* c-format.h (format_kind_info): Add alloc_char field.

	* c-format.c (scanf_flag_specs): Add 'm'.
	(scanf_flag_pairs): Add 'a', 'm' pair.
	(scan_char_table): Allow 'm' modifier for c, s, [, C and S.
	(format_types_orig): Add alloc_char fields.
	(check_format_info_main): Rename aflag to alloc_flag.
	Handle fki->alloc_char. modifier after width and before length
	modifiers.  Move FMT_FLAG_SCANF_A_KLUDGE handling before
	length modifiers as well.
	* config/sol2-c.c (solaris_format_types): Add alloc_char field.

	* gcc.dg/format/c90-scanf-5.c: New test.
	* gcc.dg/format/c99-scanf-4.c: New test.
	* gcc.dg/format/ext-7.c: New test.
	* gcc.dg/format/ext-8.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@128555 138bc75d-0d04-0410-961f-82ee72b054a4

9 files changed, 247 insertions, 38 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7bbe988d839..4c102c6578a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,16 @@
 2007-09-18  Jakub Jelinek  <jakub@redhat.com>
 
+	* c-format.h (format_kind_info): Add alloc_char field.
+	* c-format.c (scanf_flag_specs): Add 'm'.
+	(scanf_flag_pairs): Add 'a', 'm' pair.
+	(scan_char_table): Allow 'm' modifier for c, s, [, C and S.
+	(format_types_orig): Add alloc_char fields.
+	(check_format_info_main): Rename aflag to alloc_flag.
+	Handle fki->alloc_char. modifier after width and before length
+	modifiers.  Move FMT_FLAG_SCANF_A_KLUDGE handling before
+	length modifiers as well.
+	* config/sol2-c.c (solaris_format_types): Add alloc_char field.
+
 	PR middle-end/33423
 	* builtins.c (expand_builtin_memory_chk): Handle COMPOUND_EXPRs
 	returned by build_call_expr.
diff --git a/gcc/c-format.c b/gcc/c-format.c
index 25cf859a161..b703e47a008 100644
--- a/gcc/c-format.c
+++ b/gcc/c-format.c
@@ -437,6 +437,7 @@ static const format_flag_spec scanf_flag_specs[] =
 {
   { '*',  0, 0, N_("assignment suppression"), N_("the assignment suppression scanf feature"), STD_C89 },
   { 'a',  0, 0, N_("'a' flag"),               N_("the 'a' scanf flag"),                       STD_EXT },
+  { 'm',  0, 0, N_("'m' flag"),               N_("the 'm' scanf flag"),                       STD_EXT },
   { 'w',  0, 0, N_("field width"),            N_("field width in scanf format"),              STD_C89 },
   { 'L',  0, 0, N_("length modifier"),        N_("length modifier in scanf format"),          STD_C89 },
   { '\'', 0, 0, N_("''' flag"),               N_("the ''' scanf flag"),                       STD_EXT },
@@ -448,6 +449,7 @@ static const format_flag_spec scanf_flag_specs[] =
 static const format_flag_pair scanf_flag_pairs[] =
 {
   { '*', 'L', 0, 0 },
+  { 'a', 'm', 0, 0 },
   { 0, 0, 0, 0 }
 };
 
