re PR c/10675 (Compile time increases quadratically with struct size)

        PR c/10675
        * c-decl.c: Include hashtab.h.
        (detect_field_duplicates): New.
        (finish_struct): Use it.
        * Makefile.in (c-decl.o): Update.
        * c-parse.in (structsp_attr): Nreverse component_decl_list results.
        (component_decl_list, component_decl_list2,
        components, components_notype): Build list in reverse order.
        (enumlist): Clarify docs.  Use TREE_CHAIN not chainon.
        * tree.c (chainon): Special case op2 null as well.
        Reorg for clarity.

From-SVN: r66710

1 files changed, 17 insertions, 16 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index 8cff4ce..64b605a 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -1031,26 +1031,27 @@ tree
 chainon (op1, op2)
      tree op1, op2;
 {
+  tree t1;
 
-  if (op1)
-    {
-      tree t1;
-#ifdef ENABLE_TREE_CHECKING
-      tree t2;
-#endif
+  if (!op1)
+    return op2;
+  if (!op2)
+    return op1;
+
+  for (t1 = op1; TREE_CHAIN (t1); t1 = TREE_CHAIN (t1))
+    continue;
+  TREE_CHAIN (t1) = op2;
 
-      for (t1 = op1; TREE_CHAIN (t1); t1 = TREE_CHAIN (t1))
-	;
-      TREE_CHAIN (t1) = op2;
 #ifdef ENABLE_TREE_CHECKING
-      for (t2 = op2; t2; t2 = TREE_CHAIN (t2))
-	if (t2 == t1)
-	  abort ();  /* Circularity created.  */
+  {
+    tree t2;
+    for (t2 = op2; t2; t2 = TREE_CHAIN (t2))
+      if (t2 == t1)
+	abort ();  /* Circularity created.  */
+  }
 #endif
-      return op1;
-    }
-  else
-    return op2;
+
+  return op1;
 }
 
 /* Return the last node in a chain of nodes (chained through TREE_CHAIN).  */