[clang] [CIR] Represent Cleanups with Cleanup scopes (PR #180276)

[Andy Kaylor via cfe-commits]

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@@ -301,7 +345,19 @@ void CIRGenFunction::popCleanupBlock() {
     assert(!cir::MissingFeatures::ehCleanupScopeRequiresEHCleanup());
     ehStack.popCleanup();
     scope.markEmitted();
+
+    mlir::Block &block = cleanupScope.getCleanupRegion().back();
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andykaylor wrote:

Is `cleanupScope` guaranteed to be non-null here? I would add at least an assert.

https://github.com/llvm/llvm-project/pull/180276