diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index 89e05a4..60b5802 100644
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -1112,9 +1112,10 @@ c_common_post_options (const char **pfilename)
 	  /* Only -g0 and -gdwarf* are supported with PCH, for other
 	     debug formats we warn here and refuse to load any PCH files.  */
 	  if (write_symbols != NO_DEBUG && write_symbols != DWARF2_DEBUG)
-	    warning (OPT_Wdeprecated,
-		     "the %qs debug format cannot be used with "
-		     "pre-compiled headers", debug_type_names[write_symbols]);
+	      warning (OPT_Wdeprecated,
+		       "the %qs debug info cannot be used with "
+		       "pre-compiled headers",
+		       debug_set_names (write_symbols & ~DWARF2_DEBUG));
 	}
       else if (write_symbols != NO_DEBUG && write_symbols != DWARF2_DEBUG)
 	c_common_no_more_pch ();
diff --git a/gcc/c-family/c-pch.c b/gcc/c-family/c-pch.c
index fd94c37..8f0f760 100644
--- a/gcc/c-family/c-pch.c
+++ b/gcc/c-family/c-pch.c
@@ -52,7 +52,7 @@ enum {
 
 struct c_pch_validity
 {
-  unsigned char debug_info_type;
+  uint32_t pch_write_symbols;
   signed char match[MATCH_SIZE];
   void (*pch_init) (void);
   size_t target_data_length;
@@ -108,7 +108,7 @@ pch_init (void)
   pch_outfile = f;
 
   memset (&v, '\0', sizeof (v));
-  v.debug_info_type = write_symbols;
+  v.pch_write_symbols = write_symbols;
   {
     size_t i;
     for (i = 0; i < MATCH_SIZE; i++)
@@ -252,13 +252,13 @@ c_common_valid_pch (cpp_reader *pfile, const char *name, int fd)
   /* The allowable debug info combinations are that either the PCH file
      was built with the same as is being used now, or the PCH file was
      built for some kind of debug info but now none is in use.  */
-  if (v.debug_info_type != write_symbols
+  if (v.pch_write_symbols != write_symbols
       && write_symbols != NO_DEBUG)
     {
       cpp_warning (pfile, CPP_W_INVALID_PCH,
-		   "%s: created with -g%s, but used with -g%s", name,
-		   debug_type_names[v.debug_info_type],
-		   debug_type_names[write_symbols]);
+		   "%s: created with '%s' debug info, but used with '%s'", name,
+		   debug_set_names (v.pch_write_symbols),
+		   debug_set_names (write_symbols));
       return 2;
     }
 
diff --git a/gcc/common.opt b/gcc/common.opt
index a75b44e..ffb968d 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -109,7 +109,7 @@ bool exit_after_options
 ; flag-types.h for the definitions of the different possible types of
 ; debugging information.
 Variable
-enum debug_info_type write_symbols = NO_DEBUG
+uint32_t write_symbols = NO_DEBUG
 
 ; Level of debugging information we are producing.  See flag-types.h
 ; for the definitions of the different possible levels.
diff --git a/gcc/flag-types.h b/gcc/flag-types.h
index a038c8f..d60bb30 100644
--- a/gcc/flag-types.h
+++ b/gcc/flag-types.h
@@ -24,15 +24,30 @@ along with GCC; see the file COPYING3.  If not see
 
 enum debug_info_type
 {
-  NO_DEBUG,	    /* Write no debug info.  */
-  DBX_DEBUG,	    /* Write BSD .stabs for DBX (using dbxout.c).  */
-  DWARF2_DEBUG,	    /* Write Dwarf v2 debug info (using dwarf2out.c).  */
-  XCOFF_DEBUG,	    /* Write IBM/Xcoff debug info (using dbxout.c).  */
-  VMS_DEBUG,        /* Write VMS debug info (using vmsdbgout.c).  */
-  VMS_AND_DWARF2_DEBUG /* Write VMS debug info (using vmsdbgout.c).
-                          and DWARF v2 debug info (using dwarf2out.c).  */
+  DINFO_TYPE_NONE = 0,		  /* No debug info.  */
+  DINFO_TYPE_DBX = 1,		  /* BSD .stabs for DBX.  */
+  DINFO_TYPE_DWARF2 = 2,	  /* Dwarf v2 debug info.  */
+  DINFO_TYPE_XCOFF = 3,		  /* IBM/Xcoff debug info.  */
+  DINFO_TYPE_VMS = 4,		  /* VMS debug info.  */
+  DINFO_TYPE_MAX = DINFO_TYPE_VMS /* Marker only.  */
 };
 
