[CIR] Add structured ResumeOp (#170042)

Add SCF Resume op to be used before the CFG flattening pass

Issue #154992

Author: AmrDeveloper

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

@@ -898,6 +898,36 @@ def CIR_ContinueOp : CIR_Op<"continue", [Terminator]> {
   let hasLLVMLowering = false;
 }
 
+//===----------------------------------------------------------------------===//
+// Resume
+//===----------------------------------------------------------------------===//
+
+def CIR_ResumeOp : CIR_Op<"resume", [
+  ReturnLike, Terminator, HasParent<"cir::TryOp">
+]> {
+  let summary = "Resumes execution after not catching exceptions";
+  let description = [{
+    The `cir.resume` operation handles an uncaught exception scenario.
+
+    Used as the terminator of a `CatchUnwind` region of `cir.try`, where it
+    does not receive any arguments (implied from the `cir.try` scope).
+
+    This operation is used only before the CFG flatterning pass.
+
+    Examples:
+    ```mlir
+    cir.try {
+      cir.yield
+    } unwind {
+      cir.resume
+    }
+    ```
+  }];
+
+  let assemblyFormat = "attr-dict";
+  let hasLLVMLowering = false;
+}
+
 //===----------------------------------------------------------------------===//
 // ScopeOp
 //===----------------------------------------------------------------------===//

clang/test/CIR/IR/try-catch.cir

@@ -81,4 +81,26 @@ cir.func dso_local @empty_try_block_with_catch_ist() {
 // CHECK:   cir.return
 // CHECK: }
 
+cir.func @empty_try_block_with_catch_unwind_contains_resume() {
+  cir.scope {
+    cir.try {
+      cir.yield
+    } unwind {
+      cir.resume
+    }
+  }
+  cir.return
+}
+
+// CHECK: cir.func @empty_try_block_with_catch_unwind_contains_resume() {
+// CHECK:   cir.scope {
+// CHECK:     cir.try {
+// CHECK:       cir.yield
+// CHECK:     } unwind {
+// CHECK:       cir.resume
+// CHECK:     }
+// CHECK:   }
+// CHECK:   cir.return
+// CHECK: }
+
 }