llvm/mlir/lib/Dialect/Arith/Transforms/UnsignedWhenEquivalent.cpp

//===- UnsignedWhenEquivalent.cpp - Pass to replace signed operations with
// unsigned
// ones when all their arguments and results are statically non-negative --===//
//
// 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/Dialect/Arith/Transforms/Passes.h"

#include "mlir/Analysis/DataFlow/DeadCodeAnalysis.h"
#include "mlir/Analysis/DataFlow/IntegerRangeAnalysis.h"
#include "mlir/Dialect/Arith/IR/Arith.h"
#include "mlir/Transforms/DialectConversion.h"

namespace mlir {
namespace arith {
#define GEN_PASS_DEF_ARITHUNSIGNEDWHENEQUIVALENT
#include "mlir/Dialect/Arith/Transforms/Passes.h.inc"
} // namespace arith
} // namespace mlir

usingnamespacemlir;
usingnamespacemlir::arith;
usingnamespacemlir::dataflow;

/// Succeeds when a value is statically non-negative in that it has a lower
/// bound on its value (if it is treated as signed) and that bound is
/// non-negative.
static LogicalResult staticallyNonNegative(DataFlowSolver &solver, Value v) { … }

/// Succeeds if an op can be converted to its unsigned equivalent without
/// changing its semantics. This is the case when none of its openands or
/// results can be below 0 when analyzed from a signed perspective.
static LogicalResult staticallyNonNegative(DataFlowSolver &solver,
                                           Operation *op) { … }

/// Succeeds when the comparison predicate is a signed operation and all the
/// operands are non-negative, indicating that the cmpi operation `op` can have
/// its predicate changed to an unsigned equivalent.
static LogicalResult isCmpIConvertable(DataFlowSolver &solver, CmpIOp op) { … }

/// Return the unsigned equivalent of a signed comparison predicate,
/// or the predicate itself if there is none.
static CmpIPredicate toUnsignedPred(CmpIPredicate pred) { … }

namespace {
template <typename Signed, typename Unsigned>
struct ConvertOpToUnsigned : OpConversionPattern<Signed> { … };

struct ConvertCmpIToUnsigned : OpConversionPattern<CmpIOp> { … };

struct ArithUnsignedWhenEquivalentPass
    : public arith::impl::ArithUnsignedWhenEquivalentBase<
          ArithUnsignedWhenEquivalentPass> { … };
} // end anonymous namespace

std::unique_ptr<Pass> mlir::arith::createArithUnsignedWhenEquivalentPass() { … }