diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 8feab810aed9..7bd882d5f025 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -7,8 +7,10 @@ obj-y	+= xenbus/
 nostackp := $(call cc-option, -fno-stack-protector)
 CFLAGS_features.o			:= $(nostackp)
 
+ifndef CONFIG_LTO_CLANG
 CFLAGS_efi.o				+= -fshort-wchar
 LDFLAGS					+= $(call ld-option, --no-wchar-size-warning)
+endif
 
 dom0-$(CONFIG_ARM64) += arm-device.o
 dom0-$(CONFIG_PCI) += pci.o