flow.c (delete_unreachable_blocks): Do not require an edge to be marked with EDGE_FAL...

	* flow.c (delete_unreachable_blocks): Do not require an edge to
	be marked with EDGE_FALLTHRU when tidying an edge which connects
	consecutive basic blocks.
	* flow.c (can_delete_label_p): Do not convert a label into a
	deleted label here.

From-SVN: r26306

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f1ed427..d06c3a4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,12 @@
 Thu Apr  8 19:20:18 1999  Jeffrey A Law  (law@cygnus.com)
 
+       * flow.c (delete_unreachable_blocks): Do not require an edge to
+       be marked with EDGE_FALLTHRU when tidying an edge which connects
+       consecutive basic blocks.
+
+       * flow.c (can_delete_label_p): Do not convert a label into a
+       deleted label here.
+
        * cse.c (flush_hash_table): New function.
        (cse_insn): Flush the hash table when we encounter a volatile asm.
        (cse_basic_block): Use flush_hash_table instead of doing it

diff --git a/gcc/flow.c b/gcc/flow.c
index 072d208..daf3571 100644 (file)
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -1555,12 +1555,21 @@ delete_unreachable_blocks ()
       basic_block c = BASIC_BLOCK (i);
       edge s;
 
-      /* We only need care for simple unconditional jumps, which implies
-        a single successor.  */
+      /* We care about simple conditional or unconditional jumps with
+        a single successor.
+
+        If we had a conditional branch to the next instruction when
+        find_basic_blocks was called, then there will only be one
+        out edge for the block which ended with the conditional
+        branch (since we do not create duplicate edges).
+
+        Furthermore, because we create the edge for the jump to the
+        label before the fallthrough edge, we will only see the
+        jump edge.  So we do not want to check that the edge is a 
+        FALLTHRU edge.  */
       if ((s = b->succ) != NULL
          && s->succ_next == NULL
-         && s->dest == c
-         && ! (s->flags & EDGE_FALLTHRU))
+         && s->dest == c)
        tidy_fallthru_edge (s, b, c);
     }
 
@@ -1823,15 +1832,9 @@ can_delete_label_p (label)
     if (label == XEXP (x, 0))
       return 0;
 
-  /* User declared labels must be preserved, but we can
-     convert them into a NOTE instead. */
+  /* User declared labels must be preserved.  */
   if (LABEL_NAME (label) != 0)
-    {
-      PUT_CODE (label, NOTE);
-      NOTE_LINE_NUMBER (label) = NOTE_INSN_DELETED_LABEL;
-      NOTE_SOURCE_FILE (label) = 0;
-      return 0;
-    }
+    return 0;
   
   return 1;
 }