[clang] [CIR] Make UndefAttr use AttrBuilderWithInferredContext (PR #136605)

[Henrich Lauko via cfe-commits]

https://github.com/xlauko updated https://github.com/llvm/llvm-project/pull/136605

>From ab355262c3a7da4d8089a49d531870bff14d5f8c Mon Sep 17 00:00:00 2001
From: xlauko <xlauko at mail.muni.cz>
Date: Mon, 21 Apr 2025 22:03:35 +0200
Subject: [PATCH] [CIR] Make UndefAttr use AttrBuilderWithInferredContext

---
 clang/include/clang/CIR/Dialect/IR/CIRAttrs.td | 7 +++++++
 clang/lib/CIR/Dialect/IR/CIRMemorySlot.cpp     | 4 ++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td b/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td
index 214db1b1caeeb..dfe15a10fa54e 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIRAttrs.td
@@ -93,6 +93,13 @@ def UndefAttr : CIR_Attr<"Undef", "undef", [TypedAttrInterface]> {
   }];
 
   let parameters = (ins AttributeSelfTypeParameter<"">:$type);
+
+  let builders = [
+    AttrBuilderWithInferredContext<(ins "mlir::Type":$type), [{
+      return $_get(type.getContext(), type);
+    }]>
+  ];
+
   let assemblyFormat = [{}];
 }
 
diff --git a/clang/lib/CIR/Dialect/IR/CIRMemorySlot.cpp b/clang/lib/CIR/Dialect/IR/CIRMemorySlot.cpp
index 9cd5c54e6c19e..fe8a5e7428a81 100644
--- a/clang/lib/CIR/Dialect/IR/CIRMemorySlot.cpp
+++ b/clang/lib/CIR/Dialect/IR/CIRMemorySlot.cpp
@@ -34,8 +34,8 @@ llvm::SmallVector<MemorySlot> cir::AllocaOp::getPromotableSlots() {
 
 Value cir::AllocaOp::getDefaultValue(const MemorySlot &slot,
                                      OpBuilder &builder) {
-  return builder.create<cir::ConstantOp>(
-      getLoc(), slot.elemType, builder.getAttr<cir::UndefAttr>(slot.elemType));
+  return builder.create<cir::ConstantOp>(getLoc(), slot.elemType,
+                                         cir::UndefAttr::get(slot.elemType));
 }
 
 void cir::AllocaOp::handleBlockArgument(const MemorySlot &slot,