RE: [PATCH 3/3]middle-end RFC - match.pd: automatically partition *-match.cc files.

[Tamar Christina <Tamar.Christina@arm.com>]

[-- Attachment #1: Type: text/plain, Size: 15971 bytes --]

> > [1] https://gcc.gnu.org/legacy-ml/gcc-patches/2018-04/msg01125.html
> >
> > Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.
> >
> > Ok for master?
> 
> Some comments - I have to leave the Makefile bits to somebody else to see
> whether they are portable as-is.
> 
> The private functions now in gimple-match-exports.cc are not supposed to be
> public API, so the additions to gimple-match.h should be avoided - can
> you add the declarations to gimple-match-head.cc instead?  At least I don't
> see how the refactoring needs to add anything to gimple-match.h?
> 
> -decision_tree::gen (FILE *f, bool gimple)
> +decision_tree::gen (FILE **files, int n_parts, bool gimple)
> 
> can you use a vec<> please to avoid passing n_parts separately?
> 
> +  /* Set a default value for the tool to 5, but GCC itself uses
> +     whatever default is determined by the configure variable
> +     DEFAULT_MATCHPD_PARTITIONS.  */
> +  int n_parts = 5;
> +  char *input = argv[argc-2];
> ...
>           fprintf (stderr, "Usage: genmatch "
> -                  "[--gimple] [--generic] [-v[v]] input\n");
> +                  "[--gimple] [--generic] [--splits=<n>] [-v[v]]
> input outdir\n");
> 
> I don't like this - I'm using ./build/genmatch --gimple test.pd | less to debug
> genmatch changes with a small test input and like to preserve that.  Can
> you instead change the usage to
> 
>   genmatch --gimple match.pd gimple-match-1.c gimple-match-2.c
> gimple-match-3.c ...
> 
> thus
> 
> -                  "[--gimple] [--generic] [-v[v]] input\n");
> +                  "[--gimple] [--generic] [-v[v]] input [output...]\n");
> 
> and when no output is specified continue to use stdout?  Possibly when
> more than one output is given require a --header outfile argument to
> specify the header file to use (and for one output make emit_func
> not ICE but instead not emit to the header, aka header_file == NULL?).
> Ideally without makefile changes that would produce the same
> gimple-match.cc as before (minus the -head.cc changes of course).
> 
> The gimple-match-head.cc/exports changes could be split out as
> far as I can see?  Likewise the Makefile changes if the argument
> control is changed as I sugggest?
>

All changes done.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	PR bootstrap/84402
	* genmatch.cc (emit_func, SIZED_BASED_CHUNKS, get_out_file): New.
	(decision_tree::gen): Accept list of files instead of single and update
	to write function definition to header and main file.
	(write_predicate): Likewise.
	(write_header): Emit pragmas and new includes.
	(main): Create file buffers and cleanup.
	(showUsage): New.

--- inline copy of patch ---

diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc
index 716fb97aac4c3c2baae82e068df3ce158b9afee9..f56b4bc992d87cb7d707e59be2d61c44a45b68e6 100644
--- a/gcc/genmatch.cc
+++ b/gcc/genmatch.cc
@@ -183,6 +183,33 @@ fprintf_indent (FILE *f, unsigned int indent, const char *format, ...)
   va_end (ap);
 }
 
+/* Like fprintf, but print to two files, one header one C implementation.  */
+FILE *header_file = NULL;
+
+static void
+#if GCC_VERSION >= 4001
+__attribute__((format (printf, 4, 5)))
+#endif
+emit_func (FILE *f, bool open, bool close, const char *format, ...)
+{
+  va_list ap1, ap2;
+  if (header_file != stdout)
+    {
+      if (open)
+	fprintf (header_file, "extern ");
+      va_start (ap2, format);
+      vfprintf (header_file, format, ap2);
+      va_end (ap2);
+      if (close)
+	fprintf (header_file, ";\n");
+    }
+
+  va_start (ap1, format);
+  vfprintf (f, format, ap1);
+  va_end (ap1);
+  fputc ('\n', f);
+}
+
 static void
 output_line_directive (FILE *f, location_t location,
 		       bool dumpfile = false, bool fnargs = false)
@@ -217,6 +244,34 @@ output_line_directive (FILE *f, location_t location,
     fprintf (f, "/* #line %d \"%s\" */\n", loc.line, loc.file);
 }
 
