[CIR] Upstream handling for delete array #165225

monthdev · 2025-10-27T10:02:33Z

Upstream DeleteArrayOp and clang/test/CIR/CodeGen/delete-array.cpp

llvmbot · 2025-10-27T10:03:18Z

@llvm/pr-subscribers-clangir

Author: Shawn K (kimsh02)

Changes

Upstream DeleteArrayOp and clang/test/CIR/CodeGen/delete-array.cpp

Full diff: https://github.com/llvm/llvm-project/pull/165225.diff

4 Files Affected:

(modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+18)
(modified) clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp (+2-2)
(modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+37)
(added) clang/test/CIR/CodeGen/delete-array.cpp (+16)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 2b361ed0982c6..b7bdfe7d9f5b6 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -4089,6 +4089,24 @@ def CIR_PrefetchOp : CIR_Op<"prefetch"> {
     }];
 }
 
+//===----------------------------------------------------------------------===//
+// DeleteArrayOp
+//===----------------------------------------------------------------------===//
+
+def CIR_DeleteArrayOp : CIR_Op<"delete.array"> {
+  let summary = "Delete address representing an array";
+  let description = [{
+    `cir.delete.array` operation deletes an array. For example, `delete[] ptr;`
+    will be translated to `cir.delete.array %ptr`.
+  }];
+
+  let arguments = (ins CIR_PointerType:$address);
+
+  let assemblyFormat = [{
+    $address `:` type($address) attr-dict
+  }];
+}
+
 //===----------------------------------------------------------------------===//
 // PtrDiffOp
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp b/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp
index 7a35382e79a93..42d066e88225c 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp
@@ -626,8 +626,8 @@ void CIRGenFunction::emitCXXDeleteExpr(const CXXDeleteExpr *e) {
   ptr = ptr.withElementType(builder, convertTypeForMem(deleteTy));
 
   if (e->isArrayForm()) {
-    assert(!cir::MissingFeatures::deleteArray());
-    cgm.errorNYI(e->getSourceRange(), "emitCXXDeleteExpr: array delete");
+    cir::DeleteArrayOp::create(builder, ptr.getPointer().getLoc(),
+                               ptr.getPointer());
     return;
   } else {
     emitObjectDelete(*this, e, ptr, deleteTy);
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 5a6193fa8d840..aba182e2c9952 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -1704,6 +1704,43 @@ mlir::LogicalResult CIRToLLVMPrefetchOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+// Make sure the LLVM function we are about to create a call for actually
+// exists, if not create one. Returns a function
+static void getOrCreateLLVMFuncOp(mlir::ConversionPatternRewriter &rewriter,
+                                  mlir::Operation *srcOp,
+                                  llvm::StringRef fnName, mlir::Type fnTy) {
+  auto modOp = srcOp->getParentOfType<mlir::ModuleOp>();
+  auto enclosingFnOp = srcOp->getParentOfType<mlir::LLVM::LLVMFuncOp>();
+  mlir::Operation *sourceSymbol =
+      mlir::SymbolTable::lookupSymbolIn(modOp, fnName);
+  if (!sourceSymbol) {
+    mlir::OpBuilder::InsertionGuard guard(rewriter);
+    rewriter.setInsertionPoint(enclosingFnOp);
+    mlir::LLVM::LLVMFuncOp::create(rewriter, srcOp->getLoc(), fnName, fnTy);
+  }
+}
+
+mlir::LogicalResult CIRToLLVMDeleteArrayOpLowering::matchAndRewrite(
+    cir::DeleteArrayOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  StringRef fnName = "_ZdaPv";
+
+  auto voidTy = rewriter.getType<mlir::LLVM::LLVMVoidType>();
+  mlir::Type llvmPtrTy =
+      mlir::LLVM::LLVMPointerType::get(rewriter.getContext());
+
+  mlir::Type fnTy = mlir::LLVM::LLVMFunctionType::get(voidTy, {llvmPtrTy},
+                                                      /*isVarArg=*/false);
+
+  getOrCreateLLVMFuncOp(rewriter, op, fnName, fnTy);
+
+  // Replace the operation with a call to _ZdaPv with the pointer argument
+  rewriter.replaceOpWithNewOp<mlir::LLVM::CallOp>(
+      op, mlir::TypeRange{}, fnName, mlir::ValueRange{adaptor.getAddress()});
+
+  return mlir::success();
+}
+
 mlir::LogicalResult CIRToLLVMPtrDiffOpLowering::matchAndRewrite(
     cir::PtrDiffOp op, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
diff --git a/clang/test/CIR/CodeGen/delete-array.cpp b/clang/test/CIR/CodeGen/delete-array.cpp
new file mode 100644
index 0000000000000..0ff08be61ef45
--- /dev/null
+++ b/clang/test/CIR/CodeGen/delete-array.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --check-prefix=LLVM --input-file=%t-cir.ll %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 -emit-llvm %s -o %t.ll
+// RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s
+
+void test_delete_array(int *ptr) {
+  delete[] ptr;
+}
+
+// CIR: cir.delete.array
+
+// LLVM: call void @_ZdaPv{{(m)?}}(ptr
+
+// OGCG: call void @_ZdaPv{{(m)?}}(ptr

llvmbot · 2025-10-27T10:03:20Z

@llvm/pr-subscribers-clang

Author: Shawn K (kimsh02)

