1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-25 04:02:41 +01:00
llvm-mirror/include/llvm/Transforms/Scalar/MakeGuardsExplicit.h
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

47 lines
1.8 KiB
C++

//===-- 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