[mlir][memref] Fix type conversion in emulate-wide-int and emulate-narrow-type

This PR follows with llvm#112104, using `nullptr` to indicate that type conversion
failed and no fallback conversion should be attempted.

Author: CoTinker

mlir/lib/Dialect/Arith/Transforms/EmulateNarrowType.cpp

@@ -40,11 +40,11 @@ arith::NarrowTypeEmulationConverter::NarrowTypeEmulationConverter(
   addConversion([this](FunctionType ty) -> std::optional<Type> {
     SmallVector<Type> inputs;
     if (failed(convertTypes(ty.getInputs(), inputs)))
-      return std::nullopt;
+      return nullptr;
 
     SmallVector<Type> results;
     if (failed(convertTypes(ty.getResults(), results)))
-      return std::nullopt;
+      return nullptr;
 
     return FunctionType::get(ty.getContext(), inputs, results);
   });

mlir/lib/Dialect/MemRef/Transforms/EmulateNarrowType.cpp

@@ -169,7 +169,7 @@ struct ConvertMemRefAllocation final : OpConversionPattern<OpTy> {
                       std::is_same<OpTy, memref::AllocaOp>(),
                   "expected only memref::AllocOp or memref::AllocaOp");
     auto currentType = cast<MemRefType>(op.getMemref().getType());
-    auto newResultType = dyn_cast<MemRefType>(
+    auto newResultType = dyn_cast_or_null<MemRefType>(
         this->getTypeConverter()->convertType(op.getType()));
     if (!newResultType) {
       return rewriter.notifyMatchFailure(
@@ -377,8 +377,8 @@ struct ConvertMemRefReinterpretCast final
   LogicalResult
   matchAndRewrite(memref::ReinterpretCastOp op, OpAdaptor adaptor,
                   ConversionPatternRewriter &rewriter) const override {
-    MemRefType newTy =
-        dyn_cast<MemRefType>(getTypeConverter()->convertType(op.getType()));
+    MemRefType newTy = dyn_cast_or_null<MemRefType>(
+        getTypeConverter()->convertType(op.getType()));
     if (!newTy) {
       return rewriter.notifyMatchFailure(
           op->getLoc(),
@@ -466,7 +466,7 @@ struct ConvertMemRefSubview final : OpConversionPattern<memref::SubViewOp> {
   LogicalResult
   matchAndRewrite(memref::SubViewOp subViewOp, OpAdaptor adaptor,
                   ConversionPatternRewriter &rewriter) const override {
-    MemRefType newTy = dyn_cast<MemRefType>(
+    MemRefType newTy = dyn_cast_or_null<MemRefType>(
         getTypeConverter()->convertType(subViewOp.getType()));
     if (!newTy) {
       return rewriter.notifyMatchFailure(
@@ -632,14 +632,14 @@ void memref::populateMemRefNarrowTypeEmulationConversions(
         SmallVector<int64_t> strides;
         int64_t offset;
         if (failed(getStridesAndOffset(ty, strides, offset)))
-          return std::nullopt;
+          return nullptr;
         if (!strides.empty() && strides.back() != 1)
-          return std::nullopt;
+          return nullptr;
 
         auto newElemTy = IntegerType::get(ty.getContext(), loadStoreWidth,
                                           intTy.getSignedness());
         if (!newElemTy)
-          return std::nullopt;
+          return nullptr;
 
         StridedLayoutAttr layoutAttr;
         // If the offset is 0, we do not need a strided layout as the stride is

mlir/lib/Dialect/MemRef/Transforms/EmulateWideInt.cpp

@@ -159,7 +159,7 @@ void memref::populateMemRefWideIntEmulationConversions(
 
         Type newElemTy = typeConverter.convertType(intTy);
         if (!newElemTy)
-          return std::nullopt;
+          return nullptr;
 
         return ty.cloneWith(std::nullopt, newElemTy);
       });

mlir/test/Dialect/MemRef/emulate-narrow-type-unsupported.mlir

@@ -0,0 +1,25 @@
+// RUN: mlir-opt --test-emulate-narrow-int="memref-load-bitwidth=8" --verify-diagnostics --split-input-file %s
+
+func.func @negative_memref_subview_non_contiguous(%idx : index) -> i4 {
+  %c0 = arith.constant 0 : index
+  %arr = memref.alloc() : memref<40x40xi4>
+  // expected-error @+1 {{failed to legalize operation 'memref.subview' that was explicitly marked illegal}}
+  %subview = memref.subview %arr[%idx, 0] [4, 8] [1, 1] : memref<40x40xi4> to memref<4x8xi4, strided<[40, 1], offset:?>>
+  %ld = memref.load %subview[%c0, %c0] : memref<4x8xi4, strided<[40, 1], offset:?>>
+  return %ld : i4
+}
+
+// -----
+
+func.func @alloc_non_contiguous() {
+  // expected-error @+1 {{failed to legalize operation 'memref.alloc' that was explicitly marked illegal}}
+  %arr = memref.alloc() : memref<8x8xi4, strided<[1, 8]>>
+  return
+}
+
+// -----
+
+// expected-error @+1 {{failed to legalize operation 'func.func' that was explicitly marked illegal}}
+func.func @argument_non_contiguous(%arg0 : memref<8x8xi4, strided<[1, 8]>>) {
+  return
+}

