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47 lines
1.8 KiB
C++
47 lines
1.8 KiB
C++
//===-- MakeGuardsExplicit.h - Turn guard intrinsics into guard branches --===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass lowers the @llvm.experimental.guard intrinsic to the new form of
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// guard represented as widenable explicit branch to the deopt block. The
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// difference between this pass and LowerGuardIntrinsic is that after this pass
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// the guard represented as intrinsic:
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//
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// call void(i1, ...) @llvm.experimental.guard(i1 %old_cond) [ "deopt"() ]
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//
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// transforms to a guard represented as widenable explicit branch:
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//
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// %widenable_cond = call i1 @llvm.experimental.widenable.condition()
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// br i1 (%old_cond & %widenable_cond), label %guarded, label %deopt
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//
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// Here:
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// - The semantics of @llvm.experimental.widenable.condition allows to replace
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// %widenable_cond with the construction (%widenable_cond & %any_other_cond)
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// without loss of correctness;
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// - %guarded is the lower part of old guard intrinsic's parent block split by
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// the intrinsic call;
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// - %deopt is a block containing a sole call to @llvm.experimental.deoptimize
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// intrinsic.
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//
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// Therefore, this branch preserves the property of widenability.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H
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#define LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H
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#include "llvm/IR/PassManager.h"
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namespace llvm {
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struct MakeGuardsExplicitPass : public PassInfoMixin<MakeGuardsExplicitPass> {
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PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
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};
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} // namespace llvm
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#endif // LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H
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