MathToSPIRV.cpp

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//===- MathToSPIRV.cpp - Math to SPIR-V Patterns --------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements patterns to convert Math dialect to SPIR-V dialect.
//
//===----------------------------------------------------------------------===//
 
#include "../SPIRVCommon/Pattern.h"
#include "mlir/Dialect/Math/IR/Math.h"
#include "mlir/Dialect/SPIRV/IR/SPIRVOps.h"
#include "mlir/Dialect/SPIRV/Transforms/SPIRVConversion.h"
#include "mlir/IR/BuiltinTypes.h"
#include "mlir/IR/Matchers.h"
#include "mlir/IR/TypeUtilities.h"
#include "mlir/Transforms/DialectConversion.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/TypeSwitch.h"
#include "llvm/Support/FormatVariadic.h"
 
#define DEBUG_TYPE "math-to-spirv-pattern"
 
using namespace mlir;
 
//===----------------------------------------------------------------------===//
// Utility functions
//===----------------------------------------------------------------------===//
 
/// Creates a 32-bit scalar/vector integer constant. Returns nullptr if the
/// given type is not a 32-bit scalar/vector type.
static Value getScalarOrVectorI32Constant(Type type, int value,
                                          OpBuilder &builder, Location loc) {
  if (auto vectorType = dyn_cast<VectorType>(type)) {
    if (!vectorType.getElementType().isInteger(32))
      return nullptr;
    SmallVector<int> values(vectorType.getNumElements(), value);
    return spirv::ConstantOp::create(builder, loc, type,
                                     builder.getI32VectorAttr(values));
  }
  if (type.isInteger(32))
    return spirv::ConstantOp::create(builder, loc, type,
                                     builder.getI32IntegerAttr(value));
 
  return nullptr;
}
 
/// Check if the type is supported by math-to-spirv conversion. We expect to
/// only see scalars and vectors at this point, with higher-level types already
/// lowered.
static bool isSupportedSourceType(Type originalType) {
  if (originalType.isIntOrIndexOrFloat())
    return true;
 
  if (auto vecTy = dyn_cast<VectorType>(originalType)) {
    if (!vecTy.getElementType().isIntOrIndexOrFloat())
      return false;
    if (vecTy.isScalable())
      return false;
    if (vecTy.getRank() > 1)
      return false;
 
    return true;
  }
 
  return false;
}
 
/// Check if all `sourceOp` types are supported by math-to-spirv conversion.
/// Notify of a match failure othwerise and return a `failure` result.
/// This is intended to simplify type checks in `OpConversionPattern`s.
static LogicalResult checkSourceOpTypes(ConversionPatternRewriter &rewriter,
                                        Operation *sourceOp) {
  auto allTypes = llvm::to_vector(sourceOp->getOperandTypes());
  llvm::append_range(allTypes, sourceOp->getResultTypes());
 
  for (Type ty : allTypes) {
    if (!isSupportedSourceType(ty)) {
      return rewriter.notifyMatchFailure(
          sourceOp,
          llvm::formatv(
              "unsupported source type for Math to SPIR-V conversion: {0}",
              ty));
    }
  }
 
  return success();
}
 
//===----------------------------------------------------------------------===//
// Operation conversion
//===----------------------------------------------------------------------===//
 
// Note that DRR cannot be used for the patterns in this file: we may need to
// convert type along the way, which requires ConversionPattern. DRR generates
// normal RewritePattern.
 
namespace {
/// Converts elementwise unary, binary, and ternary standard operations to
/// SPIR-V operations. Checks that source `Op` types are supported.
template <typename Op, typename SPIRVOp>
struct CheckedElementwiseOpPattern final
    : public spirv::ElementwiseOpPattern<Op, SPIRVOp> {
  using BasePattern = typename spirv::ElementwiseOpPattern<Op, SPIRVOp>;
  using BasePattern::BasePattern;
 
  LogicalResult
  matchAndRewrite(Op op, typename Op::Adaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, op); failed(res))
      return res;
 
    return BasePattern::matchAndRewrite(op, adaptor, rewriter);
  }
};
 
/// Converts math.copysign to SPIR-V ops.
struct CopySignPattern final : public OpConversionPattern<math::CopySignOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::CopySignOp copySignOp, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, copySignOp);
        failed(res))
      return res;
 
