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/Target/TargetInstrInfo.h"
19 
20 namespace llvm {
21 
22 /// \brief Check if the instr pair, FirstMI and SecondMI, should be fused
23 /// together. Given SecondMI, when FirstMI is unspecified, then check if
24 /// SecondMI may be part of a fused pair at all.
25 static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,
26                                    const TargetSubtargetInfo &TSI,
27                                    const MachineInstr *FirstMI,
28                                    const MachineInstr &SecondMI) {
29   const ARMSubtarget &ST = static_cast<const ARMSubtarget&>(TSI);
30 
31   // Assume wildcards for unspecified instrs.
32   unsigned FirstOpcode =
33     FirstMI ? FirstMI->getOpcode()
34 	    : static_cast<unsigned>(ARM::INSTRUCTION_LIST_END);
35   unsigned SecondOpcode = SecondMI.getOpcode();
36 
37   if (ST.hasFuseAES())
38     // Fuse AES crypto operations.
39     switch(SecondOpcode) {
40     // AES encode.
41     case ARM::AESMC :
42       return FirstOpcode == ARM::AESE ||
43              FirstOpcode == ARM::INSTRUCTION_LIST_END;
44     // AES decode.
45     case ARM::AESIMC:
46       return FirstOpcode == ARM::AESD ||
47              FirstOpcode == ARM::INSTRUCTION_LIST_END;
48     }
49 
50   return false;
51 }
52 
53 std::unique_ptr<ScheduleDAGMutation> createARMMacroFusionDAGMutation () {
54   return createMacroFusionDAGMutation(shouldScheduleAdjacent);
55 }
56 
57 } // end namespace llvm
58