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
62
63
64
65
66
67
|
//===- DomConditionCache.cpp ----------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/DomConditionCache.h"
#include "llvm/IR/PatternMatch.h"
using namespace llvm;
using namespace llvm::PatternMatch;
// TODO: This code is very similar to findAffectedValues() in
// AssumptionCache, but currently specialized to just the patterns that
// computeKnownBits() supports, and without the notion of result elem indices
// that are AC specific. Deduplicate this code once we have a clearer picture
// of how much they can be shared.
static void findAffectedValues(Value *Cond,
SmallVectorImpl<Value *> &Affected) {
auto AddAffected = [&Affected](Value *V) {
if (isa<Argument>(V) || isa<GlobalValue>(V)) {
Affected.push_back(V);
} else if (auto *I = dyn_cast<Instruction>(V)) {
Affected.push_back(I);
// Peek through unary operators to find the source of the condition.
Value *Op;
if (match(I, m_PtrToInt(m_Value(Op)))) {
if (isa<Instruction>(Op) || isa<Argument>(Op))
Affected.push_back(Op);
}
}
};
ICmpInst::Predicate Pred;
Value *A;
if (match(Cond, m_ICmp(Pred, m_Value(A), m_Constant()))) {
AddAffected(A);
if (ICmpInst::isEquality(Pred)) {
Value *X;
// (X & C) or (X | C) or (X ^ C).
// (X << C) or (X >>_s C) or (X >>_u C).
if (match(A, m_BitwiseLogic(m_Value(X), m_ConstantInt())) ||
match(A, m_Shift(m_Value(X), m_ConstantInt())))
AddAffected(X);
} else {
Value *X;
// Handle (A + C1) u< C2, which is the canonical form of A > C3 && A < C4.
if (match(A, m_Add(m_Value(X), m_ConstantInt())))
AddAffected(X);
}
}
}
void DomConditionCache::registerBranch(BranchInst *BI) {
assert(BI->isConditional() && "Must be conditional branch");
SmallVector<Value *, 16> Affected;
findAffectedValues(BI->getCondition(), Affected);
for (Value *V : Affected) {
auto &AV = AffectedValues[V];
if (!is_contained(AV, BI))
AV.push_back(BI);
}
}
|
