File _service:tar_scm:0022-DFE-Add-Dead-Field-Elimin... of Package gcc

File _service:tar_scm:0022-DFE-Add-Dead-Field-Elimination-in-Struct-Reorg.patch of Package gcc (Revision ad77ac6b230e437386dcd71ec9574d15)

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From 9d03b0a7741915e3a0172d60b9c21bf5abbda89e Mon Sep 17 00:00:00 2001
From: Mingchuan Wu <wumingchuan1992@foxmail.com>
Date: Mon, 28 Aug 2023 18:11:02 +0800
Subject: [PATCH 22/22] [DFE] Add Dead Field Elimination in Struct-Reorg.

We can transform gimple to eliminate fields that are never read
and replace the dead fields in stmt by creating a new ssa.
---
 gcc/common.opt                                |   4 +
 gcc/ipa-struct-reorg/ipa-struct-reorg.cc      | 240 +++++++++++++++++-
 gcc/ipa-struct-reorg/ipa-struct-reorg.h       |   8 +
 gcc/opts.cc                                   |  17 ++
 gcc/testsuite/gcc.dg/struct/dfe_DTE_verify.c  |  86 +++++++
 .../gcc.dg/struct/dfe_ele_minus_verify.c      |  60 +++++
 .../gcc.dg/struct/dfe_extr_board_init.c       |  77 ++++++
 gcc/testsuite/gcc.dg/struct/dfe_extr_claw.c   |  84 ++++++
 gcc/testsuite/gcc.dg/struct/dfe_extr_dtrace.c |  56 ++++
 gcc/testsuite/gcc.dg/struct/dfe_extr_gc.c     | 162 ++++++++++++
 gcc/testsuite/gcc.dg/struct/dfe_extr_hpsa.c   | 126 +++++++++
 .../gcc.dg/struct/dfe_extr_mv_udc_core.c      |  82 ++++++
 .../gcc.dg/struct/dfe_extr_tcp_usrreq.c       |  58 +++++
 .../gcc.dg/struct/dfe_extr_ui_main.c          |  61 +++++
 .../gcc.dg/struct/dfe_mem_ref_offset.c        |  58 +++++
 .../struct/dfe_mul_layer_ptr_record_bug.c     |  30 +++
 gcc/testsuite/gcc.dg/struct/dfe_ptr_diff.c    |  71 ++++++
 .../gcc.dg/struct/dfe_ptr_negate_expr.c       |  55 ++++
 gcc/testsuite/gcc.dg/struct/dfe_ptr_ptr.c     |  55 ++++
 gcc/testsuite/gcc.dg/struct/struct-reorg.exp  |   4 +
 .../struct/wo_prof_escape_replace_type.c      |  49 ++++
 21 files changed, 1436 insertions(+), 7 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_DTE_verify.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_ele_minus_verify.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_board_init.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_claw.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_dtrace.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_gc.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_hpsa.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_mv_udc_core.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_tcp_usrreq.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_extr_ui_main.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_mem_ref_offset.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_mul_layer_ptr_record_bug.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_ptr_diff.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_ptr_negate_expr.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/dfe_ptr_ptr.c
 create mode 100644 gcc/testsuite/gcc.dg/struct/wo_prof_escape_replace_type.c

diff --git a/gcc/common.opt b/gcc/common.opt
index 14633c821..8bb735551 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -1988,6 +1988,10 @@ fipa-struct-reorg
 Common Var(flag_ipa_struct_reorg) Init(0) Optimization
 Perform structure layout optimizations.
 
+fipa-struct-reorg=
+Common RejectNegative Joined UInteger Var(struct_layout_optimize_level) Init(0) IntegerRange(0, 3)
+-fipa-struct-reorg=[0,1,2,3] adding none, struct-reorg, reorder-fields, dfe optimizations.
+
 fipa-vrp
 Common Var(flag_ipa_vrp) Optimization
 Perform IPA Value Range Propagation.
diff --git a/gcc/ipa-struct-reorg/ipa-struct-reorg.cc b/gcc/ipa-struct-reorg/ipa-struct-reorg.cc
index 3e5f9538b..eac5fac7e 100644
--- a/gcc/ipa-struct-reorg/ipa-struct-reorg.cc
+++ b/gcc/ipa-struct-reorg/ipa-struct-reorg.cc
@@ -87,6 +87,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-pretty-print.h"
 #include "gimple-pretty-print.h"
 #include "gimple-iterator.h"
+#include "gimple-walk.h"
 #include "cfg.h"
 #include "ssa.h"
 #include "tree-dfa.h"
@@ -268,10 +269,43 @@ enum srmode
   STRUCT_REORDER_FIELDS
 };
 
+/* Enum the struct layout optimize level,
+   which should be the same as the option -fstruct-reorg=.  */
+
+enum struct_layout_opt_level
+{
+  NONE = 0,
+  STRUCT_REORG,
+  STRUCT_REORDER_FIELDS_SLO,
+  DEAD_FIELD_ELIMINATION
+};
+
 static bool is_result_of_mult (tree arg, tree *num, tree struct_size);
 static bool isptrptr (tree type);
+void get_base (tree &base, tree expr);
 
 srmode current_mode;
+hash_map<tree, tree> replace_type_map;
+
+/* Return true if one of these types is created by struct-reorg.  */
+
+static bool
+is_replace_type (tree type1, tree type2)
+{
+  if (replace_type_map.is_empty ())
+    return false;
+  if (type1 == NULL_TREE || type2 == NULL_TREE)
+    return false;
+  tree *type_value = replace_type_map.get (type1);
+  if (type_value)
+    if (types_compatible_p (*type_value, type2))
+      return true;
+  type_value = replace_type_map.get (type2);
+  if (type_value)
+    if (types_compatible_p (*type_value, type1))
+      return true;
+  return false;
+}
 
 } // anon namespace
 
@@ -353,7 +387,8 @@ srfield::srfield (tree field, srtype *base)
     fielddecl (field),
     base (base),
     type (NULL),
-    clusternum (0)
+    clusternum (0),
+    field_access (EMPTY_FIELD)
 {
   for (int i = 0; i < max_split; i++)
     newfield[i] = NULL_TREE;
@@ -392,6 +427,25 @@ srtype::srtype (tree type)
     }
 }
 
+/* Check it if all fields in the RECORD_TYPE are referenced.  */
+
+bool
+srtype::has_dead_field (void)
+{
+  bool may_dfe = false;
+  srfield *this_field;
+  unsigned i;
+  FOR_EACH_VEC_ELT (fields, i, this_field)
+    {
+      if (!(this_field->field_access & READ_FIELD))
+	{
+	  may_dfe = true;
+	  break;
+	}
+    }
+  return may_dfe;
+}
+
 /* Mark the type as escaping type E at statement STMT.  */
 
 void
@@ -595,7 +649,17 @@ srtype::analyze (void)
       into 2 different structures.  In future we intend to add profile
       info and/or static heuristics to differentiate splitting process.  */
   if (fields.length () == 2)
-    fields[1]->clusternum = 1;
+    {
+      /* Currently, when the replacement structure type exists,
+	 we only split the replacement structure. */
+      for (hash_map<tree, tree>::iterator it = replace_type_map.begin ();
+	   it != replace_type_map.end (); ++it)
+	{
+	  if (types_compatible_p ((*it).second, this->type))
+	    return;
+	}
+      fields[1]->clusternum = 1;
+    }
 
   /* Otherwise we do nothing.  */
   if (fields.length () >= 3)
@@ -838,6 +902,10 @@ srtype::create_new_type (void)
   for (unsigned i = 0; i < fields.length (); i++)
     {
       srfield *f = fields[i];
+      if (current_mode == STRUCT_REORDER_FIELDS
+	  && struct_layout_optimize_level >= DEAD_FIELD_ELIMINATION
+	  && !(f->field_access & READ_FIELD))
+	continue;
       f->create_new_fields (newtype, newfields, newlast);
     }
 
@@ -856,6 +924,16 @@ srtype::create_new_type (void)
 
   warn_padded = save_warn_padded;
 
+  if (current_mode == STRUCT_REORDER_FIELDS
+      && replace_type_map.get (this->newtype[0]) == NULL)
+    replace_type_map.put (this->newtype[0], this->type);
+  if (dump_file)
+    {
+      if (current_mode == STRUCT_REORDER_FIELDS
+	  && struct_layout_optimize_level >= DEAD_FIELD_ELIMINATION
+	  && has_dead_field ())
+	fprintf (dump_file, "Dead field elimination.\n");
+    }
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
       fprintf (dump_file, "Created %d types:\n", maxclusters);
@@ -1269,6 +1347,7 @@ public:
   void maybe_mark_or_record_other_side (tree side, tree other, gimple *stmt);
 
   unsigned execute_struct_relayout (void);
+  bool remove_dead_field_stmt (tree lhs);
 };
 
 struct ipa_struct_relayout
@@ -3057,6 +3136,119 @@ ipa_struct_reorg::find_vars (gimple *stmt)
     }
 }
 
+static HOST_WIDE_INT
+get_offset (tree op, HOST_WIDE_INT offset)
+{
+  switch (TREE_CODE (op))
+    {
+      case COMPONENT_REF:
+	{
+	  return int_byte_position (TREE_OPERAND (op, 1));
+	}
+      case MEM_REF:
+	{
+	  return tree_to_uhwi (TREE_OPERAND (op, 1));
+	}
+      default:
+	return offset;
+    }
+  return offset;
+}
+
+/* Record field access.  */
+static void
+record_field_access (tree type, HOST_WIDE_INT offset,
+		     unsigned access, void *data)
+{
+  srtype *this_srtype = ((ipa_struct_reorg *)data)->find_type (type);
+  if (this_srtype == NULL)
+    return;
+  srfield *this_srfield = this_srtype->find_field (offset);
+  if (this_srfield == NULL)
+    return;
+
+  this_srfield->field_access |= access;
+  if (dump_file && (dump_flags & TDF_DETAILS))
+    {
+      fprintf (dump_file, "record field access %d:", access);
+      print_generic_expr (dump_file, type);
+      fprintf (dump_file, "  field:");
+      print_generic_expr (dump_file, this_srfield->fielddecl);
+      fprintf (dump_file, "\n");
+    }
+  return;
+
+}
+
+/* Update field_access in srfield.  */
+
+static void
+update_field_access (tree node, tree op, unsigned access, void *data)
+{
+  HOST_WIDE_INT offset = 0;
+  offset = get_offset (op, offset);
+  tree node_type = inner_type (TREE_TYPE (node));
+  record_field_access (node_type, offset, access, data);
+  tree base = node;
+  get_base (base, node);
+  tree base_type = inner_type (TREE_TYPE (base));
+  if (!types_compatible_p (base_type, node_type))
+    {
+      record_field_access (base_type, get_offset (node, offset),
+			   access, data);
+    }
+  return;
+}
+
+/* A callback for walk_stmt_load_store_ops to visit store.  */
+
+static bool
+find_field_p_store (gimple *stmt ATTRIBUTE_UNUSED,
+		    tree node, tree op, void *data)
+{
+  update_field_access (node, op, WRITE_FIELD, data);
+
+  return false;
+}
+
+/* A callback for walk_stmt_load_store_ops to visit load.  */
+
+static bool
+find_field_p_load (gimple *stmt ATTRIBUTE_UNUSED,
+		   tree node, tree op, void *data)
+{
+  update_field_access (node, op, READ_FIELD, data);
+
+  return false;
+}
+
+/* Determine whether the stmt should be deleted.  */
+
+bool
+ipa_struct_reorg::remove_dead_field_stmt (tree lhs)
+{
+  tree base = NULL_TREE;
+  bool indirect = false;
+  srtype *t = NULL;
+  srfield *f = NULL;
+  bool realpart = false;
+  bool imagpart = false;
+  bool address = false;
+  bool escape_from_base = false;
+  if (!get_type_field (lhs, base, indirect, t, f, realpart, imagpart,
+		       address, escape_from_base))
+    return false;
+  if (t ==NULL)
+    return false;
+  if (t->newtype[0] == t->type)
+    return false;
+  if (f == NULL)
+    return false;
+  if (f->newfield[0] == NULL)
+    return true;
+  return false;
+}
+
 /* Maybe record access of statement for further analaysis.  */
 
 void
@@ -3078,6 +3270,13 @@ ipa_struct_reorg::maybe_record_stmt (cgraph_node *node, gimple *stmt)
     default:
       break;
     }
+  if (current_mode == STRUCT_REORDER_FIELDS
+      && struct_layout_optimize_level >= DEAD_FIELD_ELIMINATION)
+    {
+      /* Look for loads and stores.  */
+      walk_stmt_load_store_ops (stmt, this, find_field_p_load,
+				find_field_p_store);
+    }
 }
 
