blob: aa2de571ba1bc1d0f0a847186b953a17ebf5bb08 (
plain) (
blame)
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
|
//===- llvm/Analysis/DivergenceAnalysis.h - Divergence Analysis -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The divergence analysis is an LLVM pass which can be used to find out
// if a branch instruction in a GPU program is divergent or not. It can help
// branch optimizations such as jump threading and loop unswitching to make
// better decisions.
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/DenseSet.h"
#include "llvm/IR/Function.h"
#include "llvm/Pass.h"
namespace llvm {
class Value;
class DivergenceAnalysis : public FunctionPass {
public:
static char ID;
DivergenceAnalysis() : FunctionPass(ID) {
initializeDivergenceAnalysisPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &AU) const override;
bool runOnFunction(Function &F) override;
// Print all divergent branches in the function.
void print(raw_ostream &OS, const Module *) const override;
// Returns true if V is divergent.
bool isDivergent(const Value *V) const { return DivergentValues.count(V); }
// Returns true if V is uniform/non-divergent.
bool isUniform(const Value *V) const { return !isDivergent(V); }
private:
// Stores all divergent values.
DenseSet<const Value *> DivergentValues;
};
} // End llvm namespace
|