Files
clang-p2996/mlir/lib/Conversion/MathToLibm/MathToLibm.cpp
Michele Scuttari 67d0d7ac0a [MLIR] Update pass declarations to new autogenerated files
The patch introduces the required changes to update the pass declarations and definitions to use the new autogenerated files and allow dropping the old infrastructure.

Reviewed By: mehdi_amini, rriddle

Differential Review: https://reviews.llvm.org/D132838
2022-08-31 12:28:45 +02:00

223 lines
9.2 KiB
C++

//===-- MathToLibm.cpp - conversion from Math to libm calls ---------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "mlir/Conversion/MathToLibm/MathToLibm.h"
#include "mlir/Dialect/Arithmetic/IR/Arithmetic.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
#include "mlir/Dialect/Math/IR/Math.h"
#include "mlir/Dialect/Utils/IndexingUtils.h"
#include "mlir/Dialect/Vector/IR/VectorOps.h"
#include "mlir/Dialect/Vector/Utils/VectorUtils.h"
#include "mlir/IR/BuiltinDialect.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/Pass/Pass.h"
namespace mlir {
#define GEN_PASS_DEF_CONVERTMATHTOLIBM
#include "mlir/Conversion/Passes.h.inc"
} // namespace mlir
using namespace mlir;
namespace {
// Pattern to convert vector operations to scalar operations. This is needed as
// libm calls require scalars.
template <typename Op>
struct VecOpToScalarOp : public OpRewritePattern<Op> {
public:
using OpRewritePattern<Op>::OpRewritePattern;
LogicalResult matchAndRewrite(Op op, PatternRewriter &rewriter) const final;
};
// Pattern to promote an op of a smaller floating point type to F32.
template <typename Op>
struct PromoteOpToF32 : public OpRewritePattern<Op> {
public:
using OpRewritePattern<Op>::OpRewritePattern;
LogicalResult matchAndRewrite(Op op, PatternRewriter &rewriter) const final;
};
// Pattern to convert scalar math operations to calls to libm functions.
// Additionally the libm function signatures are declared.
template <typename Op>
struct ScalarOpToLibmCall : public OpRewritePattern<Op> {
public:
using OpRewritePattern<Op>::OpRewritePattern;
ScalarOpToLibmCall<Op>(MLIRContext *context, StringRef floatFunc,
StringRef doubleFunc, PatternBenefit benefit)
: OpRewritePattern<Op>(context, benefit), floatFunc(floatFunc),
doubleFunc(doubleFunc){};
LogicalResult matchAndRewrite(Op op, PatternRewriter &rewriter) const final;
private:
std::string floatFunc, doubleFunc;
};
} // namespace
template <typename Op>
LogicalResult
VecOpToScalarOp<Op>::matchAndRewrite(Op op, PatternRewriter &rewriter) const {
auto opType = op.getType();
auto loc = op.getLoc();
auto vecType = opType.template dyn_cast<VectorType>();
if (!vecType)
return failure();
if (!vecType.hasRank())
return failure();
auto shape = vecType.getShape();
int64_t numElements = vecType.getNumElements();
Value result = rewriter.create<arith::ConstantOp>(
loc, DenseElementsAttr::get(
vecType, FloatAttr::get(vecType.getElementType(), 0.0)));
SmallVector<int64_t> ones(shape.size(), 1);
SmallVector<int64_t> strides = computeStrides(shape, ones);
for (auto linearIndex = 0; linearIndex < numElements; ++linearIndex) {
SmallVector<int64_t> positions = delinearize(strides, linearIndex);
SmallVector<Value> operands;
for (auto input : op->getOperands())
operands.push_back(
rewriter.create<vector::ExtractOp>(loc, input, positions));
Value scalarOp =
rewriter.create<Op>(loc, vecType.getElementType(), operands);
result =
rewriter.create<vector::InsertOp>(loc, scalarOp, result, positions);
}
rewriter.replaceOp(op, {result});
return success();
}
template <typename Op>
LogicalResult
PromoteOpToF32<Op>::matchAndRewrite(Op op, PatternRewriter &rewriter) const {
auto opType = op.getType();
if (!opType.template isa<Float16Type, BFloat16Type>())
return failure();
auto loc = op.getLoc();
auto f32 = rewriter.getF32Type();
auto extendedOperands = llvm::to_vector(
llvm::map_range(op->getOperands(), [&](Value operand) -> Value {
return rewriter.create<arith::ExtFOp>(loc, f32, operand);
}));
auto newOp = rewriter.create<Op>(loc, f32, extendedOperands);
rewriter.replaceOpWithNewOp<arith::TruncFOp>(op, opType, newOp);
return success();
}
template <typename Op>
LogicalResult
ScalarOpToLibmCall<Op>::matchAndRewrite(Op op,
PatternRewriter &rewriter) const {