+#define NO_DEBUG      (0U)
+/* Write DBX debug info (using dbxout.c).  */
+#define DBX_DEBUG     (1U << DINFO_TYPE_DBX)
+/* Write DWARF2 debug info (using dwarf2out.c).  */
+#define DWARF2_DEBUG  (1U << DINFO_TYPE_DWARF2)
+/* Write IBM/XCOFF debug info (using dbxout.c).  */
+#define XCOFF_DEBUG   (1U << DINFO_TYPE_XCOFF)
+/* Write VMS debug info (using vmsdbgout.c).  */
+#define VMS_DEBUG     (1U << DINFO_TYPE_VMS)
+/* Note: Adding new definitions to handle -combination- of debug formats,
+   like VMS_AND_DWARF2_DEBUG is not recommended.  This definition remains
+   here for historical reasons.  */
+/* Write VMS debug info (using vmsdbgout.c) and DWARF v2 debug info (using
+   dwarf2out.c).  */
+#define VMS_AND_DWARF2_DEBUG  ((VMS_DEBUG | DWARF2_DEBUG))
+
 enum debug_info_levels
 {
   DINFO_LEVEL_NONE,	/* Write no debugging info.  */
diff --git a/gcc/flags.h b/gcc/flags.h
index 0c4409e..3415493 100644
--- a/gcc/flags.h
+++ b/gcc/flags.h
@@ -22,9 +22,24 @@ along with GCC; see the file COPYING3.  If not see
 
 #if !defined(IN_LIBGCC2) && !defined(IN_TARGET_LIBS) && !defined(IN_RTS)
 
-/* Names of debug_info_type, for error messages.  */
+/* Names of fundamental debug info formats indexed by enum
+   debug_info_type.  */
+
 extern const char *const debug_type_names[];
 
+/* Get enum debug_info_type of the specified debug format, for error messages.
+   Can be used only for individual debug format types.  */
+
+extern enum debug_info_type debug_set_to_format (uint32_t debug_info_set);
+
+/* Get the number of debug formats enabled for output.  */
+
+unsigned int debug_set_count (uint32_t w_symbols);
+
+/* Get the names of the debug formats enabled for output.  */
+
+const char * debug_set_names (uint32_t w_symbols);
+
 extern void strip_off_ending (char *, int);
 extern int base_of_path (const char *path, const char **base_out);
 
diff --git a/gcc/objc/objc-act.c b/gcc/objc/objc-act.c
index 796256d..8d106a4 100644
--- a/gcc/objc/objc-act.c
+++ b/gcc/objc/objc-act.c
@@ -3078,7 +3078,7 @@ static void
 synth_module_prologue (void)
 {
   tree type;
-  enum debug_info_type save_write_symbols = write_symbols;
+  uint32_t save_write_symbols = write_symbols;
   const struct gcc_debug_hooks *const save_hooks = debug_hooks;
 
   /* Suppress outputting debug symbols, because
diff --git a/gcc/opts.c b/gcc/opts.c
index fe6fddb..1604241 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -37,12 +37,95 @@ along with GCC; see the file COPYING3.  If not see
 
 static void set_Wstrict_aliasing (struct gcc_options *opts, int onoff);
 
-/* Indexed by enum debug_info_type.  */
+/* Names of fundamental debug info formats indexed by enum
+   debug_info_type.  */
+
 const char *const debug_type_names[] =
 {
   "none", "stabs", "dwarf-2", "xcoff", "vms"
 };
 