    // Defer to the CL copysign op on Kernel targets.
    auto &typeConverter = *getTypeConverter<SPIRVTypeConverter>();
    if (typeConverter.getTargetEnv().allows(spirv::Capability::Kernel))
      return rewriter.notifyMatchFailure(copySignOp,
                                         "Kernel target has native CL op");
 
    Type type = getTypeConverter()->convertType(copySignOp.getType());
    if (!type)
      return failure();
 
    FloatType floatType;
    if (auto scalarType = dyn_cast<FloatType>(copySignOp.getType())) {
      floatType = scalarType;
    } else if (auto vectorType = dyn_cast<VectorType>(copySignOp.getType())) {
      floatType = cast<FloatType>(vectorType.getElementType());
    } else {
      return failure();
    }
 
    Location loc = copySignOp.getLoc();
    int bitwidth = floatType.getWidth();
    Type intType = rewriter.getIntegerType(bitwidth);
    uint64_t intValue = uint64_t(1) << (bitwidth - 1);
 
    Value signMask = spirv::ConstantOp::create(
        rewriter, loc, intType, rewriter.getIntegerAttr(intType, intValue));
    Value valueMask = spirv::ConstantOp::create(
        rewriter, loc, intType,
        rewriter.getIntegerAttr(intType, intValue - 1u));
 
    if (auto vectorType = dyn_cast<VectorType>(type)) {
      assert(vectorType.getRank() == 1);
      int count = vectorType.getNumElements();
      intType = VectorType::get(count, intType);
 
      Repeated<Value> signSplat(count, signMask);
      signMask = spirv::CompositeConstructOp::create(rewriter, loc, intType,
                                                     signSplat);
 
      Repeated<Value> valueSplat(count, valueMask);
      valueMask = spirv::CompositeConstructOp::create(rewriter, loc, intType,
                                                      valueSplat);
    }
 
    Value lhsCast =
        spirv::BitcastOp::create(rewriter, loc, intType, adaptor.getLhs());
    Value rhsCast =
        spirv::BitcastOp::create(rewriter, loc, intType, adaptor.getRhs());
 
    Value value = spirv::BitwiseAndOp::create(rewriter, loc, intType,
                                              ValueRange{lhsCast, valueMask});
    Value sign = spirv::BitwiseAndOp::create(rewriter, loc, intType,
                                             ValueRange{rhsCast, signMask});
 
    Value result = spirv::BitwiseOrOp::create(rewriter, loc, intType,
                                              ValueRange{value, sign});
    rewriter.replaceOpWithNewOp<spirv::BitcastOp>(copySignOp, type, result);
    return success();
  }
};
 
/// Converts math.ctlz to SPIR-V ops.
///
/// OpenCL targets lower math.ctlz directly to OpenCL.std clz via the generic
/// elementwise pattern. This pattern handles the shader fallback.
///
/// SPIR-V does not have a direct operations for counting leading zeros for
/// glsl. If Shader capability is supported, we can leverage GL FindUMsb to
/// calculate it.
struct CountLeadingZerosPattern final
    : public OpConversionPattern<math::CountLeadingZerosOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::CountLeadingZerosOp countOp, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, countOp); failed(res))
      return res;
 
    Type type = getTypeConverter()->convertType(countOp.getType());
    if (!type)
      return failure();
 
    auto &typeConverter = *getTypeConverter<SPIRVTypeConverter>();
    if (!typeConverter.getTargetEnv().allows(spirv::Capability::Shader))
      return rewriter.notifyMatchFailure(countOp, "requires Shader capability");
 
    // The GL FindUMsb fallback only supports 32-bit integer types for now.
    unsigned bitwidth = 0;
    if (isa<IntegerType>(type))
      bitwidth = type.getIntOrFloatBitWidth();
    if (auto vectorType = dyn_cast<VectorType>(type))
      bitwidth = vectorType.getElementTypeBitWidth();
    if (bitwidth != 32)
      return failure();
 
    Location loc = countOp.getLoc();
    Value input = adaptor.getOperand();
    Value val1 = getScalarOrVectorI32Constant(type, 1, rewriter, loc);
    Value val31 = getScalarOrVectorI32Constant(type, 31, rewriter, loc);
    Value val32 = getScalarOrVectorI32Constant(type, 32, rewriter, loc);
 