 /* Calculate the multiplier.  */
@@ -3368,8 +3567,11 @@ ipa_struct_reorg::maybe_mark_or_record_other_side (tree side, tree other,
     }
   else if (type != d->type)
     {
-      type->mark_escape (escape_cast_another_ptr, stmt);
-      d->type->mark_escape (escape_cast_another_ptr, stmt);
+      if (!is_replace_type (d->type->type, type->type))
+	{
+	  type->mark_escape (escape_cast_another_ptr, stmt);
+	  d->type->mark_escape (escape_cast_another_ptr, stmt);
+	}
     }
   /* x_1 = y.x_nodes; void *x;
      Directly mark the structure pointer type assigned
@@ -3949,8 +4151,9 @@ ipa_struct_reorg::check_type_and_push (tree newdecl, srdecl *decl,
 	}
       /* If we have a non void* or a decl (which is hard to track),
 	 then mark the type as escaping.  */
-      if (!VOID_POINTER_P (TREE_TYPE (newdecl))
-	  || DECL_P (newdecl))
+      if (replace_type_map.get (type->type) == NULL
+	  && (!VOID_POINTER_P (TREE_TYPE (newdecl))
+	      || DECL_P (newdecl)))
 	{
 	  if (dump_file && (dump_flags & TDF_DETAILS))
 	    {
@@ -4216,7 +4419,9 @@ ipa_struct_reorg::check_other_side (srdecl *decl, tree other, gimple *stmt,
     }
 
   srtype *t1 = find_type (inner_type (t));
-  if (t1 == type)
+  /* In the other side check, escape mark is added
+     when the replacement struct type exists. */
+  if (t1 == type || is_replace_type (inner_type (t), type->type))
     {
       /* In Complete Struct Relayout, if lhs type is the same
 	 as rhs type, we could return without any harm.  */
@@ -5513,6 +5718,27 @@ bool
 ipa_struct_reorg::rewrite_assign (gassign *stmt, gimple_stmt_iterator *gsi)
 {
   bool remove = false;
+
+  if (current_mode == STRUCT_REORDER_FIELDS
+      && struct_layout_optimize_level >= DEAD_FIELD_ELIMINATION
+      && remove_dead_field_stmt (gimple_assign_lhs (stmt)))
+    {
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "\n rewriting statement (remove): \n");
+	  print_gimple_stmt (dump_file, stmt, 0);
+	}
+      /* Replace the dead field in stmt by creating a dummy ssa.  */
+      tree dummy_ssa = make_ssa_name (TREE_TYPE (gimple_assign_lhs (stmt)));
+      gimple_assign_set_lhs (stmt, dummy_ssa);
+      update_stmt (stmt);
+      if (dump_file && (dump_flags & TDF_DETAILS))
+	{
+	  fprintf (dump_file, "To: \n");
+	  print_gimple_stmt (dump_file, stmt, 0);
+	}
+    }
+
   if (gimple_clobber_p (stmt))
     {
       tree lhs = gimple_assign_lhs (stmt);
diff --git a/gcc/ipa-struct-reorg/ipa-struct-reorg.h b/gcc/ipa-struct-reorg/ipa-struct-reorg.h
index 6f85adeb4..719f7b308 100644
--- a/gcc/ipa-struct-reorg/ipa-struct-reorg.h
+++ b/gcc/ipa-struct-reorg/ipa-struct-reorg.h
@@ -143,6 +143,7 @@ public:
 
   bool create_new_type (void);
   void analyze (void);
+  bool has_dead_field (void);
   void mark_escape (escape_type, gimple *stmt);
   bool has_escaped (void)
   {
@@ -164,6 +165,12 @@ public:
   }
 };
 
+/* Bitflags used for determining if a field
+     is never accessed, read or written.  */
+const unsigned EMPTY_FIELD = 0x0u;
+const unsigned READ_FIELD = 0x01u;
+const unsigned WRITE_FIELD = 0x02u;
+
 struct srfield
 {
   unsigned HOST_WIDE_INT offset;
@@ -175,6 +182,7 @@ struct srfield
   unsigned clusternum;
 
   tree newfield[max_split];
+  unsigned field_access; /* FIELD_DECL -> bitflag (use for dfe).  */
 
   // Constructors
   srfield (tree field, srtype *base);
diff --git a/gcc/opts.cc b/gcc/opts.cc
index c3cc2c169..b868d189e 100644
--- a/gcc/opts.cc
+++ b/gcc/opts.cc
@@ -2957,6 +2957,23 @@ common_handle_option (struct gcc_options *opts,
       SET_OPTION_IF_UNSET (opts, opts_set, flag_profile_correction, value);
       break;
 
