[clang] [clang][CodeGen][SPIRV] Translate `amdgpu_flat_work_group_size` into `reqd_work_group_size`. (PR #116820)

[Matt Arsenault via cfe-commits]

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@@ -245,6 +247,41 @@ SPIRVTargetCodeGenInfo::getGlobalVarAddressSpace(CodeGenModule &CGM,
   return DefaultGlobalAS;
 }
 
+void SPIRVTargetCodeGenInfo::setTargetAttributes(
+    const Decl *D, llvm::GlobalValue *GV, CodeGen::CodeGenModule &M) const {
+  if (!M.getLangOpts().HIP ||
+      M.getTarget().getTriple().getVendor() != llvm::Triple::AMD)
+    return;
+  if (GV->isDeclaration())
+    return;
+
+  auto F = dyn_cast<llvm::Function>(GV);
+  if (!F)
+    return;
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arsenm wrote:

Can this fail if the FunctionDecl below fails? 

https://github.com/llvm/llvm-project/pull/116820