loongson-simd.c: Update comment to clarify the need for mips_nanlegacy target.

2015-02-04  Robert Suchanek  <robert.suchanek@imgtec.com>

	* gcc.target/mips/loongson-simd.c: Update comment to clarify the need
	for mips_nanlegacy target.

From-SVN: r220393

gcc/testsuite/ChangeLog

+2015-02-04  Robert Suchanek  <robert.suchanek@imgtec.com>
+
+	* gcc.target/mips/loongson-simd.c: Update comment to clarify the need
+	for mips_nanlegacy target.
+
 2015-02-04  Ilya Enkovich  <ilya.enkovich@intel.com>
 
 	* gcc.target/i386/chkp-hidden-def.c: New.

gcc/testsuite/gcc.target/mips/loongson-simd.c

@@ -21,7 +21,10 @@ along with GCC; see the file COPYING3.  If not see
 /* { dg-do run } */
 /* loongson.h does not handle or check for MIPS16ness or
    microMIPSness.  There doesn't seem any good reason for it to, given
-   that the Loongson processors do not support either.  */
+   that the Loongson processors do not support either.  The effective target
+   mips_nanlegacy is required for a toolchain without the legacy NaN support
+   because inclusion of some system headers e.g. stdint.h will fail due to not
+   finding stubs-o32_hard.h.  */
 /* { dg-require-effective-target mips_nanlegacy } */
 /* { dg-options "isa=loongson -mhard-float -mno-micromips -mno-mips16 -flax-vector-conversions" } */