[MLIR][Vector] Remove vector.splat (#162167)

vector.splat has been deprecated (user: please use the very similar vector.broadcast instead) 
with the last PR landing about 6 weeks ago.

The discourse discussion is at
https://discourse.llvm.org/t/rfc-mlir-vector-deprecate-then-remove-vector-splat/87143/1
The last PR was #152230

This PR completely removes vector.splat. In addition to removing vector.splat from VectorOps.td, it

- Updates the few remaining places where vector::SplatOp is created (now vector::BroadcastOp is created)
- Removes temporary patterns where vector.splat is replaced by vector.broadcast

The only place 'vector.splat' appears is now the files

https://github.com/llvm/llvm-project/blob/main/mlir/utils/tree-sitter-mlir/test/corpus/op.txt
 and

https://github.com/llvm/llvm-project/blob/main/mlir/utils/tree-sitter-mlir/dialect/vector.js

---------

Signed-off-by: James Newling <james.newling@gmail.com>

Author: newling

flang/lib/Optimizer/Builder/PPCIntrinsicCall.cpp

@@ -2383,26 +2383,26 @@ PPCIntrinsicLibrary::genVecSplat(mlir::Type resultType,
   auto context{builder.getContext()};
   auto argBases{getBasesForArgs(args)};
 
-  mlir::vector::SplatOp splatOp{nullptr};
+  mlir::vector::BroadcastOp splatOp{nullptr};
   mlir::Type retTy{nullptr};
   switch (vop) {
   case VecOp::Splat: {
     assert(args.size() == 2);
     auto vecTyInfo{getVecTypeFromFir(argBases[0])};
 
     auto extractOp{genVecExtract(resultType, args)};
-    splatOp =
-        mlir::vector::SplatOp::create(builder, loc, *(extractOp.getUnboxed()),
-                                      vecTyInfo.toMlirVectorType(context));
+    splatOp = mlir::vector::BroadcastOp::create(
+        builder, loc, vecTyInfo.toMlirVectorType(context),
+        *(extractOp.getUnboxed()));
     retTy = vecTyInfo.toFirVectorType();
     break;
   }
   case VecOp::Splats: {
     assert(args.size() == 1);
     auto vecTyInfo{getVecTypeFromEle(argBases[0])};
 
-    splatOp = mlir::vector::SplatOp::create(
-        builder, loc, argBases[0], vecTyInfo.toMlirVectorType(context));
+    splatOp = mlir::vector::BroadcastOp::create(
+        builder, loc, vecTyInfo.toMlirVectorType(context), argBases[0]);
     retTy = vecTyInfo.toFirVectorType();
     break;
   }
@@ -2412,8 +2412,8 @@ PPCIntrinsicLibrary::genVecSplat(mlir::Type resultType,
     auto intOp{builder.createConvert(loc, eleTy, argBases[0])};
 
     // the intrinsic always returns vector(integer(4))
-    splatOp = mlir::vector::SplatOp::create(builder, loc, intOp,
-                                            mlir::VectorType::get(4, eleTy));
+    splatOp = mlir::vector::BroadcastOp::create(
+        builder, loc, mlir::VectorType::get(4, eleTy), intOp);
     retTy = fir::VectorType::get(4, eleTy);
     break;
   }
@@ -2444,7 +2444,8 @@ PPCIntrinsicLibrary::genVecXlds(mlir::Type resultType,
   auto addrConv{fir::ConvertOp::create(builder, loc, i64RefTy, addr)};
 
   auto addrVal{fir::LoadOp::create(builder, loc, addrConv)};
-  auto splatRes{mlir::vector::SplatOp::create(builder, loc, addrVal, i64VecTy)};
+  auto splatRes{
+      mlir::vector::BroadcastOp::create(builder, loc, i64VecTy, addrVal)};
 
   mlir::Value result{nullptr};
   if (mlirTy != splatRes.getType()) {

mlir/docs/Dialects/Vector.md

@@ -125,7 +125,7 @@ Some existing Arith and Vector Dialect on `n-D` `vector` types comprise:
 // Produces a vector<3x7x8xf32>
 %b = arith.mulf %0, %1 : vector<3x7x8xf32>
 // Produces a vector<3x7x8xf32>
-%c = vector.splat %1 : vector<3x7x8xf32>
+%c = vector.broadcast %1 : f32 to vector<3x7x8xf32>
 
 %d = vector.extract %0[1]: vector<7x8xf32> from vector<3x7x8xf32>
 %e = vector.extract %0[1, 5]: vector<8xf32> from vector<3x7x8xf32>
@@ -176,8 +176,6 @@ infrastructure can apply iteratively.
 ### Virtual Vector to Hardware Vector Lowering
 
 For now, `VV -> HWV` are specified in C++ (see for instance the
-[SplatOpLowering for n-D vectors](https://github.com/tensorflow/mlir/commit/0a0c4867c6a6fcb0a2f17ef26a791c1d551fe33d)
-or the
 [VectorOuterProductOp lowering](https://github.com/tensorflow/mlir/commit/957b1ca9680b4aacabb3a480fbc4ebd2506334b8)).
 
