[mlir][Transforms] Delete 1:N dialect conversion driver (#121389)

The 1:N dialect conversion driver has been deprecated. Use the regular
dialect conversion driver instead. This commit deletes the 1:N dialect
conversion driver.

Note for LLVM integration: If you are already using the regular dialect conversion, but still have argument materializations in your code base, simply delete all `addArgumentMaterialization` calls.

For details, see
https://discourse.llvm.org/t/rfc-merging-1-1-and-1-n-dialect-conversions/82513.

Author: matthias-springer

mlir/include/mlir/Dialect/Func/Transforms/OneToNFuncConversions.h

@@ -63,15 +63,6 @@ void populateSCFStructuralTypeConversions(const TypeConverter &typeConverter,
 void populateSCFStructuralTypeConversionTarget(
     const TypeConverter &typeConverter, ConversionTarget &target);
 
-/// Populates the provided pattern set with patterns that do 1:N type
-/// conversions on (some) SCF ops. This is intended to be used with
-/// applyPartialOneToNConversion.
-/// FIXME: The 1:N dialect conversion is deprecated and will be removed soon.
-/// 1:N support has been added to the regular dialect conversion driver.
-/// Use populateSCFStructuralTypeConversions() instead.
-void populateSCFStructuralOneToNTypeConversions(
-    const TypeConverter &typeConverter, RewritePatternSet &patterns);
-
 /// Populate patterns for SCF software pipelining transformation. See the
 /// ForLoopPipeliningPattern for the transformation details.
 void populateSCFLoopPipeliningPatterns(RewritePatternSet &patterns,

mlir/include/mlir/Dialect/SCF/Transforms/Patterns.h

@@ -20,7 +20,6 @@
 #include "mlir/Dialect/Vector/Transforms/VectorRewritePatterns.h"
 #include "mlir/Transforms/DialectConversion.h"
 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
-#include "mlir/Transforms/OneToNTypeConversion.h"
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/Support/LogicalResult.h"
 

mlir/include/mlir/Dialect/SPIRV/Transforms/SPIRVConversion.h

@@ -45,13 +45,11 @@ class TypeConverter {
   // Copy the registered conversions, but not the caches
   TypeConverter(const TypeConverter &other)
       : conversions(other.conversions),
-        argumentMaterializations(other.argumentMaterializations),
         sourceMaterializations(other.sourceMaterializations),
         targetMaterializations(other.targetMaterializations),
         typeAttributeConversions(other.typeAttributeConversions) {}
   TypeConverter &operator=(const TypeConverter &other) {
     conversions = other.conversions;
-    argumentMaterializations = other.argumentMaterializations;
     sourceMaterializations = other.sourceMaterializations;
     targetMaterializations = other.targetMaterializations;
     typeAttributeConversions = other.typeAttributeConversions;
@@ -180,21 +178,6 @@ class TypeConverter {
   /// can be a TypeRange; in that case, the function must return a
   /// SmallVector<Value>.
 
-  /// This method registers a materialization that will be called when
-  /// converting (potentially multiple) block arguments that were the result of
-  /// a signature conversion of a single block argument, to a single SSA value
-  /// with the old block argument type.
-  ///
-  /// Note: Argument materializations are used only with the 1:N dialect
-  /// conversion driver. The 1:N dialect conversion driver will be removed soon
-  /// and so will be argument materializations.
-  template <typename FnT, typename T = typename llvm::function_traits<
-                              std::decay_t<FnT>>::template arg_t<1>>
-  void addArgumentMaterialization(FnT &&callback) {
-    argumentMaterializations.emplace_back(
-        wrapMaterialization<T>(std::forward<FnT>(callback)));
-  }
-
   /// This method registers a materialization that will be called when
   /// converting a replacement value back to its original source type.
   /// This is used when some uses of the original value persist beyond the main
@@ -322,8 +305,6 @@ class TypeConverter {
   /// generating a cast sequence of some kind. See the respective
   /// `add*Materialization` for more information on the context for these
   /// methods.
-  Value materializeArgumentConversion(OpBuilder &builder, Location loc,
-                                      Type resultType, ValueRange inputs) const;
   Value materializeSourceConversion(OpBuilder &builder, Location loc,
                                     Type resultType, ValueRange inputs) const;
   Value materializeTargetConversion(OpBuilder &builder, Location loc,
@@ -510,7 +491,6 @@ class TypeConverter {
   SmallVector<ConversionCallbackFn, 4> conversions;
 
   /// The list of registered materialization functions.
-  SmallVector<MaterializationCallbackFn, 2> argumentMaterializations;
   SmallVector<MaterializationCallbackFn, 2> sourceMaterializations;
   SmallVector<TargetMaterializationCallbackFn, 2> targetMaterializations;
 

mlir/include/mlir/Transforms/DialectConversion.h

@@ -1,7 +1,6 @@
 add_mlir_dialect_library(MLIRFuncTransforms
   DuplicateFunctionElimination.cpp
   FuncConversions.cpp
-  OneToNFuncConversions.cpp
 
   ADDITIONAL_HEADER_DIRS
   ${MLIR_MAIN_INCLUDE_DIR}/mlir/Dialect/Func/Transforms