Index: lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp =================================================================== --- lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp +++ lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp @@ -740,28 +740,27 @@ static void ProcessSourceNode(SDNode *N, SelectionDAG *DAG, InstrEmitter &Emitter, DenseMap &VRBaseMap, - SmallVectorImpl > &Orders, - SmallSet &Seen) { + SmallVectorImpl> &Orders, + SmallSet &Seen, MachineInstr *NewInsn) { unsigned Order = N->getIROrder(); - if (!Order || !Seen.insert(Order).second) { + if (!Order || Seen.count(Order) != 0) { // Process any valid SDDbgValues even if node does not have any order // assigned. ProcessSDDbgValues(N, DAG, Emitter, Orders, VRBaseMap, 0); return; } - MachineBasicBlock *BB = Emitter.getBlock(); - auto IP = Emitter.getInsertPos(); - if (IP == BB->begin() || BB->back().isPHI() || - // Fast-isel may have inserted some instructions, in which case the - // BB->back().isPHI() test will not fire when we want it to. - std::prev(IP)->isPHI()) { - // Did not insert any instruction. - Orders.push_back({Order, (MachineInstr *)nullptr}); - return; + // If a new instruction was generated for this Order number, record it. + // Otherwise, leave this order number unseen: we will either find later + // instructions for it, or leave it unseen if there were no instructions at + // all. + if (NewInsn) { + Seen.insert(Order); + Orders.push_back({Order, NewInsn}); } - Orders.push_back({Order, &*std::prev(IP)}); + // Even if no instruction was generated, a Value may have become defined via + // earlier nodes. Try to process them now. ProcessSDDbgValues(N, DAG, Emitter, Orders, VRBaseMap, Order); } @@ -814,6 +813,40 @@ SmallSet Seen; bool HasDbg = DAG->hasDebugValues(); + // Emit a node, and determine where its first instruction is for debuginfo. + // Zero, one, or multiple instructions can be created when emitting a node. + auto EmitNode = + [&](SDNode *Node, bool IsClone, bool IsCloned, + DenseMap &VRBaseMap) -> MachineInstr * { + // Fetch instruction prior to this, or end() if nonexistant. + auto GetPrevInsn = [&](MachineBasicBlock::iterator I) { + bool BadPos = BB->begin() == BB->end() || I == BB->begin(); + if (BadPos) + return BB->end(); + else + return std::prev(Emitter.getInsertPos()); + }; + + MachineBasicBlock::iterator Before = GetPrevInsn(Emitter.getInsertPos()); + Emitter.EmitNode(Node, IsClone, IsCloned, VRBaseMap); + MachineBasicBlock::iterator After = GetPrevInsn(Emitter.getInsertPos()); + + // If the iterator changed, at least one instruction was inserted. + if (Before != After) { + if (Before == BB->end()) { + // There were no prior instructions; the new ones must start at the + // beginning of the block. + return &Emitter.getBlock()->instr_front(); + } else { + // Return first instruction after the pre-existing instructions. + return &*std::next(Before); + } + } else { + // No new instruction. + return nullptr; + } + }; + // If this is the first BB, emit byval parameter dbg_value's. if (HasDbg && BB->getParent()->begin() == MachineFunction::iterator(BB)) { SDDbgInfo::DbgIterator PDI = DAG->ByvalParmDbgBegin(); @@ -850,18 +883,18 @@ GluedNodes.push_back(N); while (!GluedNodes.empty()) { SDNode *N = GluedNodes.back(); - Emitter.EmitNode(N, SU->OrigNode != SU, SU->isCloned, VRBaseMap); + auto NewInsn = EmitNode(N, SU->OrigNode != SU, SU->isCloned, VRBaseMap); // Remember the source order of the inserted instruction. if (HasDbg) - ProcessSourceNode(N, DAG, Emitter, VRBaseMap, Orders, Seen); + ProcessSourceNode(N, DAG, Emitter, VRBaseMap, Orders, Seen, NewInsn); GluedNodes.pop_back(); } - Emitter.EmitNode(SU->getNode(), SU->OrigNode != SU, SU->isCloned, - VRBaseMap); + auto NewInsn = + EmitNode(SU->getNode(), SU->OrigNode != SU, SU->isCloned, VRBaseMap); // Remember the source order of the inserted instruction. if (HasDbg) - ProcessSourceNode(SU->getNode(), DAG, Emitter, VRBaseMap, Orders, - Seen); + ProcessSourceNode(SU->getNode(), DAG, Emitter, VRBaseMap, Orders, Seen, + NewInsn); } // Insert all the dbg_values which have not already been inserted in source @@ -886,8 +919,7 @@ unsigned Order = Orders[i].first; MachineInstr *MI = Orders[i].second; // Insert all SDDbgValue's whose order(s) are before "Order". - if (!MI) - continue; + assert(MI); for (; DI != DE; ++DI) { if ((*DI)->getOrder() < LastOrder || (*DI)->getOrder() >= Order) break; Index: test/DebugInfo/NVPTX/debug-info.ll =================================================================== --- test/DebugInfo/NVPTX/debug-info.ll +++ test/DebugInfo/NVPTX/debug-info.ll @@ -4781,8 +4781,8 @@ ; CHECK-NEXT: .b8 6 // DW_AT_call_line ; CHECK-NEXT: .b8 43 // Abbrev [43] 0x270e:0x22 DW_TAG_inlined_subroutine ; CHECK-NEXT: .b32 9791 // DW_AT_abstract_origin -; CHECK-NEXT: .b64 Ltmp8 // DW_AT_low_pc -; CHECK-NEXT: .b64 Ltmp9 // DW_AT_high_pc +; CHECK-NEXT: .b64 Ltmp9 // DW_AT_low_pc +; CHECK-NEXT: .b64 Ltmp10 // DW_AT_high_pc ; CHECK-NEXT: .b8 12 // DW_AT_call_file ; CHECK-NEXT: .b8 8 // DW_AT_call_line ; CHECK-NEXT: .b8 44 // Abbrev [44] 0x2725:0x5 DW_TAG_formal_parameter Index: test/DebugInfo/X86/pr40427.ll =================================================================== --- /dev/null +++ test/DebugInfo/X86/pr40427.ll @@ -0,0 +1,46 @@ +; RUN: llc -start-after=codegenprepare -stop-before=expand-isel-pseudos -o - < %s | FileCheck %s +; Test for correct placement of DBG_VALUE, which in PR40427 is placed before +; the load instruction it refers to. The circumstance replicated here is where +; two instructions in a row, trunc and add, begin with no-op Copy{To,From}Reg +; SDNodes that produce no instructions. +; The DBG_VALUE instruction should come immediately after the load instruction +; because the truncate is optimised out, and the DBG_VALUE should be placed +; in front of the first instruction that occurs after the dbg.value. + +; CHECK: ![[DBGVAR:[0-9]+]] = !DILocalVariable(name: "bees", + +define i16 @lolwat(i1 %spoons, i64 *%bees, i16 %yellow, i64 *%more) { +entry: + br i1 %spoons, label %trueb, label %falseb +trueb: + br label %block +falseb: + br label %block +block: +; CHECK: [[PHIREG:%[0-9]+]]:gr64 = PHI %6, %bb.2, %4, %bb.1 +; CHECK-NEXT: [[LOADR:%[0-9]+]]:gr16 = MOV16rm %0 +; CHECK-NEXT: DBG_VALUE [[LOADR]], $noreg, ![[DBGVAR]] +; CHECK-NEXT: %{{[0-9]+}}:gr32 = IMPLICIT_DEF + %foo = phi i64 *[%bees, %trueb], [%more, %falseb] + %forks = bitcast i64 *%foo to i32 * + %ret = load i32, i32 *%forks, !dbg !6 + %cast = trunc i32 %ret to i16, !dbg !6 + call void @llvm.dbg.value(metadata i16 %cast, metadata !1, metadata !DIExpression()), !dbg !6 + %orly2 = add i16 %yellow, 1 + br label %bb1 +bb1: + %cheese = add i16 %orly2, %cast + ret i16 %cheese, !dbg !6 +} + +declare void @llvm.dbg.value(metadata, metadata, metadata) + +!llvm.module.flags = !{!4} +!llvm.dbg.cu = !{!2} +!1 = !DILocalVariable(name: "bees", scope: !5, type: null) +!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "beards", isOptimized: true, runtimeVersion: 4, emissionKind: FullDebug) +!3 = !DIFile(filename: "bees.cpp", directory: "") +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = distinct !DISubprogram(name: "nope", scope: !2, file: !3, line: 1, unit: !2) +!6 = !DILocation(line: 0, scope: !5) +!7 = !DILocalVariable(name: "flannel", scope: !5, type: null) Index: test/DebugInfo/X86/sdag-dbgvalue-phi-use-2.ll =================================================================== --- test/DebugInfo/X86/sdag-dbgvalue-phi-use-2.ll +++ test/DebugInfo/X86/sdag-dbgvalue-phi-use-2.ll @@ -44,15 +44,17 @@ ; CHECK-NEXT: [[REG4:%[0-9]+]]:gr32 = PHI ; CHECK-NEXT: DBG_VALUE [[REG3]], $noreg, !16 ; CHECK-NEXT: DBG_VALUE 555, $noreg, !17 -; XXX: Shouldn't the following DBG_VALUE be placed after the add (ADD32rr). +; CHECK-NEXT: [[ADDREG:%[0-9]+]]:gr32 = nuw nsw ADD32rr ; CHECK-NEXT: DBG_VALUE [[REG2]], $noreg, !17 -; CHECK-NEXT: ADD32rr -; XXX: Shouldn't the following DBG_VALUE be placed after the mul (LEA etc). +; CHECK: [[MULREG:%[0-9]+]]:gr32 = LEA64_32r ; CHECK-NEXT: DBG_VALUE 777, $noreg, !17 -; CHECK: INC32r -; XXX: Shouldn't the following DBG_VALUE be placed after the icmp (the non-dead implicit def of $eflags) -; CHECK: DBG_VALUE [[REG4]] -; CHECK-NEXT: implicit-def $eflags +; XXX: The following DBG_VALUE should have stayed below the INC32r +; CHECK-NEXT: DBG_VALUE [[MULREG]], $noreg, !16 +; CHECK-NEXT: [[INCREG:%[0-9]+]]:gr32 = nuw nsw INC32r +; CHECK-NEXT: DBG_VALUE [[INCREG]], $noreg, !17 +; CHECK-NEXT: DBG_VALUE [[ADDREG]], $noreg, !15 +; CHECK-NEXT: implicit-def $eflags, +; CHECK-NEXT: DBG_VALUE [[REG4]] %u.023 = phi i32 [ 0, %for.body.lr.ph ], [ %inc, %for.body ] %y.022 = phi i32 [ 13, %for.body.lr.ph ], [ %mul, %for.body ] %x.021 = phi i32 [ 9, %for.body.lr.ph ], [ %add, %for.body ]