diff --git a/flang/runtime/complex-reduction.h b/flang/runtime/complex-reduction.h
--- a/flang/runtime/complex-reduction.h
+++ b/flang/runtime/complex-reduction.h
@@ -27,7 +27,7 @@
 #else
 typedef float _Complex float_Complex_t;
 typedef double _Complex double_Complex_t;
-typedef long double long_double_Complex_t;
+typedef long double _Complex long_double_Complex_t;
 #endif
 
 #define REDUCTION_ARGS \