@@ -663,17 +665,17 @@ static const format_char_info scan_char_table[] =
   { "u",     1, STD_C89, { T89_UI,  T99_UC,  T89_US,  T89_UL,  T9L_ULL, TEX_ULL, T99_ST,  T99_UPD, T99_UIM, BADLEN,  BADLEN,  BADLEN }, "*w'I", "W",   NULL },
   { "oxX",   1, STD_C89, { T89_UI,  T99_UC,  T89_US,  T89_UL,  T9L_ULL, TEX_ULL, T99_ST,  T99_UPD, T99_UIM, BADLEN,  BADLEN,  BADLEN }, "*w",   "W",   NULL },
   { "efgEG", 1, STD_C89, { T89_F,   BADLEN,  BADLEN,  T89_D,   BADLEN,  T89_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "*w'",  "W",   NULL },
-  { "c",     1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*w",   "cW",  NULL },
-  { "s",     1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*aw",  "cW",  NULL },
-  { "[",     1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*aw",  "cW[", NULL },
+  { "c",     1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*mw",   "cW",  NULL },
+  { "s",     1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*amw",  "cW",  NULL },
+  { "[",     1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*amw",  "cW[", NULL },
   { "p",     2, STD_C89, { T89_V,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*w",   "W",   NULL },
   { "n",     1, STD_C89, { T89_I,   T99_SC,  T89_S,   T89_L,   T9L_LL,  BADLEN,  T99_SST, T99_PD,  T99_IM,  BADLEN,  BADLEN,  BADLEN }, "",     "W",   NULL },
   /* C99 conversion specifiers.  */
   { "F",   1, STD_C99, { T99_F,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T99_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "*w'",  "W",   NULL },
   { "aA",   1, STD_C99, { T99_F,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T99_LD,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*w'",  "W",   NULL },
   /* X/Open conversion specifiers.  */
-  { "C",     1, STD_EXT, { TEX_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*w",   "W",   NULL },
-  { "S",     1, STD_EXT, { TEX_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*aw",  "W",   NULL },
+  { "C",     1, STD_EXT, { TEX_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*mw",   "W",   NULL },
+  { "S",     1, STD_EXT, { TEX_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "*amw",  "W",   NULL },
   { NULL, 0, 0, NOLENGTHS, NULL, NULL, NULL }
 };
 
@@ -716,59 +718,59 @@ static const format_kind_info format_types_orig[] =
   { "printf",   printf_length_specs,  print_char_table, " +#0-'I", NULL,
     printf_flag_specs, printf_flag_pairs,
     FMT_FLAG_ARG_CONVERT|FMT_FLAG_DOLLAR_MULTIPLE|FMT_FLAG_USE_DOLLAR|FMT_FLAG_EMPTY_PREC_OK,
-    'w', 0, 'p', 0, 'L',
+    'w', 0, 'p', 0, 'L', 0,
     &integer_type_node, &integer_type_node
   },
