Imported Upstream version 6.0.0.172

Former-commit-id: f3cc9b82f3e5bd8f0fd3ebc098f789556b44e9cd

external/llvm/lib/Target/Hexagon/RDFCopy.cpp

@@ -0,0 +1,213 @@
+//===- RDFCopy.cpp --------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// RDF-based copy propagation.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RDFCopy.h"
+#include "RDFGraph.h"
+#include "RDFLiveness.h"
+#include "RDFRegisters.h"
+#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineInstr.h"
+#include "llvm/CodeGen/MachineOperand.h"
+#include "llvm/CodeGen/TargetOpcodes.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+#include <cassert>
+#include <cstdint>
+#include <utility>
+
+using namespace llvm;
+using namespace rdf;
+
+#ifndef NDEBUG
+static cl::opt<unsigned> CpLimit("rdf-cp-limit", cl::init(0), cl::Hidden);
+static unsigned CpCount = 0;
+#endif
+
+bool CopyPropagation::interpretAsCopy(const MachineInstr *MI, EqualityMap &EM) {
+  unsigned Opc = MI->getOpcode();
+  switch (Opc) {
+    case TargetOpcode::COPY: {
+      const MachineOperand &Dst = MI->getOperand(0);
+      const MachineOperand &Src = MI->getOperand(1);
+      RegisterRef DstR = DFG.makeRegRef(Dst.getReg(), Dst.getSubReg());
+      RegisterRef SrcR = DFG.makeRegRef(Src.getReg(), Src.getSubReg());
+      assert(TargetRegisterInfo::isPhysicalRegister(DstR.Reg));
+      assert(TargetRegisterInfo::isPhysicalRegister(SrcR.Reg));
+      const TargetRegisterInfo &TRI = DFG.getTRI();
+      if (TRI.getMinimalPhysRegClass(DstR.Reg) !=
+          TRI.getMinimalPhysRegClass(SrcR.Reg))
+        return false;
+      EM.insert(std::make_pair(DstR, SrcR));
+      return true;
+    }
+    case TargetOpcode::REG_SEQUENCE:
+      llvm_unreachable("Unexpected REG_SEQUENCE");
+  }
+  return false;
+}
+
+void CopyPropagation::recordCopy(NodeAddr<StmtNode*> SA, EqualityMap &EM) {
+  CopyMap.insert(std::make_pair(SA.Id, EM));
+  Copies.push_back(SA.Id);
+}
+
+bool CopyPropagation::scanBlock(MachineBasicBlock *B) {
+  bool Changed = false;
+  NodeAddr<BlockNode*> BA = DFG.findBlock(B);
+
+  for (NodeAddr<InstrNode*> IA : BA.Addr->members(DFG)) {
+    if (DFG.IsCode<NodeAttrs::Stmt>(IA)) {
+      NodeAddr<StmtNode*> SA = IA;
+      EqualityMap EM;
+      if (interpretAsCopy(SA.Addr->getCode(), EM))
+        recordCopy(SA, EM);
+    }
+  }
+
+  MachineDomTreeNode *N = MDT.getNode(B);
+  for (auto I : *N)
+    Changed |= scanBlock(I->getBlock());
+
+  return Changed;
+}
+
+NodeId CopyPropagation::getLocalReachingDef(RegisterRef RefRR,
+      NodeAddr<InstrNode*> IA) {
+  NodeAddr<RefNode*> RA = L.getNearestAliasedRef(RefRR, IA);
+  if (RA.Id != 0) {
+    if (RA.Addr->getKind() == NodeAttrs::Def)
+      return RA.Id;
+    assert(RA.Addr->getKind() == NodeAttrs::Use);
+    if (NodeId RD = RA.Addr->getReachingDef())
+      return RD;
+  }
+  return 0;
+}
+
+bool CopyPropagation::run() {
+  scanBlock(&DFG.getMF().front());
+
+  if (trace()) {
+    dbgs() << "Copies:\n";
+    for (auto I : Copies) {
+      dbgs() << "Instr: " << *DFG.addr<StmtNode*>(I).Addr->getCode();
+      dbgs() << "   eq: {";
+      for (auto J : CopyMap[I])
