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	This is before LiveVariables anyway, where these kill flags are recalculated. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106157 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			529 lines
		
	
	
		
			13 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			529 lines
		
	
	
		
			13 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| //===-- NEONPreAllocPass.cpp - Allocate adjacent NEON registers--*- C++ -*-===//
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| //
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| //                     The LLVM Compiler Infrastructure
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| //
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| // This file is distributed under the University of Illinois Open Source
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| // License. See LICENSE.TXT for details.
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| //
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| //===----------------------------------------------------------------------===//
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| 
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| #define DEBUG_TYPE "neon-prealloc"
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| #include "ARM.h"
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| #include "ARMInstrInfo.h"
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| #include "llvm/CodeGen/MachineInstr.h"
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| #include "llvm/CodeGen/MachineInstrBuilder.h"
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| #include "llvm/CodeGen/MachineRegisterInfo.h"
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| #include "llvm/CodeGen/MachineFunctionPass.h"
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| using namespace llvm;
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| 
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| namespace {
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|   class NEONPreAllocPass : public MachineFunctionPass {
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|     const TargetInstrInfo *TII;
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|     MachineRegisterInfo *MRI;
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| 
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|   public:
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|     static char ID;
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|     NEONPreAllocPass() : MachineFunctionPass(&ID) {}
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| 
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|     virtual bool runOnMachineFunction(MachineFunction &MF);
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| 
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|     virtual const char *getPassName() const {
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|       return "NEON register pre-allocation pass";
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|     }
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| 
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|   private:
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|     bool FormsRegSequence(MachineInstr *MI,
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|                           unsigned FirstOpnd, unsigned NumRegs,
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|                           unsigned Offset, unsigned Stride) const;
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|     bool PreAllocNEONRegisters(MachineBasicBlock &MBB);
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|   };
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| 
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|   char NEONPreAllocPass::ID = 0;
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| }
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| 
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| static bool isNEONMultiRegOp(int Opcode, unsigned &FirstOpnd, unsigned &NumRegs,
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|                              unsigned &Offset, unsigned &Stride) {
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|   // Default to unit stride with no offset.
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|   Stride = 1;
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|   Offset = 0;
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| 
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|   switch (Opcode) {
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|   default:
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|     break;
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| 
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|   case ARM::VLD1q8:
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|   case ARM::VLD1q16:
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|   case ARM::VLD1q32:
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|   case ARM::VLD1q64:
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|   case ARM::VLD2d8:
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|   case ARM::VLD2d16:
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|   case ARM::VLD2d32:
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|   case ARM::VLD2LNd8:
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|   case ARM::VLD2LNd16:
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|   case ARM::VLD2LNd32:
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|     FirstOpnd = 0;
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|     NumRegs = 2;
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|     return true;
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| 
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|   case ARM::VLD2q8:
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|   case ARM::VLD2q16:
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|   case ARM::VLD2q32:
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|     FirstOpnd = 0;
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|     NumRegs = 4;
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|     return true;
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| 
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|   case ARM::VLD2LNq16:
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|   case ARM::VLD2LNq32:
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|     FirstOpnd = 0;
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|     NumRegs = 2;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD2LNq16odd:
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|   case ARM::VLD2LNq32odd:
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|     FirstOpnd = 0;
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|     NumRegs = 2;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD3d8:
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|   case ARM::VLD3d16:
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|   case ARM::VLD3d32:
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|   case ARM::VLD1d64T:
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|   case ARM::VLD3LNd8:
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|   case ARM::VLD3LNd16:
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|   case ARM::VLD3LNd32:
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|     FirstOpnd = 0;
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|     NumRegs = 3;
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|     return true;
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| 
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|   case ARM::VLD3q8_UPD:
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|   case ARM::VLD3q16_UPD:
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|   case ARM::VLD3q32_UPD:
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|     FirstOpnd = 0;
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|     NumRegs = 3;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD3q8odd_UPD:
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|   case ARM::VLD3q16odd_UPD:
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|   case ARM::VLD3q32odd_UPD:
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|     FirstOpnd = 0;
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|     NumRegs = 3;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD3LNq16:
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|   case ARM::VLD3LNq32:
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|     FirstOpnd = 0;
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|     NumRegs = 3;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD3LNq16odd:
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|   case ARM::VLD3LNq32odd:
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|     FirstOpnd = 0;
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|     NumRegs = 3;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD4d8:
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|   case ARM::VLD4d16:
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|   case ARM::VLD4d32:
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|   case ARM::VLD1d64Q:
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|   case ARM::VLD4LNd8:
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|   case ARM::VLD4LNd16:
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|   case ARM::VLD4LNd32:
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|     FirstOpnd = 0;
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|     NumRegs = 4;
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|     return true;
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| 
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|   case ARM::VLD4q8_UPD:
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|   case ARM::VLD4q16_UPD:
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|   case ARM::VLD4q32_UPD:
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|     FirstOpnd = 0;
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|     NumRegs = 4;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD4q8odd_UPD:
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|   case ARM::VLD4q16odd_UPD:
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|   case ARM::VLD4q32odd_UPD:
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|     FirstOpnd = 0;
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|     NumRegs = 4;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD4LNq16:
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|   case ARM::VLD4LNq32:
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|     FirstOpnd = 0;
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|     NumRegs = 4;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VLD4LNq16odd:
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|   case ARM::VLD4LNq32odd:
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|     FirstOpnd = 0;