auto module = SymbolTable::getNearestSymbolTable(op);
auto type = op.getType();
if (!type.template isa<Float32Type, Float64Type>())
return failure();
auto name = type.getIntOrFloatBitWidth() == 64 ? doubleFunc : floatFunc;
auto opFunc = dyn_cast_or_null<SymbolOpInterface>(
SymbolTable::lookupSymbolIn(module, name));
// Forward declare function if it hasn't already been
if (!opFunc) {
OpBuilder::InsertionGuard guard(rewriter);
rewriter.setInsertionPointToStart(&module->getRegion(0).front());
auto opFunctionTy = FunctionType::get(
rewriter.getContext(), op->getOperandTypes(), op->getResultTypes());
opFunc = rewriter.create<func::FuncOp>(rewriter.getUnknownLoc(), name,
opFunctionTy);
opFunc.setPrivate();
// By definition Math dialect operations imply LLVM's "readnone"
// function attribute, so we can set it here to provide more
// optimization opportunities (e.g. LICM) for backends targeting LLVM IR.
// This will have to be changed, when strict FP behavior is supported
// by Math dialect.
opFunc->setAttr(LLVM::LLVMDialect::getReadnoneAttrName(),
UnitAttr::get(rewriter.getContext()));
}
assert(isa<FunctionOpInterface>(SymbolTable::lookupSymbolIn(module, name)));
rewriter.replaceOpWithNewOp<func::CallOp>(op, name, op.getType(),
op->getOperands());
return success();
}
void mlir::populateMathToLibmConversionPatterns(
RewritePatternSet &patterns, PatternBenefit benefit,
llvm::Optional<PatternBenefit> log1pBenefit) {
patterns
.add<VecOpToScalarOp<math::Atan2Op>, VecOpToScalarOp<math::ExpM1Op>,
VecOpToScalarOp<math::TanhOp>, VecOpToScalarOp<math::CosOp>,
VecOpToScalarOp<math::SinOp>, VecOpToScalarOp<math::ErfOp>,
VecOpToScalarOp<math::RoundEvenOp>, VecOpToScalarOp<math::RoundOp>,
VecOpToScalarOp<math::AtanOp>, VecOpToScalarOp<math::TanOp>>(
patterns.getContext(), benefit);
patterns.add<PromoteOpToF32<math::Atan2Op>, PromoteOpToF32<math::ExpM1Op>,
PromoteOpToF32<math::TanhOp>, PromoteOpToF32<math::CosOp>,
PromoteOpToF32<math::SinOp>, PromoteOpToF32<math::ErfOp>,
PromoteOpToF32<math::RoundEvenOp>, PromoteOpToF32<math::RoundOp>,
PromoteOpToF32<math::AtanOp>, PromoteOpToF32<math::TanOp>>(
patterns.getContext(), benefit);
patterns.add<ScalarOpToLibmCall<math::AtanOp>>(patterns.getContext(), "atanf",
"atan", benefit);
patterns.add<ScalarOpToLibmCall<math::Atan2Op>>(patterns.getContext(),
"atan2f", "atan2", benefit);
patterns.add<ScalarOpToLibmCall<math::ErfOp>>(patterns.getContext(), "erff",
"erf", benefit);
patterns.add<ScalarOpToLibmCall<math::ExpM1Op>>(patterns.getContext(),
"expm1f", "expm1", benefit);
patterns.add<ScalarOpToLibmCall<math::TanOp>>(patterns.getContext(), "tanf",
"tan", benefit);
patterns.add<ScalarOpToLibmCall<math::TanhOp>>(patterns.getContext(), "tanhf",
"tanh", benefit);
patterns.add<ScalarOpToLibmCall<math::RoundEvenOp>>(
patterns.getContext(), "roundevenf", "roundeven", benefit);
patterns.add<ScalarOpToLibmCall<math::RoundOp>>(patterns.getContext(),
"roundf", "round", benefit);
patterns.add<ScalarOpToLibmCall<math::CosOp>>(patterns.getContext(), "cosf",
"cos", benefit);
patterns.add<ScalarOpToLibmCall<math::SinOp>>(patterns.getContext(), "sinf",
"sin", benefit);
patterns.add<ScalarOpToLibmCall<math::Log1pOp>>(
patterns.getContext(), "log1pf", "log1p", log1pBenefit.value_or(benefit));
patterns.add<ScalarOpToLibmCall<math::FloorOp>>(patterns.getContext(),
"floorf", "floor", benefit);
patterns.add<ScalarOpToLibmCall<math::CeilOp>>(patterns.getContext(), "ceilf",
"ceil", benefit);
}
namespace {
struct ConvertMathToLibmPass
: public impl::ConvertMathToLibmBase<ConvertMathToLibmPass> {
void runOnOperation() override;
};
} // namespace
void ConvertMathToLibmPass::runOnOperation() {
auto module = getOperation();
RewritePatternSet patterns(&getContext());
populateMathToLibmConversionPatterns(patterns, /*benefit=*/1);
ConversionTarget target(getContext());
target.addLegalDialect<arith::ArithmeticDialect, BuiltinDialect,
func::FuncDialect, vector::VectorDialect>();
target.addIllegalDialect<math::MathDialect>();
if (failed(applyPartialConversion(module, target, std::move(patterns))))
signalPassFailure();
}
std::unique_ptr<OperationPass<ModuleOp>> mlir::createConvertMathToLibmPass() {
return std::make_unique<ConvertMathToLibmPass>();
}