Compile pr37870.c with -mlong-double-80

On x86, the "long double" type is platforma specific, which may be the
same as double or __float128.  Since pr37870.c requires 80-bit floating
point type, it should be compiled with -mlong-double-80.

	* gcc.target/i386/pr37870.c (dg-options): Add -mlong-double-80.

From-SVN: r225578

gcc/testsuite/ChangeLog

 2015-07-08  H.J. Lu  <hongjiu.lu@intel.com>
 
+	* gcc.target/i386/pr37870.c (dg-options): Add -mlong-double-80.
+
+2015-07-08  H.J. Lu  <hongjiu.lu@intel.com>
+
 	* gcc.target/i386/readeflags-1.c (abort): New prototype.
 	* gcc.target/i386/writeeflags-1.c (abort): Likewise.
 

gcc/testsuite/gcc.target/i386/pr37870.c

 /* PR middle-end/37870 */
 /* { dg-do run } */
-/* { dg-options "-O2" } */
+/* { dg-options "-O2 -mlong-double-80" } */
 
 unsigned int
 foo (long double x)