[SYCL] Add test for unused argument warning

Author: npmiller

clang/test/Driver/sycl-no-prec-sqrt.cpp

@@ -0,0 +1,17 @@
+// REQUIRES: clang-driver
+
+// RUN: %clang -### -fsycl \
+// RUN:   -fsycl-fp32-prec-sqrt %s 2>&1 | FileCheck %s
+
+// RUN: %clang -### -fsycl -fsycl-targets=spir64_gen \
+// RUN:   -fsycl-fp32-prec-sqrt %s 2>&1 | FileCheck %s
+//
+// RUN: %clang -### -fsycl -fsycl-targets=spir64_x86_64 \
+// RUN:   -fsycl-fp32-prec-sqrt %s 2>&1 | FileCheck %s
+//
+// RUN: %clang -### -fsycl -fsycl-targets=spir64_fpga \
+// RUN:   -fsycl-fp32-prec-sqrt %s 2>&1 | FileCheck %s
+
+// CHECK: warning: argument unused during compilation: '-fsycl-fp32-prec-sqrt'
+
+void func(){};