[clang] [HLSL] Implement SV_GroupID semantic (PR #115911)

[Chris B via cfe-commits]

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@@ -784,6 +785,17 @@ void SemaHLSL::handleSV_DispatchThreadIDAttr(Decl *D, const ParsedAttr &AL) {
                  HLSLSV_DispatchThreadIDAttr(getASTContext(), AL));
 }
 
+void SemaHLSL::handleSV_GroupIDAttr(Decl *D, const ParsedAttr &AL) {
+  auto *VD = cast<ValueDecl>(D);
+  if (!isLegalTypeForHLSLSV_ThreadOrGroupID(VD->getType())) {
+    Diag(AL.getLoc(), diag::err_hlsl_attr_invalid_type)
+        << AL << "uint/uint2/uint3";
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llvm-beanz wrote:

Since this is the same diagnostic as `SV_DispatchThreadID` (and others we haven't handled yet), maybe we should move the diagnostic into `isLegalTypeForHLSLSV_DispatchThreadID`, and change that function name to something like `diagnoseInputIDType`.

Then if the function returns false, this could just early out knowing the diagnostic came from the called function. That will reduce code duplication.

https://github.com/llvm/llvm-project/pull/115911