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|     NumRegs = 4;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST1q8:
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|   case ARM::VST1q16:
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|   case ARM::VST1q32:
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|   case ARM::VST1q64:
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|   case ARM::VST2d8:
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|   case ARM::VST2d16:
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|   case ARM::VST2d32:
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|   case ARM::VST2LNd8:
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|   case ARM::VST2LNd16:
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|   case ARM::VST2LNd32:
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|     FirstOpnd = 2;
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|     NumRegs = 2;
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|     return true;
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| 
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|   case ARM::VST2q8:
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|   case ARM::VST2q16:
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|   case ARM::VST2q32:
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|     FirstOpnd = 2;
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|     NumRegs = 4;
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|     return true;
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| 
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|   case ARM::VST2LNq16:
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|   case ARM::VST2LNq32:
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|     FirstOpnd = 2;
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|     NumRegs = 2;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST2LNq16odd:
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|   case ARM::VST2LNq32odd:
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|     FirstOpnd = 2;
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|     NumRegs = 2;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST3d8:
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|   case ARM::VST3d16:
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|   case ARM::VST3d32:
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|   case ARM::VST1d64T:
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|   case ARM::VST3LNd8:
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|   case ARM::VST3LNd16:
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|   case ARM::VST3LNd32:
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|     FirstOpnd = 2;
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|     NumRegs = 3;
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|     return true;
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| 
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|   case ARM::VST3q8_UPD:
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|   case ARM::VST3q16_UPD:
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|   case ARM::VST3q32_UPD:
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|     FirstOpnd = 4;
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|     NumRegs = 3;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST3q8odd_UPD:
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|   case ARM::VST3q16odd_UPD:
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|   case ARM::VST3q32odd_UPD:
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|     FirstOpnd = 4;
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|     NumRegs = 3;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST3LNq16:
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|   case ARM::VST3LNq32:
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|     FirstOpnd = 2;
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|     NumRegs = 3;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST3LNq16odd:
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|   case ARM::VST3LNq32odd:
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|     FirstOpnd = 2;
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|     NumRegs = 3;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST4d8:
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|   case ARM::VST4d16:
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|   case ARM::VST4d32:
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|   case ARM::VST1d64Q:
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|   case ARM::VST4LNd8:
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|   case ARM::VST4LNd16:
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|   case ARM::VST4LNd32:
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|     FirstOpnd = 2;
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|     NumRegs = 4;
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|     return true;
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| 
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|   case ARM::VST4q8_UPD:
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|   case ARM::VST4q16_UPD:
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|   case ARM::VST4q32_UPD:
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|     FirstOpnd = 4;
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|     NumRegs = 4;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST4q8odd_UPD:
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|   case ARM::VST4q16odd_UPD:
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|   case ARM::VST4q32odd_UPD:
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|     FirstOpnd = 4;
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|     NumRegs = 4;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST4LNq16:
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|   case ARM::VST4LNq32:
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|     FirstOpnd = 2;
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|     NumRegs = 4;
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|     Offset = 0;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VST4LNq16odd:
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|   case ARM::VST4LNq32odd:
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|     FirstOpnd = 2;
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|     NumRegs = 4;
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|     Offset = 1;
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|     Stride = 2;
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|     return true;
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| 
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|   case ARM::VTBL2:
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|     FirstOpnd = 1;
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|     NumRegs = 2;
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|     return true;
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| 
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|   case ARM::VTBL3:
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|     FirstOpnd = 1;
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|     NumRegs = 3;
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|     return true;
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| 
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|   case ARM::VTBL4:
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|     FirstOpnd = 1;
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|     NumRegs = 4;
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|     return true;
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| 
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|   case ARM::VTBX2:
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|     FirstOpnd = 2;
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|     NumRegs = 2;
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|     return true;
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| 
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|   case ARM::VTBX3:
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|     FirstOpnd = 2;
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|     NumRegs = 3;
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|     return true;
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| 
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|   case ARM::VTBX4:
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|     FirstOpnd = 2;
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|     NumRegs = 4;
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|     return true;
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|   }
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| 
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|   return false;
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| }
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| 
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| bool
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| NEONPreAllocPass::FormsRegSequence(MachineInstr *MI,
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|                                    unsigned FirstOpnd, unsigned NumRegs,
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|                                    unsigned Offset, unsigned Stride) const {
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|   MachineOperand &FMO = MI->getOperand(FirstOpnd);
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|   assert(FMO.isReg() && FMO.getSubReg() == 0 && "unexpected operand");
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|   unsigned VirtReg = FMO.getReg();
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|   (void)VirtReg;
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|   assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
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|          "expected a virtual register");
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| 
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|   unsigned LastSubIdx = 0;
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|   if (FMO.isDef()) {
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|     MachineInstr *RegSeq = 0;
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|     for (unsigned R = 0; R < NumRegs; ++R) {
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|       const MachineOperand &MO = MI->getOperand(FirstOpnd + R);
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|       assert(MO.isReg() && MO.getSubReg() == 0 && "unexpected operand");
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|       unsigned VirtReg = MO.getReg();
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|       assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
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|              "expected a virtual register");
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|       // Feeding into a REG_SEQUENCE.
