llvm/lib/CodeGen/AllocationOrder.h
Jakob Stoklund Olesen f7999fe1cb Speed up the AllocationOrder class a bit.
Allow the central functions to be inlined, and use the argumentless
isHint() function when possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169319 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-04 22:25:16 +00:00

71 lines
2.1 KiB
C++

//===-- llvm/CodeGen/AllocationOrder.h - Allocation Order -*- C++ -*-------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements an allocation order for virtual registers.
//
// The preferred allocation order for a virtual register depends on allocation
// hints and target hooks. The AllocationOrder class encapsulates all of that.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_ALLOCATIONORDER_H
#define LLVM_CODEGEN_ALLOCATIONORDER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/MC/MCRegisterInfo.h"
namespace llvm {
class RegisterClassInfo;
class VirtRegMap;
class AllocationOrder {
SmallVector<MCPhysReg, 16> Hints;
ArrayRef<MCPhysReg> Order;
int Pos;
public:
/// Create a new AllocationOrder for VirtReg.
/// @param VirtReg Virtual register to allocate for.
/// @param VRM Virtual register map for function.
/// @param RegClassInfo Information about reserved and allocatable registers.
AllocationOrder(unsigned VirtReg,
const VirtRegMap &VRM,
const RegisterClassInfo &RegClassInfo);
/// Return the next physical register in the allocation order, or 0.
/// It is safe to call next() again after it returned 0, it will keep
/// returning 0 until rewind() is called.
unsigned next() {
if (Pos < 0)
return Hints.end()[Pos++];
while (Pos < int(Order.size())) {
unsigned Reg = Order[Pos++];
if (!isHint(Reg))
return Reg;
}
return 0;
}
/// Start over from the beginning.
void rewind() { Pos = -int(Hints.size()); }
/// Return true if the last register returned from next() was a preferred register.
bool isHint() const { return Pos <= 0; }
/// Return true if PhysReg is a preferred register.
bool isHint(unsigned PhysReg) const {
return std::find(Hints.begin(), Hints.end(), PhysReg) != Hints.end();
}
};
} // end namespace llvm
#endif