1 | //===-- MakeGuardsExplicit.h - Turn guard intrinsics into guard branches --===// |
2 | // |
3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
4 | // See https://llvm.org/LICENSE.txt for license information. |
5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
6 | // |
7 | //===----------------------------------------------------------------------===// |
8 | // |
9 | // This pass lowers the @llvm.experimental.guard intrinsic to the new form of |
10 | // guard represented as widenable explicit branch to the deopt block. The |
11 | // difference between this pass and LowerGuardIntrinsic is that after this pass |
12 | // the guard represented as intrinsic: |
13 | // |
14 | // call void(i1, ...) @llvm.experimental.guard(i1 %old_cond) [ "deopt"() ] |
15 | // |
16 | // transforms to a guard represented as widenable explicit branch: |
17 | // |
18 | // %widenable_cond = call i1 @llvm.experimental.widenable.condition() |
19 | // br i1 (%old_cond & %widenable_cond), label %guarded, label %deopt |
20 | // |
21 | // Here: |
22 | // - The semantics of @llvm.experimental.widenable.condition allows to replace |
23 | // %widenable_cond with the construction (%widenable_cond & %any_other_cond) |
24 | // without loss of correctness; |
25 | // - %guarded is the lower part of old guard intrinsic's parent block split by |
26 | // the intrinsic call; |
27 | // - %deopt is a block containing a sole call to @llvm.experimental.deoptimize |
28 | // intrinsic. |
29 | // |
30 | // Therefore, this branch preserves the property of widenability. |
31 | // |
32 | //===----------------------------------------------------------------------===// |
33 | #ifndef LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H |
34 | #define LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H |
35 | |
36 | #include "llvm/IR/PassManager.h" |
37 | |
38 | namespace llvm { |
39 | |
40 | struct MakeGuardsExplicitPass : public PassInfoMixin<MakeGuardsExplicitPass> { |
41 | PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); |
42 | }; |
43 | |
44 | } // namespace llvm |
45 | |
46 | #endif // LLVM_TRANSFORMS_SCALAR_MAKEGUARDSEXPLICIT_H |
47 | |