diff --git a/llvm/include/llvm/CodeGen/MachineInstr.h b/llvm/include/llvm/CodeGen/MachineInstr.h --- a/llvm/include/llvm/CodeGen/MachineInstr.h +++ b/llvm/include/llvm/CodeGen/MachineInstr.h @@ -280,6 +280,9 @@ const MachineBasicBlock* getParent() const { return Parent; } MachineBasicBlock* getParent() { return Parent; } + // Move the instruction before \p MovePos. + void moveBefore(MachineInstr *MovePos); + /// Return the function that contains the basic block that this instruction /// belongs to. /// diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp --- a/llvm/lib/CodeGen/MachineInstr.cpp +++ b/llvm/lib/CodeGen/MachineInstr.cpp @@ -147,6 +147,10 @@ setFlags(MI.Flags); } +void MachineInstr::moveBefore(MachineInstr *MovePos) { + MovePos->getParent()->splice(MovePos, getParent(), getIterator()); +} + /// getRegInfo - If this instruction is embedded into a MachineFunction, /// return the MachineRegisterInfo object for the current function, otherwise /// return null. diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp --- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp @@ -1034,7 +1034,29 @@ } InsertPos = Emitter.getInsertPos(); - return Emitter.getBlock(); + // In some cases, DBG_VALUEs might be inserted after the first terminator, + // which results in an invalid MBB. If that happens, move the DBG_VALUEs + // before the first terminator. + MachineBasicBlock *InsertBB = Emitter.getBlock(); + auto FirstTerm = InsertBB->getFirstTerminator(); + if (FirstTerm != InsertBB->end()) { + assert(!FirstTerm->isDebugValue() && + "first terminator cannot be a debug value"); + for (MachineInstr &MI : make_early_inc_range( + make_range(std::next(FirstTerm), InsertBB->end()))) { + if (!MI.isDebugValue()) + continue; + + if (&MI == InsertPos) + InsertPos = std::prev(InsertPos->getIterator()); + + // The DBG_VALUE was referencing a value produced by a terminator. By + // moving the DBG_VALUE, the referenced value also needs invalidating. + MI.getOperand(0).ChangeToRegister(0, false); + MI.moveBefore(&*FirstTerm); + } + } + return InsertBB; } /// Return the basic block label. diff --git a/llvm/test/CodeGen/ARM/dbg-tcreturn.ll b/llvm/test/CodeGen/ARM/dbg-tcreturn.ll --- a/llvm/test/CodeGen/ARM/dbg-tcreturn.ll +++ b/llvm/test/CodeGen/ARM/dbg-tcreturn.ll @@ -1,5 +1,4 @@ -; XFAIL: * -; RUN: llc %s -o - -stop-after=finalize-isel -verify-machineinstr | FileCheck %s +; RUN: llc %s -o - -stop-after=finalize-isel -verify-machineinstrs | FileCheck %s target datalayout = "e-m:o-p:32:32-Fi8-f64:32:64-v64:32:64-v128:32:128-a:0:32-n32-S32" target triple = "thumbv7-apple-ios7.0.0" @@ -12,8 +11,8 @@ ; CHECK-NEXT: %0:gpr = COPY $r0 ; CHECK-NEXT: $r0 = COPY %0 ; CHECK-NEXT: $r1 = COPY %1 -; CHECK-NEXT: TCRETURNdi &__divsi3, implicit $sp, implicit $r0, implicit $r1 ; CHECK-NEXT: DBG_VALUE $noreg, $noreg, !13, !DIExpression(), debug-location !16 +; CHECK-NEXT: TCRETURNdi &__divsi3, implicit $sp, implicit $r0, implicit $r1 define i32 @test(i32 %a1, i32 %a2) !dbg !5 { entry: