Remaining support for clobber high

gcc/
	* alias.c (record_set): Check for clobber high.
	* cfgexpand.c (expand_gimple_stmt): Likewise.
	* combine-stack-adj.c (single_set_for_csa): Likewise.
	* combine.c (find_single_use_1): Likewise.
	(set_nonzero_bits_and_sign_copies): Likewise.
	(get_combine_src_dest): Likewise.
	(is_parallel_of_n_reg_sets): Likewise.
	(try_combine): Likewise.
	(record_dead_and_set_regs_1): Likewise.
	(reg_dead_at_p_1): Likewise.
	(reg_dead_at_p): Likewise.
	* dce.c (deletable_insn_p): Likewise.
	(mark_nonreg_stores_1): Likewise.
	(mark_nonreg_stores_2): Likewise.
	* df-scan.c (df_find_hard_reg_defs): Likewise.
	(df_uses_record): Likewise.
	(df_get_call_refs): Likewise.
	* dwarf2out.c (mem_loc_descriptor): Likewise.
	* haifa-sched.c (haifa_classify_rtx): Likewise.
	* ira-build.c (create_insn_allocnos): Likewise.
	* ira-costs.c (scan_one_insn): Likewise.
	* ira.c (equiv_init_movable_p): Likewise.
	(rtx_moveable_p): Likewise.
	(interesting_dest_for_shprep): Likewise.
	* jump.c (mark_jump_label_1): Likewise.
	* postreload-gcse.c (record_opr_changes): Likewise.
	* postreload.c (reload_cse_simplify): Likewise.
	(struct reg_use): Add source expr.
	(reload_combine): Check for clobber high.
	(reload_combine_note_use): Likewise.
	(reload_cse_move2add): Likewise.
	(move2add_note_store): Likewise.
	* print-rtl.c (print_pattern): Likewise.
	* recog.c (decode_asm_operands): Likewise.
	(store_data_bypass_p): Likewise.
	(if_test_bypass_p): Likewise.
	* regcprop.c (kill_clobbered_value): Likewise.
	(kill_set_value): Likewise.
	* reginfo.c (reg_scan_mark_refs): Likewise.
	* reload1.c (maybe_fix_stack_asms): Likewise.
	(eliminate_regs_1): Likewise.
	(elimination_effects): Likewise.
	(mark_not_eliminable): Likewise.
	(scan_paradoxical_subregs): Likewise.
	(forget_old_reloads_1): Likewise.
	* reorg.c (find_end_label): Likewise.
	(try_merge_delay_insns): Likewise.
	(redundant_insn): Likewise.
	(own_thread_p): Likewise.
	(fill_simple_delay_slots): Likewise.
	(fill_slots_from_thread): Likewise.
	(dbr_schedule): Likewise.
	* resource.c (update_live_status): Likewise.
	(mark_referenced_resources): Likewise.
	(mark_set_resources): Likewise.
	* rtl.c (copy_rtx): Likewise.
	* rtlanal.c (reg_referenced_p): Likewise.
	(single_set_2): Likewise.
	(noop_move_p): Likewise.
	(note_stores): Likewise.
	* sched-deps.c (sched_analyze_reg): Likewise.
	(sched_analyze_insn): Likewise.

From-SVN: r263331

25 files changed, 290 insertions, 40 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 883399fd2d1..a47e00e5558 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,70 @@
 2018-08-06  Alan Hayward  <alan.hayward@arm.com>
 