+/* Find the file to write into next.  We try to evenly distribute the contents
+   over the different files.  */
+
+#define SIZED_BASED_CHUNKS 1
+
+int current_file = 0;
+FILE *get_out_file (vec <FILE *> &parts)
+{
+#ifdef SIZED_BASED_CHUNKS
+   FILE *f = NULL;
+   long min = 0;
+   /* We've started writing all the files at pos 0, so ftell is equivalent
+      to the size and should be much faster.  */
+   for (unsigned i = 0; i < parts.length (); i++)
+     {
+	long res = ftell (parts[i]);
+	if (!f || res < min)
+	  {
+	    min = res;
+	    f = parts[i];
+	  }
+     }
+  return f;
+#else
+  return parts[current_file++ % parts.length ()];
+#endif
+}
+
 
 /* Pull in tree codes and builtin function codes from their
    definition files.  */
@@ -1732,7 +1787,7 @@ public:
   dt_node *root;
 
   void insert (class simplify *, unsigned);
-  void gen (FILE *f, bool gimple);
+  void gen (vec <FILE *> &f, bool gimple);
   void print (FILE *f = stderr);
 
   decision_tree () { root = new dt_node (dt_node::DT_NODE, NULL); }
@@ -3830,7 +3885,7 @@ sinfo_hashmap_traits::equal_keys (const key_type &v,
    tree.  */
 
 void
-decision_tree::gen (FILE *f, bool gimple)
+decision_tree::gen (vec <FILE *> &files, bool gimple)
 {
   sinfo_map_t si;
 
@@ -3859,11 +3914,14 @@ decision_tree::gen (FILE *f, bool gimple)
 	  output_line_directive (stderr, s->s->s->result->location);
 	}
 
+      /* Cycle the file buffers.  */
+      FILE *f = get_out_file (files);
+
       /* Generate a split out function with the leaf transform code.  */
       s->fname = xasprintf ("%s_simplify_%u", gimple ? "gimple" : "generic",
 			    fcnt++);
       if (gimple)
-	fprintf (f, "\nstatic bool\n"
+	emit_func (f, true, false, "\nbool\n"
 		 "%s (gimple_match_op *res_op, gimple_seq *seq,\n"
 		 "                 tree (*valueize)(tree) ATTRIBUTE_UNUSED,\n"
 		 "                 const tree ARG_UNUSED (type), tree *ARG_UNUSED "
@@ -3871,27 +3929,28 @@ decision_tree::gen (FILE *f, bool gimple)
 		 s->fname);
       else
 	{
-	  fprintf (f, "\nstatic tree\n"
+	  emit_func (f, true, false, "\ntree\n"
 		   "%s (location_t ARG_UNUSED (loc), const tree ARG_UNUSED (type),\n",
 		   (*iter).second->fname);
 	  for (unsigned i = 0;
 	       i < as_a <expr *>(s->s->s->match)->ops.length (); ++i)
-	    fprintf (f, " tree ARG_UNUSED (_p%d),", i);
-	  fprintf (f, " tree *captures\n");
+	    emit_func (f, false, false, " tree ARG_UNUSED (_p%d),", i);
+	  emit_func (f, false, false, " tree *captures\n");
 	}
       for (unsigned i = 0; i < s->s->s->for_subst_vec.length (); ++i)
 	{
 	  if (! s->s->s->for_subst_vec[i].first->used)
 	    continue;
 	  if (is_a <operator_id *> (s->s->s->for_subst_vec[i].second))
-	    fprintf (f, ", const enum tree_code ARG_UNUSED (%s)",
+	    emit_func (f, false, false, ", const enum tree_code ARG_UNUSED (%s)",
 		     s->s->s->for_subst_vec[i].first->id);
 	  else if (is_a <fn_id *> (s->s->s->for_subst_vec[i].second))
-	    fprintf (f, ", const combined_fn ARG_UNUSED (%s)",
+	    emit_func (f, false, false, ", const combined_fn ARG_UNUSED (%s)",
 		     s->s->s->for_subst_vec[i].first->id);
 	}
 
-      fprintf (f, ")\n{\n");
+      emit_func (f, false, true, ")");
+      fprintf (f, "{\n");
       fprintf_indent (f, 2, "const bool debug_dump = "
 			    "dump_file && (dump_flags & TDF_FOLDING);\n");
       s->s->gen_1 (f, 2, gimple, s->s->s->result);
@@ -3921,8 +3980,12 @@ decision_tree::gen (FILE *f, bool gimple)
 		  && e->operation->kind != id_base::CODE))
 	    continue;
 
