Commit ab62fa56 authored by Hans Wennborg's avatar Hans Wennborg
Browse files

Merging r371048: 

------------------------------------------------------------------------
r371048 | jonpa | 2019-09-05 12:20:05 +0200 (Thu, 05 Sep 2019) | 7 lines

[SystemZ]  Recognize INLINEASM_BR in backend

Handle the remaining cases also by handling asm goto in
SystemZInstrInfo::getBranchInfo().

Review: Ulrich Weigand
https://reviews.llvm.org/D67151
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llvm-svn: 371057
parent d8975f4f

llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp

+13 −9
Original line number Diff line number Diff line
@@ -462,13 +462,13 @@ bool SystemZInstrInfo::analyzeBranch(MachineBasicBlock &MBB, 
      break;



    // A terminator that isn't a branch can't easily be handled by this

    // analysis.  Asm goto is not understood / optimized.

    if (!I->isBranch() || I->getOpcode() == SystemZ::INLINEASM_BR)

    // analysis.

    if (!I->isBranch())

      return true;



    // Can't handle indirect branches.

    SystemZII::Branch Branch(getBranchInfo(*I));

    if (!Branch.Target->isMBB())

    if (!Branch.hasMBBTarget())

      return true;



    // Punt on compound branches.
@@ -478,7 +478,7 @@ bool SystemZInstrInfo::analyzeBranch(MachineBasicBlock &MBB, 
    if (Branch.CCMask == SystemZ::CCMASK_ANY) {

      // Handle unconditional branches.

      if (!AllowModify) {

        TBB = Branch.Target->getMBB();

        TBB = Branch.getMBBTarget();

        continue;

      }
@@ -490,7 +490,7 @@ bool SystemZInstrInfo::analyzeBranch(MachineBasicBlock &MBB, 
      FBB = nullptr;



      // Delete the JMP if it's equivalent to a fall-through.

      if (MBB.isLayoutSuccessor(Branch.Target->getMBB())) {

      if (MBB.isLayoutSuccessor(Branch.getMBBTarget())) {

        TBB = nullptr;

        I->eraseFromParent();

        I = MBB.end();
@@ -498,7 +498,7 @@ bool SystemZInstrInfo::analyzeBranch(MachineBasicBlock &MBB, 
      }



      // TBB is used to indicate the unconditinal destination.

      TBB = Branch.Target->getMBB();

      TBB = Branch.getMBBTarget();

      continue;

    }
@@ -506,7 +506,7 @@ bool SystemZInstrInfo::analyzeBranch(MachineBasicBlock &MBB, 
    if (Cond.empty()) {

      // FIXME: add X86-style branch swap

      FBB = TBB;

      TBB = Branch.Target->getMBB();

      TBB = Branch.getMBBTarget();

      Cond.push_back(MachineOperand::CreateImm(Branch.CCValid));

      Cond.push_back(MachineOperand::CreateImm(Branch.CCMask));

      continue;
@@ -517,7 +517,7 @@ bool SystemZInstrInfo::analyzeBranch(MachineBasicBlock &MBB, 


    // Only handle the case where all conditional branches branch to the same

    // destination.

    if (TBB != Branch.Target->getMBB())

    if (TBB != Branch.getMBBTarget())

      return true;



    // If the conditions are the same, we can leave them alone.
@@ -547,7 +547,7 @@ unsigned SystemZInstrInfo::removeBranch(MachineBasicBlock &MBB, 
      continue;

    if (!I->isBranch())

      break;

    if (!getBranchInfo(*I).Target->isMBB())

    if (!getBranchInfo(*I).hasMBBTarget())

      break;

    // Remove the branch.

    I->eraseFromParent();
@@ -1545,6 +1545,10 @@ SystemZInstrInfo::getBranchInfo(const MachineInstr &MI) const { 
    return SystemZII::Branch(SystemZII::BranchCLG, SystemZ::CCMASK_ICMP,

                             MI.getOperand(2).getImm(), &MI.getOperand(3));



  case SystemZ::INLINEASM_BR:

    // Don't try to analyze asm goto, so pass nullptr as branch target argument.

    return SystemZII::Branch(SystemZII::AsmGoto, 0, 0, nullptr);



  default:

    llvm_unreachable("Unrecognized branch opcode");

  }

llvm/lib/Target/SystemZ/SystemZInstrInfo.h

+16 −6
Original line number Diff line number Diff line
@@ -100,11 +100,18 @@ enum BranchType { 


  // An instruction that decrements a 64-bit register and branches if

  // the result is nonzero.

  BranchCTG

  BranchCTG,



  // An instruction representing an asm goto statement.

  AsmGoto

};



// Information about a branch instruction.

struct Branch {

class Branch {

  // The target of the branch. In case of INLINEASM_BR, this is nullptr.

  const MachineOperand *Target;



public:

  // The type of the branch.

  BranchType Type;
@@ -114,12 +121,15 @@ struct Branch { 
  // CCMASK_<N> is set if the branch should be taken when CC == N.

  unsigned CCMask;



  // The target of the branch.

  const MachineOperand *Target;



  Branch(BranchType type, unsigned ccValid, unsigned ccMask,

         const MachineOperand *target)

    : Type(type), CCValid(ccValid), CCMask(ccMask), Target(target) {}

    : Target(target), Type(type), CCValid(ccValid), CCMask(ccMask) {}



  bool isIndirect() { return Target != nullptr && Target->isReg(); }

  bool hasMBBTarget() { return Target != nullptr && Target->isMBB(); }

  MachineBasicBlock *getMBBTarget() {

    return hasMBBTarget() ? Target->getMBB() : nullptr;

  }

};



// Kinds of fused compares in compare-and-* instructions.  Together with type

llvm/lib/Target/SystemZ/SystemZLongBranch.cpp

+1 −1
Original line number Diff line number Diff line
@@ -257,7 +257,7 @@ TerminatorInfo SystemZLongBranch::describeTerminator(MachineInstr &MI) { 
    }

    Terminator.Branch = &MI;

    Terminator.TargetBlock =

      TII->getBranchInfo(MI).Target->getMBB()->getNumber();

      TII->getBranchInfo(MI).getMBBTarget()->getNumber();

  }

  return Terminator;

}

llvm/lib/Target/SystemZ/SystemZMachineScheduler.cpp

+2 −2
Original line number Diff line number Diff line
@@ -108,8 +108,8 @@ void SystemZPostRASchedStrategy::enterMBB(MachineBasicBlock *NextMBB) { 
       I != SinglePredMBB->end(); I++) {

    LLVM_DEBUG(dbgs() << "** Emitting incoming branch: "; I->dump(););

    bool TakenBranch = (I->isBranch() &&

      (TII->getBranchInfo(*I).Target->isReg() || // Relative branch

       TII->getBranchInfo(*I).Target->getMBB() == MBB));

                        (TII->getBranchInfo(*I).isIndirect() ||

                         TII->getBranchInfo(*I).getMBBTarget() == MBB));

    HazardRec->emitInstruction(&*I, TakenBranch);

    if (TakenBranch)

      break;

llvm/test/CodeGen/SystemZ/asm-20.ll

+2 −2
Original line number Diff line number Diff line 
; Test that asm goto can be compiled.

;

; RUN: llc < %s -mtriple=s390x-linux-gnu

; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=z14



define i32 @c() {

entry:

  callbr void asm sideeffect "", "X"(i8* blockaddress(@c, %d))

  callbr void asm sideeffect "j d", "X"(i8* blockaddress(@c, %d))

          to label %asm.fallthrough [label %d]



asm.fallthrough:               ; preds = %entry