+	* alias.c (record_set): Check for clobber high.
+	* cfgexpand.c (expand_gimple_stmt): Likewise.
+	* combine-stack-adj.c (single_set_for_csa): Likewise.
+	* combine.c (find_single_use_1): Likewise.
+	(set_nonzero_bits_and_sign_copies): Likewise.
+	(get_combine_src_dest): Likewise.
+	(is_parallel_of_n_reg_sets): Likewise.
+	(try_combine): Likewise.
+	(record_dead_and_set_regs_1): Likewise.
+	(reg_dead_at_p_1): Likewise.
+	(reg_dead_at_p): Likewise.
+	* dce.c (deletable_insn_p): Likewise.
+	(mark_nonreg_stores_1): Likewise.
+	(mark_nonreg_stores_2): Likewise.
+	* df-scan.c (df_find_hard_reg_defs): Likewise.
+	(df_uses_record): Likewise.
+	(df_get_call_refs): Likewise.
+	* dwarf2out.c (mem_loc_descriptor): Likewise.
+	* haifa-sched.c (haifa_classify_rtx): Likewise.
+	* ira-build.c (create_insn_allocnos): Likewise.
+	* ira-costs.c (scan_one_insn): Likewise.
+	* ira.c (equiv_init_movable_p): Likewise.
+	(rtx_moveable_p): Likewise.
+	(interesting_dest_for_shprep): Likewise.
+	* jump.c (mark_jump_label_1): Likewise.
+	* postreload-gcse.c (record_opr_changes): Likewise.
+	* postreload.c (reload_cse_simplify): Likewise.
+	(struct reg_use): Add source expr.
+	(reload_combine): Check for clobber high.
+	(reload_combine_note_use): Likewise.
+	(reload_cse_move2add): Likewise.
+	(move2add_note_store): Likewise.
+	* print-rtl.c (print_pattern): Likewise.
+	* recog.c (decode_asm_operands): Likewise.
+	(store_data_bypass_p): Likewise.
+	(if_test_bypass_p): Likewise.
+	* regcprop.c (kill_clobbered_value): Likewise.
+	(kill_set_value): Likewise.
+	* reginfo.c (reg_scan_mark_refs): Likewise.
+	* reload1.c (maybe_fix_stack_asms): Likewise.
+	(eliminate_regs_1): Likewise.
+	(elimination_effects): Likewise.
+	(mark_not_eliminable): Likewise.
+	(scan_paradoxical_subregs): Likewise.
+	(forget_old_reloads_1): Likewise.
+	* reorg.c (find_end_label): Likewise.
+	(try_merge_delay_insns): Likewise.
+	(redundant_insn): Likewise.
+	(own_thread_p): Likewise.
+	(fill_simple_delay_slots): Likewise.
+	(fill_slots_from_thread): Likewise.
+	(dbr_schedule): Likewise.
+	* resource.c (update_live_status): Likewise.
+	(mark_referenced_resources): Likewise.
+	(mark_set_resources): Likewise.
+	* rtl.c (copy_rtx): Likewise.
+	* rtlanal.c (reg_referenced_p): Likewise.
+	(single_set_2): Likewise.
+	(noop_move_p): Likewise.
+	(note_stores): Likewise.
+	* sched-deps.c (sched_analyze_reg): Likewise.
+	(sched_analyze_insn): Likewise.
+
+2018-08-06  Alan Hayward  <alan.hayward@arm.com>
+
 	* cse.c (invalidate_reg): New function extracted from...
 	(invalidate): ...here.
 	(canonicalize_insn): Check for clobber high.
diff --git a/gcc/alias.c b/gcc/alias.c
index 2091dfbf3d7..748da2b6951 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -1554,6 +1554,17 @@ record_set (rtx dest, const_rtx set, void *data ATTRIBUTE_UNUSED)
 	  new_reg_base_value[regno] = 0;
 	  return;
 	}
+      /* A CLOBBER_HIGH only wipes out the old value if the mode of the old
+	 value is greater than that of the clobber.  */
+      else if (GET_CODE (set) == CLOBBER_HIGH)
+	{
+	  if (new_reg_base_value[regno] != 0
+	      && reg_is_clobbered_by_clobber_high (
+		   regno, GET_MODE (new_reg_base_value[regno]), XEXP (set, 0)))
+	    new_reg_base_value[regno] = 0;
+	  return;
+	}
+
       src = SET_SRC (set);
     }
   else
diff --git a/gcc/cfgexpand.c b/gcc/cfgexpand.c
index 7353d5dce12..3c5b30b79f8 100644
--- a/gcc/cfgexpand.c
+++ b/gcc/cfgexpand.c
@@ -3750,6 +3750,7 @@ expand_gimple_stmt (gimple *stmt)
 	      /* If we want exceptions for non-call insns, any
 		 may_trap_p instruction may throw.  */
 	      && GET_CODE (PATTERN (insn)) != CLOBBER
+	      && GET_CODE (PATTERN (insn)) != CLOBBER_HIGH
 	      && GET_CODE (PATTERN (insn)) != USE
 	      && insn_could_throw_p (insn))
 	    make_reg_eh_region_note (insn, 0, lp_nr);
diff --git a/gcc/combine-stack-adj.c b/gcc/combine-stack-adj.c
index 4573dc2a87d..bd7f5d0d2ec 100644
--- a/gcc/combine-stack-adj.c
+++ b/gcc/combine-stack-adj.c
@@ -133,6 +133,7 @@ single_set_for_csa (rtx_insn *insn)
 	  && SET_SRC (this_rtx) == SET_DEST (this_rtx))
 	;
       else if (GET_CODE (this_rtx) != CLOBBER
+	       && GET_CODE (this_rtx) != CLOBBER_HIGH
 	       && GET_CODE (this_rtx) != USE)
 	return NULL_RTX;
     }
diff --git a/gcc/combine.c b/gcc/combine.c
index 3a5883a4c75..7a0abf2f743 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -570,6 +570,7 @@ find_single_use_1 (rtx dest, rtx *loc)
     case SYMBOL_REF:
     CASE_CONST_ANY:
     case CLOBBER:
+    case CLOBBER_HIGH:
       return 0;
 
     case SET:
@@ -1752,6 +1753,9 @@ set_nonzero_bits_and_sign_copies (rtx x, const_rtx set, void *data)
 	  return;
 	}
 
+      /* Should not happen as we only using pseduo registers.  */
+      gcc_assert (GET_CODE (set) != CLOBBER_HIGH);
+
       /* If this register is being initialized using itself, and the
 	 register is uninitialized in this basic block, and there are
 	 no LOG_LINKS which set the register, then part of the
@@ -1910,6 +1914,7 @@ can_combine_p (rtx_insn *insn, rtx_insn *i3, rtx_insn *pred ATTRIBUTE_UNUSED,
 
 	      /* We can ignore CLOBBERs.  */
 	    case CLOBBER:
+	    case CLOBBER_HIGH:
 	      break;
 
 	    case SET:
@@ -2570,10 +2575,17 @@ is_parallel_of_n_reg_sets (rtx pat, int n)
 	|| !REG_P (SET_DEST (XVECEXP (pat, 0, i))))
       return false;
   for ( ; i < len; i++)
-    if (GET_CODE (XVECEXP (pat, 0, i)) != CLOBBER
-	|| XEXP (XVECEXP (pat, 0, i), 0) == const0_rtx)
-      return false;
-
+    switch (GET_CODE (XVECEXP (pat, 0, i)))
+      {
+      case CLOBBER:
+	if (XEXP (XVECEXP (pat, 0, i), 0) == const0_rtx)
+	  return false;
+	break;
+      case CLOBBER_HIGH:
+	break;
+      default:
+	return false;
+      }
   return true;
 }
 