+
+	  /* Cycle the file buffers.  */
+	  FILE *f = get_out_file (files);
+
 	  if (gimple)
-	    fprintf (f, "\nstatic bool\n"
+	    emit_func (f, true, false,"\nbool\n"
 		     "gimple_simplify_%s (gimple_match_op *res_op,"
 		     " gimple_seq *seq,\n"
 		     "                 tree (*valueize)(tree) "
@@ -3931,13 +3994,13 @@ decision_tree::gen (FILE *f, bool gimple)
 		     "ARG_UNUSED (type)\n",
 		     e->operation->id);
 	  else
-	    fprintf (f, "\nstatic tree\n"
+	    emit_func (f, true, false, "\ntree\n"
 		     "generic_simplify_%s (location_t ARG_UNUSED (loc), enum "
 		     "tree_code ARG_UNUSED (code), const tree ARG_UNUSED (type)",
 		     e->operation->id);
 	  for (unsigned i = 0; i < n; ++i)
-	    fprintf (f, ", tree _p%d", i);
-	  fprintf (f, ")\n");
+	    emit_func (f, false, false,", tree _p%d", i);
+	  emit_func (f, false, true, ")");
 	  fprintf (f, "{\n");
 	  fprintf_indent (f, 2, "const bool debug_dump = "
 				"dump_file && (dump_flags & TDF_FOLDING);\n");
@@ -3954,18 +4017,22 @@ decision_tree::gen (FILE *f, bool gimple)
 	 with compiler warnings, by generating a simple stub.  */
       if (! has_kids_p)
 	{
+
+	  /* Cycle the file buffers.  */
+	  FILE *f = get_out_file (files);
+
 	  if (gimple)
-	    fprintf (f, "\nbool\n"
+	    emit_func (f, true, false, "\nbool\n"
 			"gimple_simplify (gimple_match_op*, gimple_seq*,\n"
 			"                 tree (*)(tree), code_helper,\n"
 			"                 const tree");
 	  else
-	    fprintf (f, "\ntree\n"
+	    emit_func (f, true, false,"\ntree\n"
 			"generic_simplify (location_t, enum tree_code,\n"
 			"                  const tree");
 	  for (unsigned i = 0; i < n; ++i)
-	    fprintf (f, ", tree");
-	  fprintf (f, ")\n");
+	    emit_func (f, false, false, ", tree");
+	  emit_func (f, false, true, ")");
 	  fprintf (f, "{\n");
 	  if (gimple)
 	    fprintf (f, "  return false;\n");
@@ -3975,20 +4042,24 @@ decision_tree::gen (FILE *f, bool gimple)
 	  continue;
 	}
 
+
+      /* Cycle the file buffers.  */
+      FILE *f = get_out_file (files);
+
       /* Then generate the main entry with the outermost switch and
          tail-calls to the split-out functions.  */
       if (gimple)
-	fprintf (f, "\nbool\n"
+	emit_func (f, true, false, "\nbool\n"
 		 "gimple_simplify (gimple_match_op *res_op, gimple_seq *seq,\n"
 		 "                 tree (*valueize)(tree) ATTRIBUTE_UNUSED,\n"
 		 "                 code_helper code, const tree type");
       else
-	fprintf (f, "\ntree\n"
+	emit_func (f, true, false, "\ntree\n"
 		 "generic_simplify (location_t loc, enum tree_code code, "
 		 "const tree type ATTRIBUTE_UNUSED");
       for (unsigned i = 0; i < n; ++i)
-	fprintf (f, ", tree _p%d", i);
-      fprintf (f, ")\n");
+	emit_func (f, false, false, ", tree _p%d", i);
+      emit_func (f, false, true, ")");
       fprintf (f, "{\n");
 