+    case OPT_fipa_struct_reorg_:
+      /* No break here - do -fipa-struct-reorg processing.  */
+      /* FALLTHRU.  */
+    case OPT_fipa_struct_reorg:
+      opts->x_flag_ipa_struct_reorg = value;
+      if (value && !opts->x_struct_layout_optimize_level)
+	{
+	  /* Using the -fipa-struct-reorg option is equivalent to using
+	     -fipa-struct-reorg=1.  */
+	  opts->x_struct_layout_optimize_level = 1;
+	}
+      break;
+
+    case OPT_fipa_reorder_fields:
+      SET_OPTION_IF_UNSET (opts, opts_set, flag_ipa_struct_reorg, value);
+      break;
+
     case OPT_fprofile_generate_:
       opts->x_profile_data_prefix = xstrdup (arg);
       value = true;
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_DTE_verify.c b/gcc/testsuite/gcc.dg/struct/dfe_DTE_verify.c
new file mode 100644
index 000000000..0c9e384c4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_DTE_verify.c
@@ -0,0 +1,86 @@
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node node_t;
+typedef struct node *node_p;
+
+typedef struct arc arc_t;
+typedef struct arc *arc_p;
+
+typedef struct network
+{    
+  arc_p arcs;
+  arc_p sorted_arcs;
+  int x;
+  node_p nodes;
+  node_p stop_nodes;
+} network_t;
+
+struct node
+{
+  int64_t potential;
+  int orientation;
+  node_p child;
+  node_p pred;
+  node_p sibling;
+  node_p sibling_prev;
+  arc_p basic_arc;
+  arc_p firstout;
+  arc_p firstin;
+  arc_p arc_tmp;
+  int64_t flow;
+  int64_t depth;
+  int number;
+  int time;
+};
+
+struct arc
+{
+  int id;
+  int64_t cost;
+  node_p tail;
+  node_p head;
+  short ident;
+  arc_p nextout;
+  arc_p nextin;
+  int64_t flow;
+  int64_t org_cost;
+  network_t* net_add;
+};
+
+
+const int MAX = 100;
+
+/* let it escape_array, "Type is used in an array [not handled yet]".  */
+network_t* net[2];
+arc_p stop_arcs = NULL;
+
+int
+main ()
+{
+  net[0] = (network_t*) calloc (1, sizeof(network_t));
+  net[0]->arcs = (arc_p) calloc (MAX, sizeof (arc_t));
+  stop_arcs = (arc_p) calloc (MAX, sizeof (arc_t));
+
+  net[0]->arcs->id = 100;
+
+  for (unsigned i = 0; i < 3; i++)
+    {        
+      net[0]->arcs->id = net[0]->arcs->id + 2;
+      stop_arcs->cost = net[0]->arcs->id / 2;
+      stop_arcs->net_add = net[0];
+      printf("stop_arcs->cost = %ld\n", stop_arcs->cost);
+      net[0]->arcs++;
+      stop_arcs++;
+    }
+
+  if( net[1] != 0 && stop_arcs != 0)
+    {
+      return -1;
+    }
+  return 0;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 2 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_ele_minus_verify.c b/gcc/testsuite/gcc.dg/struct/dfe_ele_minus_verify.c
new file mode 100644
index 000000000..717fcc386
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_ele_minus_verify.c
@@ -0,0 +1,60 @@
+// verify newarc[cmp-1].flow
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node node_t;
+typedef struct node *node_p;
+
+typedef struct arc arc_t;
+typedef struct arc *arc_p;
+
+struct node
+{
+  int64_t potential;
+  int orientation;
+  node_p child;
+  node_p pred;
+  node_p sibling;
+  node_p sibling_prev;
+  arc_p basic_arc;
+  arc_p firstout;
+  arc_p firstin;
+  arc_p arc_tmp;
+  int64_t flow;
+  int64_t depth;
+  int number;
+  int time;
+};
+
+struct arc
+{
+  int id;
+  int64_t cost;
+  node_p tail;
+  node_p head;
+  short ident;
+  arc_p nextout;
+  arc_p nextin;
+  int64_t flow;
+  int64_t org_cost;
+};
+
+const int MAX = 100;
+arc_p ap = NULL;
+
+int
+main ()
+{
+  ap = (arc_p) calloc(MAX, sizeof(arc_t));
+  printf("%d\n", ap[0].id);
+  for (int i = 1; i < MAX; i++)
+    {
+      ap[i-1].id = 500;
+    }
+  printf("%d\n", ap[0].id);
+  return 0; 
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 2 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_board_init.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_board_init.c
new file mode 100644
index 000000000..7723c240b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_board_init.c
@@ -0,0 +1,77 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+typedef struct TYPE_5__ TYPE_2__;
+typedef struct TYPE_4__ TYPE_1__;
+
+struct TYPE_4__
+{
+  int Pin;
+  int Pull;
+  int Mode;
+  int Speed;
+};
+
+struct TYPE_5__
+{
+  int MEMRMP;
+};
+typedef TYPE_1__ GPIO_InitTypeDef;
+
+int BT_RST_PIN;
+int BT_RST_PORT;
+int CONN_POS10_PIN;
+int CONN_POS10_PORT;
+int GPIO_HIGH (int, int);
+int GPIO_MODE_INPUT;
+int GPIO_MODE_OUTPUT_PP;
+int GPIO_NOPULL;
+int GPIO_PULLUP;
+int GPIO_SPEED_FREQ_LOW;
+int HAL_GPIO_Init (int, TYPE_1__ *);
+scalar_t__ IS_GPIO_RESET (int, int);
+TYPE_2__ *SYSCFG;
+int __HAL_RCC_GPIOB_CLK_ENABLE ();
+int __HAL_RCC_GPIOC_CLK_ENABLE ();
+
+__attribute__((used)) static void 
+LBF_DFU_If_Needed (void)
+{
+  GPIO_InitTypeDef GPIO_InitStruct;
+  __HAL_RCC_GPIOC_CLK_ENABLE ();
+  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
+  GPIO_InitStruct.Pull = GPIO_NOPULL;
+  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
+  GPIO_InitStruct.Pin = BT_RST_PIN;
+  HAL_GPIO_Init (BT_RST_PORT, &GPIO_InitStruct);
+
+  GPIO_HIGH (BT_RST_PORT, BT_RST_PIN);
+  __HAL_RCC_GPIOB_CLK_ENABLE ();
+  GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
+  GPIO_InitStruct.Pull = GPIO_PULLUP;
+  GPIO_InitStruct.Pin = CONN_POS10_PIN;
+  HAL_GPIO_Init (CONN_POS10_PORT, &GPIO_InitStruct);
+
+  if (IS_GPIO_RESET (CONN_POS10_PORT, CONN_POS10_PIN))
+    {
+      SYSCFG->MEMRMP = 0x00000001;
+      asm (
+	"LDR     R0, =0x000000\n\t"
+	"LDR     SP, [R0, #0]\n\t"
+	  );
+      asm (
+	"LDR     R0, [R0, #0]\n\t"
+	"BX       R0\n\t"
+	  );
+    }
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 0 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_claw.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_claw.c
new file mode 100644
index 000000000..a1feac966
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_claw.c
@@ -0,0 +1,84 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+typedef struct TYPE_2__ TYPE_1__;
+
+struct net_device
+{
+  struct claw_privbk* ml_priv;
+};
+struct clawctl
+{
+  int linkid;
+};
+struct claw_privbk
+{
+  int system_validate_comp;
+  TYPE_1__* p_env;
+  int ctl_bk;
+};
+typedef int __u8;
+struct TYPE_2__
+{
+  scalar_t__ packing;
+  int api_type;
+};
+
+int CLAW_DBF_TEXT (int, int, char*);
+int CONNECTION_REQUEST;
+int HOST_APPL_NAME;
+scalar_t__ PACKING_ASK;
+scalar_t__ PACK_SEND;
+int WS_APPL_NAME_IP_NAME;
