[Mlir-commits] [mlir] [mlir-c] Add ConversionTarget dynamic legality C API (PR #206161)

[llvmlistbot at llvm.org]

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@@ -533,6 +533,37 @@ MLIR_CAPI_EXPORTED void
 mlirConversionTargetAddIllegalDialect(MlirConversionTarget target,
                                       MlirStringRef dialectName);
 
+/// Callback for dynamic legality checks. Return true if the operation is
+/// legal, false if illegal.
+typedef bool (*MlirConversionTargetDynamicLegalityCallback)(MlirOperation op,
+                                                            void *userData);
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PragmaTwice wrote:

I notice that in C++ the `DynamicLegalityCallbackFn` is defined as
```c++
  using DynamicLegalityCallbackFn =
      std::function<std::optional<bool>(Operation *)>;
```

Not sure what's difference between `false` and `nullopt`. Here we just use `bool` so the callback cannot return a `nullopt` state?

https://github.com/llvm/llvm-project/pull/206161