Re: Fix PR20623: ICE: fold check: original tree changed by fold with --enable-checking=fold

[Adam Nemet <anemet at caviumnetworks dot com>]

"Sebastian Pop" <sebpop@gmail.com> writes:
> 	(fold_addr_expr, debug_fold_checksum): New.

The latter should be protected with ENABLE_FOLD_CHECKING otherwise I
get this:

libbackend.a(fold-const.o)(.text+0x77c6f): In function `debug_fold_checksum':
/home/anemet/src/gcc/src/gcc/fold-const.c:12999: undefined reference to `fold_checksum_tree'
collect2: ld returned 1 exit status

I am checking this in as obvious.

Adam

        * fold-const.c (debug_fold_checksum): Move it under
        ENABLE_FOLD_CHECKING.

Index: fold-const.c
===================================================================
--- fold-const.c	(revision 125929)
+++ fold-const.c	(working copy)
@@ -12943,6 +12943,30 @@ recursive_label:
     }
 }
 
+/* Helper function for outputting the checksum of a tree T.  When
+   debugging with gdb, you can "define mynext" to be "next" followed
+   by "call debug_fold_checksum (op0)", then just trace down till the
+   outputs differ.  */
+
+void
+debug_fold_checksum (tree t)
+{
+  int i;
+  unsigned char checksum[16];
+  struct md5_ctx ctx;
+  htab_t ht = htab_create (32, htab_hash_pointer, htab_eq_pointer, NULL);
+  
+  md5_init_ctx (&ctx);
+  fold_checksum_tree (t, &ctx, ht);
+  md5_finish_ctx (&ctx, checksum);
+  htab_empty (ht);
+
+  for (i = 0; i < 16; i++)
+    fprintf (stderr, "%d ", checksum[i]);
+
+  fprintf (stderr, "\n");
+}
+
 #endif
 
 /* Fold a unary tree expression with code CODE of type TYPE with an
@@ -12982,30 +13006,6 @@ fold_build1_stat (enum tree_code code, t
   return tem;
 }
 
-/* Helper function for outputting the checksum of a tree T.  When
-   debugging with gdb, you can "define mynext" to be "next" followed
-   by "call debug_fold_checksum (op0)", then just trace down till the
-   outputs differ.  */
-
-void
-debug_fold_checksum (tree t)
-{
-  int i;
-  unsigned char checksum[16];
-  struct md5_ctx ctx;
-  htab_t ht = htab_create (32, htab_hash_pointer, htab_eq_pointer, NULL);
-  
-  md5_init_ctx (&ctx);
-  fold_checksum_tree (t, &ctx, ht);
-  md5_finish_ctx (&ctx, checksum);
-  htab_empty (ht);
-
-  for (i = 0; i < 16; i++)
-    fprintf (stderr, "%d ", checksum[i]);
-
-  fprintf (stderr, "\n");
-}
-
 /* Fold a binary tree expression with code CODE of type TYPE with
    operands OP0 and OP1.  Return a folded expression if successful.
    Otherwise, return a tree expression with code CODE of type TYPE