@@ -2860,7 +2872,8 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
       for (i = 0; ok && i < XVECLEN (p2, 0); i++)
 	{
 	  if ((GET_CODE (XVECEXP (p2, 0, i)) == SET
-	       || GET_CODE (XVECEXP (p2, 0, i)) == CLOBBER)
+	       || GET_CODE (XVECEXP (p2, 0, i)) == CLOBBER
+	       || GET_CODE (XVECEXP (p2, 0, i)) == CLOBBER_HIGH)
 	      && reg_overlap_mentioned_p (SET_DEST (PATTERN (i3)),
 					  SET_DEST (XVECEXP (p2, 0, i))))
 	    ok = false;
@@ -13315,6 +13328,15 @@ record_dead_and_set_regs_1 (rtx dest, const_rtx setter, void *data)
 			      ? SET_SRC (setter)
 			      : gen_lowpart (GET_MODE (dest),
 					     SET_SRC (setter)));
+      else if (GET_CODE (setter) == CLOBBER_HIGH)
+	{
+	  reg_stat_type *rsp = &reg_stat[REGNO (dest)];
+	  if (rsp->last_set_value
+	      && reg_is_clobbered_by_clobber_high
+		   (REGNO (dest), GET_MODE (rsp->last_set_value),
+		    XEXP (setter, 0)))
+	    record_value_for_reg (dest, NULL, NULL_RTX);
+	}
       else
 	record_value_for_reg (dest, record_dead_insn, NULL_RTX);
     }
@@ -13735,6 +13757,7 @@ get_last_value (const_rtx x)
 
 static unsigned int reg_dead_regno, reg_dead_endregno;
 static int reg_dead_flag;
+rtx reg_dead_reg;
 
 /* Function called via note_stores from reg_dead_at_p.
 
@@ -13749,6 +13772,10 @@ reg_dead_at_p_1 (rtx dest, const_rtx x, void *data ATTRIBUTE_UNUSED)
   if (!REG_P (dest))
     return;
 
+  if (GET_CODE (x) == CLOBBER_HIGH
+      && !reg_is_clobbered_by_clobber_high (reg_dead_reg, XEXP (x, 0)))
+    return;
+
   regno = REGNO (dest);
   endregno = END_REGNO (dest);
   if (reg_dead_endregno > regno && reg_dead_regno < endregno)
@@ -13772,6 +13799,7 @@ reg_dead_at_p (rtx reg, rtx_insn *insn)
   /* Set variables for reg_dead_at_p_1.  */
   reg_dead_regno = REGNO (reg);
   reg_dead_endregno = END_REGNO (reg);
+  reg_dead_reg = reg;
 
   reg_dead_flag = 0;
 
diff --git a/gcc/dce.c b/gcc/dce.c
index e4d442c62b5..7fc3fd209b5 100644
--- a/gcc/dce.c
+++ b/gcc/dce.c
@@ -145,6 +145,7 @@ deletable_insn_p (rtx_insn *insn, bool fast, bitmap arg_stores)
       return false;
 
     case CLOBBER:
+    case CLOBBER_HIGH:
       if (fast)
 	{
 	  /* A CLOBBER of a dead pseudo register serves no purpose.
@@ -213,7 +214,10 @@ static void
 mark_nonreg_stores_1 (rtx dest, const_rtx pattern, void *data)
 {
   if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
-    mark_insn ((rtx_insn *) data, true);
+    {
+      gcc_checking_assert (GET_CODE (pattern) != CLOBBER_HIGH);
+      mark_insn ((rtx_insn *) data, true);
+    }
 }
 
 
@@ -224,7 +228,10 @@ static void
 mark_nonreg_stores_2 (rtx dest, const_rtx pattern, void *data)
 {
   if (GET_CODE (pattern) != CLOBBER && !REG_P (dest))
-    mark_insn ((rtx_insn *) data, false);
+    {
+      gcc_checking_assert (GET_CODE (pattern) != CLOBBER_HIGH);
+      mark_insn ((rtx_insn *) data, false);
+    }
 }
 
 
diff --git a/gcc/df-scan.c b/gcc/df-scan.c
index cbb08fc36ae..0b119f211ea 100644
--- a/gcc/df-scan.c
+++ b/gcc/df-scan.c
@@ -2778,6 +2778,7 @@ df_find_hard_reg_defs (rtx x, HARD_REG_SET *defs)
       break;
 
     case CLOBBER:
+    case CLOBBER_HIGH:
       df_find_hard_reg_defs_1 (XEXP (x, 0), defs);
       break;
 
@@ -2837,6 +2838,10 @@ df_uses_record (struct df_collection_rec *collection_rec,
       /* If we're clobbering a REG then we have a def so ignore.  */
       return;
 
+    case CLOBBER_HIGH:
+      gcc_assert (REG_P (XEXP (x, 0)));
+      return;
+
     case MEM:
       df_uses_record (collection_rec,
 		      &XEXP (x, 0), DF_REF_REG_MEM_LOAD,
@@ -3133,6 +3138,7 @@ df_get_call_refs (struct df_collection_rec *collection_rec,
   for (note = CALL_INSN_FUNCTION_USAGE (insn_info->insn); note;
        note = XEXP (note, 1))
     {
+      gcc_assert (GET_CODE (XEXP (note, 0)) != CLOBBER_HIGH);
       if (GET_CODE (XEXP (note, 0)) == USE)
         df_uses_record (collection_rec, &XEXP (XEXP (note, 0), 0),
 			DF_REF_REG_USE, bb, insn_info, flags);
diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 1850a0f93e7..b67481dd2db 100644
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -16321,6 +16321,7 @@ mem_loc_descriptor (rtx rtl, machine_mode mode,
     case CONST_FIXED:
     case CLRSB:
     case CLOBBER:
+    case CLOBBER_HIGH:
       /* If delegitimize_address couldn't do anything with the UNSPEC, we
 	 can't express it in the debug info.  This can happen e.g. with some
 	 TLS UNSPECs.  */
diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index 4a899b56173..4f0221f6f43 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -529,6 +529,9 @@ haifa_classify_rtx (const_rtx x)
 	  /* Test if it is a 'store'.  */
 	  tmp_class = may_trap_exp (XEXP (x, 0), 1);
 	  break;
+	case CLOBBER_HIGH:
+	  gcc_assert (REG_P (XEXP (x, 0)));
+	  break;
 	case SET:
 	  /* Test if it is a store.  */
 	  tmp_class = may_trap_exp (SET_DEST (x), 1);
diff --git a/gcc/ira-build.c b/gcc/ira-build.c
index c0fd9384f8b..da017be5b3d 100644
--- a/gcc/ira-build.c
+++ b/gcc/ira-build.c
@@ -1876,6 +1876,11 @@ create_insn_allocnos (rtx x, rtx outer, bool output_p)
       create_insn_allocnos (XEXP (x, 0), NULL, true);
       return;
     }
+  else if (code == CLOBBER_HIGH)
+    {
+      gcc_assert (REG_P (XEXP (x, 0)) && HARD_REGISTER_P (XEXP (x, 0)));
+      return;
+    }
   else if (code == MEM)
     {
       create_insn_allocnos (XEXP (x, 0), NULL, false);
diff --git a/gcc/ira-costs.c b/gcc/ira-costs.c
index 2b4ae38f410..6fa917ab1a1 100644
--- a/gcc/ira-costs.c
+++ b/gcc/ira-costs.c
@@ -1444,6 +1444,13 @@ scan_one_insn (rtx_insn *insn)
       return insn;
     }
 
