Index: llvm/trunk/lib/Target/Hexagon/HexagonHardwareLoops.cpp =================================================================== --- llvm/trunk/lib/Target/Hexagon/HexagonHardwareLoops.cpp +++ llvm/trunk/lib/Target/Hexagon/HexagonHardwareLoops.cpp @@ -670,6 +670,7 @@ MachineBasicBlock *DefBB = MRI->getVRegDef(R)->getParent(); if (!MDT->properlyDominates(DefBB, Header)) return nullptr; + OldInsts.push_back(MRI->getVRegDef(R)); } return computeCount(L, InitialValue, EndValue, IVReg, IVBump, Cmp); @@ -693,12 +694,14 @@ // If so, use the immediate value rather than the register. if (Start->isReg()) { const MachineInstr *StartValInstr = MRI->getVRegDef(Start->getReg()); - if (StartValInstr && StartValInstr->getOpcode() == Hexagon::A2_tfrsi) + if (StartValInstr && (StartValInstr->getOpcode() == Hexagon::A2_tfrsi || + StartValInstr->getOpcode() == Hexagon::A2_tfrpi)) Start = &StartValInstr->getOperand(1); } if (End->isReg()) { const MachineInstr *EndValInstr = MRI->getVRegDef(End->getReg()); - if (EndValInstr && EndValInstr->getOpcode() == Hexagon::A2_tfrsi) + if (EndValInstr && (EndValInstr->getOpcode() == Hexagon::A2_tfrsi || + EndValInstr->getOpcode() == Hexagon::A2_tfrpi)) End = &EndValInstr->getOperand(1); } @@ -1832,11 +1835,14 @@ // created PHI node in the preheader. for (unsigned i = 1, n = PN->getNumOperands(); i < n; i += 2) { unsigned PredR = PN->getOperand(i).getReg(); + unsigned PredRSub = PN->getOperand(i).getSubReg(); MachineBasicBlock *PredB = PN->getOperand(i+1).getMBB(); if (PredB == Latch) continue; - NewPN->addOperand(MachineOperand::CreateReg(PredR, false)); + MachineOperand MO = MachineOperand::CreateReg(PredR, false); + MO.setSubReg(PredRSub); + NewPN->addOperand(MO); NewPN->addOperand(MachineOperand::CreateMBB(PredB)); } Index: llvm/trunk/test/CodeGen/Hexagon/hwloop-ph-deadcode.ll =================================================================== --- llvm/trunk/test/CodeGen/Hexagon/hwloop-ph-deadcode.ll +++ llvm/trunk/test/CodeGen/Hexagon/hwloop-ph-deadcode.ll @@ -0,0 +1,23 @@ +; RUN: llc -march=hexagon -mcpu=hexagonv5 -O2 -disable-block-placement=0 < %s | FileCheck %s + +; Test that there is no redundant register assignment in the hardware loop +; preheader. + +; CHECK-NOT: r{{.*}} = #5 + +@g = external global i32 + +define void @foo() #0 { +entry: + br i1 undef, label %if.end38, label %for.body + +for.body: + %loopIdx.051 = phi i32 [ %inc, %for.body ], [ 0, %entry ] + store i32 1, i32* @g, align 4 + %inc = add i32 %loopIdx.051, 1 + %cmp9 = icmp ult i32 %inc, 5 + br i1 %cmp9, label %for.body, label %if.end38 + +if.end38: + ret void +}