    Value msb = spirv::GLFindUMsbOp::create(rewriter, loc, input);
    // We need to subtract from 31 given that the index returned by GLSL
    // FindUMsb is counted from the least significant bit. Theoretically this
    // also gives the correct result even if the integer has all zero bits, in
    // which case GL FindUMsb would return -1.
    Value subMsb = spirv::ISubOp::create(rewriter, loc, val31, msb);
    // However, certain Vulkan implementations have driver bugs for the corner
    // case where the input is zero. And.. it can be smart to optimize a select
    // only involving the corner case. So separately compute the result when the
    // input is either zero or one.
    Value subInput = spirv::ISubOp::create(rewriter, loc, val32, input);
    Value cmp = spirv::ULessThanEqualOp::create(rewriter, loc, input, val1);
    rewriter.replaceOpWithNewOp<spirv::SelectOp>(countOp, cmp, subInput,
                                                 subMsb);
    return success();
  }
};
 
/// Converts math.cttz to GL FindILsb. GL FindILsb returns -1 for a zero
/// input while math.cttz must return the bitwidth, so the zero case is
/// patched up with a select.
///
/// OpenCL targets use OpenCL.std ctz. This pattern handles the shader fallback.
struct CountTrailingZerosPattern final
    : public OpConversionPattern<math::CountTrailingZerosOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::CountTrailingZerosOp countOp, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, countOp); failed(res))
      return res;
 
    Type type = getTypeConverter()->convertType(countOp.getType());
    if (!type)
      return failure();
 
    auto &typeConverter = *getTypeConverter<SPIRVTypeConverter>();
    if (!typeConverter.getTargetEnv().allows(spirv::Capability::Shader))
      return rewriter.notifyMatchFailure(countOp, "requires Shader capability");
 
    unsigned bitwidth = 0;
    if (isa<IntegerType>(type))
      bitwidth = type.getIntOrFloatBitWidth();
    else if (auto vectorType = dyn_cast<VectorType>(type))
      bitwidth = vectorType.getElementTypeBitWidth();
 
    Location loc = countOp.getLoc();
    Value input = adaptor.getOperand();
    Value val0 = spirv::ConstantOp::getZero(type, loc, rewriter);
    Type elemType = getElementTypeOrSelf(type);
    Attribute bwAttr = IntegerAttr::get(elemType, bitwidth);
    if (auto vecType = dyn_cast<VectorType>(type))
      bwAttr = SplatElementsAttr::get(vecType, bwAttr);
    Value valBitwidth = spirv::ConstantOp::create(rewriter, loc, type, bwAttr);
 
    Value lsb = spirv::GLFindILsbOp::create(rewriter, loc, input);
    Value isZero = spirv::IEqualOp::create(rewriter, loc, input, val0);
    rewriter.replaceOpWithNewOp<spirv::SelectOp>(countOp, isZero, valBitwidth,
                                                 lsb);
    return success();
  }
};
 
/// Converts math.cttz to OpenCL.std ctz, preserving the source bit width when
/// narrow integers are emulated using wider integers.
struct CountTrailingZerosOpenCLPattern final
    : public OpConversionPattern<math::CountTrailingZerosOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::CountTrailingZerosOp op, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (failed(checkSourceOpTypes(rewriter, op)))
      return failure();
 
    auto &typeConverter = *getTypeConverter<SPIRVTypeConverter>();
    if (!typeConverter.getTargetEnv().allows(spirv::Capability::Kernel))
      return rewriter.notifyMatchFailure(op, "requires Kernel capability");
    Type type = typeConverter.convertType(op.getType());
    if (!type)
      return failure();
 
    Value input = adaptor.getOperand();
    Type elementType = getElementTypeOrSelf(type);
    if (elementType.isInteger(1)) {
      // cttz(false) is true and cttz(true) is false.
      rewriter.replaceOpWithNewOp<spirv::LogicalNotOp>(op, type, input);
      return success();
    }
 