+  if (pat_code == CLOBBER_HIGH)
+    {
+      gcc_assert (REG_P (XEXP (PATTERN (insn), 0))
+		  && HARD_REGISTER_P (XEXP (PATTERN (insn), 0)));
+      return insn;
+    }
+
   counted_mem = false;
   set = single_set (insn);
   extract_insn (insn);
diff --git a/gcc/ira.c b/gcc/ira.c
index b7bcc15a15d..def194a0782 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -3086,6 +3086,7 @@ equiv_init_movable_p (rtx x, int regno)
 
     case CC0:
     case CLOBBER:
+    case CLOBBER_HIGH:
       return 0;
 
     case PRE_INC:
@@ -4411,6 +4412,7 @@ rtx_moveable_p (rtx *loc, enum op_type type)
 	      && rtx_moveable_p (&XEXP (x, 2), OP_IN));
 
     case CLOBBER:
+    case CLOBBER_HIGH:
       return rtx_moveable_p (&SET_DEST (x), OP_OUT);
 
     case UNSPEC_VOLATILE:
@@ -4863,7 +4865,9 @@ interesting_dest_for_shprep (rtx_insn *insn, basic_block call_dom)
   for (int i = 0; i < XVECLEN (pat, 0); i++)
     {
       rtx sub = XVECEXP (pat, 0, i);
-      if (GET_CODE (sub) == USE || GET_CODE (sub) == CLOBBER)
+      if (GET_CODE (sub) == USE
+	  || GET_CODE (sub) == CLOBBER
+	  || GET_CODE (sub) == CLOBBER_HIGH)
 	continue;
       if (GET_CODE (sub) != SET
 	  || side_effects_p (sub))
diff --git a/gcc/jump.c b/gcc/jump.c
index f379048f636..06f7255d24d 100644
--- a/gcc/jump.c
+++ b/gcc/jump.c
@@ -1094,6 +1094,7 @@ mark_jump_label_1 (rtx x, rtx_insn *insn, bool in_mem, bool is_target)
     case CC0:
     case REG:
     case CLOBBER:
+    case CLOBBER_HIGH:
     case CALL:
       return;
 
diff --git a/gcc/postreload-gcse.c b/gcc/postreload-gcse.c
index 152dd6ae452..afa61dcede6 100644
--- a/gcc/postreload-gcse.c
+++ b/gcc/postreload-gcse.c
@@ -791,15 +791,18 @@ record_opr_changes (rtx_insn *insn)
 	record_last_reg_set_info_regno (insn, regno);
 
       for (link = CALL_INSN_FUNCTION_USAGE (insn); link; link = XEXP (link, 1))
-	if (GET_CODE (XEXP (link, 0)) == CLOBBER)
-	  {
-	    x = XEXP (XEXP (link, 0), 0);
-	    if (REG_P (x))
-	      {
-		gcc_assert (HARD_REGISTER_P (x));
-		record_last_reg_set_info (insn, x);
-	      }
-	  }
+	{
+	  gcc_assert (GET_CODE (XEXP (link, 0)) != CLOBBER_HIGH);
+	  if (GET_CODE (XEXP (link, 0)) == CLOBBER)
+	    {
+	      x = XEXP (XEXP (link, 0), 0);
+	      if (REG_P (x))
+		{
+		  gcc_assert (HARD_REGISTER_P (x));
+		  record_last_reg_set_info (insn, x);
+		}
+	    }
+	}
 
       if (! RTL_CONST_OR_PURE_CALL_P (insn))
 	record_last_mem_set_info (insn);
diff --git a/gcc/postreload.c b/gcc/postreload.c
index 0638709639b..56cb14dc676 100644
--- a/gcc/postreload.c
+++ b/gcc/postreload.c
@@ -133,6 +133,8 @@ reload_cse_simplify (rtx_insn *insn, rtx testreg)
 	  for (i = XVECLEN (body, 0) - 1; i >= 0; --i)
 	    {
 	      rtx part = XVECEXP (body, 0, i);
+	      /* asms can only have full clobbers, not clobber_highs.  */
+	      gcc_assert (GET_CODE (part) != CLOBBER_HIGH);
 	      if (GET_CODE (part) == CLOBBER && REG_P (XEXP (part, 0)))
 		cselib_invalidate_rtx (XEXP (part, 0));
 	    }
@@ -156,6 +158,7 @@ reload_cse_simplify (rtx_insn *insn, rtx testreg)
 		}
 	    }
 	  else if (GET_CODE (part) != CLOBBER
+		   && GET_CODE (part) != CLOBBER_HIGH
 		   && GET_CODE (part) != USE)
 	    break;
 	}
@@ -667,7 +670,8 @@ struct reg_use
    STORE_RUID is always meaningful if we only want to use a value in a
    register in a different place: it denotes the next insn in the insn
    stream (i.e. the last encountered) that sets or clobbers the register.
-   REAL_STORE_RUID is similar, but clobbers are ignored when updating it.  */
+   REAL_STORE_RUID is similar, but clobbers are ignored when updating it.
+   EXPR is the expression used when storing the register.  */
 static struct
   {
     struct reg_use reg_use[RELOAD_COMBINE_MAX_USES];
@@ -677,6 +681,7 @@ static struct
     int real_store_ruid;
     int use_ruid;
     bool all_offsets_match;
+    rtx expr;
   } reg_state[FIRST_PSEUDO_REGISTER];
 
