--- a/gcc/valtrack.c	Fri Oct 27 22:46:09 2017 +0900
+++ b/gcc/valtrack.c	Thu Oct 25 07:37:49 2018 +0900
@@ -1,6 +1,6 @@
 /* Infrastructure for tracking user variable locations and values
    throughout compilation.
-   Copyright (C) 2010-2017 Free Software Foundation, Inc.
+   Copyright (C) 2010-2018 Free Software Foundation, Inc.
    Contributed by Alexandre Oliva <aoliva@redhat.com>.
 
 This file is part of GCC.
@@ -94,13 +94,15 @@
 
     case PRE_INC:
     case PRE_DEC:
-      gcc_assert (mem_mode != VOIDmode && mem_mode != BLKmode);
-      return gen_rtx_PLUS (GET_MODE (x),
-			   cleanup_auto_inc_dec (XEXP (x, 0), mem_mode),
-			   gen_int_mode (code == PRE_INC
-					 ? GET_MODE_SIZE (mem_mode)
-					 : -GET_MODE_SIZE (mem_mode),
-					 GET_MODE (x)));
+      {
+	gcc_assert (mem_mode != VOIDmode && mem_mode != BLKmode);
+	poly_int64 offset = GET_MODE_SIZE (mem_mode);
+	if (code == PRE_DEC)
+	  offset = -offset;
+	return gen_rtx_PLUS (GET_MODE (x),
+			     cleanup_auto_inc_dec (XEXP (x, 0), mem_mode),
+			     gen_int_mode (offset, GET_MODE (x)));
+      }
 
     case POST_INC:
     case POST_DEC:
@@ -171,10 +173,13 @@
 	if (REG_P (*iter) && ++cnt > 1)
 	  {
 	    rtx dval = make_debug_expr_from_rtl (old_rtx);
+	    rtx to = pair->to;
+	    if (volatile_insn_p (to))
+	      to = gen_rtx_UNKNOWN_VAR_LOC ();
 	    /* Emit a debug bind insn.  */
 	    rtx bind
 	      = gen_rtx_VAR_LOCATION (GET_MODE (old_rtx),
-				      DEBUG_EXPR_TREE_DECL (dval), pair->to,
+				      DEBUG_EXPR_TREE_DECL (dval), to,
 				      VAR_INIT_STATUS_INITIALIZED);
 	    rtx_insn *bind_insn = emit_debug_insn_before (bind, pair->insn);
 	    df_insn_rescan (bind_insn);
@@ -211,12 +216,14 @@
     {
       insn = next;
       next = NEXT_INSN (insn);
-      if (DEBUG_INSN_P (insn))
+      if (DEBUG_BIND_INSN_P (insn))
 	{
 	  loc = simplify_replace_fn_rtx (INSN_VAR_LOCATION_LOC (insn),
 					 dest, propagate_for_debug_subst, &p);
 	  if (loc == INSN_VAR_LOCATION_LOC (insn))
 	    continue;
+	  if (volatile_insn_p (loc))
+	    loc = gen_rtx_UNKNOWN_VAR_LOC ();
 	  INSN_VAR_LOCATION_LOC (insn) = loc;
 	  df_insn_rescan (insn);
 	}
@@ -550,7 +557,7 @@
 {
   if (inner_mode == VOIDmode)
     inner_mode = GET_MODE (expr);
-  int offset = subreg_lowpart_offset (outer_mode, inner_mode);
+  poly_int64 offset = subreg_lowpart_offset (outer_mode, inner_mode);
   rtx ret = simplify_gen_subreg (outer_mode, expr, inner_mode, offset);
   if (ret)
     return ret;
@@ -606,10 +613,13 @@
 	  usesp = &cur->next;
 	  *tailp = cur->next;
 	  cur->next = NULL;
+	  /* "may" rather than "must" because we want (for example)
+	     N V4SFs to win over plain V4SF even though N might be 1.  */
+	  rtx candidate = *DF_REF_REAL_LOC (cur->use);
 	  if (!reg
-	      || (GET_MODE_BITSIZE (GET_MODE (reg))
-		  < GET_MODE_BITSIZE (GET_MODE (*DF_REF_REAL_LOC (cur->use)))))
-	    reg = *DF_REF_REAL_LOC (cur->use);
+	      || maybe_lt (GET_MODE_BITSIZE (GET_MODE (reg)),
+			   GET_MODE_BITSIZE (GET_MODE (candidate))))
+	    reg = candidate;
 	}
       else
 	tailp = &(*tailp)->next;
@@ -660,6 +670,12 @@
 		}
 	      return 0;
 	    }
+	  /* Asm in DEBUG_INSN is never useful, we can't emit debug info for
+	     that.  And for volatile_insn_p, it is actually harmful
+	     - DEBUG_INSNs shouldn't have any side-effects.  */
+	  else if (GET_CODE (src) == ASM_OPERANDS
+		   || volatile_insn_p (src))
+	    set = NULL_RTX;
 	}
 
       /* ??? Should we try to extract it from a PARALLEL?  */