       if (gimple)
@@ -4043,11 +4114,11 @@ decision_tree::gen (FILE *f, bool gimple)
 void
 write_predicate (FILE *f, predicate_id *p, decision_tree &dt, bool gimple)
 {
-  fprintf (f, "\nbool\n"
-	   "%s%s (tree t%s%s)\n"
-	   "{\n", gimple ? "gimple_" : "tree_", p->id,
-	   p->nargs > 0 ? ", tree *res_ops" : "",
-	   gimple ? ", tree (*valueize)(tree) ATTRIBUTE_UNUSED" : "");
+  emit_func (f, true, true, "\nbool\n%s%s (tree t%s%s)",
+		gimple ? "gimple_" : "tree_", p->id,
+		p->nargs > 0 ? ", tree *res_ops" : "",
+		gimple ? ", tree (*valueize)(tree) ATTRIBUTE_UNUSED" : "");
+  fprintf (f, "{\n");
   /* Conveniently make 'type' available.  */
   fprintf_indent (f, 2, "const tree type = TREE_TYPE (t);\n");
   fprintf_indent (f, 2, "const bool debug_dump = "
@@ -4068,9 +4139,13 @@ write_header (FILE *f, const char *head)
 {
   fprintf (f, "/* Generated automatically by the program `genmatch' from\n");
   fprintf (f, "   a IL pattern matching and simplification description.  */\n");
+  fprintf (f, "#pragma GCC diagnostic push\n");
+  fprintf (f, "#pragma GCC diagnostic ignored \"-Wunused-variable\"\n");
+  fprintf (f, "#pragma GCC diagnostic ignored \"-Wunused-function\"\n");
 
   /* Include the header instead of writing it awkwardly quoted here.  */
-  fprintf (f, "\n#include \"%s\"\n", head);
+  if (head)
+    fprintf (f, "\n#include \"%s\"\n", head);
 }
 
 
@@ -5213,6 +5288,16 @@ round_alloc_size (size_t s)
 }
 
 
+static void
+showUsage ()
+{
+  fprintf (stderr, "Usage: genmatch [--gimple] [--generic] "
+		   "[--header=<filename>] [--include=<filename>] [-v[v]] input "
+		   "[<outputfile>...]\n");
+  fprintf (stderr, "\nWhen more then one outputfile is specified --header "
+		   "is required.\n");
+}
+
 /* The genmatch generator program.  It reads from a pattern description
    and outputs GIMPLE or GENERIC IL matching and simplification routines.  */
 
@@ -5228,25 +5313,44 @@ main (int argc, char **argv)
 
   bool gimple = true;
   verbose = 0;
-  char *input = argv[argc-1];
-  for (int i = 1; i < argc - 1; ++i)
+  char *s_header_file = NULL;
+  char *s_include_file = NULL;
+  auto_vec <char *> files;
+  char *input = NULL;
+  int last_file = argc - 1;
+  for (int i = argc - 1; i >= 1; --i)
     {
       if (strcmp (argv[i], "--gimple") == 0)
 	gimple = true;
       else if (strcmp (argv[i], "--generic") == 0)
 	gimple = false;
+      else if (strncmp (argv[i], "--header=", 9) == 0)
+	s_header_file = &argv[i][9];
+      else if (strncmp (argv[i], "--include=", 10) == 0)
+	s_include_file = &argv[i][10];
       else if (strcmp (argv[i], "-v") == 0)
 	verbose = 1;
       else if (strcmp (argv[i], "-vv") == 0)
 	verbose = 2;
+      else if (strncmp (argv[i], "--", 2) != 0 && last_file-- == i)
+	files.safe_push (argv[i]);
       else
 	{
-	  fprintf (stderr, "Usage: genmatch "
-		   "[--gimple] [--generic] [-v[v]] input\n");
+	  showUsage ();
 	  return 1;
 	}
     }
 
+  /* Validate if the combinations are valid.  */
+  if ((files.length () > 1 && !s_header_file) || files.is_empty ())
+    showUsage ();
+
+  if (!s_include_file)
+    s_include_file = s_header_file;
+
+  /* Input file is the last in the reverse list.  */
+  input = files.pop ();
+
   line_table = XCNEW (class line_maps);
   linemap_init (line_table, 0);
   line_table->reallocator = xrealloc;
@@ -5293,10 +5397,32 @@ main (int argc, char **argv)
   /* Parse ahead!  */
   parser p (r, gimple);
 
+  /* Create file buffers.  */
+  int n_parts = files.is_empty () ? 1 : files.length ();
+  auto_vec <FILE *> parts (n_parts);
+  if (files.is_empty ())
+    {
+      parts.quick_push (stdout);
+      header_file = stdout;
+      write_header (stdout, s_include_file);
+    }
+  else
+    {
+      for (char *s_file : files)
+	{
+	  parts.quick_push (fopen (s_file, "w"));
+	  write_header (parts.last (), s_include_file);
+	}
+
+      header_file = fopen (s_header_file, "w");
+      fprintf (header_file, "#ifndef GCC_GIMPLE_MATCH_AUTO_H\n"
+			    "#define GCC_GIMPLE_MATCH_AUTO_H\n");
+    }
+
   if (gimple)
-    write_header (stdout, "gimple-match-head.cc");
+    fprintf (header_file, "#include \"gimple-match-head.cc\"\n");
   else
-    write_header (stdout, "generic-match-head.cc");
+    fprintf (header_file, "#include \"generic-match-head.cc\"\n");
 
