| //===-- 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 |