+int WS_APPL_NAME_PACKED;
+int claw_send_control (struct net_device*, int, int, int, int, int, int);
+int setup;
+
+__attribute__((noinline)) int
+claw_send_control (struct net_device* net, int a, int b, int c, int d, int e, 
+		   int f)
+{
+  return net->ml_priv->system_validate_comp + a + b + c + d + f;
+}
+
+__attribute__((used)) static int
+claw_snd_conn_req (struct net_device *dev, __u8 link)
+{
+  int rc;
+  struct claw_privbk *privptr = dev->ml_priv;
+  struct clawctl *p_ctl;
+  CLAW_DBF_TEXT (2, setup, "snd_conn");
+  rc = 1;
+  p_ctl = (struct clawctl *)&privptr->ctl_bk;
+  p_ctl->linkid = link;
+  if (privptr->system_validate_comp == 0x00)
+    {
+      return rc;
+    }
+  if (privptr->p_env->packing == PACKING_ASK)
+    {
+      rc = claw_send_control (dev, CONNECTION_REQUEST, 0, 0, 0,
+			WS_APPL_NAME_PACKED, WS_APPL_NAME_PACKED);
+    }
+  if (privptr->p_env->packing == PACK_SEND)
+    {
+      rc = claw_send_control (dev, CONNECTION_REQUEST, 0, 0, 0,
+			WS_APPL_NAME_IP_NAME, WS_APPL_NAME_IP_NAME);
+    }
+  if (privptr->p_env->packing == 0)
+    {
+      rc = claw_send_control (dev, CONNECTION_REQUEST, 0, 0, 0,
+			HOST_APPL_NAME, privptr->p_env->api_type);
+    }
+  return rc;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 1 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_dtrace.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_dtrace.c
new file mode 100644
index 000000000..fd1e936ca
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_dtrace.c
@@ -0,0 +1,56 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+typedef struct TYPE_4__ TYPE_2__;
+typedef struct TYPE_3__ TYPE_1__;
+
+typedef int uint8_t;
+typedef int uint16_t;
+
+struct TYPE_4__
+{
+  size_t cpu_id;
+};
+
+struct TYPE_3__
+{
+  int cpuc_dtrace_flags;
+};
+
+TYPE_2__ *CPU;
+volatile int CPU_DTRACE_FAULT;
+TYPE_1__ *cpu_core;
+scalar_t__ dtrace_load8 (uintptr_t);
+
+__attribute__((used)) static int
+dtrace_bcmp (const void *s1, const void *s2, size_t len)
+{
+  volatile uint16_t *flags;
+  flags = (volatile uint16_t *)&cpu_core[CPU->cpu_id].cpuc_dtrace_flags;
+  if (s1 == s2)
+    return (0);
+  if (s1 == NULL || s2 == NULL)
+    return (1);
+  if (s1 != s2 && len != 0)
+    {
+      const uint8_t *ps1 = s1;
+      const uint8_t *ps2 = s2;
+      do
+	{
+	  if (dtrace_load8 ((uintptr_t)ps1++) != *ps2++)
+	    return (1);
+	}
+      while (--len != 0 && !(*flags & CPU_DTRACE_FAULT));
+    }
+  return (0);
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 0 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_gc.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_gc.c
new file mode 100644
index 000000000..b13d785a9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_gc.c
@@ -0,0 +1,162 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+struct mrb_context
+{
+  size_t stack;
+  size_t stbase;
+  size_t stend;
+  size_t eidx;
+  int *ci;
+  int *cibase;
+  int status;
+};
+
+struct RObject
+{
+  int dummy;
+};
+
+struct RHash
+{
+  int dummy;
+};
+
+struct RFiber
+{
+  struct mrb_context *cxt;
+};
+
+struct RClass
+{
+  int dummy;
+};
+
+struct RBasic
+{
+  int tt;
+};
+
+struct RArray
+{
+  int dummy;
+};
+
+typedef int mrb_state;
+typedef int mrb_gc;
+typedef int mrb_callinfo;
+size_t ARY_LEN (struct RArray *);
+size_t MRB_ENV_STACK_LEN (struct RBasic *);
+int MRB_FIBER_TERMINATED;
+
+#define MRB_TT_ARRAY 140
+#define MRB_TT_CLASS 139
+#define MRB_TT_DATA 138
+#define MRB_TT_ENV 137
+#define MRB_TT_EXCEPTION 136
+#define MRB_TT_FIBER 135
+#define MRB_TT_HASH 134
+#define MRB_TT_ICLASS 133
+#define MRB_TT_MODULE 132
+#define MRB_TT_OBJECT 131
+#define MRB_TT_PROC 130
+#define MRB_TT_RANGE 129
+#define MRB_TT_SCLASS 128
+
+size_t ci_nregs (int *);
+int gc_mark_children (int *, int *, struct RBasic *);
+size_t mrb_gc_mark_hash_size (int *, struct RHash *);
+size_t mrb_gc_mark_iv_size (int *, struct RObject *);
+size_t mrb_gc_mark_mt_size (int *, struct RClass *);
+
+__attribute__((used)) static size_t
+gc_gray_mark (mrb_state *mrb, mrb_gc *gc, struct RBasic *obj)
+{
+  size_t children = 0;
+  gc_mark_children (mrb, gc, obj);
+  switch (obj->tt)
+    {
+      case MRB_TT_ICLASS:
+	children++;
+	break;
+
+      case MRB_TT_CLASS:
+      case MRB_TT_SCLASS:
+      case MRB_TT_MODULE:
+	{
+	  struct RClass *c = (struct RClass *)obj;
+	  children += mrb_gc_mark_iv_size (mrb, (struct RObject *)obj);
+	  children += mrb_gc_mark_mt_size (mrb, c);
+	  children ++;
+	}
+	break;
+
+      case MRB_TT_OBJECT:
+      case MRB_TT_DATA:
+      case MRB_TT_EXCEPTION:
+	children += mrb_gc_mark_iv_size (mrb, (struct RObject *)obj);
+	break;
+
+      case MRB_TT_ENV:
+	children += MRB_ENV_STACK_LEN (obj);
+	break;
+
+      case MRB_TT_FIBER:
+	{
+	  struct mrb_context *c = ((struct RFiber *)obj)->cxt;
+	  size_t i;
+	  mrb_callinfo *ci;
+	  if (!c || c->status == MRB_FIBER_TERMINATED)
+	    break;
+
+	  i = c->stack - c->stbase;
+	  if (c->ci)
+	    {
+	      i += ci_nregs (c->ci);
+	    }
+	  if (c->stbase + i > c->stend)
+	    i = c->stend - c->stbase;
+
+	  children += i;
+	  children += c->eidx;
+	  if (c->cibase)
+	    {
+	      for (i = 0, ci = c->cibase; ci <= c->ci; i++, ci++)
+		;
+	    }
+	  children += i;
+	}
+	break;
+
+      case MRB_TT_ARRAY:
+	{
+	  struct RArray *a = (struct RArray *)obj;
+	  children += ARY_LEN (a);
+	}
+	break;
+
+      case MRB_TT_HASH:
+	children += mrb_gc_mark_iv_size (mrb, (struct RObject *)obj);
+	children += mrb_gc_mark_hash_size (mrb, (struct RHash *)obj);
+	break;
+
+      case MRB_TT_PROC:
+      case MRB_TT_RANGE:
+	children += 2;
+	break;
+      default:
+	break;
+    }
+
+  return children;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 0 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_hpsa.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_hpsa.c
new file mode 100644
index 000000000..bc28a658a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_hpsa.c
@@ -0,0 +1,126 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+typedef struct TYPE_6__ TYPE_3__;
+typedef struct TYPE_5__ TYPE_2__;
+typedef struct TYPE_4__ TYPE_1__;
+
+struct io_accel2_cmd
+{
+  int dummy;
+};
+
+struct hpsa_tmf_struct
+{
+  int it_nexus;
+};
+
+struct hpsa_scsi_dev_t
+{
+  int nphysical_disks;
+  int ioaccel_handle;
+  struct hpsa_scsi_dev_t **phys_disk;
+};
+
+struct ctlr_info
+{