   { "asm_fprintf",   asm_fprintf_length_specs,  asm_fprintf_char_table, " +#0-", NULL,
     asm_fprintf_flag_specs, asm_fprintf_flag_pairs,
     FMT_FLAG_ARG_CONVERT|FMT_FLAG_EMPTY_PREC_OK,
-    'w', 0, 'p', 0, 'L',
+    'w', 0, 'p', 0, 'L', 0,
     NULL, NULL
   },
   { "gcc_diag",   gcc_diag_length_specs,  gcc_diag_char_table, "q+", NULL,
     gcc_diag_flag_specs, gcc_diag_flag_pairs,
     FMT_FLAG_ARG_CONVERT,
-    0, 0, 'p', 0, 'L',
+    0, 0, 'p', 0, 'L', 0,
     NULL, &integer_type_node
   },
   { "gcc_tdiag",   gcc_tdiag_length_specs,  gcc_tdiag_char_table, "q+", NULL,
     gcc_tdiag_flag_specs, gcc_tdiag_flag_pairs,
     FMT_FLAG_ARG_CONVERT,
-    0, 0, 'p', 0, 'L',
+    0, 0, 'p', 0, 'L', 0,
     NULL, &integer_type_node
   },
   { "gcc_cdiag",   gcc_cdiag_length_specs,  gcc_cdiag_char_table, "q+", NULL,
     gcc_cdiag_flag_specs, gcc_cdiag_flag_pairs,
     FMT_FLAG_ARG_CONVERT,
-    0, 0, 'p', 0, 'L',
+    0, 0, 'p', 0, 'L', 0,
     NULL, &integer_type_node
   },
   { "gcc_cxxdiag",   gcc_cxxdiag_length_specs,  gcc_cxxdiag_char_table, "q+#", NULL,
     gcc_cxxdiag_flag_specs, gcc_cxxdiag_flag_pairs,
     FMT_FLAG_ARG_CONVERT,
-    0, 0, 'p', 0, 'L',
+    0, 0, 'p', 0, 'L', 0,
     NULL, &integer_type_node
   },
   { "gcc_gfc", gcc_gfc_length_specs, gcc_gfc_char_table, "", NULL,
     NULL, gcc_gfc_flag_pairs,
     FMT_FLAG_ARG_CONVERT,
-    0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0,
     NULL, NULL
   },
   { "scanf",    scanf_length_specs,   scan_char_table,  "*'I", NULL,
     scanf_flag_specs, scanf_flag_pairs,
     FMT_FLAG_ARG_CONVERT|FMT_FLAG_SCANF_A_KLUDGE|FMT_FLAG_USE_DOLLAR|FMT_FLAG_ZERO_WIDTH_BAD|FMT_FLAG_DOLLAR_GAP_POINTER_OK,
-    'w', 0, 0, '*', 'L',
+    'w', 0, 0, '*', 'L', 'm',
     NULL, NULL
   },
   { "strftime", NULL,                 time_char_table,  "_-0^#", "EO",
     strftime_flag_specs, strftime_flag_pairs,
-    FMT_FLAG_FANCY_PERCENT_OK, 'w', 0, 0, 0, 0,
+    FMT_FLAG_FANCY_PERCENT_OK, 'w', 0, 0, 0, 0, 0,
     NULL, NULL
   },
   { "strfmon",  strfmon_length_specs, monetary_char_table, "=^+(!-", NULL,
     strfmon_flag_specs, strfmon_flag_pairs,
-    FMT_FLAG_ARG_CONVERT, 'w', '#', 'p', 0, 'L',
+    FMT_FLAG_ARG_CONVERT, 'w', '#', 'p', 0, 'L', 0,
     NULL, NULL
   }
 };
@@ -1482,7 +1484,7 @@ check_format_info_main (format_check_results *res,
       const format_length_info *fli = NULL;
       const format_char_info *fci = NULL;
       char flag_chars[256];
-      int aflag = 0;
+      int alloc_flag = 0;
       const char *format_start = format_chars;
       if (*format_chars == 0)
 	{
@@ -1741,6 +1743,31 @@ check_format_info_main (format_check_results *res,
 	    }
 	}
 
