re PR middle-end/44071 (ICE with asm goto and __builtin_unreachable())

	PR middle-end/44071
	* cfglayout.c (fixup_reorder_chain): Allow asm goto to have
	no fallthru edge.
	* cfgcleanup.c (try_optimize_cfg): When in cfglayout mode
	optimizing away empty bb with no successors, move over its
	footer chain to fallthru predecessor.
	* cfgrtl.c (patch_jump_insn): Update also REG_LABEL_OPERAND.
	(rtl_split_edge): For asm goto call patch_jump_insn even if
	splitting fallthru edge.

	* c-c++-common/asmgoto-4.c: New test.
	* gcc.target/i386/pr44071.c: New test.

From-SVN: r159288

gcc/ChangeLog

 2010-05-11  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/44071
+	* cfglayout.c (fixup_reorder_chain): Allow asm goto to have
+	no fallthru edge.
+	* cfgcleanup.c (try_optimize_cfg): When in cfglayout mode
+	optimizing away empty bb with no successors, move over its
+	footer chain to fallthru predecessor.
+	* cfgrtl.c (patch_jump_insn): Update also REG_LABEL_OPERAND.
+	(rtl_split_edge): For asm goto call patch_jump_insn even if
+	splitting fallthru edge.
+
 	PR c++/44059
 	* config/elfos.h (ASM_DECLARE_OBJECT_NAME): Use qnu_unique_object
 	even for DECL_ONE_ONLY DECL_ARTIFICIAL !TREE_READONLY decls.

gcc/cfgcleanup.c

@@ -1999,6 +1999,25 @@ try_optimize_cfg (int mode)
 		      && single_succ_edge (ENTRY_BLOCK_PTR)->dest != b))
 		{
 		  c = b->prev_bb;
+		  if ((mode & CLEANUP_CFGLAYOUT)
+		      && EDGE_COUNT (b->preds) > 0
+		      && b->il.rtl->footer
+		      && BARRIER_P (b->il.rtl->footer))
+		    {
+		      edge e;
+		      edge_iterator ei;
+
+		      FOR_EACH_EDGE (e, ei, b->preds)
+			if (e->flags & EDGE_FALLTHRU)
+			  {
+			    if (e->src->il.rtl->footer == NULL)
+			      {
+				e->src->il.rtl->footer = b->il.rtl->footer;
+				b->il.rtl->footer = NULL;
+			      }
+			    break;
+			  }
+		    }
 		  delete_basic_block (b);
 		  if (!(mode & CLEANUP_CFGLAYOUT))
 		    changed = true;

gcc/cfglayout.c

 /* Basic block reordering routines for the GNU compiler.
-   Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+   Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -861,8 +861,11 @@ fixup_reorder_chain (void)
 	    }
 	  else if (extract_asm_operands (PATTERN (bb_end_insn)) != NULL)
 	    {
-	      /* If the old fallthru is still next, nothing to do.  */
-	      if (bb->aux == e_fall->dest
+	      /* If the old fallthru is still next or if
+		 asm goto doesn't have a fallthru (e.g. when followed by
+		 __builtin_unreachable ()), nothing to do.  */
+	      if (! e_fall
+		  || bb->aux == e_fall->dest
 		  || e_fall->dest == EXIT_BLOCK_PTR)
 		continue;
 

gcc/cfgrtl.c

@@ -994,6 +994,9 @@ patch_jump_insn (rtx insn, rtx old_label, basic_block new_bb)
 	      && !find_reg_note (insn, REG_LABEL_TARGET, new_label))
 	    add_reg_note (insn, REG_LABEL_TARGET, new_label);
 	}
+      while ((note = find_reg_note (insn, REG_LABEL_OPERAND, old_label))
+	     != NULL_RTX)
+	XEXP (note, 0) = new_label;
     }
   else
     {
@@ -1407,7 +1410,22 @@ rtl_split_edge (edge edge_in)
       gcc_assert (redirected);
     }
   else
-    redirect_edge_succ (edge_in, bb);
+    {
+      if (edge_in->src != ENTRY_BLOCK_PTR)
+	{
+	  /* For asm goto even splitting of fallthru edge might
+	     need insn patching, as other labels might point to the
+	     old label.  */
+	  rtx last = BB_END (edge_in->src);
+	  if (last
+	      && JUMP_P (last)
+	      && edge_in->dest != EXIT_BLOCK_PTR
+	      && extract_asm_operands (PATTERN (last)) != NULL_RTX
+	      && patch_jump_insn (last, before, bb))
+	    df_set_bb_dirty (edge_in->src);
+	}
+      redirect_edge_succ (edge_in, bb);
+    }
 