 /* Reverse linear uid.  This is increased in reload_combine while scanning
@@ -1341,6 +1346,10 @@ reload_combine (void)
 	    {
 	      rtx setuse = XEXP (link, 0);
 	      rtx usage_rtx = XEXP (setuse, 0);
+	      /* We could support CLOBBER_HIGH and treat it in the same way as
+		 HARD_REGNO_CALL_PART_CLOBBERED, but no port needs that yet.  */
+	      gcc_assert (GET_CODE (setuse) != CLOBBER_HIGH);
+
 	      if ((GET_CODE (setuse) == USE || GET_CODE (setuse) == CLOBBER)
 		  && REG_P (usage_rtx))
 	        {
@@ -1516,6 +1525,10 @@ reload_combine_note_use (rtx *xp, rtx_insn *insn, int ruid, rtx containing_mem)
 	}
       break;
 
+    case CLOBBER_HIGH:
+      gcc_assert (REG_P (SET_DEST (x)));
+      return;
+
     case PLUS:
       /* We are interested in (plus (reg) (const_int)) .  */
       if (!REG_P (XEXP (x, 0))
@@ -2135,6 +2148,9 @@ reload_cse_move2add (rtx_insn *first)
 	    {
 	      rtx setuse = XEXP (link, 0);
 	      rtx usage_rtx = XEXP (setuse, 0);
+	      /* CALL_INSN_FUNCTION_USAGEs can only have full clobbers, not
+		 clobber_highs.  */
+	      gcc_assert (GET_CODE (setuse) != CLOBBER_HIGH);
 	      if (GET_CODE (setuse) == CLOBBER
 		  && REG_P (usage_rtx))
 	        {
@@ -2297,6 +2313,13 @@ move2add_note_store (rtx dst, const_rtx set, void *data)
 
       move2add_record_mode (dst);
     }
+  else if (GET_CODE (set) == CLOBBER_HIGH)
+    {
+      /* Only invalidate if actually clobbered.  */
+      if (reg_mode[regno] == BLKmode
+	  || reg_is_clobbered_by_clobber_high (regno, reg_mode[regno], dst))
+	 goto invalidate;
+    }
   else
     {
     invalidate:
diff --git a/gcc/print-rtl.c b/gcc/print-rtl.c
index 37c0d53fae2..ba9ac02fce7 100644
--- a/gcc/print-rtl.c
+++ b/gcc/print-rtl.c
@@ -1742,6 +1742,7 @@ print_pattern (pretty_printer *pp, const_rtx x, int verbose)
       print_exp (pp, x, verbose);
       break;
     case CLOBBER:
+    case CLOBBER_HIGH:
     case USE:
       pp_printf (pp, "%s ", GET_RTX_NAME (GET_CODE (x)));
       print_value (pp, XEXP (x, 0), verbose);
diff --git a/gcc/recog.c b/gcc/recog.c
index 0a8fa2ce46c..d7c69439683 100644
--- a/gcc/recog.c
+++ b/gcc/recog.c
@@ -1600,6 +1600,7 @@ decode_asm_operands (rtx body, rtx *operands, rtx **operand_locs,
 	      {
 		if (GET_CODE (XVECEXP (body, 0, i)) == CLOBBER)
 		  break;		/* Past last SET */
+		gcc_assert (GET_CODE (XVECEXP (body, 0, i)) == SET);
 		if (operands)
 		  operands[i] = SET_DEST (XVECEXP (body, 0, i));
 		if (operand_locs)
@@ -3715,7 +3716,8 @@ store_data_bypass_p_1 (rtx_insn *out_insn, rtx in_set)
     {
       rtx out_exp = XVECEXP (out_pat, 0, i);
 
-      if (GET_CODE (out_exp) == CLOBBER || GET_CODE (out_exp) == USE)
+      if (GET_CODE (out_exp) == CLOBBER || GET_CODE (out_exp) == USE
+	  || GET_CODE (out_exp) == CLOBBER_HIGH)
 	continue;
 
       gcc_assert (GET_CODE (out_exp) == SET);
@@ -3746,7 +3748,8 @@ store_data_bypass_p (rtx_insn *out_insn, rtx_insn *in_insn)
     {
       rtx in_exp = XVECEXP (in_pat, 0, i);
 
-      if (GET_CODE (in_exp) == CLOBBER || GET_CODE (in_exp) == USE)
+      if (GET_CODE (in_exp) == CLOBBER || GET_CODE (in_exp) == USE
+	  || GET_CODE (in_exp) == CLOBBER_HIGH)
 	continue;
 
       gcc_assert (GET_CODE (in_exp) == SET);
@@ -3798,7 +3801,7 @@ if_test_bypass_p (rtx_insn *out_insn, rtx_insn *in_insn)
 	{
 	  rtx exp = XVECEXP (out_pat, 0, i);
 
