[clang] [CIR] Upstream StackSave and StackRestoreOp (PR #136426)

[Henrich Lauko via cfe-commits]

================
@@ -242,6 +242,26 @@ class CIRToLLVMPtrStrideOpLowering
   matchAndRewrite(cir::PtrStrideOp op, OpAdaptor,
                   mlir::ConversionPatternRewriter &) const override;
 };
+
+class CIRToLLVMStackSaveOpLowering
+    : public mlir::OpConversionPattern<cir::StackSaveOp> {
+public:
+  using mlir::OpConversionPattern<cir::StackSaveOp>::OpConversionPattern;
----------------
xlauko wrote:

```suggestion
  using mlir::OpConversionPattern<cir::StackSaveOp>::OpConversionPattern;

```

https://github.com/llvm/llvm-project/pull/136426