    Type sourceElementType = getElementTypeOrSelf(op.getType());
    unsigned targetWidth = elementType.getIntOrFloatBitWidth();
    // Index values use the bit width chosen by the type converter.
    unsigned sourceWidth = sourceElementType.isIndex()
                               ? targetWidth
                               : sourceElementType.getIntOrFloatBitWidth();
    if (sourceWidth < targetWidth) {
      // Set the bit immediately above the original value. This bounds the
      // count by sourceWidth, even when the emulated value has nonzero high
      // bits, and gives the correct result for a zero source value.
      Attribute sentinel = IntegerAttr::get(
          elementType, APInt::getOneBitSet(targetWidth, sourceWidth));
      if (auto vectorType = dyn_cast<VectorType>(type))
        sentinel = SplatElementsAttr::get(vectorType, sentinel);
      Value mask =
          spirv::ConstantOp::create(rewriter, op.getLoc(), type, sentinel);
      input = spirv::BitwiseOrOp::create(rewriter, op.getLoc(), input, mask);
    }
    rewriter.replaceOpWithNewOp<spirv::CLCtzOp>(op, type, input);
    return success();
  }
};
 
/// Converts math.expm1 to SPIR-V ops.
///
/// SPIR-V does not have a direct operations for exp(x)-1. Explicitly lower to
/// these operations.
template <typename ExpOp>
struct ExpM1OpPattern final : public OpConversionPattern<math::ExpM1Op> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::ExpM1Op operation, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    assert(adaptor.getOperands().size() == 1);
    if (LogicalResult res = checkSourceOpTypes(rewriter, operation);
        failed(res))
      return res;
 
    Location loc = operation.getLoc();
    Type type = this->getTypeConverter()->convertType(operation.getType());
    if (!type)
      return failure();
 
    Value exp = ExpOp::create(rewriter, loc, type, adaptor.getOperand());
    auto one = spirv::ConstantOp::getOne(type, loc, rewriter);
    rewriter.replaceOpWithNewOp<spirv::FSubOp>(operation, exp, one);
    return success();
  }
};
 
/// Converts math.log1p to SPIR-V ops.
///
/// SPIR-V does not have a direct operations for log(1+x). Explicitly lower to
/// these operations.
template <typename LogOp>
struct Log1pOpPattern final : public OpConversionPattern<math::Log1pOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::Log1pOp operation, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    assert(adaptor.getOperands().size() == 1);
    if (LogicalResult res = checkSourceOpTypes(rewriter, operation);
        failed(res))
      return res;
 
    Location loc = operation.getLoc();
    Type type = this->getTypeConverter()->convertType(operation.getType());
    if (!type)
      return failure();
 
    auto one = spirv::ConstantOp::getOne(type, operation.getLoc(), rewriter);
    Value onePlus =
        spirv::FAddOp::create(rewriter, loc, one, adaptor.getOperand());
    rewriter.replaceOpWithNewOp<LogOp>(operation, type, onePlus);
    return success();
  }
};
 
/// Converts math.log10 to GLSL SPIR-V ops.
///
/// GLSL.std.450 has no Log10 instruction. Lower it as:
///   log10(x) = log(x) * 1/log(10)
struct Log10OpPattern final : public OpConversionPattern<math::Log10Op> {
  using Base::Base;
 
  static constexpr double log10Reciprocal =
      0.4342944819032518276511289189166050822943970058036665661144537832;
 
  LogicalResult
  matchAndRewrite(math::Log10Op operation, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    assert(adaptor.getOperands().size() == 1);
    if (LogicalResult res = checkSourceOpTypes(rewriter, operation);
        failed(res))
      return res;
 
    Location loc = operation.getLoc();
    Type type = this->getTypeConverter()->convertType(operation.getType());
    if (!type)
      return rewriter.notifyMatchFailure(operation, "type conversion failed");
 
    auto getConstantValue = [&](double value) {
      if (auto floatType = dyn_cast<FloatType>(type)) {
        return spirv::ConstantOp::create(
            rewriter, loc, type, rewriter.getFloatAttr(floatType, value));
      }
      if (auto vectorType = dyn_cast<VectorType>(type)) {
        Type elemType = vectorType.getElementType();
 
        if (isa<FloatType>(elemType)) {
          return spirv::ConstantOp::create(
              rewriter, loc, type,
              DenseFPElementsAttr::get(
                  vectorType, FloatAttr::get(elemType, value).getValue()));
        }
      }
      llvm_unreachable("unimplemented type for log10");
    };
 
