diff --git a/sys/dev/acpica/acpi_thermal.c b/sys/dev/acpica/acpi_thermal.c
index 4acf3c4db609..dab1ac94f991 100644
--- a/sys/dev/acpica/acpi_thermal.c
+++ b/sys/dev/acpica/acpi_thermal.c
@@ -785,7 +785,7 @@ acpi_tz_temp_sysctl(SYSCTL_HANDLER_ARGS)
     int		 		error;
 
     sc = oidp->oid_arg1;
-    temp_ptr = (int *)((uintptr_t)sc + oidp->oid_arg2);
+    temp_ptr = (int *)(void *)(uintptr_t)((uintptr_t)sc + oidp->oid_arg2);
     temp = *temp_ptr;
     error = sysctl_handle_int(oidp, &temp, 0, req);
 
@@ -814,7 +814,7 @@ acpi_tz_passive_sysctl(SYSCTL_HANDLER_ARGS)
     int				error;
 
     sc = oidp->oid_arg1;
-    val_ptr = (int *)((uintptr_t)sc + oidp->oid_arg2);
+    val_ptr = (int *)(void *)(uintptr_t)((uintptr_t)sc + oidp->oid_arg2);
     val = *val_ptr;
     error = sysctl_handle_int(oidp, &val, 0, req);