flow.c (verify_flow_info): Revamp code to verify that the head and end of each basic...

        * flow.c (verify_flow_info): Revamp code to verify that the
        head and end of each basic block are in the insn chain.

From-SVN: r35160

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a0da767e7e4d617ff5195cf3789078df545bc12b..1a6b8bde42476464cbd272b940052fce7298bea1 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Thu Jul 20 18:13:52 2000  Jeffrey A Law  (law@cygnus.com)
+
+       * flow.c (verify_flow_info): Revamp code to verify that the
+       head and end of each basic block are in the insn chain.
+
 Thu Jul 20 18:02:35 2000  Michael Matz <matzmich@cs.tu-berlin.de>
 
        * gcse.c (record_one_set): Prepend instead of append onto

diff --git a/gcc/flow.c b/gcc/flow.c
index 2dc2b173089eb1b48144a8ade75da797e4c16d3a..7019dbf8cd2a0de8ba3688a36ace505740945f27 100644 (file)
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -6342,34 +6342,37 @@ verify_flow_info ()
 {
   const int max_uid = get_max_uid ();
   const rtx rtx_first = get_insns ();
+  rtx last_head = get_last_insn ();
   basic_block *bb_info;
   rtx x;
   int i, last_bb_num_seen, num_bb_notes, err = 0;
 
   bb_info = (basic_block *) xcalloc (max_uid, sizeof (basic_block));
 
-  /* First pass check head/end pointers and set bb_info array used by
-     later passes.  */
   for (i = n_basic_blocks - 1; i >= 0; i--)
     {
       basic_block bb = BASIC_BLOCK (i);
+      rtx head = bb->head;
+      rtx end = bb->end;
 
-      /* Check the head pointer and make sure that it is pointing into
-         insn list.  */
-      for (x = rtx_first; x != NULL_RTX; x = NEXT_INSN (x))
-       if (x == bb->head)
+      /* Verify the end of the basic block is in the INSN chain.  */
+      for (x = last_head; x != NULL_RTX; x = PREV_INSN (x))
+       if (x == end)
          break;
       if (!x)
        {
-         error ("Head insn %d for block %d not found in the insn stream.",
-                INSN_UID (bb->head), bb->index);
+         error ("End insn %d for block %d not found in the insn stream.",
+                INSN_UID (end), bb->index);
          err = 1;
        }
 
-      /* Check the end pointer and make sure that it is pointing into
-         insn list.  */
-      for (x = bb->head; x != NULL_RTX; x = NEXT_INSN (x))
+      /* Work backwards from the end to the head of the basic block
+        to verify the head is in the RTL chain.  */
+      for ( ; x != NULL_RTX; x = PREV_INSN (x))
        {
+         /* While walking over the insn chain, verify insns appear
+            in only one basic block and initialize the BB_INFO array
+            used by other passes.  */
          if (bb_info[INSN_UID (x)] != NULL)
            {
              error ("Insn %d is in multiple basic blocks (%d and %d)",
@@ -6378,15 +6381,17 @@ verify_flow_info ()
            }
          bb_info[INSN_UID (x)] = bb;
 
-         if (x == bb->end)
+         if (x == head)
            break;
        }
       if (!x)
        {
-         error ("End insn %d for block %d not found in the insn stream.",
-                INSN_UID (bb->end), bb->index);
+         error ("Head insn %d for block %d not found in the insn stream.",
+                INSN_UID (head), bb->index);
          err = 1;
        }
+
+      last_head = x;
     }
 
   /* Now check the basic blocks (boundaries etc.) */