mlir/test/Dialect/MemRef/emulate-narrow-type.mlir

@@ -1,5 +1,5 @@
-// RUN: mlir-opt --test-emulate-narrow-int="memref-load-bitwidth=8" --cse --verify-diagnostics --split-input-file %s | FileCheck %s
-// RUN: mlir-opt --test-emulate-narrow-int="memref-load-bitwidth=32" --cse --verify-diagnostics --split-input-file %s | FileCheck %s --check-prefix=CHECK32
+// RUN: mlir-opt --test-emulate-narrow-int="memref-load-bitwidth=8" --cse --split-input-file %s | FileCheck %s
+// RUN: mlir-opt --test-emulate-narrow-int="memref-load-bitwidth=32" --cse --split-input-file %s | FileCheck %s --check-prefix=CHECK32
 
 // Expect no conversions.
 func.func @memref_i8() -> i8 {
@@ -203,18 +203,6 @@ func.func @memref_subview_dynamic_offset_i4(%idx : index) -> i4 {
 
 // -----
 
-
-func.func @negative_memref_subview_non_contiguous(%idx : index) -> i4 {
-  %c0 = arith.constant 0 : index
-  %arr = memref.alloc() : memref<40x40xi4>
-  // expected-error @+1 {{failed to legalize operation 'memref.subview' that was explicitly marked illegal}}
-  %subview = memref.subview %arr[%idx, 0] [4, 8] [1, 1] : memref<40x40xi4> to memref<4x8xi4, strided<[40, 1], offset:?>>
-  %ld = memref.load %subview[%c0, %c0] : memref<4x8xi4, strided<[40, 1], offset:?>>
-  return %ld : i4
-}
-
-// -----
-
 func.func @reinterpret_cast_memref_load_0D() -> i4 {
     %0 = memref.alloc() : memref<5xi4>
     %reinterpret_cast_0 = memref.reinterpret_cast %0 to offset: [0], sizes: [], strides: [] : memref<5xi4> to memref<i4>
@@ -540,16 +528,3 @@ func.func @memref_copy_i4(%arg0: memref<32x128xi4, 1>, %arg1: memref<32x128xi4>)
 //  CHECK32-SAME:   %[[ARG0:.*]]: memref<512xi32, 1>, %[[ARG1:.*]]: memref<512xi32>
 //       CHECK32:     memref.copy %[[ARG0]], %[[ARG1]]
 //       CHECK32:     return
-
-// -----
-
-!colMajor = memref<8x8xi4, strided<[1, 8]>>
-func.func @copy_distinct_layouts(%idx : index) -> i4 {
-  %c0 = arith.constant 0 : index
-  %arr = memref.alloc() : memref<8x8xi4>
-  %arr2 = memref.alloc() : !colMajor
-  // expected-error @+1 {{failed to legalize operation 'memref.copy' that was explicitly marked illegal}}
-  memref.copy %arr, %arr2 : memref<8x8xi4> to !colMajor
-  %ld = memref.load %arr2[%c0, %c0] : !colMajor
-  return %ld : i4
-}

mlir/test/Dialect/MemRef/emulate-wide-int-unsupported.mlir

@@ -0,0 +1,28 @@
+// RUN: mlir-opt --memref-emulate-wide-int="widest-int-supported=32" \
+// RUN:   --split-input-file --verify-diagnostics %s
+
+// Make sure we do not crash on unsupported types.
+
+func.func @alloc_i128() {
+  // expected-error@+1 {{failed to legalize operation 'memref.alloc' that was explicitly marked illegal}}
+  %m = memref.alloc() : memref<4xi128, 1>
+  return
+}
+
+// -----
+
+func.func @load_i128(%m: memref<4xi128, 1>) {
+  %c0 = arith.constant 0 : index
+  // expected-error@+1 {{failed to legalize operation 'memref.load' that was explicitly marked illegal}}
+  %v = memref.load %m[%c0] : memref<4xi128, 1>
+  return
+}
+
+// -----
+
+func.func @store_i128(%c1: i128, %m: memref<4xi128, 1>) {
+  %c0 = arith.constant 0 : index
+  // expected-error@+1 {{failed to legalize operation 'memref.store' that was explicitly marked illegal}}
+  memref.store %c1, %m[%c0] : memref<4xi128, 1>
+  return
+}