   return bb;
 }

gcc/testsuite/ChangeLog

 2010-05-11  Jakub Jelinek  <jakub@redhat.com>
 
+	PR middle-end/44071
+	* c-c++-common/asmgoto-4.c: New test.
+	* gcc.target/i386/pr44071.c: New test.
+
 	PR c++/44062
 	* c-c++-common/Wunused-var-7.c: New test.
 	* g++.dg/warn/Wunused-var-9.C: New test.

gcc/testsuite/c-c++-common/asmgoto-4.c

+/* PR middle-end/44071 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+static inline int
+f1 (void)
+{
+  asm goto ("" : : : : l1, l2);
+  __builtin_unreachable ();
+ l1:
+  return 1;
+ l2:
+  return 0;
+}
+
+int
+b1 (int x)
+{
+  if (f1 () || x == 6)
+    x = 1;
+  else
+    x = 2;
+  return x;
+}
+
+static inline int
+f2 (void)
+{
+  asm goto ("" : : : : l1, l2);
+ l1:
+  return 1;
+ l2:
+  return 0;
+}
+
+int
+b2 (int x)
+{
+  if (f2 () || x == 6)
+    x = 1;
+  else
+    x = 2;
+  return x;
+}

gcc/testsuite/gcc.target/i386/pr44071.c

+/* PR middle-end/44071 */
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+static inline int
+f1 (void)
+{
+  asm goto ("jmp %l[l1]" : : : : l1, l2);
+  __builtin_unreachable ();
+ l1:
+  return 1;
+ l2:
+  return 0;
+}
+
+__attribute__((noinline)) int
+b1 (int x)
+{
+  if (f1 () || x == 6)
+    x = 1;
+  else
+    x = 2;
+  return x;
+}
+
+static inline int
+f2 (void)
+{
+  asm goto ("jmp %l[l2]" : : : : l1, l2);
+  __builtin_unreachable ();
+ l1:
+  return 1;
+ l2:
+  return 0;
+}
+
+__attribute__((noinline)) int
+b2 (int x)
+{
+  if (f2 () || x == 6)
+    x = 1;
+  else
+    x = 2;
+  return x;
+}
+
+static inline int
+f3 (void)
+{
+  asm goto ("jmp %l[l1]" : : : : l1, l2);
+ l1:
+  return 1;
+ l2:
+  return 0;
+}
+
+__attribute__((noinline)) int
+b3 (int x)
+{
+  if (f3 () || x == 6)
+    x = 1;
+  else
+    x = 2;
+  return x;
+}
+
+static inline int
+f4 (void)
+{
+  asm goto ("jmp %l[l2]" : : : : l1, l2);
+ l1:
+  return 1;
+ l2:
+  return 0;
+}
+
+__attribute__((noinline)) int
+b4 (int x)
+{
+  if (f4 () || x == 6)
+    x = 1;
+  else
+    x = 2;
+  return x;
+}
+
+extern void abort (void);
+
+int
+main (void)
+{
+  int x;
+  asm ("" : "=r" (x) : "0" (0));
+  if (b1 (x) != 1 || b1 (x + 6) != 1)
+    abort ();
+  if (b2 (x) != 2 || b2 (x + 6) != 1)
+    abort ();
+  if (b3 (x) != 1 || b3 (x + 6) != 1)
+    abort ();
+  if (b4 (x) != 2 || b4 (x + 6) != 1)
+    abort ();
+  return 0;
+}