--- gcc/valtrack.h.jj	2012-10-03 09:01:35.000000000 +0200
+++ gcc/valtrack.h	2012-10-26 10:21:31.655376061 +0200
@@ -130,7 +130,12 @@ enum debug_temp_where
     /* Bind a newly-created debug temporary to a REG for UREGNO, and
        insert the debug insn after INSN.  REG is expected to be set at
        INSN.  */
-    DEBUG_TEMP_AFTER_WITH_REG = 1
+    DEBUG_TEMP_AFTER_WITH_REG = 1,
+    /* Like DEBUG_TEMP_AFTER_WITH_REG, but force addition of a debug
+       temporary even if there is just a single debug use.  This is used
+       on regs that are becoming REG_DEAD on INSN and so uses of the
+       reg later on are invalid.  */
+    DEBUG_TEMP_AFTER_WITH_REG_FORCE = 2
   };
 
 extern void dead_debug_global_init (struct dead_debug_global *, bitmap);
--- gcc/valtrack.c.jj	2012-10-03 09:01:35.000000000 +0200
+++ gcc/valtrack.c	2012-10-26 10:22:38.646999016 +0200
@@ -648,7 +648,8 @@ dead_debug_insert_temp (struct dead_debu
 			       DEBUG_EXPR_TREE_DECL (dval), breg,
 			       VAR_INIT_STATUS_INITIALIZED);
 
-  if (where == DEBUG_TEMP_AFTER_WITH_REG)
+  if (where == DEBUG_TEMP_AFTER_WITH_REG
+      || where == DEBUG_TEMP_AFTER_WITH_REG_FORCE)
     bind = emit_debug_insn_after (bind, insn);
   else
     bind = emit_debug_insn_before (bind, insn);
--- gcc/dce.c.jj	2012-10-19 11:01:03.000000000 +0200
+++ gcc/dce.c	2012-10-26 10:24:11.956465043 +0200
@@ -1,5 +1,5 @@
 /* RTL dead code elimination.
-   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
+   Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -880,7 +880,10 @@ word_dce_process_block (basic_block bb,
 
 	    for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
 	      dead_debug_insert_temp (&debug, DF_REF_REGNO (*def_rec), insn,
-				      DEBUG_TEMP_BEFORE_WITH_VALUE);
+				      marked_insn_p (insn)
+				      && !control_flow_insn_p (insn)
+				      ? DEBUG_TEMP_AFTER_WITH_REG_FORCE
+				      : DEBUG_TEMP_BEFORE_WITH_VALUE);
 	  }
 
 	if (dump_file)
@@ -981,7 +984,9 @@ dce_process_block (basic_block bb, bool
 	if (debug.used && !bitmap_empty_p (debug.used))
 	  for (def_rec = DF_INSN_DEFS (insn); *def_rec; def_rec++)
 	    dead_debug_insert_temp (&debug, DF_REF_REGNO (*def_rec), insn,
-				    DEBUG_TEMP_BEFORE_WITH_VALUE);
+				    needed && !control_flow_insn_p (insn)
+				    ? DEBUG_TEMP_AFTER_WITH_REG_FORCE
+				    : DEBUG_TEMP_BEFORE_WITH_VALUE);
       }
 
   dead_debug_local_finish (&debug, NULL);