+      if (fki->alloc_char && fki->alloc_char == *format_chars)
+	{
+	  i = strlen (flag_chars);
+	  flag_chars[i++] = fki->alloc_char;
+	  flag_chars[i] = 0;
+	  format_chars++;
+	}
+
+      /* Handle the scanf allocation kludge.  */
+      if (fki->flags & (int) FMT_FLAG_SCANF_A_KLUDGE)
+	{
+	  if (*format_chars == 'a' && !flag_isoc99)
+	    {
+	      if (format_chars[1] == 's' || format_chars[1] == 'S'
+		  || format_chars[1] == '[')
+		{
+		  /* 'a' is used as a flag.  */
+		  i = strlen (flag_chars);
+		  flag_chars[i++] = 'a';
+		  flag_chars[i] = 0;
+		  format_chars++;
+		}
+	    }
+	}
+
       /* Read any length modifier, if this kind of format has them.  */
       fli = fki->length_char_specs;
       length_chars = NULL;
@@ -1803,23 +1830,6 @@ check_format_info_main (format_check_results *res,
 	    }
 	}
 
-      /* Handle the scanf allocation kludge.  */
-      if (fki->flags & (int) FMT_FLAG_SCANF_A_KLUDGE)
-	{
-	  if (*format_chars == 'a' && !flag_isoc99)
-	    {
-	      if (format_chars[1] == 's' || format_chars[1] == 'S'
-		  || format_chars[1] == '[')
-		{
-		  /* 'a' is used as a flag.  */
-		  i = strlen (flag_chars);
-		  flag_chars[i++] = 'a';
-		  flag_chars[i] = 0;
-		  format_chars++;
-		}
-	    }
-	}
-
       format_char = *format_chars;
       if (format_char == 0
 	  || (!(fki->flags & (int) FMT_FLAG_FANCY_PERCENT_OK)
@@ -1892,7 +1902,9 @@ check_format_info_main (format_check_results *res,
 
       if ((fki->flags & (int) FMT_FLAG_SCANF_A_KLUDGE)
 	  && strchr (flag_chars, 'a') != 0)
-	aflag = 1;
+	alloc_flag = 1;
+      if (fki->alloc_char && strchr (flag_chars, fki->alloc_char) != 0)
+	alloc_flag = 1;
 
       if (fki->suppression_char
 	  && strchr (flag_chars, fki->suppression_char) != 0)
@@ -2064,13 +2076,13 @@ check_format_info_main (format_check_results *res,
 
 	      wanted_type_ptr->wanted_type = wanted_type;
 	      wanted_type_ptr->wanted_type_name = wanted_type_name;
-	      wanted_type_ptr->pointer_count = fci->pointer_count + aflag;
+	      wanted_type_ptr->pointer_count = fci->pointer_count + alloc_flag;
 	      wanted_type_ptr->char_lenient_flag = 0;
 	      if (strchr (fci->flags2, 'c') != 0)
 		wanted_type_ptr->char_lenient_flag = 1;
 	      wanted_type_ptr->writing_in_flag = 0;
 	      wanted_type_ptr->reading_from_flag = 0;
-	      if (aflag)
+	      if (alloc_flag)
 		wanted_type_ptr->writing_in_flag = 1;
 	      else
 		{
diff --git a/gcc/c-format.h b/gcc/c-format.h
index 23476f698af..90cbb179e68 100644
--- a/gcc/c-format.h
+++ b/gcc/c-format.h
@@ -236,6 +236,8 @@ typedef struct
      specifiers, but is used to check for bad combinations such as length
      modifier with assignment suppression in scanf.  */
   int length_code_char;
+  /* Assignment-allocation flag character ('m' in scanf), otherwise 0.  */
+  int alloc_char;
   /* Pointer to type of argument expected if '*' is used for a width,
      or NULL if '*' not used for widths.  */
   tree *width_type;
diff --git a/gcc/config/sol2-c.c b/gcc/config/sol2-c.c
index 5e835107e7c..69426a4596b 100644
--- a/gcc/config/sol2-c.c
+++ b/gcc/config/sol2-c.c
@@ -1,5 +1,5 @@
 /* Solaris support needed only by C/C++ frontends.
-   Copyright (C) 2004, 2005 , 2007 Free Software Foundation, Inc.
+   Copyright (C) 2004, 2005, 2007 Free Software Foundation, Inc.
    Contributed by CodeSourcery, LLC.
 
 This file is part of GCC.
@@ -73,7 +73,7 @@ const format_kind_info solaris_format_types[] = {
   { "cmn_err",  cmn_err_length_specs,  cmn_err_char_table, "", NULL,
     cmn_err_flag_specs, cmn_err_flag_pairs,
     FMT_FLAG_ARG_CONVERT|FMT_FLAG_EMPTY_PREC_OK,
-    'w', 0, 0, 0, 'L',
+    'w', 0, 0, 0, 'L', 0,
     &integer_type_node, &integer_type_node
   }
 };
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a110de35d12..1583b66decd 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2007-09-18  Jakub Jelinek  <jakub@redhat.com>
 
+	* gcc.dg/format/c90-scanf-5.c: New test.
+	* gcc.dg/format/c99-scanf-4.c: New test.
+	* gcc.dg/format/ext-7.c: New test.
+	* gcc.dg/format/ext-8.c: New test.
+
 	PR middle-end/33423
 	* gcc.c-torture/compile/20070915-1.c: New test.
 