    Value constantValue = getConstantValue(log10Reciprocal);
    Value log = spirv::GLLogOp::create(rewriter, loc, adaptor.getOperand());
    rewriter.replaceOpWithNewOp<spirv::FMulOp>(operation, type, log,
                                               constantValue);
    return success();
  }
};
 
/// Converts math.powf to SPIRV-Ops.
struct PowFOpPattern final : public OpConversionPattern<math::PowFOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::PowFOp powfOp, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, powfOp); failed(res))
      return res;
 
    Type dstType = getTypeConverter()->convertType(powfOp.getType());
    if (!dstType)
      return failure();
 
    Location loc = powfOp.getLoc();
    Type operandType = adaptor.getRhs().getType();
 
    // Parity-based lowering requires an integer-valued constant exponent.
    // Otherwise fall back to exp(y*log(x)), which yields NaN for x<0 (matches
    // C).
    auto isOdd = [](const APFloat &v) {
      APSInt i(/*BitWidth=*/64, /*isUnsigned=*/false);
      bool ignored;
      v.convertToInteger(i, APFloat::rmTowardZero, &ignored);
      return i[0];
    };
 
    SmallVector<bool> oddMask;
    Attribute rhsAttr;
    if (matchPattern(adaptor.getRhs(), m_Constant(&rhsAttr))) {
      TypeSwitch<Attribute>(rhsAttr)
          .Case([&](FloatAttr a) {
            if (a.getValue().isInteger())
              oddMask.push_back(isOdd(a.getValue()));
          })
          .Case([&](SplatElementsAttr a) {
            APFloat splat = a.getSplatValue<APFloat>();
            if (splat.isInteger())
              oddMask.push_back(isOdd(splat));
          })
          .Case([&](DenseElementsAttr a) {
            SmallVector<bool> mask;
            for (const APFloat &elt : a.getValues<APFloat>()) {
              if (!elt.isInteger())
                return;
              mask.push_back(isOdd(elt));
            }
            oddMask = std::move(mask);
          });
    }
 
    if (oddMask.empty()) {
      Value log = spirv::GLLogOp::create(rewriter, loc, adaptor.getLhs());
      Value mul = spirv::FMulOp::create(rewriter, loc, adaptor.getRhs(), log);
      rewriter.replaceOpWithNewOp<spirv::GLExpOp>(powfOp, mul);
      return success();
    }
 
    // GL.Pow is undefined for x < 0; take abs and conditionally negate the
    // result for lanes whose exponent is odd.
    Value abs = spirv::GLFAbsOp::create(rewriter, loc, adaptor.getLhs());
    Value pow = spirv::GLPowOp::create(rewriter, loc, abs, adaptor.getRhs());
 
    // No odd-parity element: result has the same sign as |lhs|^rhs >= 0.
    if (llvm::none_of(oddMask, [](bool b) { return b; })) {
      rewriter.replaceOp(powfOp, pow);
      return success();
    }
 
    Value zero = spirv::ConstantOp::getZero(operandType, loc, rewriter);
    Value lessThan =
        spirv::FOrdLessThanOp::create(rewriter, loc, adaptor.getLhs(), zero);
    Value negate = spirv::FNegateOp::create(rewriter, loc, pow);
 
    Value shouldNegate;
    if (llvm::all_equal(oddMask)) {
      // Every lane has odd exponent: negate iff lhs < 0.
      shouldNegate = lessThan;
    } else {
      // Mixed parity (non-splat dense vector): AND lhs<0 with a per-element
      // constant odd-mask.
      auto vecType = cast<VectorType>(operandType);
      auto maskType = VectorType::get(vecType.getShape(), rewriter.getI1Type());
      Value oddConst = spirv::ConstantOp::create(
          rewriter, loc, maskType, DenseElementsAttr::get(maskType, oddMask));
      shouldNegate =
          spirv::LogicalAndOp::create(rewriter, loc, lessThan, oddConst);
    }
 
    rewriter.replaceOpWithNewOp<spirv::SelectOp>(powfOp, shouldNegate, negate,
                                                 pow);
    return success();
  }
};
 
/// Converts math.fpowi to spirv.CL.pown.
struct PowIOpPattern final : public OpConversionPattern<math::FPowIOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::FPowIOp op, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, op); failed(res))
      return res;
 