Changes

Upstream DeleteArrayOp and clang/test/CIR/CodeGen/delete-array.cpp

Full diff: https://github.com/llvm/llvm-project/pull/165225.diff

4 Files Affected:

(modified) clang/include/clang/CIR/Dialect/IR/CIROps.td (+18)
(modified) clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp (+2-2)
(modified) clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp (+37)
(added) clang/test/CIR/CodeGen/delete-array.cpp (+16)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 2b361ed0982c6..b7bdfe7d9f5b6 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -4089,6 +4089,24 @@ def CIR_PrefetchOp : CIR_Op<"prefetch"> {
     }];
 }
 
+//===----------------------------------------------------------------------===//
+// DeleteArrayOp
+//===----------------------------------------------------------------------===//
+
+def CIR_DeleteArrayOp : CIR_Op<"delete.array"> {
+  let summary = "Delete address representing an array";
+  let description = [{
+    `cir.delete.array` operation deletes an array. For example, `delete[] ptr;`
+    will be translated to `cir.delete.array %ptr`.
+  }];
+
+  let arguments = (ins CIR_PointerType:$address);
+
+  let assemblyFormat = [{
+    $address `:` type($address) attr-dict
+  }];
+}
+
 //===----------------------------------------------------------------------===//
 // PtrDiffOp
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp b/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp
index 7a35382e79a93..42d066e88225c 100644
--- a/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp
@@ -626,8 +626,8 @@ void CIRGenFunction::emitCXXDeleteExpr(const CXXDeleteExpr *e) {
   ptr = ptr.withElementType(builder, convertTypeForMem(deleteTy));
 
   if (e->isArrayForm()) {
-    assert(!cir::MissingFeatures::deleteArray());
-    cgm.errorNYI(e->getSourceRange(), "emitCXXDeleteExpr: array delete");
+    cir::DeleteArrayOp::create(builder, ptr.getPointer().getLoc(),
+                               ptr.getPointer());
     return;
   } else {
     emitObjectDelete(*this, e, ptr, deleteTy);
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 5a6193fa8d840..aba182e2c9952 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -1704,6 +1704,43 @@ mlir::LogicalResult CIRToLLVMPrefetchOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+// Make sure the LLVM function we are about to create a call for actually
+// exists, if not create one. Returns a function
+static void getOrCreateLLVMFuncOp(mlir::ConversionPatternRewriter &rewriter,
+                                  mlir::Operation *srcOp,
+                                  llvm::StringRef fnName, mlir::Type fnTy) {
+  auto modOp = srcOp->getParentOfType<mlir::ModuleOp>();
+  auto enclosingFnOp = srcOp->getParentOfType<mlir::LLVM::LLVMFuncOp>();
+  mlir::Operation *sourceSymbol =
+      mlir::SymbolTable::lookupSymbolIn(modOp, fnName);
+  if (!sourceSymbol) {
+    mlir::OpBuilder::InsertionGuard guard(rewriter);
+    rewriter.setInsertionPoint(enclosingFnOp);
+    mlir::LLVM::LLVMFuncOp::create(rewriter, srcOp->getLoc(), fnName, fnTy);
+  }
+}
+
+mlir::LogicalResult CIRToLLVMDeleteArrayOpLowering::matchAndRewrite(
+    cir::DeleteArrayOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  StringRef fnName = "_ZdaPv";
+
+  auto voidTy = rewriter.getType<mlir::LLVM::LLVMVoidType>();
+  mlir::Type llvmPtrTy =
+      mlir::LLVM::LLVMPointerType::get(rewriter.getContext());
+
+  mlir::Type fnTy = mlir::LLVM::LLVMFunctionType::get(voidTy, {llvmPtrTy},
+                                                      /*isVarArg=*/false);
+
+  getOrCreateLLVMFuncOp(rewriter, op, fnName, fnTy);
+
+  // Replace the operation with a call to _ZdaPv with the pointer argument
+  rewriter.replaceOpWithNewOp<mlir::LLVM::CallOp>(
+      op, mlir::TypeRange{}, fnName, mlir::ValueRange{adaptor.getAddress()});
+
+  return mlir::success();
+}
+
 mlir::LogicalResult CIRToLLVMPtrDiffOpLowering::matchAndRewrite(
     cir::PtrDiffOp op, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
diff --git a/clang/test/CIR/CodeGen/delete-array.cpp b/clang/test/CIR/CodeGen/delete-array.cpp
new file mode 100644
index 0000000000000..0ff08be61ef45
--- /dev/null
+++ b/clang/test/CIR/CodeGen/delete-array.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --check-prefix=LLVM --input-file=%t-cir.ll %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 -emit-llvm %s -o %t.ll
+// RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s
+
+void test_delete_array(int *ptr) {
+  delete[] ptr;
+}
+
+// CIR: cir.delete.array
+
+// LLVM: call void @_ZdaPv{{(m)?}}(ptr
+
+// OGCG: call void @_ZdaPv{{(m)?}}(ptr

monthdev · 2025-10-27T10:04:07Z

I referenced https://godbolt.org/z/63K4779ej . Please let me know if the checks need fixing.

