Index: compiler-rt/lib/builtins/int_types.h
===================================================================
--- compiler-rt/lib/builtins/int_types.h
+++ compiler-rt/lib/builtins/int_types.h
@@ -137,6 +137,16 @@
 #endif /* _YUGA_LITTLE_ENDIAN */
 } uqwords;
 
+/* Indicate if we have an Intel style extended 80 bit long double. Notably, on
+ * Windows, MSVC makes long double 64 bits, but GCC still makes it 80 bits.
+ * Clang will match whatever compiler it is pretending to be.
+ */
+#if (defined(__i386__) || defined(__x86_64__)) && !defined(_MSC_VER)
+#define HAS_80_BIT_LONG_DOUBLE 1
+#else
+#define HAS_80_BIT_LONG_DOUBLE 0
+#endif
+
 typedef union
 {
     uqwords     u;
Index: compiler-rt/test/builtins/Unit/fixxfdi_test.c
===================================================================
--- compiler-rt/test/builtins/Unit/fixxfdi_test.c
+++ compiler-rt/test/builtins/Unit/fixxfdi_test.c
@@ -26,7 +26,7 @@
 // gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
 // 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
 
-COMPILER_RT_ABI di_int __sfixxfdi(long double a);
+COMPILER_RT_ABI di_int __fixxfdi(long double a);
 
 int test__fixxfdi(long double a, di_int expected)
 {