diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp index 81fd30ca0529..4c55158a0048 100644 --- a/llvm/lib/CodeGen/MachineSink.cpp +++ b/llvm/lib/CodeGen/MachineSink.cpp @@ -105,9 +105,6 @@ namespace { using AllSuccsCache = std::map>; - // Remember debug uses of vregs seen, so we know what to sink out of blocks. - DenseMap> SeenDbgUsers; - public: static char ID; // Pass identification @@ -135,7 +132,6 @@ namespace { private: bool ProcessBlock(MachineBasicBlock &MBB); - void ProcessDbgInst(MachineInstr &MI); bool isWorthBreakingCriticalEdge(MachineInstr &MI, MachineBasicBlock *From, MachineBasicBlock *To); @@ -157,14 +153,8 @@ namespace { MachineBasicBlock *To, bool BreakPHIEdge); bool SinkInstruction(MachineInstr &MI, bool &SawStore, - AllSuccsCache &AllSuccessors); - /// If we sink a COPY inst, some debug users of it's destination may no - /// longer be dominated by the COPY, and will eventually be dropped. - /// This is easily rectified by forwarding the non-dominated debug uses - /// to the copy source. - void SalvageUnsunkDebugUsersOfCopy(MachineInstr &, - MachineBasicBlock *TargetBlock); + AllSuccsCache &AllSuccessors); bool AllUsesDominatedByBlock(unsigned Reg, MachineBasicBlock *MBB, MachineBasicBlock *DefMBB, bool &BreakPHIEdge, bool &LocalUse) const; @@ -377,11 +367,8 @@ bool MachineSinking::ProcessBlock(MachineBasicBlock &MBB) { if (!ProcessedBegin) --I; - if (MI.isDebugInstr()) { - if (MI.isDebugValue()) - ProcessDbgInst(MI); + if (MI.isDebugInstr()) continue; - } bool Joined = PerformTrivialForwardCoalescing(MI, &MBB); if (Joined) { @@ -397,23 +384,9 @@ bool MachineSinking::ProcessBlock(MachineBasicBlock &MBB) { // If we just processed the first instruction in the block, we're done. } while (!ProcessedBegin); - SeenDbgUsers.clear(); - return MadeChange; } -void MachineSinking::ProcessDbgInst(MachineInstr &MI) { - // When we see DBG_VALUEs for registers, record any vreg it reads, so that - // we know what to sink if the vreg def sinks. - assert(MI.isDebugValue() && "Expected DBG_VALUE for processing"); - - MachineOperand &MO = MI.getOperand(0); - if (!MO.isReg() || !MO.getReg().isVirtual()) - return; - - SeenDbgUsers[MO.getReg()].push_back(&MI); -} - bool MachineSinking::isWorthBreakingCriticalEdge(MachineInstr &MI, MachineBasicBlock *From, MachineBasicBlock *To) { @@ -758,13 +731,22 @@ static bool SinkingPreventsImplicitNullCheck(MachineInstr &MI, MBP.LHS.getReg() == BaseOp->getReg(); } -/// Sink an instruction and its associated debug instructions. +/// Sink an instruction and its associated debug instructions. If the debug +/// instructions to be sunk are already known, they can be provided in DbgVals. static void performSink(MachineInstr &MI, MachineBasicBlock &SuccToSinkTo, MachineBasicBlock::iterator InsertPos, - SmallVectorImpl &DbgValuesToSink) { + SmallVectorImpl *DbgVals = nullptr) { const MachineRegisterInfo &MRI = MI.getMF()->getRegInfo(); const TargetInstrInfo &TII = *MI.getMF()->getSubtarget().getInstrInfo(); + // If debug values are provided use those, otherwise call collectDebugValues. + SmallVector DbgValuesToSink; + if (DbgVals) + DbgValuesToSink.insert(DbgValuesToSink.begin(), + DbgVals->begin(), DbgVals->end()); + else + MI.collectDebugValues(DbgValuesToSink); + // If we cannot find a location to use (merge with), then we erase the debug // location to prevent debug-info driven tools from potentially reporting // wrong location information. @@ -947,25 +929,7 @@ bool MachineSinking::SinkInstruction(MachineInstr &MI, bool &SawStore, while (InsertPos != SuccToSinkTo->end() && InsertPos->isPHI()) ++InsertPos; - // Collect debug users of any vreg that this inst defines. - SmallVector DbgUsersToSink; - for (auto &MO : MI.operands()) { - if (!MO.isReg() || !MO.isDef() || !MO.getReg().isVirtual()) - continue; - if (!SeenDbgUsers.count(MO.getReg())) - continue; - - auto &Users = SeenDbgUsers[MO.getReg()]; - DbgUsersToSink.insert(DbgUsersToSink.end(), Users.begin(), Users.end()); - } - - // After sinking, some debug users may not be dominated any more. If possible, - // copy-propagate their operands. As it's expensive, don't do this if there's - // no debuginfo in the program. - if (MI.getMF()->getFunction().getSubprogram() && MI.isCopy()) - SalvageUnsunkDebugUsersOfCopy(MI, SuccToSinkTo); - - performSink(MI, *SuccToSinkTo, InsertPos, DbgUsersToSink); + performSink(MI, *SuccToSinkTo, InsertPos); // Conservatively, clear any kill flags, since it's possible that they are no // longer correct. @@ -980,41 +944,6 @@ bool MachineSinking::SinkInstruction(MachineInstr &MI, bool &SawStore, return true; } -void MachineSinking::SalvageUnsunkDebugUsersOfCopy( - MachineInstr &MI, MachineBasicBlock *TargetBlock) { - assert(MI.isCopy()); - assert(MI.getOperand(1).isReg()); - - // Enumerate all users of vreg operands that are def'd. Skip those that will - // be sunk. For the rest, if they are not dominated by the block we will sink - // MI into, propagate the copy source to them. - SmallVector DbgDefUsers; - const MachineRegisterInfo &MRI = MI.getMF()->getRegInfo(); - for (auto &MO : MI.operands()) { - if (!MO.isReg() || !MO.isDef() || !MO.getReg().isVirtual()) - continue; - for (auto &User : MRI.use_instructions(MO.getReg())) { - if (!User.isDebugValue() || DT->dominates(TargetBlock, User.getParent())) - continue; - - // If is in same block, will either sink or be use-before-def. - if (User.getParent() == MI.getParent()) - continue; - - assert(User.getOperand(0).isReg() && - "DBG_VALUE user of vreg, but non reg operand?"); - DbgDefUsers.push_back(&User); - } - } - - // Point the users of this copy that are no longer dominated, at the source - // of the copy. - for (auto *User : DbgDefUsers) { - User->getOperand(0).setReg(MI.getOperand(1).getReg()); - User->getOperand(0).setSubReg(MI.getOperand(1).getSubReg()); - } -} - //===----------------------------------------------------------------------===// // This pass is not intended to be a replacement or a complete alternative // for the pre-ra machine sink pass. It is only designed to sink COPY @@ -1324,7 +1253,7 @@ bool PostRAMachineSinking::tryToSinkCopy(MachineBasicBlock &CurBB, // block. clearKillFlags(MI, CurBB, UsedOpsInCopy, UsedRegUnits, TRI); MachineBasicBlock::iterator InsertPos = SuccBB->getFirstNonPHI(); - performSink(*MI, *SuccBB, InsertPos, DbgValsToSink); + performSink(*MI, *SuccBB, InsertPos, &DbgValsToSink); updateLiveIn(MI, SuccBB, UsedOpsInCopy, DefedRegsInCopy); Changed = true; diff --git a/llvm/test/DebugInfo/MIR/X86/machinesink.mir b/llvm/test/DebugInfo/MIR/X86/machinesink.mir deleted file mode 100644 index 3df80ee15f51..000000000000 --- a/llvm/test/DebugInfo/MIR/X86/machinesink.mir +++ /dev/null @@ -1,105 +0,0 @@ -# RUN: llc -mtriple=x86_64-unknown-unknown -run-pass=machine-sink -o - %s | FileCheck %s -# Check various things when we sink machine instructions: -# a) DBG_VALUEs should sink with defs -# b) Undefs should be left behind -# c) DBG_VALUEs not immediately following the defining