Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===-- MakeGuardsExplicit.h - Turn guard intrinsics into guard branches --===//

//

// 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 lowers the @llvm.experimental.guard intrinsic to the new form of

// guard represented as widenable explicit branch to the deopt block. The

// difference between this pass and LowerGuardIntrinsic is that after this pass

// the guard represented as intrinsic:

//

//   call void(i1, ...) @llvm.experimental.guard(i1 %old_cond) [ "deopt"() ]

//

// transforms to a guard represented as widenable explicit branch:

//

//   %widenable_cond = call i1 @llvm.experimental.widenable.condition()

//   br i1 (%old_cond & %widenable_cond), label %guarded, label %deopt

//

// Here:

//   - The semantics of @llvm.experimental.widenable.condition allows to replace

//     %widenable_cond with the construction (%widenable_cond & %any_other_cond)

//     without loss of correctness;

//   - %guarded is the lower part of old guard intrinsic's parent block split by

//     the intrinsic call;

//   - %deopt is a block containing a sole call to @llvm.experimental.deoptimize

//     intrinsic.

//

// Therefore, this branch preserves the property of widenability.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H

#define LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H

#include "llvm/IR/PassManager.h"

namespace llvm {

struct MakeGuardsExplicitPass : public PassInfoMixin<MakeGuardsExplicitPass> {

  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);

};

} // namespace llvm

#endif // LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H