andykaylor

I'm afraid this is an instance where the implementation in the incubator is incorrect. In particular, this doesn't handle the case of deleting an array of objects that require destruction.

https://godbolt.org/z/bTsqWzbPG

I think this needs to be fixed in the incubator (using the test case I linked above as a reference) before it is upstreamed. If you want to take that on, you'll need to use the behavior in classic codegen as a guide.

Because this implementation (when done correctly) involves reading the array cookie, which is target-specific, it would be nice to have a high-level CIR abstraction like cir.delete.array, but that will eventually need to incorporate array cookie handling when it is lowered, and it needs to get the name of the delete function from the AST, because _ZdaPv (which is hard-coded in the incubator implementation and this PR) isn't always the correct function to call.

I would suggest starting with a lower-level implementation (in the incubator) which follows classic codegen more closely and calls the delete function directly. This will be analogous to the way we are currently handling array new. Later, after this is working, we can introduce higher level cir.array.new and cir.array.delete operations to remove the ABI-specific details.

@wizardengineer is starting to look into this kind of upleveling of the CIR implementation, and I think it's important to have a correctly working implementation as the basis of the upleveling work. It seems cir.delete.array is an example of an operation where we were too hasty in pushing to the higher level representation and missed some important details in the process.

monthdev · 2025-11-03T20:49:35Z

@andykaylor Okay, thanks for the description of the issue. I'll start taking a look at it. It may take me a while because I'm very inexperienced and don't know much of anything 😅

bcardosolopes · 2025-11-03T20:55:31Z

I think this needs to be fixed in the incubator (using the test case I linked above as a reference) before it is upstreamed

+1

xlauko

Add also print/parse roudn-trip test for the operation to test/CIR/IR

xlauko · 2025-11-04T07:48:13Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+// DeleteArrayOp
+//===----------------------------------------------------------------------===//
+
+def CIR_DeleteArrayOp : CIR_Op<"delete.array"> {


Suggested change

def CIR_DeleteArrayOp : CIR_Op<"delete.array"> {

def CIR_DeleteArrayOp : CIR_Op<"delete_array"> {

xlauko · 2025-11-04T07:48:21Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+def CIR_DeleteArrayOp : CIR_Op<"delete.array"> {
+  let summary = "Delete address representing an array";
+  let description = [{
+    `cir.delete.array` operation deletes an array. For example, `delete[] ptr;`


Suggested change

`cir.delete.array` operation deletes an array. For example, `delete[] ptr;`

`cir.delete_array` operation deletes an array. For example, `delete[] ptr;`

xlauko · 2025-11-04T07:50:06Z

clang/include/clang/CIR/Dialect/IR/CIROps.td

+  let arguments = (ins CIR_PointerType:$address);
+
+  let assemblyFormat = [{
+    $address `:` type($address) attr-dict


Suggested change

$address `:` type($address) attr-dict

$address `:` qualified(type($address)) attr-dict

xlauko · 2025-11-04T07:50:31Z

clang/test/CIR/CodeGen/delete-array.cpp

+// CIR: cir.delete.array
+
+// LLVM: call void @_ZdaPv{{(m)?}}(ptr
+
+// OGCG: call void @_ZdaPv{{(m)?}}(ptr


Make more explicit checks

[CIR] Upstream handling for delete array

c42f2e6

monthdev requested review from andykaylor, bcardosolopes, lanza and xlauko as code owners October 27, 2025 10:02

llvmbot added clang Clang issues not falling into any other category ClangIR Anything related to the ClangIR project labels Oct 27, 2025

andykaylor requested changes Nov 3, 2025

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monthdev marked this pull request as draft November 3, 2025 20:05

xlauko reviewed Nov 4, 2025

View reviewed changes

monthdev mentioned this pull request Nov 5, 2025

[CIR] Fix C++ array delete lowering to match classic codegen llvm/clangir#1968

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[CIR] Upstream handling for delete array #165225

[CIR] Upstream handling for delete array #165225

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	def CIR_DeleteArrayOp : CIR_Op<"delete.array"> {
	def CIR_DeleteArrayOp : CIR_Op<"delete_array"> {

	`cir.delete.array` operation deletes an array. For example, `delete[] ptr;`
	`cir.delete_array` operation deletes an array. For example, `delete[] ptr;`

	$address `:` type($address) attr-dict
	$address `:` qualified(type($address)) attr-dict

[CIR] Upstream handling for delete array #165225

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[CIR] Upstream handling for delete array #165225

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