mirror of
https://github.com/RPCSX/llvm.git
synced 2024-12-12 06:06:19 +00:00
8383a7b7a6
such as those in PR2235. Right now the pass is not very effective. :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50000 91177308-0d34-0410-b5e6-96231b3b80d8
53 lines
1.8 KiB
C++
53 lines
1.8 KiB
C++
//===- JumpThreading.cpp - Thread control through conditional blocks ------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This pass performs 'jump threading', which looks at blocks that have multiple
|
|
// predecessors and multiple successors. If one or more of the predecessors of
|
|
// the block can be proven to always jump to one of the successors, we forward
|
|
// the edge from the predecessor to the successor by duplicating the contents of
|
|
// this block.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#define DEBUG_TYPE "jump-threading"
|
|
#include "llvm/Transforms/Scalar.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/ADT/Statistic.h"
|
|
#include "llvm/Support/CommandLine.h"
|
|
#include "llvm/Support/Compiler.h"
|
|
using namespace llvm;
|
|
|
|
//STATISTIC(NumThreads, "Number of jumps threaded");
|
|
|
|
namespace {
|
|
cl::opt<unsigned>
|
|
Threshold("jump-threading-threshold",
|
|
cl::desc("Max block size to duplicate for jump threading"),
|
|
cl::init(6), cl::Hidden);
|
|
class VISIBILITY_HIDDEN JumpThreading : public FunctionPass {
|
|
public:
|
|
static char ID; // Pass identification
|
|
JumpThreading() : FunctionPass((intptr_t)&ID) {}
|
|
|
|
bool runOnFunction(Function &F);
|
|
};
|
|
char JumpThreading::ID = 0;
|
|
RegisterPass<JumpThreading> X("jump-threading", "Jump Threading");
|
|
}
|
|
|
|
// Public interface to the Jump Threading pass
|
|
FunctionPass *llvm::createJumpThreadingPass() { return new JumpThreading(); }
|
|
|
|
/// runOnFunction - Top level algorithm.
|
|
///
|
|
bool JumpThreading::runOnFunction(Function &F) {
|
|
bool Changed = false;
|
|
return Changed;
|
|
}
|