    Type dstType = getTypeConverter()->convertType(op.getType());
    if (!dstType)
      return failure();
 
    rewriter.replaceOpWithNewOp<spirv::CLPownOp>(op, dstType, adaptor.getLhs(),
                                                 adaptor.getRhs());
    return success();
  }
};
 
/// Converts math.fpowi to GLSL SPIR-V ops. GL has no integer-power op, so the
/// exponent is converted to float and lowered through spirv.GL.Pow. As GL.Pow
/// is undefined for a negative base, the base is made positive and the result
/// is negated when the base is negative and the exponent is odd.
struct PowIOpGLPattern final : public OpConversionPattern<math::FPowIOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::FPowIOp op, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, op); failed(res))
      return res;
 
    Type dstType = getTypeConverter()->convertType(op.getType());
    if (!dstType)
      return failure();
 
    Location loc = op.getLoc();
    Value base = adaptor.getLhs();
    Value power = adaptor.getRhs();
 
    Value expFloat =
        spirv::ConvertSToFOp::create(rewriter, loc, dstType, power);
    Value abs = spirv::GLFAbsOp::create(rewriter, loc, base);
    Value pow = spirv::GLPowOp::create(rewriter, loc, abs, expFloat);
 
    Value zeroF = spirv::ConstantOp::getZero(dstType, loc, rewriter);
    Value lessThan = spirv::FOrdLessThanOp::create(rewriter, loc, base, zeroF);
 
    Type powerType = power.getType();
    Value oneI = spirv::ConstantOp::getOne(powerType, loc, rewriter);
    Value lowBit = spirv::BitwiseAndOp::create(rewriter, loc, power, oneI);
    Value isOdd = spirv::IEqualOp::create(rewriter, loc, lowBit, oneI);
 
    Value shouldNegate =
        spirv::LogicalAndOp::create(rewriter, loc, lessThan, isOdd);
    Value negate = spirv::FNegateOp::create(rewriter, loc, pow);
    rewriter.replaceOpWithNewOp<spirv::SelectOp>(op, shouldNegate, negate, pow);
    return success();
  }
};
 
/// Converts math.sincos to SPIR-V ops.
///
/// SPIR-V has no fused sincos instruction, so emit separate sin and cos ops
/// sharing the same operand.
template <typename SinOp, typename CosOp>
struct SincosOpPattern final : public OpConversionPattern<math::SincosOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::SincosOp operation, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, operation);
        failed(res))
      return res;
 
    Type type =
        getTypeConverter()->convertType(operation.getOperand().getType());
    if (!type)
      return failure();
 
    Location loc = operation.getLoc();
    Value sin = SinOp::create(rewriter, loc, type, adaptor.getOperand());
    Value cos = CosOp::create(rewriter, loc, type, adaptor.getOperand());
    rewriter.replaceOp(operation, {sin, cos});
    return success();
  }
};
 
/// Converts math.round to GLSL SPIRV extended ops.
struct RoundOpPattern final : public OpConversionPattern<math::RoundOp> {
  using Base::Base;
 
  LogicalResult
  matchAndRewrite(math::RoundOp roundOp, OpAdaptor adaptor,
                  ConversionPatternRewriter &rewriter) const override {
    if (LogicalResult res = checkSourceOpTypes(rewriter, roundOp); failed(res))
      return res;
 
    Location loc = roundOp.getLoc();
    auto ty = getTypeConverter()->convertType(adaptor.getOperand().getType());
    if (!ty) {
      return rewriter.notifyMatchFailure(
          roundOp->getLoc(),
          llvm::formatv("failed to convert type {0} for SPIR-V",
                        roundOp.getType()));
    }
 