inst should sink too -# d) If we generate debug-use-before-defs through sinking, and can copy -# propagate to a different value, we should do that. ---- | - target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" - target triple = "x86_64-unknown-linux-gnu" - - @x = common local_unnamed_addr global i32 0, align 4, !dbg !0 - - ; Function Attrs: noreturn nounwind uwtable - define void @Process(i32* nocapture readonly %p) local_unnamed_addr !dbg !9 { - ; Stripped - entry: - br label %nou - nou: - br label %exit - exit: - ret void - } - - ; Function Attrs: nounwind readnone - declare void @llvm.dbg.value(metadata, i64, metadata, metadata) - - !llvm.dbg.cu = !{!1} - !llvm.module.flags = !{!6, !7} - !llvm.ident = !{!8} - - !0 = !DIGlobalVariableExpression(var: !DIGlobalVariable(name: "x", scope: !1, file: !2, line: 1, type: !5, isLocal: false, isDefinition: true), expr: !DIExpression()) - !1 = distinct !DICompileUnit(language: DW_LANG_C99, file: !2, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !3, globals: !4) - !2 = !DIFile(filename: "t.c", directory: "") - !3 = !{} - !4 = !{!0} - !5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) - !6 = !{i32 2, !"Dwarf Version", i32 4} - !7 = !{i32 2, !"Debug Info Version", i32 3} - !8 = !{!"clang version 4.0.0 "} - !9 = distinct !DISubprogram(name: "Process", scope: !2, file: !2, line: 2, type: !10, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !1, retainedNodes: !15) - !10 = !DISubroutineType(types: !11) - !11 = !{null, !12} - !12 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !13, size: 64) - !13 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !14) - !14 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned) - !15 = !{!16} - !16 = !DILocalVariable(name: "p", arg: 1, scope: !9, file: !2, line: 2, type: !12) - !17 = !DIExpression() - !18 = !DILocation(line: 2, column: 34, scope: !9) - !28 = !DILexicalBlockFile(scope: !9, file: !2, discriminator: 1) - - ; CHECK: [[VARNUM:![0-9]+]] = !DILocalVariable(name: "p", - -... ---- -name: Process -tracksRegLiveness: true -liveins: - - { reg: '$rdi', virtual-reg: '%2' } - - { reg: '$rsi', virtual-reg: '%2' } -body: | - bb.0.entry: - successors: %bb.1.nou(0x80000000), %bb.2.exit - liveins: $rdi, $esi - - ; This block should have the vreg copy sunk from it, the DBG_VALUE with it, - ; and a copy-prop'd DBG_VALUE left over. - ; CHECK-LABEL: bb.0.entry: - ; CHECK: [[ARG0VREG:%[0-9]+]]:gr64 = COPY $rdi - ; CHECK-NEXT: CMP32ri $esi, 0 - ; CHECK-NEXT: DBG_VALUE [[ARG0VREG]], $noreg, [[VARNUM]] - ; CHECK-NEXT: JCC_1 %bb.1, 4 - ; CHECK-NEXT: JMP_1 - - %2:gr64 = COPY $rdi - %5:gr64 = COPY %2 - CMP32ri $esi, 0, implicit-def $eflags - DBG_VALUE %5, $noreg, !16, !17, debug-location !18 - JCC_1 %bb.1.nou, 4, implicit $eflags - JMP_1 %bb.2.exit - - bb.1.nou: - successors: %bb.2.exit(0x80000000) - - ; This block should receive the sunk copy and DBG_VALUE - ; CHECK-LABEL: bb.1.nou: - ; CHECK: [[SUNKVREG:%[0-9]+]]:gr64 = COPY [[ARG0VREG]] - ; CHECK-NEXT: DBG_VALUE [[SUNKVREG]], $noreg, [[VARNUM]] - ; CHECK-NEXT: ADD64ri8 - ; CHECK-NEXT: JMP_1 - %1:gr64 = ADD64ri8 %5, 4, implicit-def dead $eflags - JMP_1 %bb.2.exit - - bb.2.exit: - ; The DBG_VALUE below should have its operand copy-propagated after - ; the copy to %5 is sunk. - ; CHECK-LABEL: bb.2.exit: - ; CHECK: DBG_VALUE [[ARG0VREG]], $noreg, [[VARNUM]] - ; CHECK-NEXT: $rax = MOV64rr [[ARG0VREG]] - ; CHECK-NEXT: RET 0 - DBG_VALUE %5, _, !16, !17, debug-location !18 - $rax = MOV64rr %2 - RET 0 -...