   /* Go over all predicates defined with patterns and perform
      lowering and code generation.  */
@@ -5316,7 +5442,10 @@ main (int argc, char **argv)
       if (verbose == 2)
 	dt.print (stderr);
 
-      write_predicate (stdout, pred, dt, gimple);
+      /* Cycle the file buffers.  */
+      FILE *f = get_out_file (parts);
+
+      write_predicate (f, pred, dt, gimple);
     }
 
   /* Lower the main simplifiers and generate code for them.  */
@@ -5333,7 +5462,19 @@ main (int argc, char **argv)
   if (verbose == 2)
     dt.print (stderr);
 
-  dt.gen (stdout, gimple);
+  dt.gen (parts, gimple);
+
+  for (FILE *f : parts)
+    {
+      fprintf (f, "#pragma GCC diagnostic pop\n");
+      fclose (f);
+    }
+
+  if (!files.is_empty ())
+    {
+      fprintf (header_file, "#endif /* GCC_GIMPLE_MATCH_AUTO_H.  */\n");
+      fclose (header_file);
+    }
 
   /* Finalize.  */
   cpp_finish (r, NULL);

[-- Attachment #2: rb17159.patch --]
[-- Type: application/octet-stream, Size: 12757 bytes --]

diff --git a/gcc/genmatch.cc b/gcc/genmatch.cc
index 716fb97aac4c3c2baae82e068df3ce158b9afee9..f56b4bc992d87cb7d707e59be2d61c44a45b68e6 100644
--- a/gcc/genmatch.cc
+++ b/gcc/genmatch.cc
@@ -183,6 +183,33 @@ fprintf_indent (FILE *f, unsigned int indent, const char *format, ...)
   va_end (ap);
 }
 
+/* Like fprintf, but print to two files, one header one C implementation.  */
+FILE *header_file = NULL;
+
+static void
+#if GCC_VERSION >= 4001
+__attribute__((format (printf, 4, 5)))
+#endif
+emit_func (FILE *f, bool open, bool close, const char *format, ...)
+{
+  va_list ap1, ap2;
+  if (header_file != stdout)
+    {
+      if (open)
+	fprintf (header_file, "extern ");
+      va_start (ap2, format);
+      vfprintf (header_file, format, ap2);
+      va_end (ap2);
+      if (close)
+	fprintf (header_file, ";\n");
+    }
+
+  va_start (ap1, format);
+  vfprintf (f, format, ap1);
+  va_end (ap1);
+  fputc ('\n', f);
+}
+
 static void
 output_line_directive (FILE *f, location_t location,
 		       bool dumpfile = false, bool fnargs = false)
@@ -217,6 +244,34 @@ output_line_directive (FILE *f, location_t location,
     fprintf (f, "/* #line %d \"%s\" */\n", loc.line, loc.file);
 }
 
+/* Find the file to write into next.  We try to evenly distribute the contents
+   over the different files.  */
+
+#define SIZED_BASED_CHUNKS 1
+
+int current_file = 0;
+FILE *get_out_file (vec <FILE *> &parts)
+{
+#ifdef SIZED_BASED_CHUNKS
+   FILE *f = NULL;
+   long min = 0;
+   /* We've started writing all the files at pos 0, so ftell is equivalent
+      to the size and should be much faster.  */
+   for (unsigned i = 0; i < parts.length (); i++)
+     {
+	long res = ftell (parts[i]);
+	if (!f || res < min)
+	  {
+	    min = res;
+	    f = parts[i];
+	  }
+     }
+  return f;
+#else
+  return parts[current_file++ % parts.length ()];
+#endif
+}
+
 
 /* Pull in tree codes and builtin function codes from their
    definition files.  */
@@ -1732,7 +1787,7 @@ public:
   dt_node *root;
 
   void insert (class simplify *, unsigned);
-  void gen (FILE *f, bool gimple);
+  void gen (vec <FILE *> &f, bool gimple);
   void print (FILE *f = stderr);
 
   decision_tree () { root = new dt_node (dt_node::DT_NODE, NULL); }
@@ -3830,7 +3885,7 @@ sinfo_hashmap_traits::equal_keys (const key_type &v,
    tree.  */
 
 void
-decision_tree::gen (FILE *f, bool gimple)
+decision_tree::gen (vec <FILE *> &files, bool gimple)
 {
   sinfo_map_t si;
 