 Simple

mlir/include/mlir/Dialect/Vector/IR/VectorOps.td

@@ -2881,53 +2881,6 @@ def Vector_PrintOp :
     }];
 }
 
-//===----------------------------------------------------------------------===//
-// SplatOp
-//===----------------------------------------------------------------------===//
-
-def Vector_SplatOp : Vector_Op<"splat", [
-    Pure,
-    DeclareOpInterfaceMethods<InferIntRangeInterface, ["inferResultRanges"]>,
-    TypesMatchWith<"operand type matches element type of result",
-                   "aggregate", "input",
-                   "::llvm::cast<VectorType>($_self).getElementType()">
-  ]> {
-  let summary = "vector splat or broadcast operation";
-  let description = [{
-    Note: This operation is deprecated. Please use vector.broadcast.
-
-    Broadcast the operand to all elements of the result vector. The type of the
-    operand must match the element type of the vector type.
-
-    Example:
-
-    ```mlir
-    %s = arith.constant 10.1 : f32
-    %t = vector.splat %s : vector<8x16xf32>
-    ```
-
-    This operation is deprecated, the preferred representation of the above is:
-
-    ```mlir
-    %s = arith.constant 10.1 : f32
-    %t = vector.broadcast %s : f32 to vector<8x16xf32>
-    ```
-  }];
-
-  let arguments = (ins AnyType:$input);
-  let results = (outs AnyVectorOfAnyRank:$aggregate);
-
-  let builders = [
-    OpBuilder<(ins "Value":$element, "Type":$aggregateType),
-    [{ build($_builder, $_state, aggregateType, element); }]>];
-  let assemblyFormat = "$input attr-dict `:` type($aggregate)";
-
-  let hasFolder = 1;
-
-  // vector.splat is deprecated, and vector.broadcast should be used instead.
-  // Canonicalize vector.splat to vector.broadcast.
-  let hasCanonicalizer = 1;
-}
 
 //===----------------------------------------------------------------------===//
 // VectorScaleOp

mlir/lib/Conversion/ArithToAMDGPU/ArithToAMDGPU.cpp

@@ -432,10 +432,6 @@ static Value getOriginalVectorValue(Value value) {
                         current = op.getSource();
                         return false;
                       })
-                      .Case<vector::SplatOp>([&current](auto op) {
-                        current = op.getInput();
-                        return false;
-                      })
                       .Default([](Operation *) { return false; });
 
     if (!skipOp) {

mlir/lib/Conversion/ArmSMEToSCF/ArmSMEToSCF.cpp

@@ -236,7 +236,7 @@ struct TileLoadOpConversion : public OpRewritePattern<arm_sme::TileLoadOp> {
 ///  AFTER:
 ///  ```mlir
 ///  ...
-///  %pad_1d = vector.splat %pad : vector<[4]xi32>
+///  %pad_1d = vector.broadcast %pad : i32 to vector<[4]xi32>
 ///  %tile = scf.for %tile_slice_idx = %c0 to %svl_s step %c1
 ///                iter_args(%iter_tile = %init_tile) -> (vector<[4]x[4]xi32>) {
 ///    ...

mlir/lib/Conversion/VectorToArmSME/VectorToArmSME.cpp

@@ -731,28 +731,14 @@ struct ExtractFromCreateMaskToPselLowering
   }
 };
 
-// Convert all `vector.splat` to `vector.broadcast`. There is a path from
-// `vector.broadcast` to ArmSME via another pattern.
-struct ConvertSplatToBroadcast : public OpRewritePattern<vector::SplatOp> {
-  using Base::Base;
-
-  LogicalResult matchAndRewrite(vector::SplatOp splatOp,
-                                PatternRewriter &rewriter) const final {
-
-    rewriter.replaceOpWithNewOp<vector::BroadcastOp>(splatOp, splatOp.getType(),
-                                                     splatOp.getInput());
-    return success();
-  }
-};
-
 } // namespace
 
 void mlir::populateVectorToArmSMEPatterns(RewritePatternSet &patterns,
                                           MLIRContext &ctx) {
-  patterns.add<BroadcastOpToArmSMELowering, ConvertSplatToBroadcast,
-               TransferReadToArmSMELowering, TransferWriteToArmSMELowering,
-               TransposeOpToArmSMELowering, VectorLoadToArmSMELowering,
-               VectorStoreToArmSMELowering, VectorOuterProductToArmSMELowering,
+  patterns.add<BroadcastOpToArmSMELowering, TransferReadToArmSMELowering,
+               TransferWriteToArmSMELowering, TransposeOpToArmSMELowering,
+               VectorLoadToArmSMELowering, VectorStoreToArmSMELowering,
+               VectorOuterProductToArmSMELowering,
                VectorExtractToArmSMELowering, VectorInsertToArmSMELowering,
                VectorPrintToArmSMELowering, FoldTransferWriteOfExtractTileSlice,
                ExtractFromCreateMaskToPselLowering>(&ctx);

mlir/lib/Conversion/VectorToLLVM/ConvertVectorToLLVM.cpp

@@ -2161,19 +2161,6 @@ class TransposeOpToMatrixTransposeOpLowering
   }
 };
 
-/// Convert `vector.splat` to `vector.broadcast`. There is a path to LLVM from
-/// `vector.broadcast` through other patterns.
-struct VectorSplatToBroadcast : public ConvertOpToLLVMPattern<vector::SplatOp> {
-  using ConvertOpToLLVMPattern::ConvertOpToLLVMPattern;
-  LogicalResult
-  matchAndRewrite(vector::SplatOp splat, OpAdaptor adaptor,
-                  ConversionPatternRewriter &rewriter) const override {
-    rewriter.replaceOpWithNewOp<vector::BroadcastOp>(splat, splat.getType(),
-                                                     adaptor.getInput());
-    return success();
-  }
-};
-
 } // namespace
 
 void mlir::vector::populateVectorRankReducingFMAPattern(
@@ -2212,7 +2199,7 @@ void mlir::populateVectorToLLVMConversionPatterns(
                VectorInsertOpConversion, VectorPrintOpConversion,
                VectorTypeCastOpConversion, VectorScaleOpConversion,
                VectorExpandLoadOpConversion, VectorCompressStoreOpConversion,
-               VectorSplatToBroadcast, VectorBroadcastScalarToLowRankLowering,
+               VectorBroadcastScalarToLowRankLowering,
                VectorBroadcastScalarToNdLowering,
                VectorScalableInsertOpLowering, VectorScalableExtractOpLowering,
                MaskedReductionOpConversion, VectorInterleaveOpLowering,

mlir/lib/Conversion/VectorToSPIRV/VectorToSPIRV.cpp

@@ -22,7 +22,6 @@
 #include "mlir/IR/BuiltinAttributes.h"
 #include "mlir/IR/BuiltinTypes.h"
 #include "mlir/IR/Location.h"
-#include "mlir/IR/Matchers.h"
 #include "mlir/IR/PatternMatch.h"
 #include "mlir/IR/TypeUtilities.h"
 #include "mlir/Transforms/DialectConversion.h"
@@ -79,20 +78,6 @@ struct VectorShapeCast final : public OpConversionPattern<vector::ShapeCastOp> {
   }
 };
 
-// Convert `vector.splat` to `vector.broadcast`. There is a path from
-// `vector.broadcast` to SPIRV via other patterns.
-struct VectorSplatToBroadcast final
-    : public OpConversionPattern<vector::SplatOp> {
-  using Base::Base;
-  LogicalResult
-  matchAndRewrite(vector::SplatOp splat, OpAdaptor adaptor,
-                  ConversionPatternRewriter &rewriter) const override {
-    rewriter.replaceOpWithNewOp<vector::BroadcastOp>(splat, splat.getType(),
-                                                     adaptor.getInput());
-    return success();
-  }
-};
-
 struct VectorBitcastConvert final
     : public OpConversionPattern<vector::BitCastOp> {
   using Base::Base;
@@ -1092,10 +1077,10 @@ void mlir::populateVectorToSPIRVPatterns(
       VectorReductionPattern<CL_INT_MAX_MIN_OPS>,
       VectorReductionFloatMinMax<CL_FLOAT_MAX_MIN_OPS>,
       VectorReductionFloatMinMax<GL_FLOAT_MAX_MIN_OPS>, VectorShapeCast,
-      VectorSplatToBroadcast, VectorInsertStridedSliceOpConvert,
-      VectorShuffleOpConvert, VectorInterleaveOpConvert,
-      VectorDeinterleaveOpConvert, VectorScalarBroadcastPattern,
-      VectorLoadOpConverter, VectorStoreOpConverter, VectorStepOpConvert>(
+      VectorInsertStridedSliceOpConvert, VectorShuffleOpConvert,
+      VectorInterleaveOpConvert, VectorDeinterleaveOpConvert,
+      VectorScalarBroadcastPattern, VectorLoadOpConverter,
+      VectorStoreOpConverter, VectorStepOpConvert>(
       typeConverter, patterns.getContext(), PatternBenefit(1));
 