-	  if (GET_CODE (exp) == CLOBBER)
+	  if (GET_CODE (exp) == CLOBBER  || GET_CODE (exp) == CLOBBER_HIGH)
 	    continue;
 
 	  gcc_assert (GET_CODE (exp) == SET);
diff --git a/gcc/regcprop.c b/gcc/regcprop.c
index 18132425ab2..1f805765b93 100644
--- a/gcc/regcprop.c
+++ b/gcc/regcprop.c
@@ -237,7 +237,11 @@ static void
 kill_clobbered_value (rtx x, const_rtx set, void *data)
 {
   struct value_data *const vd = (struct value_data *) data;
-  if (GET_CODE (set) == CLOBBER)
+  gcc_assert (GET_CODE (set) != CLOBBER_HIGH || REG_P (x));
+
+  if (GET_CODE (set) == CLOBBER
+      || (GET_CODE (set) == CLOBBER_HIGH
+	  && reg_is_clobbered_by_clobber_high (x, XEXP (set, 0))))
     kill_value (x, vd);
 }
 
@@ -257,7 +261,9 @@ kill_set_value (rtx x, const_rtx set, void *data)
   struct kill_set_value_data *ksvd = (struct kill_set_value_data *) data;
   if (rtx_equal_p (x, ksvd->ignore_set_reg))
     return;
-  if (GET_CODE (set) != CLOBBER)
+
+  gcc_assert (GET_CODE (set) != CLOBBER_HIGH || REG_P (x));
+  if (GET_CODE (set) != CLOBBER && GET_CODE (set) != CLOBBER_HIGH)
     {
       kill_value (x, ksvd->vd);
       if (REG_P (x))
diff --git a/gcc/reginfo.c b/gcc/reginfo.c
index f4071dac8b4..1f36d141c73 100644
--- a/gcc/reginfo.c
+++ b/gcc/reginfo.c
@@ -1100,6 +1100,10 @@ reg_scan_mark_refs (rtx x, rtx_insn *insn)
 	reg_scan_mark_refs (XEXP (XEXP (x, 0), 0), insn);
       break;
 
+    case CLOBBER_HIGH:
+      gcc_assert (!(MEM_P (XEXP (x, 0))));
+      break;
+
     case SET:
       /* Count a set of the destination if it is a register.  */
       for (dest = SET_DEST (x);
diff --git a/gcc/reload1.c b/gcc/reload1.c
index a4cc3ee02ea..8e15160c6ad 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -1339,6 +1339,8 @@ maybe_fix_stack_asms (void)
 	  rtx t = XVECEXP (pat, 0, i);
 	  if (GET_CODE (t) == CLOBBER && STACK_REG_P (XEXP (t, 0)))
 	    SET_HARD_REG_BIT (clobbered, REGNO (XEXP (t, 0)));
+	  /* CLOBBER_HIGH is only supported for LRA.  */
+	  gcc_assert (GET_CODE (t) != CLOBBER_HIGH);
 	}
 
       /* Get the operand values and constraints out of the insn.  */
@@ -2879,6 +2881,7 @@ eliminate_regs_1 (rtx x, machine_mode mem_mode, rtx insn,
       return x;
 
     case CLOBBER:
+    case CLOBBER_HIGH:
     case ASM_OPERANDS:
       gcc_assert (insn && DEBUG_INSN_P (insn));
       break;
@@ -3089,6 +3092,10 @@ elimination_effects (rtx x, machine_mode mem_mode)
       elimination_effects (XEXP (x, 0), mem_mode);
       return;
 
+    case CLOBBER_HIGH:
+      /* CLOBBER_HIGH is only supported for LRA.  */
+      return;
+
     case SET:
       /* Check for setting a register that we know about.  */
       if (REG_P (SET_DEST (x)))
@@ -3810,6 +3817,9 @@ mark_not_eliminable (rtx dest, const_rtx x, void *data ATTRIBUTE_UNUSED)
   if (dest == hard_frame_pointer_rtx)
     return;
 
+  /* CLOBBER_HIGH is only supported for LRA.  */
+  gcc_assert (GET_CODE (x) != CLOBBER_HIGH);
+
   for (i = 0; i < NUM_ELIMINABLE_REGS; i++)
     if (reg_eliminate[i].can_eliminate && dest == reg_eliminate[i].to_rtx
 	&& (GET_CODE (x) != SET
@@ -4445,6 +4455,7 @@ scan_paradoxical_subregs (rtx x)
     case PC:
     case USE:
     case CLOBBER:
+    case CLOBBER_HIGH:
       return;
 
     case SUBREG:
@@ -4899,7 +4910,7 @@ reload_as_needed (int live_known)
    to be forgotten later.  */
 
 static void
-forget_old_reloads_1 (rtx x, const_rtx ignored ATTRIBUTE_UNUSED,
+forget_old_reloads_1 (rtx x, const_rtx setter,
 		      void *data)
 {
   unsigned int regno;
@@ -4919,6 +4930,9 @@ forget_old_reloads_1 (rtx x, const_rtx ignored ATTRIBUTE_UNUSED,
   if (!REG_P (x))
     return;
 
+  /* CLOBBER_HIGH is only supported for LRA.  */
+  gcc_assert (GET_CODE (setter) != CLOBBER_HIGH);
+
   regno = REGNO (x);
 
   if (regno >= FIRST_PSEUDO_REGISTER)
diff --git a/gcc/reorg.c b/gcc/reorg.c
index 904d91ec9e8..f8a986cea1d 100644
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -397,7 +397,8 @@ find_end_label (rtx kind)
   while (NOTE_P (insn)
 	 || (NONJUMP_INSN_P (insn)
 	     && (GET_CODE (PATTERN (insn)) == USE
-		 || GET_CODE (PATTERN (insn)) == CLOBBER)))
+		 || GET_CODE (PATTERN (insn)) == CLOBBER
+		 || GET_CODE (PATTERN (insn)) == CLOBBER_HIGH)))
     insn = PREV_INSN (insn);
 
   /* When a target threads its epilogue we might already have a
@@ -1297,7 +1298,8 @@ try_merge_delay_insns (rtx_insn *insn, rtx_insn *thread)
 
