[C PATCH] Use error_operand_p more

[Marek Polacek]

It occured to me that we should probably use error_operand_p
in the C FE where appropriate.  Following change is meant only
as a little cleanup.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2014-10-04  Marek Polacek  <pola...@redhat.com>

        * c-convert.c (convert): Use error_operand_p.
        * c-typeck.c (require_complete_type): Likewise.
        (really_atomic_lvalue): Likewise.
        (digest_init): Likewise.
        (handle_omp_array_sections_1): Likewise.

diff --git gcc/c/c-convert.c gcc/c/c-convert.c
index 38bacda..95be453 100644
--- gcc/c/c-convert.c
+++ gcc/c/c-convert.c
@@ -72,8 +72,7 @@ convert (tree type, tree expr)
   location_t loc = EXPR_LOCATION (expr);
 
   if (type == error_mark_node
-      || expr == error_mark_node
-      || TREE_TYPE (expr) == error_mark_node)
+      || error_operand_p (expr))
     return error_mark_node;
 
   if ((invalid_conv_diag
diff --git gcc/c/c-typeck.c gcc/c/c-typeck.c
index f69c28b..b3b82bb 100644
--- gcc/c/c-typeck.c
+++ gcc/c/c-typeck.c
@@ -192,7 +192,7 @@ require_complete_type (tree value)
 {
   tree type = TREE_TYPE (value);
 
-  if (value == error_mark_node || type == error_mark_node)
+  if (error_operand_p (value))
     return error_mark_node;
 
   /* First, detect a valid value with a complete type.  */
@@ -1950,7 +1950,7 @@ default_function_array_read_conversion (location_t loc, 
struct c_expr exp)
 static bool
 really_atomic_lvalue (tree expr)
 {
-  if (expr == error_mark_node || TREE_TYPE (expr) == error_mark_node)
+  if (error_operand_p (expr))
     return false;
   if (!TYPE_ATOMIC (TREE_TYPE (expr)))
     return false;
@@ -6492,8 +6492,7 @@ digest_init (location_t init_loc, tree type, tree init, 
tree origtype,
 
   if (type == error_mark_node
       || !init
-      || init == error_mark_node
-      || TREE_TYPE (init) == error_mark_node)
+      || error_operand_p (init))
     return error_mark_node;
 
   STRIP_TYPE_NOPS (inside_init);
@@ -11365,7 +11364,7 @@ handle_omp_array_sections_1 (tree c, tree t, vec<tree> 
&types,
   tree ret, low_bound, length, type;
   if (TREE_CODE (t) != TREE_LIST)
     {
-      if (t == error_mark_node || TREE_TYPE (t) == error_mark_node)
+      if (error_operand_p (t))
        return error_mark_node;
       if (TREE_CODE (t) != VAR_DECL && TREE_CODE (t) != PARM_DECL)
        {

        Marek