cfgrtl.c (try_redirect_by_replacing_jump): Allow redirect_jump to fail if target is EXIT_BLOCK_PTR, die otherwise.

* cfgrtl.c (try_redirect_by_replacing_jump): Allow redirect_jump
	to fail if target is EXIT_BLOCK_PTR, die otherwise.
	(redirect_edge_and_branch): Likewise.
	* cfgcleanup.c (try_forward_edge): Don't force jump redirecting
	if target is EXIT_BLOCK_PTR.

	* gcc.c-torture/compile/20011229-2.c: New test.

From-SVN: r48399

gcc/ChangeLog

@@ -1,3 +1,11 @@
+2001-12-30  Jakub Jelinek  <jakub@redhat.com>
+
+	* cfgrtl.c (try_redirect_by_replacing_jump): Allow redirect_jump
+	to fail if target is EXIT_BLOCK_PTR, die otherwise.
+	(redirect_edge_and_branch): Likewise.
+	* cfgcleanup.c (try_forward_edge): Don't force jump redirecting
+	if target is EXIT_BLOCK_PTR.
+
 2001-12-29  David Edelsohn  <edelsohn@gnu.org>
 
 	* gcc.c (init_gcc_spec): Do not link with static libgcc.a if

gcc/cfgcleanup.c

@@ -440,7 +440,8 @@ try_forward_edges (mode, b)
 	  int edge_probability = e->probability;
 	  int edge_frequency;
 
-	  if (threaded)
+	  /* Don't force if target is exit block.  */
+	  if (threaded && target != EXIT_BLOCK_PTR)
 	    {
 	      notice_new_block (redirect_edge_and_branch_force (e, target));
 	      if (rtl_dump_file)

gcc/cfgrtl.c

@@ -687,9 +687,18 @@ try_redirect_by_replacing_jump (e, target)
       if (rtl_dump_file)
 	fprintf (rtl_dump_file, "Redirecting jump %i from %i to %i.\n",
 		 INSN_UID (insn), e->dest->index, target->index);
-      redirect_jump (insn, block_label (target), 0);
+      if (!redirect_jump (insn, block_label (target), 0))
+	{
+	  if (target == EXIT_BLOCK_PTR)
+	    return false;
+	  abort ();
+	}
     }
 
+  /* Cannot do anything for target exit block.  */
+  else if (target == EXIT_BLOCK_PTR)
+    return false;
+
   /* Or replace possibly complicated jump insn by simple jump insn.  */
   else
     {
@@ -806,6 +815,8 @@ redirect_edge_and_branch (e, target)
       int j;
       rtx new_label = block_label (target);
 
+      if (target == EXIT_BLOCK_PTR)
+	return false;
       if (GET_CODE (PATTERN (tmp)) == ADDR_VEC)
 	vec = XVEC (PATTERN (tmp), 0);
       else
@@ -843,11 +854,18 @@ redirect_edge_and_branch (e, target)
 	return false;
 
       /* If the insn doesn't go where we think, we're confused.  */
-      if (JUMP_LABEL (insn) != old_label
-	  /* If the substitution doesn't succeed, die.  This can happen
-	     if the back end emitted unrecognizable instructions.  */
-	  || !redirect_jump (insn, block_label (target), 0))
+      if (JUMP_LABEL (insn) != old_label)
 	abort ();
+
+      /* If the substitution doesn't succeed, die.  This can happen
+	 if the back end emitted unrecognizable instructions or if
+	 target is exit block on some arches.  */
+      if (!redirect_jump (insn, block_label (target), 0))
+	{
+	  if (target == EXIT_BLOCK_PTR)
+	    return false;
+	  abort ();
+	}
     }
 
   if (rtl_dump_file)

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2001-12-30  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.c-torture/compile/20011229-2.c: New test.
+
 2001-12-29  Jakub Jelinek  <jakub@redhat.com>
 
 	* gcc.dg/debug-3.c: New test.

gcc/testsuite/gcc.c-torture/compile/20011229-2.c

@@ -0,0 +1,17 @@
+/* Test whether jump threading doesn't ICE if redirecting the jump to exit
+   block.  */
+
+extern int bar ();
+extern void baz ();
+
+void foo ()
+{
+  int x;
+
+  do
+    {
+      if ((x = bar ()) == 1)
+	baz ();
+    }
+  while (x == 1);
+}