Index: lib/Headers/opencl-c.h
===================================================================
--- lib/Headers/opencl-c.h
+++ lib/Headers/opencl-c.h
@@ -16014,8 +16014,10 @@
 
 // OpenCL v2.0 s6.13.16 - Pipe Functions
 #if __OPENCL_C_VERSION__ >= CL_VERSION_2_0
-#define PIPE_RESERVE_ID_VALID_BIT (1U << 30)
-#define CLK_NULL_RESERVE_ID (__builtin_astype(((void*)(__SIZE_MAX__)), reserve_id_t))
+// The most significant bit of valid reserve_id must be set to one.
+#define __PIPE_RESERVE_ID_VALID_BIT ((size_t)1 << (sizeof(size_t) * 8 - 1))
+// The macro CLK_NULL_RESERVE_ID refers to an invalid reservation ID.
+#define CLK_NULL_RESERVE_ID (__builtin_astype((void *)0, reserve_id_t))
 bool __ovld is_valid_reserve_id(reserve_id_t reserve_id);
 #endif //__OPENCL_C_VERSION__ >= CL_VERSION_2_0