diff --git a/gcc/testsuite/gcc.dg/format/c90-scanf-5.c b/gcc/testsuite/gcc.dg/format/c90-scanf-5.c
new file mode 100644
index 00000000000..c94e25f222a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/c90-scanf-5.c
@@ -0,0 +1,19 @@
+/* Test for scanf formats.  Formats using extensions to the standard
+   should be rejected in strict pedantic mode.
+*/
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1990 -pedantic -Wformat" } */
+
+#include "format.h"
+
+void
+foo (char **sp, wchar_t **lsp)
+{
+  /* m assignment-allocation modifier, recognized in both C90
+     and C99 modes, is a POSIX and ISO/IEC WDTR 24731-2 extension.  */
+  scanf ("%ms", sp); /* { dg-warning "C" "%ms" } */
+  scanf ("%mS", lsp); /* { dg-warning "C" "%mS" } */
+  scanf ("%mls", lsp); /* { dg-warning "C" "%mls" } */
+  scanf ("%m[bcd]", sp); /* { dg-warning "C" "%m[]" } */
+  scanf ("%ml[bcd]", lsp); /* { dg-warning "C" "%ml[]" } */
+}
diff --git a/gcc/testsuite/gcc.dg/format/c99-scanf-4.c b/gcc/testsuite/gcc.dg/format/c99-scanf-4.c
new file mode 100644
index 00000000000..9c7a5e4b273
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/c99-scanf-4.c
@@ -0,0 +1,19 @@
+/* Test for scanf formats.  Formats using extensions to the standard
+   should be rejected in strict pedantic mode.
+*/
+/* { dg-do compile } */
+/* { dg-options "-std=iso9899:1999 -pedantic -Wformat" } */
+
+#include "format.h"
+
+void
+foo (char **sp, wchar_t **lsp)
+{
+  /* m assignment-allocation modifier, recognized in both C90
+     and C99 modes, is a POSIX and ISO/IEC WDTR 24731-2 extension.  */
+  scanf ("%ms", sp); /* { dg-warning "C" "%ms" } */
+  scanf ("%mS", lsp); /* { dg-warning "C" "%mS" } */
+  scanf ("%mls", lsp); /* { dg-warning "C" "%mls" } */
+  scanf ("%m[bcd]", sp); /* { dg-warning "C" "%m[]" } */
+  scanf ("%ml[bcd]", lsp); /* { dg-warning "C" "%ml[]" } */
+}
diff --git a/gcc/testsuite/gcc.dg/format/ext-7.c b/gcc/testsuite/gcc.dg/format/ext-7.c
new file mode 100644
index 00000000000..d9bd0e8ffd0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/ext-7.c
@@ -0,0 +1,85 @@
+/* Test for scanf formats.  %a and %m extensions.  */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu89 -Wformat" } */
+
+#include "format.h"
+
+void
+foo (char **sp, wchar_t **lsp, int *ip, float *fp, void **pp, double *dp)
+{
+  /* %a formats for allocation, only recognized in C90 mode, are a
+     GNU extension.  Followed by other characters, %a is not treated
+     specially.
+  */
+  scanf ("%as", sp);
+  scanf ("%aS", lsp);
+  scanf ("%las", dp);
+  scanf ("%la", lsp);	/* { dg-warning "but argument 2 has type" } */
+  scanf ("%las", lsp);	/* { dg-warning "but argument 2 has type" } */
+  scanf ("%a[bcd]", sp);
+  scanf ("%la[bcd]", dp);
+  scanf ("%*as");
+  scanf ("%*aS");
+  scanf ("%*las");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*a[bcd]");
+  scanf ("%*la[bcd]");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%10as", sp);
+  scanf ("%5aS", lsp);
+  scanf ("%9las", dp);
+  scanf ("%25a[bcd]", sp);
+  scanf ("%48la[bcd]", dp);
+  scanf ("%*10as");
+  scanf ("%*5aS");
+  scanf ("%*9las");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*25a[bcd]");
+  scanf ("%*48la[bcd]"); /* { dg-warning "assignment suppression and length modifier" } */
+
+  /* m assignment-allocation modifier, recognized in both C90
+     and C99 modes, is a POSIX and ISO/IEC WDTR 24731-2 extension.  */
+  scanf ("%ms", sp);
+  scanf ("%mS", lsp);
+  scanf ("%mls", lsp);
+  scanf ("%m[bcd]", sp);
+  scanf ("%ml[bcd]", lsp);
+  scanf ("%mc", sp);
+  scanf ("%mlc", lsp);
+  scanf ("%mC", lsp);
+  scanf ("%*ms");
+  scanf ("%*mS");