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|       if (!MRI->hasOneNonDBGUse(VirtReg))
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|         return false;
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|       MachineInstr *UseMI = &*MRI->use_nodbg_begin(VirtReg);
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|       if (!UseMI->isRegSequence())
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|         return false;
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|       if (RegSeq && RegSeq != UseMI)
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|         return false;
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|       unsigned OpIdx = 1 + (Offset + R * Stride) * 2;
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|       if (UseMI->getOperand(OpIdx).getReg() != VirtReg)
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|         llvm_unreachable("Malformed REG_SEQUENCE instruction!");
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|       unsigned SubIdx = UseMI->getOperand(OpIdx + 1).getImm();
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|       if (LastSubIdx) {
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|         if (LastSubIdx != SubIdx-Stride)
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|           return false;
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|       } else {
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|         // Must start from dsub_0 or qsub_0.
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|         if (SubIdx != (ARM::dsub_0+Offset) &&
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|             SubIdx != (ARM::qsub_0+Offset))
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|           return false;
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|       }
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|       RegSeq = UseMI;
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|       LastSubIdx = SubIdx;
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|     }
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| 
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|     // In the case of vld3, etc., make sure the trailing operand of
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|     // REG_SEQUENCE is an undef.
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|     if (NumRegs == 3) {
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|       unsigned OpIdx = 1 + (Offset + 3 * Stride) * 2;
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|       const MachineOperand &MO = RegSeq->getOperand(OpIdx);
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|       unsigned VirtReg = MO.getReg();
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|       MachineInstr *DefMI = MRI->getVRegDef(VirtReg);
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|       if (!DefMI || !DefMI->isImplicitDef())
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|         return false;
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|     }
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|     return true;
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|   }
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| 
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|   unsigned LastSrcReg = 0;
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|   SmallVector<unsigned, 4> SubIds;
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|   for (unsigned R = 0; R < NumRegs; ++R) {
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|     const MachineOperand &MO = MI->getOperand(FirstOpnd + R);
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|     assert(MO.isReg() && MO.getSubReg() == 0 && "unexpected operand");
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|     unsigned VirtReg = MO.getReg();
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|     assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
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|            "expected a virtual register");
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|     // Extracting from a Q or QQ register.
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|     MachineInstr *DefMI = MRI->getVRegDef(VirtReg);
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|     if (!DefMI || !DefMI->isExtractSubreg())
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|       return false;
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|     VirtReg = DefMI->getOperand(1).getReg();
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|     if (LastSrcReg && LastSrcReg != VirtReg)
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|       return false;
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|     LastSrcReg = VirtReg;
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|     const TargetRegisterClass *RC = MRI->getRegClass(VirtReg);
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|     if (RC != ARM::QPRRegisterClass &&
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|         RC != ARM::QQPRRegisterClass &&
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|         RC != ARM::QQQQPRRegisterClass)
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|       return false;
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|     unsigned SubIdx = DefMI->getOperand(2).getImm();
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|     if (LastSubIdx) {
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|       if (LastSubIdx != SubIdx-Stride)
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|         return false;
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|     } else {
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|       // Must start from dsub_0 or qsub_0.
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|       if (SubIdx != (ARM::dsub_0+Offset) &&
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|           SubIdx != (ARM::qsub_0+Offset))
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|         return false;
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|     }
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|     SubIds.push_back(SubIdx);
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|     LastSubIdx = SubIdx;
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|   }
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| 
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|   // FIXME: Update the uses of EXTRACT_SUBREG from REG_SEQUENCE is
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|   // currently required for correctness. e.g.
