llvm/llvm/lib/CodeGen/ExpandLargeDivRem.cpp

//===--- ExpandLargeDivRem.cpp - Expand large div/rem ---------------------===//
//
// 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 pass expands div/rem instructions with a bitwidth above a threshold
// into a call to auto-generated functions.
// This is useful for targets like x86_64 that cannot lower divisions
// with more than 128 bits or targets like x86_32 that cannot lower divisions
// with more than 64 bits.
//
//===----------------------------------------------------------------------===//

#include "llvm/CodeGen/ExpandLargeDivRem.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/PassManager.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Utils/IntegerDivision.h"

usingnamespacellvm;

static cl::opt<unsigned>
    ExpandDivRemBits("expand-div-rem-bits", cl::Hidden,
                     cl::init(llvm::IntegerType::MAX_INT_BITS),
                     cl::desc("div and rem instructions on integers with "
                              "more than <N> bits are expanded."));

static bool isConstantPowerOfTwo(llvm::Value *V, bool SignedOp) { … }

static bool isSigned(unsigned int Opcode) { … }

static void scalarize(BinaryOperator *BO,
                      SmallVectorImpl<BinaryOperator *> &Replace) { … }

static bool runImpl(Function &F, const TargetLowering &TLI) { … }

namespace {
class ExpandLargeDivRemLegacyPass : public FunctionPass { … };
} // namespace

PreservedAnalyses ExpandLargeDivRemPass::run(Function &F,
                                             FunctionAnalysisManager &FAM) { … }

char ExpandLargeDivRemLegacyPass::ID = …;
INITIALIZE_PASS_BEGIN(ExpandLargeDivRemLegacyPass, "expand-large-div-rem",
                      "Expand large div/rem", false, false)
INITIALIZE_PASS_END(ExpandLargeDivRemLegacyPass, "expand-large-div-rem",
                    "Expand large div/rem", false, false)

FunctionPass *llvm::createExpandLargeDivRemPass() { … }