    Type ety = getElementTypeOrSelf(ty);
 
    auto zero = spirv::ConstantOp::getZero(ty, loc, rewriter);
    auto one = spirv::ConstantOp::getOne(ty, loc, rewriter);
    Value half;
    if (VectorType vty = dyn_cast<VectorType>(ty)) {
      half = spirv::ConstantOp::create(
          rewriter, loc, vty,
          DenseElementsAttr::get(vty,
                                 rewriter.getFloatAttr(ety, 0.5).getValue()));
    } else {
      half = spirv::ConstantOp::create(rewriter, loc, ty,
                                       rewriter.getFloatAttr(ety, 0.5));
    }
 
    auto abs = spirv::GLFAbsOp::create(rewriter, loc, adaptor.getOperand());
    auto floor = spirv::GLFloorOp::create(rewriter, loc, abs);
    auto sub = spirv::FSubOp::create(rewriter, loc, abs, floor);
    auto greater =
        spirv::FOrdGreaterThanEqualOp::create(rewriter, loc, sub, half);
    auto select = spirv::SelectOp::create(rewriter, loc, greater, one, zero);
    auto add = spirv::FAddOp::create(rewriter, loc, floor, select);
    rewriter.replaceOpWithNewOp<math::CopySignOp>(roundOp, add,
                                                  adaptor.getOperand());
    return success();
  }
};
} // namespace
 
//===----------------------------------------------------------------------===//
// Pattern population
//===----------------------------------------------------------------------===//
 
namespace mlir {
void populateMathToSPIRVPatterns(const SPIRVTypeConverter &typeConverter,
                                 RewritePatternSet &patterns) {
  // Core patterns
  patterns
      .add<CopySignPattern,
           CheckedElementwiseOpPattern<math::CtPopOp, spirv::BitCountOp>,
           CheckedElementwiseOpPattern<math::IsInfOp, spirv::IsInfOp>,
           CheckedElementwiseOpPattern<math::IsNaNOp, spirv::IsNanOp>,
           CheckedElementwiseOpPattern<math::IsFiniteOp, spirv::IsFiniteOp>,
           CheckedElementwiseOpPattern<math::IsNormalOp, spirv::IsNormalOp>>(
          typeConverter, patterns.getContext());
 
  // GLSL patterns
  patterns
      .add<CountLeadingZerosPattern, CountTrailingZerosPattern,
           Log1pOpPattern<spirv::GLLogOp>, Log10OpPattern,
           ExpM1OpPattern<spirv::GLExpOp>, PowFOpPattern, PowIOpGLPattern,
           RoundOpPattern, SincosOpPattern<spirv::GLSinOp, spirv::GLCosOp>,
           CheckedElementwiseOpPattern<math::AbsFOp, spirv::GLFAbsOp>,
           CheckedElementwiseOpPattern<math::AbsIOp, spirv::GLSAbsOp>,
           CheckedElementwiseOpPattern<math::AtanOp, spirv::GLAtanOp>,
           CheckedElementwiseOpPattern<math::Atan2Op, spirv::GLAtan2Op>,
           CheckedElementwiseOpPattern<math::CeilOp, spirv::GLCeilOp>,
           CheckedElementwiseOpPattern<math::ClampFOp, spirv::GLFClampOp>,
           CheckedElementwiseOpPattern<math::CosOp, spirv::GLCosOp>,
           CheckedElementwiseOpPattern<math::ExpOp, spirv::GLExpOp>,
           CheckedElementwiseOpPattern<math::Exp2Op, spirv::GLExp2Op>,
           CheckedElementwiseOpPattern<math::FloorOp, spirv::GLFloorOp>,
           CheckedElementwiseOpPattern<math::FmaOp, spirv::GLFmaOp>,
           CheckedElementwiseOpPattern<math::LogOp, spirv::GLLogOp>,
           CheckedElementwiseOpPattern<math::Log2Op, spirv::GLLog2Op>,
           CheckedElementwiseOpPattern<math::RoundEvenOp, spirv::GLRoundEvenOp>,
           CheckedElementwiseOpPattern<math::RsqrtOp, spirv::GLInverseSqrtOp>,
           CheckedElementwiseOpPattern<math::SinOp, spirv::GLSinOp>,
           CheckedElementwiseOpPattern<math::SqrtOp, spirv::GLSqrtOp>,
           CheckedElementwiseOpPattern<math::TanhOp, spirv::GLTanhOp>,
           CheckedElementwiseOpPattern<math::TanOp, spirv::GLTanOp>,
           CheckedElementwiseOpPattern<math::TruncOp, spirv::GLTruncOp>,
           CheckedElementwiseOpPattern<math::AsinOp, spirv::GLAsinOp>,
           CheckedElementwiseOpPattern<math::AcosOp, spirv::GLAcosOp>,
           CheckedElementwiseOpPattern<math::SinhOp, spirv::GLSinhOp>,
           CheckedElementwiseOpPattern<math::CoshOp, spirv::GLCoshOp>,
           CheckedElementwiseOpPattern<math::AsinhOp, spirv::GLAsinhOp>,
           CheckedElementwiseOpPattern<math::AcoshOp, spirv::GLAcoshOp>,
           CheckedElementwiseOpPattern<math::AtanhOp, spirv::GLAtanhOp>>(
          typeConverter, patterns.getContext());
 
  // OpenCL patterns
  patterns.add<
      Log1pOpPattern<spirv::CLLogOp>, ExpM1OpPattern<spirv::CLExpOp>,
      SincosOpPattern<spirv::CLSinOp, spirv::CLCosOp>,
      CheckedElementwiseOpPattern<math::AbsFOp, spirv::CLFAbsOp>,
      CheckedElementwiseOpPattern<math::AbsIOp, spirv::CLSAbsOp>,
      CheckedElementwiseOpPattern<math::CountLeadingZerosOp, spirv::CLClzOp>,
      CountTrailingZerosOpenCLPattern,
      CheckedElementwiseOpPattern<math::AtanOp, spirv::CLAtanOp>,
      CheckedElementwiseOpPattern<math::Atan2Op, spirv::CLAtan2Op>,
      CheckedElementwiseOpPattern<math::CbrtOp, spirv::CLCbrtOp>,
      CheckedElementwiseOpPattern<math::CeilOp, spirv::CLCeilOp>,
      CheckedElementwiseOpPattern<math::CopySignOp, spirv::CLCopysignOp>,
      CheckedElementwiseOpPattern<math::CosOp, spirv::CLCosOp>,
      CheckedElementwiseOpPattern<math::ErfOp, spirv::CLErfOp>,
      CheckedElementwiseOpPattern<math::ErfcOp, spirv::CLErfcOp>,
      CheckedElementwiseOpPattern<math::ExpOp, spirv::CLExpOp>,
      CheckedElementwiseOpPattern<math::Exp2Op, spirv::CLExp2Op>,
      CheckedElementwiseOpPattern<math::FloorOp, spirv::CLFloorOp>,
      CheckedElementwiseOpPattern<math::FmaOp, spirv::CLFmaOp>,
      CheckedElementwiseOpPattern<math::LogOp, spirv::CLLogOp>,
      CheckedElementwiseOpPattern<math::Log2Op, spirv::CLLog2Op>,
      CheckedElementwiseOpPattern<math::Log10Op, spirv::CLLog10Op>,
      CheckedElementwiseOpPattern<math::PowFOp, spirv::CLPowOp>, PowIOpPattern,
      CheckedElementwiseOpPattern<math::RoundEvenOp, spirv::CLRintOp>,
      CheckedElementwiseOpPattern<math::RoundOp, spirv::CLRoundOp>,
      CheckedElementwiseOpPattern<math::RsqrtOp, spirv::CLRsqrtOp>,
      CheckedElementwiseOpPattern<math::SinOp, spirv::CLSinOp>,
      CheckedElementwiseOpPattern<math::SqrtOp, spirv::CLSqrtOp>,
      CheckedElementwiseOpPattern<math::TanhOp, spirv::CLTanhOp>,
      CheckedElementwiseOpPattern<math::TanOp, spirv::CLTanOp>,
      CheckedElementwiseOpPattern<math::TruncOp, spirv::CLTruncOp>,
      CheckedElementwiseOpPattern<math::AsinOp, spirv::CLAsinOp>,
      CheckedElementwiseOpPattern<math::AcosOp, spirv::CLAcosOp>,
      CheckedElementwiseOpPattern<math::SinhOp, spirv::CLSinhOp>,
      CheckedElementwiseOpPattern<math::CoshOp, spirv::CLCoshOp>,
      CheckedElementwiseOpPattern<math::AsinhOp, spirv::CLAsinhOp>,
      CheckedElementwiseOpPattern<math::AcoshOp, spirv::CLAcoshOp>,
      CheckedElementwiseOpPattern<math::AtanhOp, spirv::CLAtanhOp>>(
      typeConverter, patterns.getContext());
}
} // namespace mlir