   // Make sure that the more specialized dot product pattern has higher benefit

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

@@ -123,8 +123,7 @@ void mlir::arith::populateEmulateUnsupportedFloatsLegality(
                                vector::OuterProductOp, vector::ScanOp>(
       [&](Operation *op) { return converter.isLegal(op); });
   target.addLegalOp<arith::BitcastOp, arith::ExtFOp, arith::TruncFOp,
-                    arith::ConstantOp, arith::SelectOp, vector::SplatOp,
-                    vector::BroadcastOp>();
+                    arith::ConstantOp, arith::SelectOp, vector::BroadcastOp>();
 }
 
 void EmulateUnsupportedFloatsPass::runOnOperation() {

mlir/lib/Dialect/Vector/IR/VectorOps.cpp

@@ -1665,10 +1665,10 @@ static bool hasZeroDimVectors(Operation *op) {
          llvm::any_of(op->getResultTypes(), hasZeroDimVectorType);
 }
 
-/// All BroadcastOps and SplatOps, as well as ShapeCastOps that only prepend
-/// 1s, are considered to be 'broadcastlike'.
+/// All BroadcastOps, as well as ShapeCastOps that only prepend 1s, are
+/// considered to be 'broadcastlike'.
 static bool isBroadcastLike(Operation *op) {
-  if (isa<BroadcastOp, SplatOp>(op))
+  if (isa<BroadcastOp>(op))
     return true;
 
   auto shapeCast = dyn_cast<ShapeCastOp>(op);
@@ -3249,23 +3249,18 @@ struct Canonicalize0DShuffleOp : public OpRewritePattern<ShuffleOp> {
 };
 
 /// Consider the defining operation `defOp` of `value`. If `defOp` is a
-/// vector.splat or a vector.broadcast with a scalar operand, return the scalar
-/// value that is splatted. Otherwise return null.
+/// vector.broadcast with a scalar operand, return the scalar value that is
+/// splatted. Otherwise return null.
 ///
-/// Examples:
+/// Example:
 ///
-/// scalar_source --> vector.splat --> value     - return scalar_source
 /// scalar_source --> vector.broadcast --> value - return scalar_source
 static Value getScalarSplatSource(Value value) {
   // Block argument:
   Operation *defOp = value.getDefiningOp();
   if (!defOp)
     return {};
 
-  // Splat:
-  if (auto splat = dyn_cast<vector::SplatOp>(defOp))
-    return splat.getInput();
-
   auto broadcast = dyn_cast<vector::BroadcastOp>(defOp);
 
   // Not broadcast (and not splat):
@@ -7511,41 +7506,6 @@ void mlir::vector::populateVectorToVectorCanonicalizationPatterns(
           patterns.getContext(), benefit);
 }
 
-//===----------------------------------------------------------------------===//
-// SplatOp
-//===----------------------------------------------------------------------===//
-
-OpFoldResult SplatOp::fold(FoldAdaptor adaptor) {
-  auto constOperand = adaptor.getInput();
-  if (!isa_and_nonnull<IntegerAttr, FloatAttr>(constOperand))
-    return {};
-
-  // SplatElementsAttr::get treats single value for second arg as being a splat.
-  return SplatElementsAttr::get(getType(), {constOperand});
-}
-
-// Canonicalizer for vector.splat. It always gets canonicalized to a
-// vector.broadcast.
-class SplatToBroadcastPattern final : public OpRewritePattern<SplatOp> {
-public:
-  using Base::Base;
-  LogicalResult matchAndRewrite(SplatOp splatOp,
-                                PatternRewriter &rewriter) const override {
-    rewriter.replaceOpWithNewOp<vector::BroadcastOp>(splatOp, splatOp.getType(),
-                                                     splatOp.getOperand());
-    return success();
-  }
-};
-void SplatOp::getCanonicalizationPatterns(RewritePatternSet &results,
-                                          MLIRContext *context) {
-  results.add<SplatToBroadcastPattern>(context);
-}
-
-void SplatOp::inferResultRanges(ArrayRef<ConstantIntRanges> argRanges,
-                                SetIntRangeFn setResultRanges) {
-  setResultRanges(getResult(), argRanges.front());
-}
-
 Value mlir::vector::makeArithReduction(OpBuilder &b, Location loc,
                                        CombiningKind kind, Value v1, Value acc,
                                        arith::FastMathFlagsAttr fastmath,