+  TYPE_3__ *pdev;
+  struct io_accel2_cmd *ioaccel2_cmd_pool;
+};
+struct TYPE_4__
+{
+  int LunAddrBytes;
+};
+
+struct TYPE_5__
+{
+  TYPE_1__ LUN;
+};
+
+struct CommandList
+{
+  size_t cmdindex;
+  int cmd_type;
+  struct hpsa_scsi_dev_t *phys_disk;
+  TYPE_2__ Header;
+};
+
+struct TYPE_6__
+{
+  int dev;
+};
+
+int BUG ();
+#define CMD_IOACCEL1 132
+#define CMD_IOACCEL2 131
+#define CMD_IOCTL_PEND 130
+#define CMD_SCSI 129
+#define IOACCEL2_TMF 128
+int dev_err (int *, char *, int);
+scalar_t__ hpsa_is_cmd_idle (struct CommandList *);
+int le32_to_cpu (int);
+int test_memcmp (unsigned char *, int *, int);
+
+__attribute__((used)) static bool
+hpsa_cmd_dev_match (struct ctlr_info *h, struct CommandList *c,
+		    struct hpsa_scsi_dev_t *dev, unsigned char *scsi3addr)
+{
+  int i;
+  bool match = false;
+  struct io_accel2_cmd * c2 = &h->ioaccel2_cmd_pool[c->cmdindex];
+  struct hpsa_tmf_struct *ac = (struct hpsa_tmf_struct *)c2;
+
+  if (hpsa_is_cmd_idle (c))
+    return false;
+
+  switch (c->cmd_type)
+    {
+      case CMD_SCSI:
+      case CMD_IOCTL_PEND:
+	match = !test_memcmp (scsi3addr, &c->Header.LUN.LunAddrBytes,
+			      sizeof (c->Header.LUN.LunAddrBytes));
+	break;
+
+      case CMD_IOACCEL1:
+      case CMD_IOACCEL2:
+	if (c->phys_disk == dev)
+	  {
+	    match = true;
+	  }
+	else
+	  {
+	    for (i = 0; i < dev->nphysical_disks && !match; i++)
+	      {
+		match = dev->phys_disk[i] == c->phys_disk;
+	      }
+	  }
+	break;
+
+      case IOACCEL2_TMF:
+	for (i = 0; i < dev->nphysical_disks && !match; i++)
+	  {
+	    match = dev->phys_disk[i]->ioaccel_handle == 
+		    le32_to_cpu (ac->it_nexus);
+	  }
+	break;
+
+      case 0:
+	match = false;
+	break;
+      default:
+	dev_err (&h->pdev->dev, "unexpected cmd_type: %d\n", c->cmd_type);
+	BUG ();
+    }
+
+  return match;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 0 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_mv_udc_core.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_mv_udc_core.c
new file mode 100644
index 000000000..0a585ac3d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_mv_udc_core.c
@@ -0,0 +1,82 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+typedef struct TYPE_4__ TYPE_2__;
+typedef struct TYPE_3__ TYPE_1__;
+typedef int u32;
+
+struct mv_udc
+{
+  TYPE_2__ *op_regs;
+  TYPE_1__ *ep_dqh;
+  struct mv_ep *eps;
+};
+
+struct mv_ep
+{
+  TYPE_1__ *dqh;
+  struct mv_udc *udc;
+};
+
+struct TYPE_4__
+{
+  int *epctrlx;
+};
+
+struct TYPE_3__
+{
+  int max_packet_length;
+  int next_dtd_ptr;
+};
+
+int EP0_MAX_PKT_SIZE;
+int EPCTRL_RX_ENABLE;
+int EPCTRL_RX_EP_TYPE_SHIFT;
+int EPCTRL_TX_ENABLE;
+int EPCTRL_TX_EP_TYPE_SHIFT;
+int EP_QUEUE_HEAD_IOS;
+int EP_QUEUE_HEAD_MAX_PKT_LEN_POS;
+int EP_QUEUE_HEAD_NEXT_TERMINATE;
+int USB_ENDPOINT_XFER_CONTROL;
+int readl (int *);
+int writel (int, int *);
+
+__attribute__((used)) static void
+ep0_reset (struct mv_udc *udc)
+{
+  struct mv_ep *ep;
+  u32 epctrlx;
+  int i = 0;
+  for (i = 0; i < 2; i++)
+    {
+      ep = &udc->eps[i];
+      ep->udc = udc;
+      ep->dqh = &udc->ep_dqh[i];
+      ep->dqh->max_packet_length =
+	(EP0_MAX_PKT_SIZE << EP_QUEUE_HEAD_MAX_PKT_LEN_POS)
+	| EP_QUEUE_HEAD_IOS;
+      ep->dqh->next_dtd_ptr = EP_QUEUE_HEAD_NEXT_TERMINATE;
+      epctrlx = readl (&udc->op_regs->epctrlx[0]);
+      if (i)
+	{
+	  epctrlx |= EPCTRL_TX_ENABLE
+		  | (USB_ENDPOINT_XFER_CONTROL << EPCTRL_TX_EP_TYPE_SHIFT);
+	}
+      else
+	{
+	  epctrlx |= EPCTRL_RX_ENABLE
+		  | (USB_ENDPOINT_XFER_CONTROL << EPCTRL_RX_EP_TYPE_SHIFT);
+	}
+      writel (epctrlx, &udc->op_regs->epctrlx[0]);
+    }
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 2 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_tcp_usrreq.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_tcp_usrreq.c
new file mode 100644
index 000000000..bddd862fe
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_tcp_usrreq.c
@@ -0,0 +1,58 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+struct tcpcb
+{
+  int t_state;
+};
+
+struct socket
+{
+  int dummy;
+};
+
+struct proc
+{
+  int dummy;
+};
+
+struct inpcb
+{
+  scalar_t__ inp_lport;
+};
+
+int COMMON_END (int);
+int COMMON_START ();
+int PRU_LISTEN;
+int TCPS_LISTEN;
+int in_pcbbind (struct inpcb *, int *, struct proc *);
+struct inpcb* sotoinpcb (struct socket *);
+
+__attribute__((used)) static void
+tcp_usr_listen (struct socket *so, struct proc *p)
+{
+  int error = 0;
+  struct inpcb *inp = sotoinpcb (so);
+  struct tcpcb *tp;
+
+  COMMON_START ();
+  if (inp->inp_lport == 0)
+  {
+    error = in_pcbbind (inp, NULL, p);
+  }
+  if (error == 0)
+  {
+    tp->t_state = TCPS_LISTEN;
+  }
+  COMMON_END (PRU_LISTEN);
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 1 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_extr_ui_main.c b/gcc/testsuite/gcc.dg/struct/dfe_extr_ui_main.c
new file mode 100644
index 000000000..1a06f5eec
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_extr_ui_main.c
@@ -0,0 +1,61 @@
+/* { dg-do compile} */
+
+#define NULL ((void*)0)
+typedef unsigned long size_t;
+typedef long intptr_t;
+typedef unsigned long uintptr_t;
+typedef long scalar_t__;
+typedef int bool;
+#define false 0
+#define true 1
+
+typedef struct TYPE_4__ TYPE_2__;
+typedef struct TYPE_3__ TYPE_1__;
+
+struct TYPE_4__
+{
+  size_t modCount;
+  TYPE_1__ *modList;
+};
+
+struct TYPE_3__
+{
+  void *modDescr;
+  void *modName;
+};
+
+size_t MAX_MODS;
+void *String_Alloc (char *);
+int test_strlen (char *);
+int trap_FD_GetFileList (char *, char *, char *, int);
+TYPE_2__ uiInfo;
+
+__attribute__((used)) static void
+UI_LoadMods ()
+{
+  int numdirs;
+  char dirlist[2048];
+  char *dirptr;
+  char *descptr;
+  int i;
+  int dirlen;
+
+  uiInfo.modCount = 0;
+  numdirs = trap_FD_GetFileList ("$modelist", "", dirlist, sizeof (dirlist));
+  dirptr = dirlist;
+  for (i = 0; i < numdirs; i++)
+    {
+      dirlen = test_strlen (dirptr) + 1;
+      descptr = dirptr + dirlen;
+      uiInfo.modList[uiInfo.modCount].modName = String_Alloc (dirptr);
+      uiInfo.modList[uiInfo.modCount].modDescr = String_Alloc (descptr);
+      dirptr += dirlen + test_strlen (descptr) + 1;
+      uiInfo.modCount++;
+      if (uiInfo.modCount >= MAX_MODS)
+        {
+	  break;
+        }
+    }
