llvm-project

504b5078 - [mlir][Transforms] Dialect conversion: Add support for `replaceUsesWithIf` (#169606)

[mlir][Transforms] Dialect conversion: Add support for `replaceUsesWithIf` (#169606) This commit adds support for `replaceUsesWithIf` (and variants such as `replaceAllUsesExcept`) to the `ConversionPatternRewriter`. This API is supported only in no-rollback mode. An assertion is triggered in rollback mode. (This missing assertion has been confusing for users because it seemed that the API supported, while it was actually not working properly.) This commit brings us a bit closer towards removing [this](https://github.com/llvm/llvm-project/blob/76ec25f729fcc7ae576caf21293cc393e68e7cf7/mlir/lib/Transforms/Utils/DialectConversion.cpp#L1214) workaround. Additional changes are needed to support this API in rollback mode. In particular, no entries should be added to the `ConversionValueMapping` for conditional replacements. It's unclear at this point if this API can be supported in rollback mode, so this is deferred to later. This commit turns `replaceUsesWithIf` into a virtual function, so that the `ConversionPatternRewriter` can override it. All other API functions for conditional value replacements call that function. Note for LLVM integration: If you are seeing failed assertions due to this change, you are using unsupported API in your dialect conversion. You have 3 options: (1) Migrate to the no-rollback driver. (2) Rewrite your patterns without the unsupported API. (3) Last resort: bypass the rewriter and call `replaceUsesWithIf` etc. directly on the `Value` object.