+/* Bitmasks of fundamental debug info formats indexed by enum
+   debug_info_type.  */
+
+static uint32_t debug_type_masks[] =
+{
+  NO_DEBUG, DBX_DEBUG, DWARF2_DEBUG, XCOFF_DEBUG, VMS_DEBUG
+};
+
+/* Names of the set of debug formats requested by user.  Updated and accessed
+   via debug_set_names.  */
+
+static char df_set_names[sizeof "none stabs dwarf-2 xcoff vms"];
+
+/* Get enum debug_info_type of the specified debug format, for error messages.
+   Can be used only for individual debug format types.  */
+
+enum debug_info_type
+debug_set_to_format (uint32_t debug_info_set)
+{
+  int idx = 0;
+  enum debug_info_type dinfo_type = DINFO_TYPE_NONE;
+  /* Find first set bit.  */
+  if (debug_info_set)
+    idx = exact_log2 (debug_info_set & - debug_info_set);
+  /* Check that only one bit is set, if at all.  This function is meant to be
+     used only for vanilla debug_info_set bitmask values, i.e. for individual
+     debug format types upto DINFO_TYPE_MAX.  */
+  gcc_assert ((debug_info_set & (debug_info_set - 1)) == 0);
+  dinfo_type = (enum debug_info_type)idx;
+  gcc_assert (dinfo_type <= DINFO_TYPE_MAX);
+  return dinfo_type;
+}
+
+/* Get the number of debug formats enabled for output.  */
+
+unsigned int
+debug_set_count (uint32_t w_symbols)
+{
+  unsigned int count = 0;
+  while (w_symbols)
+    {
+      ++ count;
+      w_symbols &= ~ (w_symbols & - w_symbols);
+    }
+  return count;
+}
+
+/* Get the names of the debug formats enabled for output.  */
+
+const char *
+debug_set_names (uint32_t w_symbols)
+{
+  uint32_t df_mask = 0;
+  /* Reset the string to be returned.  */
+  memset (df_set_names, 0, sizeof (df_set_names));
+  /* Get the popcount.  */
+  int num_set_df = debug_set_count (w_symbols);
+  /* Iterate over the debug formats.  Add name string for those enabled.  */
+  for (int i = DINFO_TYPE_NONE; i <= DINFO_TYPE_MAX; i++)
+    {
+      df_mask = debug_type_masks[i];
+      if (w_symbols & df_mask)
+	{
+	  strcat (df_set_names, debug_type_names[i]);
+	  num_set_df--;
+	  if (num_set_df)
+	    strcat (df_set_names, " ");
+	  else
+	    break;
+	}
+      else if (!w_symbols)
+	{
+	  /* No debug formats enabled.  */
+	  gcc_assert (i == DINFO_TYPE_NONE);
+	  strcat (df_set_names, debug_type_names[i]);
+	  break;
+	}
+    }
+  return df_set_names;
+}
+
 /* Parse the -femit-struct-debug-detailed option value
    and set the flag variables. */
 
@@ -190,7 +273,7 @@ static const char use_diagnosed_msg[] = N_("Uses of this option are diagnosed.")
 
 typedef char *char_p; /* For DEF_VEC_P.  */
 
-static void set_debug_level (enum debug_info_type type, int extended,
+static void set_debug_level (uint32_t dinfo, int extended,
 			     const char *arg, struct gcc_options *opts,
 			     struct gcc_options *opts_set,
 			     location_t loc);
@@ -3027,17 +3110,17 @@ fast_math_flags_struct_set_p (struct cl_optimization *opt)
 }
 
 /* Handle a debug output -g switch for options OPTS
-   (OPTS_SET->x_write_symbols storing whether a debug type was passed
+   (OPTS_SET->x_write_symbols storing whether a debug format was passed
    explicitly), location LOC.  EXTENDED is true or false to support
    extended output (2 is special and means "-ggdb" was given).  */
 static void
-set_debug_level (enum debug_info_type type, int extended, const char *arg,
+set_debug_level (uint32_t dinfo, int extended, const char *arg,
 		 struct gcc_options *opts, struct gcc_options *opts_set,
 		 location_t loc)
 {
   opts->x_use_gnu_debug_info_extensions = extended;
 
