(distribute_notes): If can't find place for REG_DEAD note, add an INSN

with a USE to hold it.

From-SVN: r8625

gcc/combine.c

@@ -10515,9 +10515,10 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
 	    reg_n_refs[REGNO (XEXP (note, 0))] = 3;
 
 	  if (place == 0)
+	    {
 	      for (tem = prev_nonnote_insn (i3);
-		 tem && (GET_CODE (tem) == INSN
-			 || GET_CODE (tem) == CALL_INSN);
+		   place == 0 && tem
+		   && (GET_CODE (tem) == INSN || GET_CODE (tem) == CALL_INSN);
 		   tem = prev_nonnote_insn (tem))
 		{
 		  /* If the register is being set at TEM, see if that is all
@@ -10569,6 +10570,17 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
 		  }
 		}
 	      
+	      /* If we haven't found an insn for the death note and it
+		 is still a REG_DEAD note, but we have hit a CODE_LABEL,
+		 insert a USE insn for the register at that label and
+		 put the death node there.  This prevents problems with
+		 call-state tracking in caller-save.c.  */
+	      if (REG_NOTE_KIND (note) == REG_DEAD && place == 0 && tem != 0)
+		place
+		  = emit_insn_after (gen_rtx (USE, VOIDmode, XEXP (note, 0)),
+				     tem);
+	    }
+
 	  /* If the register is set or already dead at PLACE, we needn't do
 	     anything with this note if it is still a REG_DEAD note.