@@ -3859,11 +3914,14 @@ decision_tree::gen (FILE *f, bool gimple)
 	  output_line_directive (stderr, s->s->s->result->location);
 	}
 
+      /* Cycle the file buffers.  */
+      FILE *f = get_out_file (files);
+
       /* Generate a split out function with the leaf transform code.  */
       s->fname = xasprintf ("%s_simplify_%u", gimple ? "gimple" : "generic",
 			    fcnt++);
       if (gimple)
-	fprintf (f, "\nstatic bool\n"
+	emit_func (f, true, false, "\nbool\n"
 		 "%s (gimple_match_op *res_op, gimple_seq *seq,\n"
 		 "                 tree (*valueize)(tree) ATTRIBUTE_UNUSED,\n"
 		 "                 const tree ARG_UNUSED (type), tree *ARG_UNUSED "
@@ -3871,27 +3929,28 @@ decision_tree::gen (FILE *f, bool gimple)
 		 s->fname);
       else
 	{
-	  fprintf (f, "\nstatic tree\n"
+	  emit_func (f, true, false, "\ntree\n"
 		   "%s (location_t ARG_UNUSED (loc), const tree ARG_UNUSED (type),\n",
 		   (*iter).second->fname);
 	  for (unsigned i = 0;
 	       i < as_a <expr *>(s->s->s->match)->ops.length (); ++i)
-	    fprintf (f, " tree ARG_UNUSED (_p%d),", i);
-	  fprintf (f, " tree *captures\n");
+	    emit_func (f, false, false, " tree ARG_UNUSED (_p%d),", i);
+	  emit_func (f, false, false, " tree *captures\n");
 	}
       for (unsigned i = 0; i < s->s->s->for_subst_vec.length (); ++i)
 	{
 	  if (! s->s->s->for_subst_vec[i].first->used)
 	    continue;
 	  if (is_a <operator_id *> (s->s->s->for_subst_vec[i].second))
-	    fprintf (f, ", const enum tree_code ARG_UNUSED (%s)",
+	    emit_func (f, false, false, ", const enum tree_code ARG_UNUSED (%s)",
 		     s->s->s->for_subst_vec[i].first->id);
 	  else if (is_a <fn_id *> (s->s->s->for_subst_vec[i].second))
-	    fprintf (f, ", const combined_fn ARG_UNUSED (%s)",
+	    emit_func (f, false, false, ", const combined_fn ARG_UNUSED (%s)",
 		     s->s->s->for_subst_vec[i].first->id);
 	}
 
-      fprintf (f, ")\n{\n");
+      emit_func (f, false, true, ")");
+      fprintf (f, "{\n");
       fprintf_indent (f, 2, "const bool debug_dump = "
 			    "dump_file && (dump_flags & TDF_FOLDING);\n");
       s->s->gen_1 (f, 2, gimple, s->s->s->result);
@@ -3921,8 +3980,12 @@ decision_tree::gen (FILE *f, bool gimple)
 		  && e->operation->kind != id_base::CODE))
 	    continue;
 
+
+	  /* Cycle the file buffers.  */
+	  FILE *f = get_out_file (files);
+
 	  if (gimple)
-	    fprintf (f, "\nstatic bool\n"
+	    emit_func (f, true, false,"\nbool\n"
 		     "gimple_simplify_%s (gimple_match_op *res_op,"
 		     " gimple_seq *seq,\n"
 		     "                 tree (*valueize)(tree) "
@@ -3931,13 +3994,13 @@ decision_tree::gen (FILE *f, bool gimple)
 		     "ARG_UNUSED (type)\n",
 		     e->operation->id);
 	  else
-	    fprintf (f, "\nstatic tree\n"
+	    emit_func (f, true, false, "\ntree\n"
 		     "generic_simplify_%s (location_t ARG_UNUSED (loc), enum "
 		     "tree_code ARG_UNUSED (code), const tree ARG_UNUSED (type)",
 		     e->operation->id);
 	  for (unsigned i = 0; i < n; ++i)
-	    fprintf (f, ", tree _p%d", i);
-	  fprintf (f, ")\n");
+	    emit_func (f, false, false,", tree _p%d", i);
+	  emit_func (f, false, true, ")");
 	  fprintf (f, "{\n");
 	  fprintf_indent (f, 2, "const bool debug_dump = "
 				"dump_file && (dump_flags & TDF_FOLDING);\n");
@@ -3954,18 +4017,22 @@ decision_tree::gen (FILE *f, bool gimple)
 	 with compiler warnings, by generating a simple stub.  */
       if (! has_kids_p)
 	{
+
+	  /* Cycle the file buffers.  */
+	  FILE *f = get_out_file (files);
+
 	  if (gimple)
-	    fprintf (f, "\nbool\n"
+	    emit_func (f, true, false, "\nbool\n"
 			"gimple_simplify (gimple_match_op*, gimple_seq*,\n"
 			"                 tree (*)(tree), code_helper,\n"
 			"                 const tree");
 	  else
-	    fprintf (f, "\ntree\n"
+	    emit_func (f, true, false,"\ntree\n"
 			"generic_simplify (location_t, enum tree_code,\n"
 			"                  const tree");
 	  for (unsigned i = 0; i < n; ++i)
-	    fprintf (f, ", tree");
-	  fprintf (f, ")\n");
+	    emit_func (f, false, false, ", tree");
+	  emit_func (f, false, true, ")");
 	  fprintf (f, "{\n");
 	  if (gimple)
 	    fprintf (f, "  return false;\n");
@@ -3975,20 +4042,24 @@ decision_tree::gen (FILE *f, bool gimple)
 	  continue;
 	}
 
