diff --git a/openmp/libomptarget/deviceRTLs/target_interface.h b/openmp/libomptarget/deviceRTLs/target_interface.h
--- a/openmp/libomptarget/deviceRTLs/target_interface.h
+++ b/openmp/libomptarget/deviceRTLs/target_interface.h
@@ -25,7 +25,6 @@
 EXTERN NOINLINE int __kmpc_get_hardware_num_threads_in_block();
 EXTERN unsigned __kmpc_get_warp_size();
 EXTERN unsigned GetWarpId();
-EXTERN unsigned GetWarpSize();
 EXTERN unsigned GetLaneId();
 
 // Atomics