forked from OSchip/llvm-project
74 lines
2.5 KiB
C++
74 lines
2.5 KiB
C++
//== ---lib/CodeGen/GlobalISel/GICombinerHelper.cpp --------------------- == //
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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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#include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
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#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
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#include "llvm/CodeGen/GlobalISel/Utils.h"
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#define DEBUG_TYPE "gi-combine"
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using namespace llvm;
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CombinerHelper::CombinerHelper(MachineIRBuilder &B) :
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Builder(B), MRI(Builder.getMF().getRegInfo()) {}
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bool CombinerHelper::tryCombineCopy(MachineInstr &MI) {
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if (MI.getOpcode() != TargetOpcode::COPY)
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return false;
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unsigned DstReg = MI.getOperand(0).getReg();
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unsigned SrcReg = MI.getOperand(1).getReg();
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LLT DstTy = MRI.getType(DstReg);
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LLT SrcTy = MRI.getType(SrcReg);
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// Simple Copy Propagation.
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// a(sx) = COPY b(sx) -> Replace all uses of a with b.
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if (DstTy.isValid() && SrcTy.isValid() && DstTy == SrcTy) {
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MI.eraseFromParent();
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MRI.replaceRegWith(DstReg, SrcReg);
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return true;
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}
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return false;
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}
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bool CombinerHelper::tryCombineExtendingLoads(MachineInstr &MI) {
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if (MI.getOpcode() != TargetOpcode::G_ANYEXT &&
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MI.getOpcode() != TargetOpcode::G_SEXT &&
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MI.getOpcode() != TargetOpcode::G_ZEXT)
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return false;
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unsigned DstReg = MI.getOperand(0).getReg();
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unsigned SrcReg = MI.getOperand(1).getReg();
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LLT DstTy = MRI.getType(DstReg);
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if (!DstTy.isScalar())
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return false;
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if (MachineInstr *DefMI = getOpcodeDef(TargetOpcode::G_LOAD, SrcReg, MRI)) {
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unsigned PtrReg = DefMI->getOperand(1).getReg();
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MachineMemOperand &MMO = **DefMI->memoperands_begin();
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DEBUG(dbgs() << ".. Combine MI: " << MI;);
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Builder.setInstr(MI);
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Builder.buildLoadInstr(MI.getOpcode() == TargetOpcode::G_SEXT
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? TargetOpcode::G_SEXTLOAD
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: MI.getOpcode() == TargetOpcode::G_ZEXT
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? TargetOpcode::G_ZEXTLOAD
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: TargetOpcode::G_LOAD,
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DstReg, PtrReg, MMO);
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MI.eraseFromParent();
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return true;
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}
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return false;
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}
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bool CombinerHelper::tryCombine(MachineInstr &MI) {
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if (tryCombineCopy(MI))
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return true;
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return tryCombineExtendingLoads(MI);
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}
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