type (tree name, tree size, tsubst_flags_t complain)
 	   NOP_EXPR with TREE_SIDE_EFFECTS; don't fold in that case.  */;
       else
 	{
-	  size = fold_non_dependent_expr_sfinae (size, complain);
+	  size = instantiate_non_dependent_expr_sfinae (size, complain);
 
 	  if (CLASS_TYPE_P (type)
 	      && CLASSTYPE_LITERAL_P (type))
@@ -12999,6 +12999,11 @@ build_enumerator (tree name, tree value, tree enumtype, location_t loc)
   tree context;
   tree type;
 
+  /* integral_constant_value will pull out this expression, so make sure
+     it's folded as appropriate.  */
+  if (processing_template_decl)
+    value = fold_non_dependent_expr (value);
+
   /* If the VALUE was erroneous, pretend it wasn't there; that will
      result in the enum being assigned the next value in sequence.  */
   if (value == error_mark_node)

gcc/cp/decl2.c

@@ -4951,7 +4951,7 @@ mark_used (tree decl, tsubst_flags_t complain)
   if (processing_template_decl)
     return true;
 
-  /* Check this too in case we're within fold_non_dependent_expr.  */
+  /* Check this too in case we're within instantiate_non_dependent_expr.  */
   if (DECL_TEMPLATE_INFO (decl)
       && uses_template_parms (DECL_TI_ARGS (decl)))
     return true;

gcc/cp/parser.c

@@ -6886,7 +6886,7 @@ cp_parser_parenthesized_expression_list (cp_parser* parser,
 	      }
 
 	    if (fold_expr_p)
-	      expr = fold_non_dependent_expr (expr);
+	      expr = instantiate_non_dependent_expr (expr);
 
             /* If we have an ellipsis, then this is an expression
 	       expansion.  */
@@ -15996,10 +15996,6 @@ cp_parser_enumerator_definition (cp_parser* parser, tree type)
   if (check_for_bare_parameter_packs (value))
     value = error_mark_node;
 
-  /* integral_constant_value will pull out this expression, so make sure
-     it's folded as appropriate.  */
-  value = fold_non_dependent_expr (value);
-
   /* Create the enumerator.  */
   build_enumerator (identifier, value, type, loc);
 }

gcc/cp/pt.c

@@ -5216,7 +5216,7 @@ redeclare_class_template (tree type, tree parms)
    (possibly simplified) expression.  */
 
 tree
-fold_non_dependent_expr_sfinae (tree expr, tsubst_flags_t complain)
+instantiate_non_dependent_expr_sfinae (tree expr, tsubst_flags_t complain)
 {
   if (expr == NULL_TREE)
     return NULL_TREE;
@@ -5248,9 +5248,9 @@ fold_non_dependent_expr_sfinae (tree expr, tsubst_flags_t complain)
 }
 
 tree
-fold_non_dependent_expr (tree expr)
+instantiate_non_dependent_expr (tree expr)
 {
-  return fold_non_dependent_expr_sfinae (expr, tf_error);
+  return instantiate_non_dependent_expr_sfinae (expr, tf_error);
 }
 
 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
@@ -5740,7 +5740,7 @@ convert_nontype_argument (tree type, tree expr, tsubst_flags_t complain)
       && has_value_dependent_address (expr))
     /* If we want the address and it's value-dependent, don't fold.  */;
   else if (!type_unknown_p (expr))
-    expr = fold_non_dependent_expr_sfinae (expr, complain);
+    expr = instantiate_non_dependent_expr_sfinae (expr, complain);
   if (error_operand_p (expr))
     return error_mark_node;
   expr_type = TREE_TYPE (expr);
@@ -8314,7 +8314,7 @@ uses_template_parms (tree t)
 
 /* Returns true iff current_function_decl is an incompletely instantiated
    template.  Useful instead of processing_template_decl because the latter
-   is set to 0 during fold_non_dependent_expr.  */
+   is set to 0 during instantiate_non_dependent_expr.  */
 
 bool
 in_template_function (void)
@@ -15138,8 +15138,7 @@ tsubst_copy_and_build (tree t,
     case COND_EXPR:
       {
 	tree cond = RECUR (TREE_OPERAND (t, 0));
-	tree folded_cond = (maybe_constant_value
+	tree folded_cond = fold_non_dependent_expr (cond);
-			    (fold_non_dependent_expr_sfinae (cond, tf_none)));
 	tree exp1, exp2;
 
 	if (TREE_CODE (folded_cond) == INTEGER_CST)
@@ -21110,7 +21109,7 @@ value_dependent_expression_p (tree expression)
 
     case STMT_EXPR:
       /* Treat a GNU statement expression as dependent to avoid crashing
-	 under fold_non_dependent_expr; it can't be constant.  */
+	 under instantiate_non_dependent_expr; it can't be constant.  */
       return true;
 
     default:
@@ -21864,7 +21863,7 @@ build_non_dependent_expr (tree expr)
   /* Try to get a constant value for all non-dependent expressions in
       order to expose bugs in *_dependent_expression_p and constexpr.  */
   if (cxx_dialect >= cxx11)
-    maybe_constant_value (fold_non_dependent_expr_sfinae (expr, tf_none));
+    fold_non_dependent_expr (expr);
 #endif
 
