Line data    Source code

       1             : //===- ARMMacroFusion.cpp - ARM Macro Fusion ----------------------===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : /// \file This file contains the ARM implementation of the DAG scheduling
      11             : ///  mutation to pair instructions back to back.
      12             : //
      13             : //===----------------------------------------------------------------------===//
      14             : 
      15             : #include "ARMMacroFusion.h"
      16             : #include "ARMSubtarget.h"
      17             : #include "llvm/CodeGen/MacroFusion.h"
      18             : #include "llvm/CodeGen/TargetInstrInfo.h"
      19             : 
      20             : namespace llvm {
      21             : 
      22             : // Fuse AES crypto encoding or decoding.
      23         136 : static bool isAESPair(const MachineInstr *FirstMI,
      24             :                       const MachineInstr &SecondMI) {
      25             :   // Assume the 1st instr to be a wildcard if it is unspecified.
      26         272 :   switch(SecondMI.getOpcode()) {
      27             :   // AES encode.
      28          20 :   case ARM::AESMC :
      29          20 :     return FirstMI == nullptr || FirstMI->getOpcode() == ARM::AESE;
      30             :   // AES decode.
      31          16 :   case ARM::AESIMC:
      32          16 :     return FirstMI == nullptr || FirstMI->getOpcode() == ARM::AESD;
      33             :   }
      34             : 
      35             :   return false;
      36             : }
      37             : 
      38             : // Fuse literal generation.
      39             : static bool isLiteralsPair(const MachineInstr *FirstMI,
      40             :                            const MachineInstr &SecondMI) {
      41             :   // Assume the 1st instr to be a wildcard if it is unspecified.
      42          44 :   if ((FirstMI == nullptr || FirstMI->getOpcode() == ARM::MOVi16) &&
      43          44 :       SecondMI.getOpcode() == ARM::MOVTi16)
      44             :     return true;
      45             : 
      46             :   return false;
      47             : }
      48             : 
      49             : /// Check if the instr pair, FirstMI and SecondMI, should be fused
      50             : /// together. Given SecondMI, when FirstMI is unspecified, then check if
      51             : /// SecondMI may be part of a fused pair at all.
      52         180 : static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,
      53             :                                    const TargetSubtargetInfo &TSI,
      54             :                                    const MachineInstr *FirstMI,
      55             :                                    const MachineInstr &SecondMI) {
      56             :   const ARMSubtarget &ST = static_cast<const ARMSubtarget&>(TSI);
      57             : 
      58         180 :   if (ST.hasFuseAES() && isAESPair(FirstMI, SecondMI))
      59             :     return true;
      60         144 :   if (ST.hasFuseLiterals() && isLiteralsPair(FirstMI, SecondMI))
      61          10 :     return true;
      62             : 
      63             :   return false;
      64             : }
      65             : 
      66           7 : std::unique_ptr<ScheduleDAGMutation> createARMMacroFusionDAGMutation () {
      67           7 :   return createMacroFusionDAGMutation(shouldScheduleAdjacent);
      68             : }
      69             : 
      70             : } // end namespace llvm