[mlir][ArmSME] Remove ArmSMETypeConverter (and configure LLVM one instead)

This patch removes the ArmSMETypeConverter, and instead updates
`configureArmSMEToLLVMConversionLegality()` to add an ArmSME vector type
conversion to the existing LLVMTypeConverter. This makes it easier to
add these patterns to an existing `-to-llvm` lowering pass.

Author: MacDue

mlir/include/mlir/Conversion/ArmSMEToLLVM/ArmSMEToLLVM.h

@@ -20,17 +20,16 @@ class RewritePatternSet;
 #define GEN_PASS_DECL_CONVERTARMSMETOLLVM
 #include "mlir/Conversion/Passes.h.inc"
 
-using arm_sme::ArmSMETypeConverter;
-
 /// Create a pass to convert from the ArmSME dialect to LLVM intrinsics.
 std::unique_ptr<Pass> createConvertArmSMEToLLVMPass();
 
 /// Configure target to convert from the ArmSME dialect to LLVM intrinsics.
-void configureArmSMEToLLVMConversionLegality(ConversionTarget &target);
+void configureArmSMEToLLVMConversionLegality(ConversionTarget &target,
+                                             LLVMTypeConverter &typeConverter);
 
 /// Populate the given list with patterns that convert from the ArmSME dialect
 /// to LLVM intrinsics.
-void populateArmSMEToLLVMConversionPatterns(ArmSMETypeConverter &converter,
+void populateArmSMEToLLVMConversionPatterns(LLVMTypeConverter &converter,
                                             RewritePatternSet &patterns);
 
 } // namespace mlir

mlir/include/mlir/Dialect/ArmSME/Transforms/Passes.h

@@ -32,14 +32,6 @@ std::unique_ptr<Pass> createEnableArmStreamingPass(
 /// Pass that allocates tile IDs to ArmSME operations.
 std::unique_ptr<Pass> createTileAllocationPass();
 
-//===----------------------------------------------------------------------===//
-// Type ArmSMETypeConverter pass.
-//===----------------------------------------------------------------------===//
-class ArmSMETypeConverter : public LLVMTypeConverter {
-public:
-  ArmSMETypeConverter(MLIRContext *ctx, const LowerToLLVMOptions &options);
-};
-
 //===----------------------------------------------------------------------===//
 // Registration
 //===----------------------------------------------------------------------===//

mlir/lib/Conversion/ArmSMEToLLVM/ArmSMEToLLVM.cpp

@@ -538,10 +538,8 @@ struct ConvertArmSMEToLLVMPass
   void runOnOperation() override {
     LLVMConversionTarget target(getContext());
     RewritePatternSet patterns(&getContext());
-    ArmSMETypeConverter converter(&getContext(),
-                                  LowerToLLVMOptions(&getContext()));
-
-    configureArmSMEToLLVMConversionLegality(target);
+    LLVMTypeConverter converter(&getContext());
+    configureArmSMEToLLVMConversionLegality(target, converter);
     populateArmSMEToLLVMConversionPatterns(converter, patterns);
 
     if (failed(applyPartialConversion(getOperation(), target,
@@ -552,7 +550,8 @@ struct ConvertArmSMEToLLVMPass
 
 } // namespace
 
-void mlir::configureArmSMEToLLVMConversionLegality(ConversionTarget &target) {
+void mlir::configureArmSMEToLLVMConversionLegality(
+    ConversionTarget &target, LLVMTypeConverter &typeConverter) {
   target.addIllegalDialect<arm_sme::ArmSMEDialect>();
   target.addLegalOp<
       arm_sme::MaterializeSSATileOp, arm_sme::aarch64_sme_zero,
@@ -571,10 +570,17 @@ void mlir::configureArmSMEToLLVMConversionLegality(ConversionTarget &target) {
       arm_sme::aarch64_sme_write_vert, arm_sme::aarch64_sme_mopa>();
   target.addLegalDialect<arith::ArithDialect>();
   target.addLegalOp<UnrealizedConversionCastOp>();
+  typeConverter.addConversion([&](VectorType type) -> std::optional<Type> {
+    // There's no LLVM type for SME tiles, but after lowering to intrinsics all
+    // SME vector types should be eliminated.
+    if (arm_sme::isValidSMETileVectorType(type))
+      return type;
+    return std::nullopt;
+  });
 }
 
-void mlir::populateArmSMEToLLVMConversionPatterns(
-    ArmSMETypeConverter &converter, RewritePatternSet &patterns) {
+void mlir::populateArmSMEToLLVMConversionPatterns(LLVMTypeConverter &converter,
+                                                  RewritePatternSet &patterns) {
   patterns.add<LoadTileSliceConversion, MoveTileSliceToVectorConversion,
                MoveVectorToTileSliceConversion, StoreTileSliceConversion,
                OuterProductOpConversion, ZeroOpConversion, GetTileConversion>(

mlir/lib/Dialect/ArmSME/Transforms/ArmSMETypeConverter.cpp

@@ -1,5 +1,4 @@
 add_mlir_dialect_library(MLIRArmSMETransforms
-  ArmSMETypeConverter.cpp
   EnableArmStreaming.cpp
   TileAllocation.cpp