diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index c7b8648..44e46e6 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -3620,6 +3620,10 @@ insn-preds.c: s-preds; @true
 tm-preds.h: s-preds-h; @true
 tm-constrs.h: s-constrs-h; @true
 
+.PHONY: mddump
+mddump: $(BUILD_RTL) $(MD_DEPS) build/genmddump$(build_exeext)
+	$(RUN_GEN) build/genmddump$(build_exeext) $(md_file) > tmp-mddump.md
+
 s-preds: $(MD_DEPS) build/genpreds$(build_exeext)
 	$(RUN_GEN) build/genpreds$(build_exeext) $(md_file) > tmp-preds.c
 	$(SHELL) $(srcdir)/../move-if-change tmp-preds.c insn-preds.c
@@ -3937,6 +3941,8 @@ build/genrecog.o : genrecog.c $(RTL_BASE_H) $(BCONFIG_H) $(SYSTEM_H)	\
   coretypes.h $(GTM_H) errors.h $(READ_MD_H) gensupport.h
 build/genhooks.o : genhooks.c $(TARGET_DEF) $(C_TARGET_DEF)		\
   $(COMMON_TARGET_DEF) $(BCONFIG_H) $(SYSTEM_H) errors.h
+build/genmddump.o : genmddump.c $(RTL_BASE_H) $(BCONFIG_H) $(SYSTEM_H)	\
+  coretypes.h $(GTM_H) errors.h $(READ_MD_H) gensupport.h
 
 # Compile the programs that generate insn-* from the machine description.
 # They are compiled with $(COMPILER_FOR_BUILD), and associated libraries,
@@ -3945,7 +3951,7 @@ build/genhooks.o : genhooks.c $(TARGET_DEF) $(C_TARGET_DEF)		\
 
 # All these programs use the RTL reader ($(BUILD_RTL)).
 genprogrtl = attr attr-common attrtab automata codes conditions config emit \
-	     extract flags opinit output peep preds recog
+	     extract flags opinit output peep preds recog mddump
 $(genprogrtl:%=build/gen%$(build_exeext)): $(BUILD_RTL)
 
 # All these programs use the MD reader ($(BUILD_MD)).
diff --git a/gcc/genmddump.c b/gcc/genmddump.c
new file mode 100644
index 0000000..76a1550
--- /dev/null
+++ b/gcc/genmddump.c
@@ -0,0 +1,67 @@
+/* Generate code from machine description to recognize rtl as insns.
+   Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1997, 1998,
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010,
+   2012 Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   GCC is distributed in the hope that it will be useful, but WITHOUT
+   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+   License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+
+/* This program is used to produce tmp-mddump.md, which represents
+   md-file with expanded iterators and after define_subst transformation
+   is performed.
+
+   The only argument of the program is a source md-file (e.g.
+   config/i386/i386.md).  STDERR is used for the program output.  */
+
+#include "bconfig.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "rtl.h"
+#include "errors.h"
+#include "read-md.h"
+#include "gensupport.h"
+
+
+extern int main (int, char **);
+
+int
+main (int argc, char **argv)
+{
+  rtx desc;
+  int pattern_lineno;
+  int code; /* not used */
+  progname = "genmddump";
+
+  if (!init_rtx_reader_args (argc, argv))
+    return (FATAL_EXIT_CODE);
+
+  /* Read the machine description.  */
+  while (1)
+    {
+      desc = read_md_rtx (&pattern_lineno, &code);
+      if (desc == NULL)
+	break;
+      printf (";; %s: %d\n", read_md_filename, pattern_lineno);
+      print_inline_rtx (stdout, desc, 0);
+      printf ("\n\n");
+    }
+
+  fflush (stdout);
+  return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
+}
+