+
+      /* Cycle the file buffers.  */
+      FILE *f = get_out_file (files);
+
       /* Then generate the main entry with the outermost switch and
          tail-calls to the split-out functions.  */
       if (gimple)
-	fprintf (f, "\nbool\n"
+	emit_func (f, true, false, "\nbool\n"
 		 "gimple_simplify (gimple_match_op *res_op, gimple_seq *seq,\n"
 		 "                 tree (*valueize)(tree) ATTRIBUTE_UNUSED,\n"
 		 "                 code_helper code, const tree type");
       else
-	fprintf (f, "\ntree\n"
+	emit_func (f, true, false, "\ntree\n"
 		 "generic_simplify (location_t loc, enum tree_code code, "
 		 "const tree type ATTRIBUTE_UNUSED");
       for (unsigned i = 0; i < n; ++i)
-	fprintf (f, ", tree _p%d", i);
-      fprintf (f, ")\n");
+	emit_func (f, false, false, ", tree _p%d", i);
+      emit_func (f, false, true, ")");
       fprintf (f, "{\n");
 
       if (gimple)
@@ -4043,11 +4114,11 @@ decision_tree::gen (FILE *f, bool gimple)
 void
 write_predicate (FILE *f, predicate_id *p, decision_tree &dt, bool gimple)
 {
-  fprintf (f, "\nbool\n"
-	   "%s%s (tree t%s%s)\n"
-	   "{\n", gimple ? "gimple_" : "tree_", p->id,
-	   p->nargs > 0 ? ", tree *res_ops" : "",
-	   gimple ? ", tree (*valueize)(tree) ATTRIBUTE_UNUSED" : "");
+  emit_func (f, true, true, "\nbool\n%s%s (tree t%s%s)",
+		gimple ? "gimple_" : "tree_", p->id,
+		p->nargs > 0 ? ", tree *res_ops" : "",
+		gimple ? ", tree (*valueize)(tree) ATTRIBUTE_UNUSED" : "");
+  fprintf (f, "{\n");
   /* Conveniently make 'type' available.  */
   fprintf_indent (f, 2, "const tree type = TREE_TYPE (t);\n");
   fprintf_indent (f, 2, "const bool debug_dump = "
@@ -4068,9 +4139,13 @@ write_header (FILE *f, const char *head)
 {
   fprintf (f, "/* Generated automatically by the program `genmatch' from\n");
   fprintf (f, "   a IL pattern matching and simplification description.  */\n");
+  fprintf (f, "#pragma GCC diagnostic push\n");
+  fprintf (f, "#pragma GCC diagnostic ignored \"-Wunused-variable\"\n");
+  fprintf (f, "#pragma GCC diagnostic ignored \"-Wunused-function\"\n");
 
   /* Include the header instead of writing it awkwardly quoted here.  */
-  fprintf (f, "\n#include \"%s\"\n", head);
+  if (head)
+    fprintf (f, "\n#include \"%s\"\n", head);
 }
 
