1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
| //===-- 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
|