mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-21 18:29:46 +00:00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60141 91177308-0d34-0410-b5e6-96231b3b80d8
79 lines
2.4 KiB
C++
79 lines
2.4 KiB
C++
//===-- LoopAligner.cpp - Loop aligner pass. ------------------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file implements the pass that align loop headers to target specific
|
|
// alignment boundary.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#define DEBUG_TYPE "loopalign"
|
|
#include "llvm/CodeGen/MachineLoopInfo.h"
|
|
#include "llvm/CodeGen/MachineFunctionPass.h"
|
|
#include "llvm/CodeGen/Passes.h"
|
|
#include "llvm/Target/TargetLowering.h"
|
|
#include "llvm/Target/TargetMachine.h"
|
|
#include "llvm/Support/Compiler.h"
|
|
#include "llvm/Support/Debug.h"
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
class LoopAligner : public MachineFunctionPass {
|
|
public:
|
|
static char ID;
|
|
LoopAligner() : MachineFunctionPass(&ID) {}
|
|
|
|
virtual bool runOnMachineFunction(MachineFunction &MF);
|
|
virtual const char *getPassName() const { return "Loop aligner"; }
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
|
|
AU.addRequired<MachineLoopInfo>();
|
|
AU.addPreserved<MachineLoopInfo>();
|
|
AU.addPreservedID(MachineDominatorsID);
|
|
MachineFunctionPass::getAnalysisUsage(AU);
|
|
}
|
|
};
|
|
|
|
char LoopAligner::ID = 0;
|
|
} // end anonymous namespace
|
|
|
|
FunctionPass *llvm::createLoopAlignerPass() { return new LoopAligner(); }
|
|
|
|
bool LoopAligner::runOnMachineFunction(MachineFunction &MF) {
|
|
const MachineLoopInfo *MLI = &getAnalysis<MachineLoopInfo>();
|
|
|
|
if (MLI->empty())
|
|
return false; // No loops.
|
|
|
|
const TargetLowering *TLI = MF.getTarget().getTargetLowering();
|
|
if (!TLI)
|
|
return false;
|
|
|
|
unsigned Align = TLI->getPrefLoopAlignment();
|
|
if (!Align)
|
|
return false; // Don't care about loop alignment.
|
|
|
|
const Function *F = MF.getFunction();
|
|
if (F->hasFnAttr(Attribute::OptimizeForSize))
|
|
return false;
|
|
|
|
for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ++I) {
|
|
MachineBasicBlock *MBB = I;
|
|
if (MLI->isLoopHeader(MBB)) {
|
|
MachineBasicBlock *PredBB = prior(I);
|
|
if (MLI->getLoopFor(MBB) == MLI->getLoopFor(PredBB))
|
|
// If previously BB is in the same loop, don't align this BB. We want
|
|
// to prevent adding noop's inside a loop.
|
|
continue;
|
|
MBB->setAlignment(Align);
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|