 
@@ -5213,6 +5288,16 @@ round_alloc_size (size_t s)
 }
 
 
+static void
+showUsage ()
+{
+  fprintf (stderr, "Usage: genmatch [--gimple] [--generic] "
+		   "[--header=<filename>] [--include=<filename>] [-v[v]] input "
+		   "[<outputfile>...]\n");
+  fprintf (stderr, "\nWhen more then one outputfile is specified --header "
+		   "is required.\n");
+}
+
 /* The genmatch generator program.  It reads from a pattern description
    and outputs GIMPLE or GENERIC IL matching and simplification routines.  */
 
@@ -5228,25 +5313,44 @@ main (int argc, char **argv)
 
   bool gimple = true;
   verbose = 0;
-  char *input = argv[argc-1];
-  for (int i = 1; i < argc - 1; ++i)
+  char *s_header_file = NULL;
+  char *s_include_file = NULL;
+  auto_vec <char *> files;
+  char *input = NULL;
+  int last_file = argc - 1;
+  for (int i = argc - 1; i >= 1; --i)
     {
       if (strcmp (argv[i], "--gimple") == 0)
 	gimple = true;
       else if (strcmp (argv[i], "--generic") == 0)
 	gimple = false;
+      else if (strncmp (argv[i], "--header=", 9) == 0)
+	s_header_file = &argv[i][9];
+      else if (strncmp (argv[i], "--include=", 10) == 0)
+	s_include_file = &argv[i][10];
       else if (strcmp (argv[i], "-v") == 0)
 	verbose = 1;
       else if (strcmp (argv[i], "-vv") == 0)
 	verbose = 2;
+      else if (strncmp (argv[i], "--", 2) != 0 && last_file-- == i)
+	files.safe_push (argv[i]);
       else
 	{
-	  fprintf (stderr, "Usage: genmatch "
-		   "[--gimple] [--generic] [-v[v]] input\n");
+	  showUsage ();
 	  return 1;
 	}
     }
 
+  /* Validate if the combinations are valid.  */
+  if ((files.length () > 1 && !s_header_file) || files.is_empty ())
+    showUsage ();
+
+  if (!s_include_file)
+    s_include_file = s_header_file;
+
+  /* Input file is the last in the reverse list.  */
+  input = files.pop ();
+
   line_table = XCNEW (class line_maps);
   linemap_init (line_table, 0);
   line_table->reallocator = xrealloc;
@@ -5293,10 +5397,32 @@ main (int argc, char **argv)
   /* Parse ahead!  */
   parser p (r, gimple);
 
+  /* Create file buffers.  */
+  int n_parts = files.is_empty () ? 1 : files.length ();
+  auto_vec <FILE *> parts (n_parts);
+  if (files.is_empty ())
+    {
+      parts.quick_push (stdout);
+      header_file = stdout;
+      write_header (stdout, s_include_file);
+    }
+  else
+    {
+      for (char *s_file : files)
+	{
+	  parts.quick_push (fopen (s_file, "w"));
+	  write_header (parts.last (), s_include_file);
+	}
+
+      header_file = fopen (s_header_file, "w");
+      fprintf (header_file, "#ifndef GCC_GIMPLE_MATCH_AUTO_H\n"
+			    "#define GCC_GIMPLE_MATCH_AUTO_H\n");
+    }
+
   if (gimple)
-    write_header (stdout, "gimple-match-head.cc");
+    fprintf (header_file, "#include \"gimple-match-head.cc\"\n");
   else
-    write_header (stdout, "generic-match-head.cc");
+    fprintf (header_file, "#include \"generic-match-head.cc\"\n");
 
   /* Go over all predicates defined with patterns and perform
      lowering and code generation.  */
@@ -5316,7 +5442,10 @@ main (int argc, char **argv)
       if (verbose == 2)
 	dt.print (stderr);
 
-      write_predicate (stdout, pred, dt, gimple);
+      /* Cycle the file buffers.  */
+      FILE *f = get_out_file (parts);
+
+      write_predicate (f, pred, dt, gimple);
     }
 
   /* Lower the main simplifiers and generate code for them.  */
@@ -5333,7 +5462,19 @@ main (int argc, char **argv)
   if (verbose == 2)
     dt.print (stderr);
 
-  dt.gen (stdout, gimple);
+  dt.gen (parts, gimple);
+
+  for (FILE *f : parts)
+    {
+      fprintf (f, "#pragma GCC diagnostic pop\n");
+      fclose (f);
+    }
+
+  if (!files.is_empty ())
+    {
+      fprintf (header_file, "#endif /* GCC_GIMPLE_MATCH_AUTO_H.  */\n");
+      fclose (header_file);
+    }
 
   /* Finalize.  */
   cpp_finish (r, NULL);