re PR c/25993 (-std= produces incorrect preprocessor output for .S)

gcc/
	PR c/25993
	* c-opts.c (c_common_handle_option): Ignore the -std options
	if the input language is assembly.

testsuite/
	PR c/25993
	* gcc.dg/pr25993.c: New test.

From-SVN: r117005

gcc/ChangeLog

+2006-09-17  Steven Bosscher  <steven@gcc.gnu.org>
+
+	PR c/25993
+	* c-opts.c (c_common_handle_option): Ignore the -std options
+	if the input language is assembly.
+
 2006-09-17  Ira Rosen  <irar@il.ibm.com>
 
         PR tree-opt/21591

gcc/c-opts.c

@@ -268,6 +268,10 @@ c_common_handle_option (size_t scode, const char *arg, int value)
   enum opt_code code = (enum opt_code) scode;
   int result = 1;
 
+  /* Prevent resetting the language standard to a C dialect when the driver
+     has already determined that we're looking at assembler input.  */
+  bool preprocessing_asm_p = (cpp_get_options (parse_in)->lang == CLK_ASM);
+ 
   switch (code)
     {
     default:
@@ -905,29 +909,34 @@ c_common_handle_option (size_t scode, const char *arg, int value)
 
     case OPT_std_c__98:
     case OPT_std_gnu__98:
-      set_std_cxx98 (code == OPT_std_c__98 /* ISO */);
+      if (!preprocessing_asm_p)
+	set_std_cxx98 (code == OPT_std_c__98 /* ISO */);
       break;
 
     case OPT_std_c89:
     case OPT_std_iso9899_1990:
     case OPT_std_iso9899_199409:
-      set_std_c89 (code == OPT_std_iso9899_199409 /* c94 */, true /* ISO */);
+      if (!preprocessing_asm_p)
+	set_std_c89 (code == OPT_std_iso9899_199409 /* c94 */, true /* ISO */);
       break;
 
     case OPT_std_gnu89:
-      set_std_c89 (false /* c94 */, false /* ISO */);
+      if (!preprocessing_asm_p)
+	set_std_c89 (false /* c94 */, false /* ISO */);
       break;
 
     case OPT_std_c99:
     case OPT_std_c9x:
     case OPT_std_iso9899_1999:
     case OPT_std_iso9899_199x:
-      set_std_c99 (true /* ISO */);
+      if (!preprocessing_asm_p)
+	set_std_c99 (true /* ISO */);
       break;
 
     case OPT_std_gnu99:
     case OPT_std_gnu9x:
-      set_std_c99 (false /* ISO */);
+      if (!preprocessing_asm_p)
+	set_std_c99 (false /* ISO */);
       break;
 
     case OPT_trigraphs:

gcc/testsuite/ChangeLog

+2006-09-16  Steven Bosscher  <steven@gcc.gnu.org>
+
+	PR c/25993
+	* gcc.dg/pr25993.c: New test.
+
 2006-09-17  Ira Rosen  <irar@il.ibm.com>
 
         PR tree-opt/21591

gcc/testsuite/gcc.dg/pr25993.c

+/* { dg-do assemble { target i?86-*-* x86_64-*-* } } */
+/* { dg-options "-std=c99 -x assembler-with-cpp" } */
+
+#ifndef __ASSEMBLER__
+extern int func(void);
+#else
+.global func
+.type func,%function
+.align 4
+func:
+        ret
+.size func,.-func
+#endif
+