[OpenCL] Add missing -cl-no-signed-zeros option into driver

Add OCL option -cl-no-signed-zeros to driver options.

Also added to opencl.cl testcases.

Patch by Aaron En Ye Shi.

Differential Revision: http://reviews.llvm.org/D22067

llvm-svn: 274923
diff --git a/clang/test/CodeGenOpenCL/no-signed-zeros.cl b/clang/test/CodeGenOpenCL/no-signed-zeros.cl
new file mode 100644
index 0000000..14f6411
--- /dev/null
+++ b/clang/test/CodeGenOpenCL/no-signed-zeros.cl
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s -check-prefix=NORMAL

+// RUN: %clang_cc1 %s -emit-llvm -cl-no-signed-zeros -o - | FileCheck %s -check-prefix=NO-SIGNED-ZEROS

+

+float signedzeros(float a) {

+  return a;

+}

+

+// CHECK: attributes

+// NORMAL: "no-signed-zeros-fp-math"="false"

+// NO-SIGNED-ZEROS: "no-signed-zeros-fp-math"="true"