1 //===- MachineCopyPropagation.cpp - Machine Copy Propagation Pass ---------===//
8 //===----------------------------------------------------------------------===//
10 // This is an extremely simple MachineInstr-level copy propagation pass.
12 //===----------------------------------------------------------------------===//
22 #include "llvm/Pass.h"
30 #define DEBUG_TYPE "codegen-cp"
45     static char ID; // Pass identification, replacement for typeid
69     /// Def -> available copies map.
71     /// Def -> copies map.
73     /// Src -> Def map
81 INITIALIZE_PASS(MachineCopyPropagation, "machine-cp",
82                 "Machine Copy Propagation Pass", false, false)
104     unsigned Reg = I->first;  in removeClobberedRegsFromMap()
117       removeRegsFromMap(AvailCopyMap, SI->second, *TRI);  in ClobberRegister()
137   if (!TRI->isSubRegister(PreviousSrc, Src))  in isNopCopy()
139   unsigned SubIdx = TRI->getSubRegIndex(PreviousSrc, Src);  in isNopCopy()
140   return SubIdx == TRI->getSubRegIndex(PreviousDef, Def);  in isNopCopy()
150   if (MRI->isReserved(Src) || MRI->isReserved(Def))  in eraseIfRedundant()
154   Reg2MIMap::iterator CI = AvailCopyMap.find(Def);  in eraseIfRedundant()  local
155   if (CI == AvailCopyMap.end())  in eraseIfRedundant()
159   MachineInstr &PrevCopy = *CI->second;  in eraseIfRedundant()
187     if (MI->isCopy()) {  in CopyPropagateBlock()
188       unsigned Def = MI->getOperand(0).getReg();  in CopyPropagateBlock()
189       unsigned Src = MI->getOperand(1).getReg();  in CopyPropagateBlock()
216         Reg2MIMap::iterator CI = CopyMap.find(*AI);  in CopyPropagateBlock()  local
217         if (CI != CopyMap.end()) {  in CopyPropagateBlock()
218           DEBUG(dbgs() << "MCP: Copy is no longer dead: "; CI->second->dump());  in CopyPropagateBlock()
219           MaybeDeadCopies.remove(CI->second);  in CopyPropagateBlock()
223       DEBUG(dbgs() << "MCP: Copy is a deletion candidate: "; MI->dump());  in CopyPropagateBlock()
226       if (!MRI->isReserved(Def))  in CopyPropagateBlock()
257     for (const MachineOperand &MO : MI->operands()) {  in CopyPropagateBlock()
277         Reg2MIMap::iterator CI = CopyMap.find(*AI);  in CopyPropagateBlock()  local
278         if (CI != CopyMap.end()) {  in CopyPropagateBlock()
279           DEBUG(dbgs() << "MCP: Copy is used - not dead: "; CI->second->dump());  in CopyPropagateBlock()
280           MaybeDeadCopies.remove(CI->second);  in CopyPropagateBlock()
302         unsigned Reg = MaybeDead->getOperand(0).getReg();  in CopyPropagateBlock()
303         assert(!MRI->isReserved(Reg));  in CopyPropagateBlock()
305         if (!RegMask->clobbersPhysReg(Reg)) {  in CopyPropagateBlock()
311               MaybeDead->dump());  in CopyPropagateBlock()
316         MaybeDead->eraseFromParent();  in CopyPropagateBlock()
326         if (RegMask->clobbersPhysReg(I->first)) {  in CopyPropagateBlock()
327           removeRegsFromMap(AvailCopyMap, I->second, *TRI);  in CopyPropagateBlock()
339   // If MBB does have successors, then conservative assume the defs are live-out  in CopyPropagateBlock()
340   // since we don't want to trust live-in lists.  in CopyPropagateBlock()
343       assert(!MRI->isReserved(MaybeDead->getOperand(0).getReg()));  in CopyPropagateBlock()
344       MaybeDead->eraseFromParent();  in CopyPropagateBlock()