   /* Preserve OVERLOADs; the functions must be available to resolve

gcc/cp/semantics.c

@@ -511,8 +511,7 @@ begin_maybe_infinite_loop (tree cond)
   bool maybe_infinite = true;
   if (cond)
     {
-      cond = fold_non_dependent_expr_sfinae (cond, tf_none);
+      cond = fold_non_dependent_expr (cond);
-      cond = maybe_constant_value (cond);
       maybe_infinite = integer_nonzerop (cond);
     }
   vec_safe_push (cp_function_chain->infinite_loops,
@@ -543,7 +542,6 @@ end_maybe_infinite_loop (tree cond)
   if (current != NULL_TREE)
     {
       cond = fold_non_dependent_expr (cond);
-      cond = maybe_constant_value (cond);
       if (integer_nonzerop (cond))
 	current_function_infinite_loop = 1;
     }
@@ -7043,7 +7041,7 @@ finish_static_assert (tree condition, tree message, location_t location,
     }
 
   /* Fold the expression and convert it to a boolean value. */
-  condition = fold_non_dependent_expr (condition);
+  condition = instantiate_non_dependent_expr (condition);
   condition = cp_convert (boolean_type_node, condition, tf_warning_or_error);
   condition = maybe_constant_value (condition);
 

gcc/cp/tree.c

@@ -4143,7 +4143,7 @@ fold_if_not_in_template (tree expr)
   /* In the body of a template, there is never any need to call
      "fold".  We will call fold later when actually instantiating the
      template.  Integral constant expressions in templates will be
-     evaluated via fold_non_dependent_expr, as necessary.  */
+     evaluated via instantiate_non_dependent_expr, as necessary.  */
   if (processing_template_decl)
     return expr;
 

gcc/cp/typeck.c

@@ -1787,7 +1787,7 @@ cxx_alignas_expr (tree e)
     /* Leave value-dependent expression alone for now. */
     return e;
 
-  e = fold_non_dependent_expr (e);
+  e = instantiate_non_dependent_expr (e);
   e = mark_rvalue_use (e);
 
   /* [dcl.align]/2 says:
@@ -4135,8 +4135,7 @@ cp_build_binary_op (location_t location,
 	      || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
 	{
 	  enum tree_code tcode0 = code0, tcode1 = code1;
-	  tree cop1 = fold_non_dependent_expr_sfinae (op1, tf_none);
+	  tree cop1 = fold_non_dependent_expr (op1);
-	  cop1 = maybe_constant_value (cop1);
 	  doing_div_or_mod = true;
 	  warn_for_div_by_zero (location, cop1);
 
@@ -4175,8 +4174,7 @@ cp_build_binary_op (location_t location,
     case TRUNC_MOD_EXPR:
     case FLOOR_MOD_EXPR:
       {
-	tree cop1 = fold_non_dependent_expr_sfinae (op1, tf_none);
+	tree cop1 = fold_non_dependent_expr (op1);
-	cop1 = maybe_constant_value (cop1);
 	doing_div_or_mod = true;
 	warn_for_div_by_zero (location, cop1);
       }
@@ -4270,8 +4268,7 @@ cp_build_binary_op (location_t location,
 	}
       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
 	{
-	  tree const_op1 = fold_non_dependent_expr_sfinae (op1, tf_none);
+	  tree const_op1 = fold_non_dependent_expr (op1);
-	  const_op1 = maybe_constant_value (const_op1);
 	  if (TREE_CODE (const_op1) != INTEGER_CST)
 	    const_op1 = op1;
 	  result_type = type0;
@@ -4320,8 +4317,7 @@ cp_build_binary_op (location_t location,
 	}
       else if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
 	{
-	  tree const_op1 = fold_non_dependent_expr_sfinae (op1, tf_none);
+	  tree const_op1 = fold_non_dependent_expr (op1);
-	  const_op1 = maybe_constant_value (const_op1);
 	  if (TREE_CODE (const_op1) != INTEGER_CST)
 	    const_op1 = op1;
 	  result_type = type0;
@@ -4993,10 +4989,8 @@ cp_build_binary_op (location_t location,
       /* OP0 and/or OP1 might have side-effects.  */
       op0 = cp_save_expr (op0);
       op1 = cp_save_expr (op1);
-      op0 = maybe_constant_value (fold_non_dependent_expr_sfinae (op0,
+      op0 = fold_non_dependent_expr (op0);
-								  tf_none));
+      op1 = fold_non_dependent_expr (op1);
-      op1 = maybe_constant_value (fold_non_dependent_expr_sfinae (op1,
-								  tf_none));
       if (doing_div_or_mod && (flag_sanitize & (SANITIZE_DIVIDE
 						| SANITIZE_FLOAT_DIVIDE)))
 	{

gcc/cp/typeck2.c

@@ -797,7 +797,7 @@ store_init_value (tree decl, tree init, vec<tree, va_gc>** cleanups, int flags)
   if (decl_maybe_constant_var_p (decl) || TREE_STATIC (decl))
     {
       bool const_init;
-      value = fold_non_dependent_expr (value);
+      value = instantiate_non_dependent_expr (value);
       if (DECL_DECLARED_CONSTEXPR_P (decl)
 	  || DECL_IN_AGGR_P (decl))
 	{
@@ -872,7 +872,7 @@ check_narrowing (tree type, tree init, tsubst_flags_t complain)
       return ok;
     }
 
-  init = maybe_constant_value (fold_non_dependent_expr_sfinae (init, tf_none));
+  init = fold_non_dependent_expr (init);
 
   if (TREE_CODE (type) == INTEGER_TYPE
       && TREE_CODE (ftype) == REAL_TYPE)
@@ -1176,7 +1176,7 @@ massage_init_elt (tree type, tree init, tsubst_flags_t complain)
     init = TARGET_EXPR_INITIAL (init);
   /* When we defer constant folding within a statement, we may want to
      defer this folding as well.  */
-  tree t = fold_non_dependent_expr_sfinae (init, complain);
+  tree t = fold_non_dependent_expr (init);
   t = maybe_constant_init (t);
   if (TREE_CONSTANT (t))
     init = t;