       /* TRIAL must be a CALL_INSN or INSN.  Skip USE and CLOBBER.  */
       if (NONJUMP_INSN_P (trial)
-	  && (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER))
+	  && (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER
+	      || GET_CODE (pat) == CLOBBER_HIGH))
 	continue;
 
       if (GET_CODE (next_to_match) == GET_CODE (trial)
@@ -1491,7 +1493,8 @@ redundant_insn (rtx insn, rtx_insn *target, const vec<rtx_insn *> &delay_list)
       --insns_to_search;
 
       pat = PATTERN (trial);
-      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
+      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER
+	  || GET_CODE (pat) == CLOBBER_HIGH)
 	continue;
 
       if (GET_CODE (trial) == DEBUG_INSN)
@@ -1589,7 +1592,8 @@ redundant_insn (rtx insn, rtx_insn *target, const vec<rtx_insn *> &delay_list)
       --insns_to_search;
 
       pat = PATTERN (trial);
-      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
+      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER
+	  || GET_CODE (pat) == CLOBBER_HIGH)
 	continue;
 
       if (GET_CODE (trial) == DEBUG_INSN)
@@ -1701,7 +1705,8 @@ own_thread_p (rtx thread, rtx label, int allow_fallthrough)
 	|| LABEL_P (insn)
 	|| (NONJUMP_INSN_P (insn)
 	    && GET_CODE (PATTERN (insn)) != USE
-	    && GET_CODE (PATTERN (insn)) != CLOBBER))
+	    && GET_CODE (PATTERN (insn)) != CLOBBER
+	    && GET_CODE (PATTERN (insn)) != CLOBBER_HIGH))
       return 0;
 
   return 1;
@@ -2024,7 +2029,8 @@ fill_simple_delay_slots (int non_jumps_p)
 	      pat = PATTERN (trial);
 
 	      /* Stand-alone USE and CLOBBER are just for flow.  */
-	      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
+	      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER
+		  || GET_CODE (pat) == CLOBBER_HIGH)
 		continue;
 
 	      /* And DEBUG_INSNs never go into delay slots.  */
@@ -2150,7 +2156,8 @@ fill_simple_delay_slots (int non_jumps_p)
 	      pat = PATTERN (trial);
 
 	      /* Stand-alone USE and CLOBBER are just for flow.  */
-	      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
+	      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER
+		  || GET_CODE (pat) == CLOBBER_HIGH)
 		continue;
 
 	      /* And DEBUG_INSNs do not go in delay slots.  */
@@ -2418,7 +2425,8 @@ fill_slots_from_thread (rtx_jump_insn *insn, rtx condition,
 	}
 
       pat = PATTERN (trial);
-      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER)
+      if (GET_CODE (pat) == USE || GET_CODE (pat) == CLOBBER
+	  || GET_CODE (pat) == CLOBBER_HIGH)
 	continue;
 
       if (GET_CODE (trial) == DEBUG_INSN)
@@ -3818,7 +3826,8 @@ dbr_schedule (rtx_insn *first)
 	  if (! insn->deleted ()
 	      && NONJUMP_INSN_P (insn)
 	      && GET_CODE (PATTERN (insn)) != USE
-	      && GET_CODE (PATTERN (insn)) != CLOBBER)
+	      && GET_CODE (PATTERN (insn)) != CLOBBER
+	      && GET_CODE (PATTERN (insn)) != CLOBBER_HIGH)
 	    {
 	      if (GET_CODE (PATTERN (insn)) == SEQUENCE)
 		{
diff --git a/gcc/resource.c b/gcc/resource.c
index 0822daebde7..fdfab6916d4 100644
--- a/gcc/resource.c
+++ b/gcc/resource.c
@@ -108,6 +108,11 @@ update_live_status (rtx dest, const_rtx x, void *data ATTRIBUTE_UNUSED)
   if (GET_CODE (x) == CLOBBER)
     for (i = first_regno; i < last_regno; i++)
       CLEAR_HARD_REG_BIT (current_live_regs, i);
+  else if (GET_CODE (x) == CLOBBER_HIGH)
+    /* No current target supports both branch delay slots and CLOBBER_HIGH.
+       We'd need more elaborate liveness tracking to handle that
+       combination.  */
+    gcc_unreachable ();
   else
     for (i = first_regno; i < last_regno; i++)
       {
@@ -293,6 +298,7 @@ mark_referenced_resources (rtx x, struct resources *res,
       return;
 
     case CLOBBER:
+    case CLOBBER_HIGH:
       return;
 
     case CALL_INSN:
@@ -668,9 +674,15 @@ mark_set_resources (rtx x, struct resources *res, int in_dest,
 
 	  for (link = CALL_INSN_FUNCTION_USAGE (call_insn);
 	       link; link = XEXP (link, 1))
-	    if (GET_CODE (XEXP (link, 0)) == CLOBBER)
-	      mark_set_resources (SET_DEST (XEXP (link, 0)), res, 1,
-				  MARK_SRC_DEST);
+	    {
+	      /* We could support CLOBBER_HIGH and treat it in the same way as
+		 HARD_REGNO_CALL_PART_CLOBBERED, but no port needs that
+		 yet.  */
+	      gcc_assert (GET_CODE (XEXP (link, 0)) != CLOBBER_HIGH);
+	      if (GET_CODE (XEXP (link, 0)) == CLOBBER)
+		mark_set_resources (SET_DEST (XEXP (link, 0)), res, 1,
+				    MARK_SRC_DEST);
+	    }
 
 	  /* Check for a REG_SETJMP.  If it exists, then we must
 	     assume that this call can clobber any register.  */
@@ -713,6 +725,12 @@ mark_set_resources (rtx x, struct resources *res, int in_dest,
       mark_set_resources (XEXP (x, 0), res, 1, MARK_SRC_DEST);
       return;
 
