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
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
//===--- SimplifyUnreachableContainingBlocks.cpp --------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
///
/// \file
///
/// This file contains a simple utility pass that simplifies blocks that contain
/// unreachables by eliminating all other instructions. This includes
/// instructions with side-effects and no-return functions. It is only intended
/// to be used to simplify IR for testing or exploratory purposes.
///
//===----------------------------------------------------------------------===//
#include "swift/SILOptimizer/PassManager/Passes.h"
#include "swift/SIL/SILBasicBlock.h"
#include "swift/SILOptimizer/PassManager/Transforms.h"
using namespace swift;
namespace {
class SimplifyUnreachableContainingBlocks : public SILFunctionTransform {
void run() override {
// For each block...
for (auto &BB : *getFunction()) {
// If the block does not contain an unreachable, just continue. There is
// no further work to do.
auto *UI = dyn_cast<UnreachableInst>(BB.getTerminator());
if (!UI)
continue;
// Otherwise, eliminate all other instructions in the block.
for (auto II = BB.begin(); &*II != UI;) {
// Avoid iterator invalidation.
auto *I = &*II;
++II;
I->replaceAllUsesOfAllResultsWithUndef();
I->eraseFromParent();
}
}
}
};
} // end anonymous namespace
//===----------------------------------------------------------------------===//
// Top Level Entry Point
//===----------------------------------------------------------------------===//
SILTransform *swift::createSimplifyUnreachableContainingBlocks() {
return new SimplifyUnreachableContainingBlocks();
}
|
