diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
index 8bdc8a6b038..58e4e50b315 100644
--- a/gcc/fortran/invoke.texi
+++ b/gcc/fortran/invoke.texi
@@ -1227,6 +1227,17 @@ compiler itself. The output generated by this option might change
 between releases.  This option may also generate internal compiler
 errors for features which have only recently been added.
 
+@item -fdebug-aux-vars
+@opindex @code{debug-aux-vars}
+Make internal variables generated by the gfortran front end visible to a
+debugger.  This option also renames these internal variables shown by
+@code{-fdump-tree-original} to a form @code{string:number} and enables
+compiler warnings on them.
+
+This option is only really useful when debugging the gfortran compiler
+itself together with @code{-g} or @code{-ggdb3} and
+@code{-fdump-tree-original}.
+
 @item -ffpe-trap=@var{list}
 @opindex @code{ffpe-trap=}@var{list}
 Specify a list of floating point exception traps to enable.  On most
diff --git a/gcc/fortran/lang.opt b/gcc/fortran/lang.opt
index 96ed208cb85..57b0264458e 100644
--- a/gcc/fortran/lang.opt
+++ b/gcc/fortran/lang.opt
@@ -452,6 +452,10 @@ fd-lines-as-comments
 Fortran RejectNegative
 Treat lines with 'D' in column one as comments.
 
+fdebug-aux-vars
+Fortran Var(flag_debug_aux_vars)
+Issue debug information for compiler-generated auxiliary variables.
+
 fdec
 Fortran Var(flag_dec)
 Enable all DEC language extensions.
diff --git a/gcc/fortran/trans.c b/gcc/fortran/trans.c
index 025abe38985..1d5f6c28c7a 100644
--- a/gcc/fortran/trans.c
+++ b/gcc/fortran/trans.c
@@ -73,6 +73,40 @@ gfc_advance_chain (tree t, int n)
   return t;
 }
 
+static int num_var;
+
+#define MAX_PREFIX_LEN 20
+
+static tree
+create_var_debug_raw (tree type, const char *prefix)
+{
+  /* Space for prefix + @ + 9-digit-number + \0.  */
+  char name_buf[MAX_PREFIX_LEN + 1 + 9 + 1];
+  tree t;
+
+  if (prefix == NULL)
+    prefix = "gfc";
+  else
+    gcc_assert (strlen(prefix) <= MAX_PREFIX_LEN);
+
+  snprintf (name_buf, sizeof(name_buf), "%s:%d", prefix, num_var++);
+  t = build_decl (input_location, VAR_DECL, get_identifier (name_buf), type);
+
+  /* We want debug info for it.  */
+  DECL_IGNORED_P (t) = 0;
+  /* It should not be nameless.  */
+  DECL_NAMELESS (t) = 0;
+
+  /* Make the variable writable.  */
+  TREE_READONLY (t) = 0;
+
+  DECL_EXTERNAL (t) = 0;
+  TREE_STATIC (t) = 0;
+  TREE_USED (t) = 1;
+
+  return t;
+}
+
 /* Creates a variable declaration with a given TYPE.  */
 
 tree
@@ -80,6 +114,9 @@ gfc_create_var_np (tree type, const char *prefix)
 {
   tree t;
 
+  if (flag_debug_aux_vars)
+    return create_var_debug_raw (type, prefix);
+
   t = create_tmp_var_raw (type, prefix);
 
   /* No warnings for anonymous variables.  */