[clang] [CIR] Upstream overflow builtins (PR #166643)

[Henrich Lauko via cfe-commits]

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@@ -2503,6 +2503,118 @@ mlir::LogicalResult CIRToLLVMCmpOpLowering::matchAndRewrite(
   return cmpOp.emitError() << "unsupported type for CmpOp: " << type;
 }
 
+mlir::LogicalResult CIRToLLVMBinOpOverflowOpLowering::matchAndRewrite(
+    cir::BinOpOverflowOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  auto loc = op.getLoc();
+  auto arithKind = op.getKind();
+  auto operandTy = op.getLhs().getType();
+  auto resultTy = op.getResult().getType();
+
+  auto encompassedTyInfo = computeEncompassedTypeWidth(operandTy, resultTy);
+  auto encompassedLLVMTy = rewriter.getIntegerType(encompassedTyInfo.width);
+
+  auto lhs = adaptor.getLhs();
+  auto rhs = adaptor.getRhs();
+  if (operandTy.getWidth() < encompassedTyInfo.width) {
+    if (operandTy.isSigned()) {
+      lhs = rewriter.create<mlir::LLVM::SExtOp>(loc, encompassedLLVMTy, lhs);
+      rhs = rewriter.create<mlir::LLVM::SExtOp>(loc, encompassedLLVMTy, rhs);
+    } else {
+      lhs = rewriter.create<mlir::LLVM::ZExtOp>(loc, encompassedLLVMTy, lhs);
+      rhs = rewriter.create<mlir::LLVM::ZExtOp>(loc, encompassedLLVMTy, rhs);
----------------
xlauko wrote:

rewriter.create is deprecated construct, use `Op::create(rewriter,` instead

https://github.com/llvm/llvm-project/pull/166643