void TR::RegDepCopyRemoval::makeFreshCopy(TR_GlobalRegisterNumber reg) { RegDepInfo &dep = getRegDepInfo(reg); if (!performTransformation(comp(), "%schange %s in GlRegDeps n%un to an explicit copy of n%un\n", optDetailString(), registerName(reg), _regDeps->getGlobalIndex(), dep.value->getGlobalIndex())) return; // Split the block at fallthrough if necessary to avoid putting copies // between branches and BBEnd. TR::Node *curNode = _treetop->getNode(); if (curNode->getOpCodeValue() == TR::BBEnd) { TR::Block *curBlock = curNode->getBlock(); if (curBlock->getLastRealTreeTop() != curBlock->getLastNonControlFlowTreeTop()) { TR::Block *fallthrough = curBlock->getNextBlock(); fallthrough = curBlock->splitEdge(curBlock, fallthrough, comp()); TR_ASSERT(curBlock->getNextBlock() == fallthrough, "bad block placement from splitEdge\n"); fallthrough->setIsExtensionOfPreviousBlock(); _treetop = fallthrough->getExit(); TR::Node *newNode = _treetop->getNode(); newNode->setChild(0, _regDeps); newNode->setNumChildren(1); curNode->setNumChildren(0); if (trace()) traceMsg(comp(), "\tsplit fallthrough edge to insert copy, created block_%d\n", fallthrough->getNumber()); } } // Make and insert the copy TR::Node *copyNode = NULL; if (dep.value->getOpCode().isLoadConst()) { // No need to depend on the other register. // TODO heuristic for whether this is really better than a reg-reg move? generateRegcopyDebugCounter("const-remat"); copyNode = TR::Node::create(dep.value->getOpCodeValue(), 0); copyNode->setConstValue(dep.value->getConstValue()); } else { generateRegcopyDebugCounter("fresh-copy"); copyNode = TR::Node::create(TR::PassThrough, 1, dep.value); copyNode->setCopyToNewVirtualRegister(); } TR::Node *copyTreetopNode = TR::Node::create(TR::treetop, 1, copyNode); _treetop->insertBefore(TR::TreeTop::create(comp(), copyTreetopNode)); if (trace()) traceMsg(comp(), "\tcopy is n%un\n", copyNode->getGlobalIndex()); updateSingleRegDep(reg, copyNode); }