+        dbgs() << ' ' << Print<RegisterRef>(J.first, DFG) << '='
+               << Print<RegisterRef>(J.second, DFG);
+      dbgs() << " }\n";
+    }
+  }
+
+  bool Changed = false;
+#ifndef NDEBUG
+  bool HasLimit = CpLimit.getNumOccurrences() > 0;
+#endif
+
+  auto MinPhysReg = [this] (RegisterRef RR) -> unsigned {
+    const TargetRegisterInfo &TRI = DFG.getTRI();
+    const TargetRegisterClass &RC = *TRI.getMinimalPhysRegClass(RR.Reg);
+    if ((RC.LaneMask & RR.Mask) == RC.LaneMask)
+      return RR.Reg;
+    for (MCSubRegIndexIterator S(RR.Reg, &TRI); S.isValid(); ++S)
+      if (RR.Mask == TRI.getSubRegIndexLaneMask(S.getSubRegIndex()))
+        return S.getSubReg();
+    llvm_unreachable("Should have found a register");
+    return 0;
+  };
+
+  for (auto C : Copies) {
+#ifndef NDEBUG
+    if (HasLimit && CpCount >= CpLimit)
+      break;
+#endif
+    auto SA = DFG.addr<InstrNode*>(C);
+    auto FS = CopyMap.find(SA.Id);
+    if (FS == CopyMap.end())
+      continue;
+
+    EqualityMap &EM = FS->second;
+    for (NodeAddr<DefNode*> DA : SA.Addr->members_if(DFG.IsDef, DFG)) {
+      RegisterRef DR = DA.Addr->getRegRef(DFG);
+      auto FR = EM.find(DR);
+      if (FR == EM.end())
+        continue;
+      RegisterRef SR = FR->second;
+      if (DR == SR)
+        continue;
+
+      NodeId AtCopy = getLocalReachingDef(SR, SA);
+
+      for (NodeId N = DA.Addr->getReachedUse(), NextN; N; N = NextN) {
+        auto UA = DFG.addr<UseNode*>(N);
+        NextN = UA.Addr->getSibling();
+        uint16_t F = UA.Addr->getFlags();
+        if ((F & NodeAttrs::PhiRef) || (F & NodeAttrs::Fixed))
+          continue;
+        if (UA.Addr->getRegRef(DFG) != DR)
+          continue;
+
+        NodeAddr<InstrNode*> IA = UA.Addr->getOwner(DFG);
+        assert(DFG.IsCode<NodeAttrs::Stmt>(IA));
+        NodeId AtUse = getLocalReachingDef(SR, IA);
+        if (AtCopy != AtUse)
+          continue;
+
+        MachineOperand &Op = UA.Addr->getOp();
+        if (Op.isTied())
+          continue;
+        if (trace()) {
+          dbgs() << "Can replace " << Print<RegisterRef>(DR, DFG)
+                 << " with " << Print<RegisterRef>(SR, DFG) << " in "
+                 << *NodeAddr<StmtNode*>(IA).Addr->getCode();
+        }
+
+        unsigned NewReg = MinPhysReg(SR);
+        Op.setReg(NewReg);
+        Op.setSubReg(0);
+        DFG.unlinkUse(UA, false);
+        if (AtCopy != 0) {
+          UA.Addr->linkToDef(UA.Id, DFG.addr<DefNode*>(AtCopy));
+        } else {
+          UA.Addr->setReachingDef(0);
+          UA.Addr->setSibling(0);
+        }
+
+        Changed = true;
+  #ifndef NDEBUG
+        if (HasLimit && CpCount >= CpLimit)
+          break;
+        CpCount++;
+  #endif
+
+        auto FC = CopyMap.find(IA.Id);
+        if (FC != CopyMap.end()) {
+          // Update the EM map in the copy's entry.
+          auto &M = FC->second;
+          for (auto &J : M) {
+            if (J.second != DR)
+              continue;
+            J.second = SR;
+            break;
+          }
+        }
+      } // for (N in reached-uses)
+    } // for (DA in defs)
+  } // for (C in Copies)
+
+  return Changed;
+}