xref: /llvm-project-15.0.7/llvm/include/llvm/Transforms/Utils/GuardUtils.h (revision 8ba56f32)

//===-- GuardUtils.h - Utils for work with guards ---------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
// Utils that are used to perform transformations related to guards and their
// conditions.
//===----------------------------------------------------------------------===//

#ifndef LLVM_TRANSFORMS_UTILS_GUARDUTILS_H
#define LLVM_TRANSFORMS_UTILS_GUARDUTILS_H

namespace llvm {

class BranchInst;
class CallInst;
class Function;
class Value;

/// Splits control flow at point of \p Guard, replacing it with explicit branch
/// by the condition of guard's first argument. The taken branch then goes to
/// the block that contains  \p Guard's successors, and the non-taken branch
/// goes to a newly-created deopt block that contains a sole call of the
/// deoptimize function \p DeoptIntrinsic.  If 'UseWC' is set, preserve the
/// widenable nature of the guard by lowering to equivelent form.  If not set,
/// lower to a form without widenable semantics.
void makeGuardControlFlowExplicit(Function *DeoptIntrinsic, CallInst *Guard,
                                  bool UseWC);

/// Given a branch we know is widenable (defined per Analysis/GuardUtils.h),
/// widen it such that condition 'NewCond' is also known to hold on the taken
/// path.  Branch remains widenable after transform.
void widenWidenableBranch(BranchInst *WidenableBR, Value *NewCond);

/// Given a branch we know is widenable (defined per Analysis/GuardUtils.h),
/// *set* it's condition such that (only) 'Cond' is known to hold on the taken
/// path and that the branch remains widenable after transform.
void setWidenableBranchCond(BranchInst *WidenableBR, Value *Cond);

} // llvm

#endif // LLVM_TRANSFORMS_UTILS_GUARDUTILS_H