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

[Andy Kaylor via cfe-commits]

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@@ -271,16 +314,61 @@ mlir::Attribute ConstantEmitter::tryEmitPrivate(const APValue &value,
         cgm.getASTContext().getTargetInfo().useFP16ConversionIntrinsics()) {
       cgm.errorNYI("ConstExprEmitter::tryEmitPrivate half");
       return {};
-    } else {
-      mlir::Type ty = cgm.convertType(destType);
-      assert(mlir::isa<cir::CIRFPTypeInterface>(ty) &&
-             "expected floating-point type");
-      return cgm.getBuilder().getAttr<cir::FPAttr>(ty, init);
     }
+
+    mlir::Type ty = cgm.convertType(destType);
+    assert(mlir::isa<cir::CIRFPTypeInterface>(ty) &&
+           "expected floating-point type");
+    return cgm.getBuilder().getAttr<cir::FPAttr>(ty, init);
   }
   case APValue::Array: {
-    cgm.errorNYI("ConstExprEmitter::tryEmitPrivate array");
-    return {};
+    const ArrayType *arrayTy = cgm.getASTContext().getAsArrayType(destType);
+    const QualType arrayElementTy = arrayTy->getElementType();
+    const unsigned numElements = value.getArraySize();
+    const unsigned numInitElts = value.getArrayInitializedElts();
+
+    mlir::Attribute filter;
+    if (value.hasArrayFiller()) {
+      filter =
+          tryEmitPrivate(value.getArrayFiller(), arrayTy->getElementType());
+      if (!filter)
+        return {};
+    }
+
+    SmallVector<mlir::TypedAttr, 16> elements;
+    if (filter && builder.isNullValue(filter))
+      elements.reserve(numInitElts + 1);
+    else
+      elements.reserve(numInitElts);
+
+    mlir::Type commonElementType;
+    for (unsigned i = 0; i < numInitElts; ++i) {
+      const APValue &arrayElement = value.getArrayInitializedElt(i);
+      const mlir::Attribute element =
+          tryEmitPrivateForMemory(arrayElement, arrayElementTy);
+      if (!element)
+        return {};
+
+      const mlir::TypedAttr elementTyped = mlir::cast<mlir::TypedAttr>(element);
+      if (i == 0)
+        commonElementType = elementTyped.getType();
+      else if (elementTyped.getType() != commonElementType) {
+        cgm.errorNYI("ConstExprEmitter::tryEmitPrivate Array without common "
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andykaylor wrote:

If you just set commonElementType to `{}` as is done in the incubator, this will eventually reach the NYI state in emitConstantArray and this code won't need to be updated later.

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