[clang] [CIR] Upstream global initialization for ArrayType (PR #131657)

[Amr Hesham via cfe-commits]

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@@ -158,13 +158,56 @@ class ConstExprEmitter
 
 // TODO(cir): this can be shared with LLVM's codegen
 static QualType getNonMemoryType(CIRGenModule &cgm, QualType type) {
-  if (auto at = type->getAs<AtomicType>()) {
+  if (const auto *at = type->getAs<AtomicType>()) {
     return cgm.getASTContext().getQualifiedType(at->getValueType(),
                                                 type.getQualifiers());
   }
   return type;
 }
 
+static mlir::Attribute
+emitArrayConstant(CIRGenModule &cgm, mlir::Type desiredType,
+                  mlir::Type commonElementType, unsigned arrayBound,
+                  SmallVectorImpl<mlir::TypedAttr> &elements,
+                  mlir::TypedAttr filter) {
+  const auto &builder = cgm.getBuilder();
+
+  unsigned nonzeroLength = arrayBound;
+  if (elements.size() < nonzeroLength && builder.isNullValue(filter))
+    nonzeroLength = elements.size();
+
+  if (nonzeroLength == elements.size()) {
+    while (nonzeroLength > 0 &&
+           builder.isNullValue(elements[nonzeroLength - 1]))
+      --nonzeroLength;
+  }
+
+  if (nonzeroLength == 0)
+    return cir::ZeroAttr::get(builder.getContext(), desiredType);
+
+  const unsigned trailingZeroes = arrayBound - nonzeroLength;
+  if (trailingZeroes >= 8) {
+    if (elements.size() < nonzeroLength)
+      cgm.errorNYI("missing initializer for non-zero element");
+  } else if (elements.size() != arrayBound) {
+    elements.resize(arrayBound, filter);
+
+    if (filter.getType() != commonElementType)
+      cgm.errorNYI(
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AmrDeveloper wrote:

My point is that it's will not be assert or error after we support StructType

https://github.com/llvm/llvm-project/pull/131657