[clang] [AMDGPU] Stop coercing structs with FP and int fields to integer arrays (PR #185083)

[Shilei Tian via cfe-commits]

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@@ -155,17 +211,27 @@ ABIArgInfo AMDGPUABIInfo::classifyReturnType(QualType RetTy) const {
           RD && RD->hasFlexibleArrayMember())
         return DefaultABIInfo::classifyReturnType(RetTy);
 
-      // Pack aggregates <= 4 bytes into single VGPR or pair.
+      // Pack aggregates <= 8 bytes into single VGPR or pair, but only if they
+      // contain sub-32-bit integer types. Aggregates with floats or full-sized
+      // integers should preserve their original types.
       uint64_t Size = getContext().getTypeSize(RetTy);
-      if (Size <= 16)
-        return ABIArgInfo::getDirect(llvm::Type::getInt16Ty(getVMContext()));
-
-      if (Size <= 32)
-        return ABIArgInfo::getDirect(llvm::Type::getInt32Ty(getVMContext()));
-
       if (Size <= 64) {
-        llvm::Type *I32Ty = llvm::Type::getInt32Ty(getVMContext());
-        return ABIArgInfo::getDirect(llvm::ArrayType::get(I32Ty, 2));
+        const auto *RD = RetTy->getAsRecordDecl();
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shiltian wrote:

no auto

https://github.com/llvm/llvm-project/pull/185083