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 1 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_mem_ref_offset.c b/gcc/testsuite/gcc.dg/struct/dfe_mem_ref_offset.c
new file mode 100644
index 000000000..94eb88d5c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_mem_ref_offset.c
@@ -0,0 +1,58 @@
+/* Supports the MEM_REF offset.
+   _1 = MEM[(struct arc *)ap_4 + 72B].flow;
+   Old rewrite：_1 = ap.reorder.0_8->flow;
+   New rewrite：_1 = MEM[(struct arc.reorder.0 *)ap.reorder.0_8 + 64B].flow.  */
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node node_t;
+typedef struct node *node_p;
+
+typedef struct arc arc_t;
+typedef struct arc *arc_p;
+
+struct node
+{
+  int64_t potential;
+  int orientation;
+  node_p child;
+  node_p pred;
+  node_p sibling;
+  node_p sibling_prev;
+  arc_p basic_arc;
+  arc_p firstout;
+  arc_p firstin;
+  arc_p arc_tmp;
+  int64_t flow;
+  int64_t depth;
+  int number;
+  int time;
+};
+
+struct arc
+{
+  int id;
+  int64_t cost;
+  node_p tail;
+  node_p head;
+  short ident;
+  arc_p nextout;
+  arc_p nextin;
+  int64_t flow;
+  int64_t org_cost;
+};
+
+int
+main ()
+{
+  const int MAX = 100;
+  /* A similar scenario can be reproduced only by using local variables.  */
+  arc_p ap = NULL;
+  ap = (arc_p) calloc(MAX, sizeof(arc_t));
+  printf("%d\n", ap[1].flow);
+  return 0; 
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 2 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_mul_layer_ptr_record_bug.c b/gcc/testsuite/gcc.dg/struct/dfe_mul_layer_ptr_record_bug.c
new file mode 100644
index 000000000..bbf9420d0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_mul_layer_ptr_record_bug.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct T_HASH_ENTRY
+{ 
+  unsigned int hash;
+  unsigned int klen;
+  char *key;
+} iHashEntry;
+
+typedef struct T_HASH
+{
+  unsigned int size;
+  unsigned int fill;
+  unsigned int keys;
+
+  iHashEntry **array;
+} uHash;
+
+uHash *retval;
+
+int
+main() {
+  retval->array = (iHashEntry **)calloc(sizeof(iHashEntry *), retval->size);
+  return 0;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 2 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_ptr_diff.c b/gcc/testsuite/gcc.dg/struct/dfe_ptr_diff.c
new file mode 100644
index 000000000..f706db968
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_ptr_diff.c
@@ -0,0 +1,71 @@
+// support POINTER_DIFF_EXPR & NOP_EXPR to avoid 
+// escape_unhandled_rewrite, "Type escapes via a unhandled rewrite stmt"
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node node_t;
+typedef struct node *node_p;
+
+typedef struct arc arc_t;
+typedef struct arc *arc_p;
+
+typedef struct network
+{    
+  arc_p arcs;
+  arc_p sorted_arcs;
+  int x;
+  node_p nodes;
+  node_p stop_nodes;
+} network_t;
+
+struct node
+{
+  int64_t potential;
+  int orientation;
+  node_p child;
+  node_p pred;
+  node_p sibling;
+  node_p sibling_prev;
+  arc_p basic_arc;
+  arc_p firstout;
+  arc_p firstin;
+  arc_p arc_tmp;
+  int64_t flow;
+  int64_t depth;
+  int number;
+  int time;
+};
+
+struct arc
+{
+  int id;
+  int64_t cost;
+  node_p tail;
+  node_p head;
+  short ident;
+  arc_p nextout;
+  arc_p nextin;
+  int64_t flow;
+  int64_t org_cost;
+};
+
+int
+main ()
+{
+  arc_t *old_arcs;
+  node_t *node;
+  node_t *stop;
+  size_t off;
+  network_t* net;
+
+  for( ; node->number < stop->number; node++ )
+    {
+      off = node->basic_arc - old_arcs;
+      node->basic_arc = (arc_t *)(net->arcs + off);
+    }
+  return 0;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 3 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_ptr_negate_expr.c b/gcc/testsuite/gcc.dg/struct/dfe_ptr_negate_expr.c
new file mode 100644
index 000000000..963295cb4
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_ptr_negate_expr.c
@@ -0,0 +1,55 @@
+// support NEGATE_EXPR rewriting
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node node_t;
+typedef struct node *node_p;
+
+typedef struct arc arc_t;
+typedef struct arc *arc_p;
+
+struct node
+{
+  int64_t potential;
+  int orientation;
+  node_p child;
+  node_p pred;
+  node_p sibling;
+  node_p sibling_prev;
+  arc_p basic_arc;
+  arc_p firstout;
+  arc_p firstin;
+  arc_p arc_tmp;
+  int64_t flow;
+  int64_t depth;
+  int number;
+  int time;
+};
+
+struct arc
+{
+  int id;
+  int64_t cost;
+  node_p tail;
+  node_p head;
+  short ident;
+  arc_p nextout;
+  arc_p nextin;
+  int64_t flow;
+  int64_t org_cost;
+};
+
+int
+main ()
+{
+  int64_t susp = 0;
+  const int MAX = 100;
+  arc_p ap = (arc_p) calloc(MAX, sizeof(arc_t));
+  ap -= susp;
+  printf("%d\n", ap[1].flow);
+  return 0; 
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 2 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/dfe_ptr_ptr.c b/gcc/testsuite/gcc.dg/struct/dfe_ptr_ptr.c
new file mode 100644
index 000000000..aa10506a1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/dfe_ptr_ptr.c
@@ -0,0 +1,55 @@
+// release escape_ptr_ptr, "Type is used in a pointer to a pointer [not handled yet]";
+/* { dg-do compile } */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct node node_t;
+typedef struct node *node_p;
+
+typedef struct arc arc_t;
+typedef struct arc *arc_p;
+
+struct node
+{
+  int64_t potential;
+  int orientation;
+  node_p child;
+  node_p pred;
+  node_p sibling;
+  node_p sibling_prev;
+  arc_p basic_arc;
+  arc_p firstout;
+  arc_p firstin;
+  arc_p arc_tmp;
+  int64_t flow;
+  int64_t depth;
+  int number;
+  int time;
+};
+
+struct arc
+{
+  int id;
+  int64_t cost;
+  node_p tail;
+  node_p head;
+  short ident;
+  arc_p nextout;
+  arc_p nextin;
+  int64_t flow;
+  int64_t org_cost;
+};
+
+const int MAX = 100;
+arc_t **ap = NULL;
+
+int
+main ()
+{
+  ap = (arc_t**) malloc(MAX * sizeof(arc_t*));
+  (*ap)[0].id = 300;
+  return 0;
+}
+
+/* { dg-final { scan-ipa-dump-times "Dead field elimination" 2 "reorder_fields" } } */
diff --git a/gcc/testsuite/gcc.dg/struct/struct-reorg.exp b/gcc/testsuite/gcc.dg/struct/struct-reorg.exp
index 5a476e8f9..6ccb753b5 100644
--- a/gcc/testsuite/gcc.dg/struct/struct-reorg.exp
+++ b/gcc/testsuite/gcc.dg/struct/struct-reorg.exp
@@ -43,6 +43,10 @@ gcc-dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/csr_*.c]] \
 gcc-dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/rf_*.c]] \
 	"" "-fipa-reorder-fields -fdump-ipa-all -flto-partition=one -fwhole-program"
 
