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

[Andy Kaylor via cfe-commits]

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@@ -228,6 +257,42 @@ mlir::Value CIRAttrToValue::visitCirAttr(cir::FPAttr fltAttr) {
       loc, converter->convertType(fltAttr.getType()), fltAttr.getValue());
 }
 
+// ConstArrayAttr visitor
+mlir::Value CIRAttrToValue::visitCirAttr(cir::ConstArrayAttr attr) {
+  mlir::Type llvmTy = converter->convertType(attr.getType());
+  mlir::Location loc = parentOp->getLoc();
+  mlir::Value result;
+
+  if (auto zeros = attr.getTrailingZerosNum()) {
+    mlir::Type arrayTy = attr.getType();
+    result = rewriter.create<mlir::LLVM::ZeroOp>(
+        loc, converter->convertType(arrayTy));
+  } else {
+    result = rewriter.create<mlir::LLVM::UndefOp>(loc, llvmTy);
+  }
+
+  // Iteratively lower each constant element of the array.
+  if (auto arrayAttr = mlir::dyn_cast<mlir::ArrayAttr>(attr.getElts())) {
+    for (auto [idx, elt] : llvm::enumerate(arrayAttr)) {
+      mlir::DataLayout dataLayout(parentOp->getParentOfType<mlir::ModuleOp>());
+      mlir::Value init = visit(elt);
+      result =
+          rewriter.create<mlir::LLVM::InsertValueOp>(loc, result, init, idx);
+    }
+  } else {
+    llvm_unreachable("unexpected ConstArrayAttr elements");
+  }
+
+  return result;
+}
+
+/// ZeroAttr visitor.
+mlir::Value CIRAttrToValue::visitCirAttr(cir::ZeroAttr attr) {
+  auto loc = parentOp->getLoc();
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andykaylor wrote:

You missed one `auto` here. Feel free to merge this now and submit a follow-up to fix this. I'm waiting for this PR to be merged so I can rebase my type alias change without breaking tests for PRs that are ready to be merged.

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