[clang] [HLSL] get inout/out ABI for array parameters working (PR #111047)

[Chris B via cfe-commits]

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@@ -2249,6 +2235,25 @@ static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
 
     SCS.setAllToTypes(ToType);
     return true;
+  } else if (argIsLValue && !FromType->canDecayToPointerType() &&
+             S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) {
+    // Lvalue-to-rvalue conversion (C++11 4.1):
+    //   A glvalue (3.10) of a non-function, non-array type T can
+    //   be converted to a prvalue.
+
+    SCS.First = ICK_Lvalue_To_Rvalue;
+
+    // C11 6.3.2.1p2:
+    //   ... if the lvalue has atomic type, the value has the non-atomic version
+    //   of the type of the lvalue ...
+    if (const AtomicType *Atomic = FromType->getAs<AtomicType>())
+      FromType = Atomic->getValueType();
+
+    // If T is a non-class type, the type of the rvalue is the
+    // cv-unqualified version of T. Otherwise, the type of the rvalue
+    // is T (C++ 4.1p1). C++ can't get here with class types; in C, we
+    // just strip the qualifiers because they don't matter.
+    FromType = FromType.getUnqualifiedType();
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llvm-beanz wrote:

It looks like you moved this block down from above. I assume this is because the ordering of these checks matters, could you add a comment above the HLSL-specific `if` block explaining why?

https://github.com/llvm/llvm-project/pull/111047