Index: llvm/trunk/lib/Target/Mips/MipsHazardSchedule.cpp =================================================================== --- llvm/trunk/lib/Target/Mips/MipsHazardSchedule.cpp +++ llvm/trunk/lib/Target/Mips/MipsHazardSchedule.cpp @@ -103,23 +103,24 @@ // Find the next real instruction from the current position, looking through // basic block boundaries. -static Iter getNextMachineInstr(Iter Position, MachineBasicBlock *Parent) { +static std::pair getNextMachineInstr(Iter Position, MachineBasicBlock * Parent) { if (Position == Parent->end()) { - MachineBasicBlock *Succ = Parent->getNextNode(); - if (Succ != nullptr && Parent->isSuccessor(Succ)) { - Position = Succ->begin(); - Parent = Succ; - } else { - llvm_unreachable( - "Should have identified the end of the function earlier!"); - } + do { + MachineBasicBlock *Succ = Parent->getNextNode(); + if (Succ != nullptr && Parent->isSuccessor(Succ)) { + Position = Succ->begin(); + Parent = Succ; + } else { + return std::make_pair(Position, true); + } + } while (Parent->empty()); } Iter Instr = getNextMachineInstrInBB(Position); if (Instr == Parent->end()) { return getNextMachineInstr(Instr, Parent); } - return Instr; + return std::make_pair(Instr, false); } bool MipsHazardSchedule::runOnMachineFunction(MachineFunction &MF) { @@ -145,7 +146,9 @@ bool LastInstInFunction = std::next(I) == FI->end() && std::next(FI) == MF.end(); if (!LastInstInFunction) { - Inst = getNextMachineInstr(std::next(I), &*FI); + std::pair Res = getNextMachineInstr(std::next(I), &*FI); + LastInstInFunction |= Res.second; + Inst = Res.first; } if (LastInstInFunction || !TII->SafeInForbiddenSlot(*Inst)) { Index: llvm/trunk/test/CodeGen/Mips/compactbranches/empty-block.mir =================================================================== --- llvm/trunk/test/CodeGen/Mips/compactbranches/empty-block.mir +++ llvm/trunk/test/CodeGen/Mips/compactbranches/empty-block.mir @@ -0,0 +1,92 @@ +# RUN: llc -march=mipsel -mcpu=mips32r6 -start-after=block-placement %s -o - | FileCheck %s + +# Check that empty blocks in the cfg don't cause the mips hazard scheduler to +# crash and that the nop is inserted correctly. + +# CHECK: blezc +# CHECK: nop +# CHECK: # BB#1: +# CHECK: .insn +# CHECK: # BB#2: +# CHECK: .insn +# CHECK: # BB#3: +# CHECK: jal + +--- | + ; ModuleID = '' + source_filename = "" + target datalayout = "e-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64" + + declare i32 @k() + + declare void @f(i32) + + define void @l5() { + entry: + %call = tail call i32 @k() + %cmp = icmp sgt i32 %call, 0 + br i1 %cmp, label %if.then, label %if.end + + if.then: ; preds = %entry + tail call void @f(i32 signext 2) + br label %if.end + + if.end: ; preds = %if.then, %entry + ret void + } + +--- +name: l5 +alignment: 2 +exposesReturnsTwice: false +noVRegs: true +legalized: false +regBankSelected: false +selected: false +tracksRegLiveness: true +frameInfo: + isFrameAddressTaken: false + isReturnAddressTaken: false + hasStackMap: false + hasPatchPoint: false + stackSize: 24 + offsetAdjustment: 0 + maxAlignment: 4 + adjustsStack: true + hasCalls: true + maxCallFrameSize: 16 + hasOpaqueSPAdjustment: false + hasVAStart: false + hasMustTailInVarArgFunc: false +stack: + - { id: 0, type: spill-slot, offset: -4, size: 4, alignment: 4, callee-saved-register: '%ra' } +body: | + bb.0.entry: + successors: %bb.1.if.then(0x50000000), %bb.4.if.end(0x30000000) + liveins: %ra + + %sp = ADDiu %sp, -24 + CFI_INSTRUCTION def_cfa_offset 24 + SW killed %ra, %sp, 20 :: (store 4 into %stack.0) + CFI_INSTRUCTION offset %ra_64, -4 + JAL @k, csr_o32_fp64, implicit-def dead %ra, implicit-def %sp, implicit-def %v0 + BLEZ %v0, %bb.4.if.end, implicit-def %at + + bb.1.if.then: + successors: %bb.2.if.then(0x80000000) + + bb.2.if.then: + successors: %bb.3.if.then(0x80000000) + + bb.3.if.then: + successors: %bb.4.if.end(0x80000000) + + %a0 = ADDiu %zero, 2 + JAL @f, csr_o32_fp64, implicit-def dead %ra, implicit killed %a0, implicit-def %sp + + bb.4.if.end: + %ra = LW %sp, 20 :: (load 4 from %stack.0) + %sp = ADDiu %sp, 24 + PseudoReturn undef %ra + +...