+    case CLOBBER_HIGH:
+      /* No current target supports both branch delay slots and CLOBBER_HIGH.
+	 We'd need more elaborate liveness tracking to handle that
+	 combination.  */
+      gcc_unreachable ();
+
     case SEQUENCE:
       {
         rtx_sequence *seq = as_a <rtx_sequence *> (x);
diff --git a/gcc/rtl.c b/gcc/rtl.c
index 985db1c14f0..f9146afcf2c 100644
--- a/gcc/rtl.c
+++ b/gcc/rtl.c
@@ -304,6 +304,10 @@ copy_rtx (rtx orig)
 	return orig;
       break;
 
+    case CLOBBER_HIGH:
+	gcc_assert (REG_P (XEXP (orig, 0)));
+	return orig;
+
     case CONST:
       if (shared_const_p (orig))
 	return orig;
diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c
index 1cab1545744..6c620a4a3e5 100644
--- a/gcc/rtlanal.c
+++ b/gcc/rtlanal.c
@@ -1198,6 +1198,10 @@ reg_referenced_p (const_rtx x, const_rtx body)
 	  return 1;
       return 0;
 
+    case CLOBBER_HIGH:
+      gcc_assert (REG_P (XEXP (body, 0)));
+      return 0;
+
     case COND_EXEC:
       if (reg_overlap_mentioned_p (x, COND_EXEC_TEST (body)))
 	return 1;
@@ -1420,7 +1424,11 @@ set_of_1 (rtx x, const_rtx pat, void *data1)
 {
   struct set_of_data *const data = (struct set_of_data *) (data1);
   if (rtx_equal_p (x, data->pat)
-      || (!MEM_P (x) && reg_overlap_mentioned_p (data->pat, x)))
+      || (GET_CODE (pat) == CLOBBER_HIGH
+	  && REGNO(data->pat) == REGNO(XEXP (pat, 0))
+	  && reg_is_clobbered_by_clobber_high (data->pat, XEXP (pat, 0)))
+      || (GET_CODE (pat) != CLOBBER_HIGH && !MEM_P (x)
+	  && reg_overlap_mentioned_p (data->pat, x)))
     data->found = pat;
 }
 
@@ -1509,6 +1517,7 @@ single_set_2 (const rtx_insn *insn, const_rtx pat)
 	    {
 	    case USE:
 	    case CLOBBER:
+	    case CLOBBER_HIGH:
 	      break;
 
 	    case SET:
@@ -1663,7 +1672,8 @@ noop_move_p (const rtx_insn *insn)
 	  rtx tem = XVECEXP (pat, 0, i);
 
 	  if (GET_CODE (tem) == USE
-	      || GET_CODE (tem) == CLOBBER)
+	      || GET_CODE (tem) == CLOBBER
+	      || GET_CODE (tem) == CLOBBER_HIGH)
 	    continue;
 
 	  if (GET_CODE (tem) != SET || ! set_noop_p (tem))
@@ -1895,7 +1905,9 @@ note_stores (const_rtx x, void (*fun) (rtx, const_rtx, void *), void *data)
   if (GET_CODE (x) == COND_EXEC)
     x = COND_EXEC_CODE (x);
 
-  if (GET_CODE (x) == SET || GET_CODE (x) == CLOBBER)
+  if (GET_CODE (x) == SET
+      || GET_CODE (x) == CLOBBER
+      || GET_CODE (x) == CLOBBER_HIGH)
     {
       rtx dest = SET_DEST (x);
 
diff --git a/gcc/sched-deps.c b/gcc/sched-deps.c
index 120b5f0ddc1..f89f28269fd 100644
--- a/gcc/sched-deps.c
+++ b/gcc/sched-deps.c
@@ -2319,6 +2319,13 @@ sched_analyze_reg (struct deps_desc *deps, int regno, machine_mode mode,
 	  while (--i >= 0)
 	    note_reg_use (regno + i);
 	}
+      else if (ref == CLOBBER_HIGH)
+	{
+	  gcc_assert (i == 1);
+	  /* We don't know the current state of the register, so have to treat
+	     the clobber high as a full clobber.  */
+	  note_reg_clobber (regno);
+	}
       else
 	{
 	  while (--i >= 0)
@@ -2342,6 +2349,8 @@ sched_analyze_reg (struct deps_desc *deps, int regno, machine_mode mode,
       else if (ref == USE)
 	note_reg_use (regno);
       else
+	/* For CLOBBER_HIGH, we don't know the current state of the register,
+	   so have to treat it as a full clobber.  */
 	note_reg_clobber (regno);
 
       /* Pseudos that are REG_EQUIV to something may be replaced
@@ -2962,7 +2971,7 @@ sched_analyze_insn (struct deps_desc *deps, rtx x, rtx_insn *insn)
 	      sub = COND_EXEC_CODE (sub);
 	      code = GET_CODE (sub);
 	    }
-	  if (code == SET || code == CLOBBER)
+	  else if (code == SET || code == CLOBBER || code == CLOBBER_HIGH)
 	    sched_analyze_1 (deps, sub, insn);
 	  else
 	    sched_analyze_2 (deps, sub, insn);
@@ -2978,6 +2987,10 @@ sched_analyze_insn (struct deps_desc *deps, rtx x, rtx_insn *insn)
 	{
 	  if (GET_CODE (XEXP (link, 0)) == CLOBBER)
 	    sched_analyze_1 (deps, XEXP (link, 0), insn);
+	  else if (GET_CODE (XEXP (link, 0)) == CLOBBER_HIGH)
+	    /* We could support CLOBBER_HIGH and treat it in the same way as
+	      HARD_REGNO_CALL_PART_CLOBBERED, but no port needs that yet.  */
+	    gcc_unreachable ();
 	  else if (GET_CODE (XEXP (link, 0)) != SET)
 	    sched_analyze_2 (deps, XEXP (link, 0), insn);
 	}