[clang] [CIR] Support zero-result ops in clangir TableGen lowering (PR #202273)

[Jiahao Guo via cfe-commits]

https://github.com/E00N777 updated https://github.com/llvm/llvm-project/pull/202273

>From 37db106233b35a53d97a918201eaf3fa4f483d53 Mon Sep 17 00:00:00 2001
From: E0N777 <E0N_gjh at 163.com>
Date: Mon, 8 Jun 2026 15:11:04 +0800
Subject: [PATCH] [CIR] Support zero-result ops in clangir TableGen lowering

---
 clang/include/clang/CIR/Dialect/IR/CIROps.td  |  2 ++
 .../CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp | 15 ---------------
 clang/utils/TableGen/CIRLoweringEmitter.cpp   | 19 +++++++++++++------
 3 files changed, 15 insertions(+), 21 deletions(-)

diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
index 29644fa35aa74..1e05457775577 100644
--- a/clang/include/clang/CIR/Dialect/IR/CIROps.td
+++ b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -4876,6 +4876,7 @@ def CIR_LifetimeStartOp : CIR_Op<"lifetime.start"> {
   let arguments = (ins CIR_PointerType:$ptr);
   let assemblyFormat = "$ptr attr-dict `:` qualified(type($ptr))";
   let hasVerifier = 1;
+  let llvmOp = "LifetimeStartOp";
 }
 
 def CIR_LifetimeEndOp : CIR_Op<"lifetime.end"> {
@@ -4911,6 +4912,7 @@ def CIR_LifetimeEndOp : CIR_Op<"lifetime.end"> {
   let arguments = (ins CIR_PointerType:$ptr);
   let assemblyFormat = "$ptr attr-dict `:` qualified(type($ptr))";
   let hasVerifier = 1;
+  let llvmOp = "LifetimeEndOp";
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
index 39ab2dc359958..c7eccd2f19c19 100644
--- a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
+++ b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -4156,21 +4156,6 @@ mlir::LogicalResult CIRToLLVMStackRestoreOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
-mlir::LogicalResult CIRToLLVMLifetimeStartOpLowering::matchAndRewrite(
-    cir::LifetimeStartOp op, OpAdaptor adaptor,
-    mlir::ConversionPatternRewriter &rewriter) const {
-  rewriter.replaceOpWithNewOp<mlir::LLVM::LifetimeStartOp>(op,
-                                                           adaptor.getPtr());
-  return mlir::success();
-}
-
-mlir::LogicalResult CIRToLLVMLifetimeEndOpLowering::matchAndRewrite(
-    cir::LifetimeEndOp op, OpAdaptor adaptor,
-    mlir::ConversionPatternRewriter &rewriter) const {
-  rewriter.replaceOpWithNewOp<mlir::LLVM::LifetimeEndOp>(op, adaptor.getPtr());
-  return mlir::success();
-}
-
 mlir::LogicalResult CIRToLLVMVecCreateOpLowering::matchAndRewrite(
     cir::VecCreateOp op, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
diff --git a/clang/utils/TableGen/CIRLoweringEmitter.cpp b/clang/utils/TableGen/CIRLoweringEmitter.cpp
index d7417ee38875e..4c4d0c370e4cd 100644
--- a/clang/utils/TableGen/CIRLoweringEmitter.cpp
+++ b/clang/utils/TableGen/CIRLoweringEmitter.cpp
@@ -138,7 +138,7 @@ void GenerateLLVMLoweringPattern(llvm::StringRef OpName,
                                  llvm::StringRef PatternName, bool IsRecursive,
                                  llvm::StringRef ExtraDecl,
                                  const Record *CustomCtorRec,
-                                 llvm::StringRef LLVMOp) {
+                                 llvm::StringRef LLVMOp, bool IsZeroResult) {
   std::optional<CustomLoweringCtor> CustomCtor =
       parseCustomLoweringCtor(CustomCtorRec);
   std::string CodeBuffer;
@@ -188,10 +188,15 @@ void GenerateLLVMLoweringPattern(llvm::StringRef OpName,
         << "  mlir::LogicalResult matchAndRewrite(cir::" << OpName
         << " op, OpAdaptor adaptor, mlir::ConversionPatternRewriter &rewriter) "
            "const override {\n";
-    Code
-        << "    mlir::Type resTy = typeConverter->convertType(op.getType());\n";
-    Code << "    rewriter.replaceOpWithNewOp<mlir::LLVM::" << LLVMOp
-         << ">(op, resTy, adaptor.getOperands());\n";
+    if (IsZeroResult) {
+      Code << "    rewriter.replaceOpWithNewOp<mlir::LLVM::" << LLVMOp
+           << ">(op, mlir::TypeRange{}, adaptor.getOperands());\n";
+    } else {
+      Code << "    mlir::Type resTy = "
+              "typeConverter->convertType(op.getType());\n";
+      Code << "    rewriter.replaceOpWithNewOp<mlir::LLVM::" << LLVMOp
+           << ">(op, resTy, adaptor.getOperands());\n";
+    }
     Code << "    return mlir::success();\n";
     Code << "  }\n";
   } else {
@@ -236,8 +241,10 @@ void Generate(const Record *OpRecord) {
                           "' has both llvmOp and a custom lowering "
                           "constructor, which is not supported");
 
+    const DagInit *ResultsDag = OpRecord->getValueAsDag("results");
+    bool IsZeroResult = ResultsDag->getNumArgs() == 0;
     GenerateLLVMLoweringPattern(OpName, PatternName, IsRecursive, ExtraDecl,
-                                CustomCtor, LLVMOp);
+                                CustomCtor, LLVMOp, IsZeroResult);
     // Only automatically register patterns that use the default constructor.
     // Patterns with a custom constructor must be manually registered by the
     // lowering pass.