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

[Henrich Lauko via cfe-commits]

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@@ -1419,6 +1419,48 @@ def CallOp : CIR_CallOpBase<"call", [NoRegionArguments]> {
     }]>];
 }
 
+//===----------------------------------------------------------------------===//
+// StackSave & StackRestoreOp
+//===----------------------------------------------------------------------===//
+
+def StackSaveOp : CIR_Op<"stack_save"> {
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xlauko wrote:

nit: Also any reason not to mirror `llvm` names, i.e. to have `cir.stacksave` and `cir.stackrestore`?

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