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|   //  %reg1041<def> = REG_SEQUENCE %reg1040<kill>, 5, %reg1035<kill>, 6
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|   //  %reg1042<def> = EXTRACT_SUBREG %reg1041, 6
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|   //  %reg1043<def> = EXTRACT_SUBREG %reg1041, 5
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|   //  VST1q16 %reg1025<kill>, 0, %reg1043<kill>, %reg1042<kill>,
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|   // reg1042 and reg1043 should be replaced with reg1041:6 and reg1041:5
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|   // respectively.
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|   // We need to change how we model uses of REG_SEQUENCE.
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|   for (unsigned R = 0; R < NumRegs; ++R) {
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|     MachineOperand &MO = MI->getOperand(FirstOpnd + R);
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|     unsigned OldReg = MO.getReg();
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|     MachineInstr *DefMI = MRI->getVRegDef(OldReg);
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|     assert(DefMI->isExtractSubreg());
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|     MO.setReg(LastSrcReg);
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|     MO.setSubReg(SubIds[R]);
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|     MO.setIsKill(false);
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|     // Delete the EXTRACT_SUBREG if its result is now dead.
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|     if (MRI->use_empty(OldReg))
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|       DefMI->eraseFromParent();
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|   }
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| 
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|   return true;
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| }
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| 
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| bool NEONPreAllocPass::PreAllocNEONRegisters(MachineBasicBlock &MBB) {
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|   bool Modified = false;
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| 
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|   MachineBasicBlock::iterator MBBI = MBB.begin(), E = MBB.end();
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|   for (; MBBI != E; ++MBBI) {
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|     MachineInstr *MI = &*MBBI;
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|     unsigned FirstOpnd, NumRegs, Offset, Stride;
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|     if (!isNEONMultiRegOp(MI->getOpcode(), FirstOpnd, NumRegs, Offset, Stride))
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|       continue;
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|     if (FormsRegSequence(MI, FirstOpnd, NumRegs, Offset, Stride))
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|       continue;
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| 
 | |
|     MachineBasicBlock::iterator NextI = llvm::next(MBBI);
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|     for (unsigned R = 0; R < NumRegs; ++R) {
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|       MachineOperand &MO = MI->getOperand(FirstOpnd + R);
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|       assert(MO.isReg() && MO.getSubReg() == 0 && "unexpected operand");
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|       unsigned VirtReg = MO.getReg();
 | |
|       assert(TargetRegisterInfo::isVirtualRegister(VirtReg) &&
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|              "expected a virtual register");
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| 
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|       // For now, just assign a fixed set of adjacent registers.
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|       // This leaves plenty of room for future improvements.
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|       static const unsigned NEONDRegs[] = {
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|         ARM::D0, ARM::D1, ARM::D2, ARM::D3,
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|         ARM::D4, ARM::D5, ARM::D6, ARM::D7
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|       };
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|       MO.setReg(NEONDRegs[Offset + R * Stride]);
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| 
 | |
|       if (MO.isUse()) {
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|         // Insert a copy from VirtReg.
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|         TII->copyRegToReg(MBB, MBBI, MO.getReg(), VirtReg,
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|                           ARM::DPRRegisterClass, ARM::DPRRegisterClass,
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|                           DebugLoc());
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|         if (MO.isKill()) {
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|           MachineInstr *CopyMI = prior(MBBI);
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|           CopyMI->findRegisterUseOperand(VirtReg)->setIsKill();
 | |
|         }
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|         MO.setIsKill();
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|       } else if (MO.isDef() && !MO.isDead()) {
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|         // Add a copy to VirtReg.
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|         TII->copyRegToReg(MBB, NextI, VirtReg, MO.getReg(),
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|                           ARM::DPRRegisterClass, ARM::DPRRegisterClass,
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|                           DebugLoc());
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|       }
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|     }
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|   }
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| 
 | |
|   return Modified;
 | |
| }
 | |
| 
 | |
| bool NEONPreAllocPass::runOnMachineFunction(MachineFunction &MF) {
 | |
|   TII = MF.getTarget().getInstrInfo();
 | |
|   MRI = &MF.getRegInfo();
 | |
| 
 | |
|   bool Modified = false;
 | |
|   for (MachineFunction::iterator MFI = MF.begin(), E = MF.end(); MFI != E;
 | |
|        ++MFI) {
 | |
|     MachineBasicBlock &MBB = *MFI;
 | |
|     Modified |= PreAllocNEONRegisters(MBB);
 | |
|   }
 | |
| 
 | |
|   return Modified;
 | |
| }
 | |
| 
 | |
| /// createNEONPreAllocPass - returns an instance of the NEON register
 | |
| /// pre-allocation pass.
 | |
| FunctionPass *llvm::createNEONPreAllocPass() {
 | |
|   return new NEONPreAllocPass();
 | |
| }
 |