llvm-project

8bc0d4d1 - [mlir][Transforms] Dialect conversion: Add flag to disable rollback (#136490)

[mlir][Transforms] Dialect conversion: Add flag to disable rollback (#136490) This commit adds a new flag to `ConversionConfig` to disallow the rollback of IR modification. This commit is in preparation of the One-Shot Dialect Conversion refactoring, which will remove the ability to roll back IR modifications from the conversion driver. RFC: https://discourse.llvm.org/t/rfc-a-new-one-shot-dialect-conversion-driver/79083/46 By default, this flag is set to "true". I.e., the rollback of IR modifications is allowed. When set to "false", the conversion driver will report a fatal LLVM error when an IR rollback is requested. The name of the rolled back pattern is included in the error message. Moreover, the original IR is no longer restored after a failed conversion. Example: ``` within split at llvm-project/mlir/test/Conversion/ArithToSPIRV/fast-math.mlir:1 offset :11:8: error: pattern '(anonymous namespace)::CmpFOpNanKernelPattern' produced IR that could not be legalized %0 = arith.cmpf ord, %arg0, %arg1 fastmath<fast> : f32 ^ within split at llvm-project/mlir/test/Conversion/ArithToSPIRV/fast-math.mlir:1 offset :11:8: note: see current operation: %1 = "arith.cmpf"(%arg0, %arg1) <{fastmath = #arith.fastmath<fast>, predicate = 7 : i64}> : (f32, f32) -> i1 pattern '(anonymous namespace)::CmpFOpNanKernelPattern' rollback of IR modifications requested UNREACHABLE executed at llvm-project/mlir/lib/Transforms/Utils/DialectConversion.cpp:1231! ``` The majority of patterns in MLIR have already been updated such that they do not trigger any rollbacks, but a few SPIRV patterns remain. More information in the RFC.