+# -fipa-struct-reorg=3
+gcc-dg-runtest [lsort [glob -nocomplain $srcdir/$subdir/dfe*.c]] \
+	"" "-fipa-reorder-fields -fipa-struct-reorg=3 -fdump-ipa-all -flto-partition=one -fwhole-program"
+
 # All done.
 torture-finish
 dg-finish
diff --git a/gcc/testsuite/gcc.dg/struct/wo_prof_escape_replace_type.c b/gcc/testsuite/gcc.dg/struct/wo_prof_escape_replace_type.c
new file mode 100644
index 000000000..fa8c66b9e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/struct/wo_prof_escape_replace_type.c
@@ -0,0 +1,49 @@
+/* { dg-do compile } */
+
+#include <stdlib.h>
+
+struct AngleDef
+{
+  double K;
+  double th0;
+};
+typedef struct AngleDef angldef;
+
+struct bndangdihe
+{
+  int nbond;
+  int nangl;
+  int ndihe;
+};
+typedef struct bndangdihe bah;
+
+struct ambprmtop
+{
+  double *AnglK;
+  double *AnglEq;
+  bah nBAH;
+  angldef *AParam;
+  char source[512];
+  char eprulesource[512];
+};
+typedef struct ambprmtop prmtop;
+
+static void OrderBondParameters (prmtop *tp)
+{
+  int i;
+  tp->AParam = (angldef *)malloc (tp->nBAH.nangl * sizeof (angldef));
+  for (i = 0; i < tp->nBAH.nangl; i++)
+    {
+      tp->AParam[i].K = tp->AnglK[i];
+      tp->AParam[i].th0 = tp->AnglEq[i];
+    }
+}
+
+void main ()
+{
+  prmtop *tp = (prmtop *)malloc (100 * sizeof (prmtop));
+  OrderBondParameters (tp);
+}
+
+/*---------------------------------------------------------------------------------------------*/
+/* { dg-final { scan-ipa-dump "No structures to transform" "struct_reorg" } } */
-- 
2.33.0