tools/llvm-reduce/deltas/ReduceInstructionFlags.cpp

//===- ReduceInstructionFlags.cpp - Specialized Delta Pass ----------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Try to remove optimization flags on instructions
//
//===----------------------------------------------------------------------===//

#include "ReduceInstructionFlags.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Operator.h"

using namespace llvm;

void llvm::reduceInstructionFlagsDeltaPass(Oracle &O,
                                           ReducerWorkItem &WorkItem) {
  // Keep this in sync with computeIRComplexityScoreImpl().
  for (Function &F : WorkItem.getModule()) {
    for (Instruction &I : instructions(F)) {
      if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(&I)) {
        if (OBO->hasNoSignedWrap() && !O.shouldKeep())
          I.setHasNoSignedWrap(false);
        if (OBO->hasNoUnsignedWrap() && !O.shouldKeep())
          I.setHasNoUnsignedWrap(false);
      } else if (auto *Trunc = dyn_cast<TruncInst>(&I)) {
        if (Trunc->hasNoSignedWrap() && !O.shouldKeep())
          Trunc->setHasNoSignedWrap(false);
        if (Trunc->hasNoUnsignedWrap() && !O.shouldKeep())
          Trunc->setHasNoUnsignedWrap(false);
      } else if (auto *PE = dyn_cast<PossiblyExactOperator>(&I)) {
        if (PE->isExact() && !O.shouldKeep())
          I.setIsExact(false);
      } else if (auto *NNI = dyn_cast<PossiblyNonNegInst>(&I)) {
        if (NNI->hasNonNeg() && !O.shouldKeep())
          NNI->setNonNeg(false);
      } else if (auto *PDI = dyn_cast<PossiblyDisjointInst>(&I)) {
        if (PDI->isDisjoint() && !O.shouldKeep())
          PDI->setIsDisjoint(false);
      } else if (auto *ICmp = dyn_cast<ICmpInst>(&I)) {
        if (ICmp->hasSameSign() && !O.shouldKeep())
          ICmp->setSameSign(false);
      } else if (auto *GEP = dyn_cast<GetElementPtrInst>(&I)) {
        GEPNoWrapFlags NW = GEP->getNoWrapFlags();
        if (NW.isInBounds() && !O.shouldKeep())
          NW = NW.withoutInBounds();
        if (NW.hasNoUnsignedSignedWrap() && !O.shouldKeep())
          NW = NW.withoutNoUnsignedSignedWrap();
        if (NW.hasNoUnsignedWrap() && !O.shouldKeep())
          NW = NW.withoutNoUnsignedWrap();
        GEP->setNoWrapFlags(NW);
      } else if (auto *FPOp = dyn_cast<FPMathOperator>(&I)) {
        FastMathFlags Flags = FPOp->getFastMathFlags();

        if (Flags.allowReassoc() && !O.shouldKeep())
          Flags.setAllowReassoc(false);

        if (Flags.noNaNs() && !O.shouldKeep())
          Flags.setNoNaNs(false);

        if (Flags.noInfs() && !O.shouldKeep())
          Flags.setNoInfs(false);

        if (Flags.noSignedZeros() && !O.shouldKeep())
          Flags.setNoSignedZeros(false);

        if (Flags.allowReciprocal() && !O.shouldKeep())
          Flags.setAllowReciprocal(false);

        if (Flags.allowContract() && !O.shouldKeep())
          Flags.setAllowContract(false);

        if (Flags.approxFunc() && !O.shouldKeep())
          Flags.setApproxFunc(false);

        I.copyFastMathFlags(Flags);
      }
    }
  }
}