add the test file

Author: YixingZhang007

llvm/test/CodeGen/SPIRV/extensions/SPV_KHR_bfloat16/bfloat16.ll

@@ -0,0 +1,16 @@
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown --spirv-ext=+SPV_KHR_bfloat16 %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv64-unknown-unknown --spirv-ext=+SPV_KHR_bfloat16 %s -o - -filetype=obj | spirv-val %}
+; XFAIL: *
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv32-unknown-unknown %s -o - | FileCheck %s --check-prefix=CHECK-ERROR
+
+; CHECK-ERROR: BFloat16TypeKHR requires the following SPIR-V extension: SPV_KHR_subgroup_rotate
+
+; CHECK-DAG: OpCapability BFloat16TypeKHR
+; CHECK-DAG: OpExtension "SPV_KHR_bfloat16"
+; CHECK: %[[#BFLOAT:]] = OpTypeFloat 16 0
+; CHECK: %[[#]] = OpTypeVector %[[#BFLOAT]] 2
+
+define spir_kernel void @test() {
+entry:
+  ret void
+}