-  if (type == NO_DEBUG)
+  if (dinfo == NO_DEBUG)
     {
       if (opts->x_write_symbols == NO_DEBUG)
 	{
@@ -3058,14 +3141,18 @@ set_debug_level (enum debug_info_type type, int extended, const char *arg,
     }
   else
     {
-      /* Does it conflict with an already selected type?  */
+      /* Does it conflict with an already selected debug format?  */
       if (opts_set->x_write_symbols != NO_DEBUG
 	  && opts->x_write_symbols != NO_DEBUG
-	  && type != opts->x_write_symbols)
-	error_at (loc, "debug format %qs conflicts with prior selection",
-		  debug_type_names[type]);
-      opts->x_write_symbols = type;
-      opts_set->x_write_symbols = type;
+	  && dinfo != opts->x_write_symbols)
+	{
+	  gcc_assert (debug_set_count (dinfo) <= 1);
+	  error_at (loc, "debug format %qs conflicts with prior selection",
+		    debug_type_names[debug_set_to_format (dinfo)]);
+	}
+
+      opts->x_write_symbols = dinfo;
+      opts_set->x_write_symbols = dinfo;
     }
 
   /* A debug flag without a level defaults to level 2.
diff --git a/gcc/testsuite/gcc.dg/pch/valid-1.c b/gcc/testsuite/gcc.dg/pch/valid-1.c
index d445c47..6e9abda 100644
--- a/gcc/testsuite/gcc.dg/pch/valid-1.c
+++ b/gcc/testsuite/gcc.dg/pch/valid-1.c
@@ -1,7 +1,7 @@
 /* { dg-require-effective-target pch_supported_debug } */
 /* { dg-options "-I. -Winvalid-pch -g" } */
 
-#include "valid-1.h"/* { dg-warning "created with -gnone, but used with -g" } */
+#include "valid-1.h"/* { dg-warning "created with .none. debug info, but used with" } */
 /* { dg-error "No such file" "no such file" { target *-*-* } 0 } */
 /* { dg-error "they were invalid" "invalid files" { target *-*-* } 0 } */
 /* { dg-message "terminated" "" { target *-*-* } 0 } */
diff --git a/gcc/testsuite/lib/dg-pch.exp b/gcc/testsuite/lib/dg-pch.exp
index 1f60fde..bb0ce46 100644
--- a/gcc/testsuite/lib/dg-pch.exp
+++ b/gcc/testsuite/lib/dg-pch.exp
@@ -28,7 +28,7 @@ proc pch-init { args } {
 
     set result [check_compile pchtest object "int i;" "-g -x c-header"]
     set pch_unsupported_debug \
-	[regexp "debug format cannot be used with pre-compiled headers" \
+	[regexp "debug info cannot be used with pre-compiled headers" \
 		[lindex $result 0]]
     remote_file build delete [lindex $result 1]
 
@@ -38,7 +38,7 @@ proc pch-init { args } {
 
 	set result [check_compile pchtest object "int i;" "-x c-header"]
 	set pch_unsupported \
-	    [regexp "debug format cannot be used with pre-compiled headers" \
+	    [regexp "debug info cannot be used with pre-compiled headers" \
 		 [lindex $result 0]]
 	remote_file build delete [lindex $result 1]
     }
diff --git a/gcc/toplev.c b/gcc/toplev.c
index 7e23253..1016fb9 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -1461,9 +1461,12 @@ process_options (void)
     debug_hooks = &dwarf2_lineno_debug_hooks;
 #endif
   else
-    error_at (UNKNOWN_LOCATION,
-	      "target system does not support the %qs debug format",
-	      debug_type_names[write_symbols]);
+    {
+      gcc_assert (debug_set_count (write_symbols) <= 1);
+      error_at (UNKNOWN_LOCATION,
+		"target system does not support the %qs debug format",
+		debug_type_names[debug_set_to_format (write_symbols)]);
+    }
 
   /* We know which debug output will be used so we can set flag_var_tracking
      and flag_var_tracking_uninit if the user has not specified them.  */
