Disable 16bit Store with RWByteAddressBuffer for SPIRV

tools/clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -8069,6 +8069,8 @@ def err_hlsl_vk_pointer_cast_alignment: Error<
   "Vulkan buffer pointer cannot be cast to greater alignment">;
 def err_hlsl_vk_static_pointer_cast_type: Error<
   "vk::static_pointer_cast() content type must be base class of argument's content type">;
+def err_hlsl_vk_rwbyteaddressbuffer_16bit_store : Error<
+  "RWByteAddressBuffer does not support storing 16bit types in Vulkan">;
 def warn_spirv_node_shaders_experimental : Warning<
   "SPIR-V implementation of node shaders is experimental and subject to change">;
 // SPIRV Change Ends

tools/clang/lib/Sema/SemaHLSL.cpp

@@ -11332,6 +11332,18 @@ HLSLExternalSource::DeduceTemplateArgumentsForHLSL(
       IsBABLoad = intrinsicOp == (UINT)IntrinsicOp::MOP_Load;
       IsBABStore = intrinsicOp == (UINT)IntrinsicOp::MOP_Store;
     }
+#ifdef ENABLE_SPIRV_CODEGEN
+    // We don't support 16 bit stores in SPIRV for RWByteAddressBuffer due to
+    // representing the buffer as a series of 32 bit values.
+    // See https://github.com/microsoft/DirectXShaderCompiler/issues/8172
+    if (IsBABStore && getSema()->getLangOpts().SPIRV) {
+      if (getSema()->getASTContext().getIntWidth(argTypes[2]) == 16) {
+        getSema()->Diag(Args[1]->getLocStart(),
+                        diag::err_hlsl_vk_rwbyteaddressbuffer_16bit_store);
+        return Sema::TemplateDeductionResult::TDK_Invalid;
+      }
+    }
+#endif
     if (ExplicitTemplateArgs && ExplicitTemplateArgs->size() >= 1) {
       SourceLocation Loc = ExplicitTemplateArgs->getLAngleLoc();
       if (!IsBABLoad && !IsBABStore) {

tools/clang/test/SemaHLSL/rwbyteaddressbuffer-store-16bit-spirv.hlsl

@@ -0,0 +1,10 @@
+// REQUIRES: spirv
+// RUN: %dxc -T cs_6_2 -E main -spirv -enable-16bit-types -fcgl %s -verify
+
+RWByteAddressBuffer DstBuffer : register(u1);
+
+[numthreads(1, 1, 1)]
+void main()
+{
+  DstBuffer.Store<uint16_t>(0, 1); // expected-error {{RWByteAddressBuffer does not support storing 16bit types in Vulkan}}
+}