+  scanf ("%*mls");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*m[bcd]");
+  scanf ("%*ml[bcd]");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*mc");
+  scanf ("%*mlc");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*mC");
+  scanf ("%10ms", sp);
+  scanf ("%5mS", lsp);
+  scanf ("%9mls", lsp);
+  scanf ("%25m[bcd]", sp);
+  scanf ("%41ml[bcd]", lsp);
+  scanf ("%131mc", sp);
+  scanf ("%27mlc", lsp);
+  scanf ("%2mC", lsp);
+  scanf ("%*10ms");
+  scanf ("%*5mS");
+  scanf ("%*9mls");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*25m[bcd]");
+  scanf ("%*41ml[bcd]"); /* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*131mc");
+  scanf ("%*27mlc");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*2mC");
+
+  scanf ("%md", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mi", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mo", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mu", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mx", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%me", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%mf", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%mg", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%mp", pp);	/* { dg-warning "flag used with" } */
+
+  scanf ("%mas", sp);	/* { dg-warning "flag together" } */
+  scanf ("%maS", lsp);	/* { dg-warning "flag together" } */
+  scanf ("%ma[bcd]", sp);	/* { dg-warning "flag together" } */
+}
diff --git a/gcc/testsuite/gcc.dg/format/ext-8.c b/gcc/testsuite/gcc.dg/format/ext-8.c
new file mode 100644
index 00000000000..b50cc81d573
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/ext-8.c
@@ -0,0 +1,56 @@
+/* Test for scanf formats.  %m extensions.  */
+/* { dg-do compile } */
+/* { dg-options "-std=gnu99 -Wformat" } */
+
+#include "format.h"
+
+void
+foo (char **sp, wchar_t **lsp, int *ip, float *fp, void **pp)
+{
+  /* m assignment-allocation modifier, recognized in both C90
+     and C99 modes, is a POSIX and ISO/IEC WDTR 24731-2 extension.  */
+  scanf ("%ms", sp);
+  scanf ("%mS", lsp);
+  scanf ("%mls", lsp);
+  scanf ("%m[bcd]", sp);
+  scanf ("%ml[bcd]", lsp);
+  scanf ("%mc", sp);
+  scanf ("%mlc", lsp);
+  scanf ("%mC", lsp);
+  scanf ("%*ms");
+  scanf ("%*mS");
+  scanf ("%*mls");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*m[bcd]");
+  scanf ("%*ml[bcd]");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*mc");
+  scanf ("%*mlc");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*mC");
+  scanf ("%10ms", sp);
+  scanf ("%5mS", lsp);
+  scanf ("%9mls", lsp);
+  scanf ("%25m[bcd]", sp);
+  scanf ("%41ml[bcd]", lsp);
+  scanf ("%131mc", sp);
+  scanf ("%27mlc", lsp);
+  scanf ("%2mC", lsp);
+  scanf ("%*10ms");
+  scanf ("%*5mS");
+  scanf ("%*9mls");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*25m[bcd]");
+  scanf ("%*41ml[bcd]"); /* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*131mc");
+  scanf ("%*27mlc");	/* { dg-warning "assignment suppression and length modifier" } */
+  scanf ("%*2mC");
+
+  scanf ("%md", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mi", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mo", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mu", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%mx", ip);	/* { dg-warning "flag used with" } */
+  scanf ("%ma", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%mA", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%me", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%mf", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%mg", fp);	/* { dg-warning "flag used with" } */
+  scanf ("%mp", pp);	/* { dg-warning "flag used with" } */
+}