diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/CodeGen/MachineSink.cpp | 61 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/postra-ignore-dbg-instrs.mir | 88 |
2 files changed, 124 insertions, 25 deletions
diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp index c09539d9903..354f46e9e62 100644 --- a/llvm/lib/CodeGen/MachineSink.cpp +++ b/llvm/lib/CodeGen/MachineSink.cpp @@ -753,6 +753,37 @@ static bool SinkingPreventsImplicitNullCheck(MachineInstr &MI, MBP.LHS.getReg() == BaseReg; } +/// Sink an instruction and its associated debug instructions. +static void performSink(MachineInstr &MI, MachineBasicBlock &SuccToSinkTo, + MachineBasicBlock::iterator InsertPos) { + // Collect matching debug values. + SmallVector<MachineInstr *, 2> DbgValuesToSink; + collectDebugValues(MI, 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. + if (!SuccToSinkTo.empty() && InsertPos != SuccToSinkTo.end()) + MI.setDebugLoc(DILocation::getMergedLocation(MI.getDebugLoc(), + InsertPos->getDebugLoc())); + else + MI.setDebugLoc(DebugLoc()); + + // Move the instruction. + MachineBasicBlock *ParentBlock = MI.getParent(); + SuccToSinkTo.splice(InsertPos, ParentBlock, MI, + ++MachineBasicBlock::iterator(MI)); + + // Move previously adjacent debug value instructions to the insert position. + for (SmallVectorImpl<MachineInstr *>::iterator DBI = DbgValuesToSink.begin(), + DBE = DbgValuesToSink.end(); + DBI != DBE; ++DBI) { + MachineInstr *DbgMI = *DBI; + SuccToSinkTo.splice(InsertPos, ParentBlock, DbgMI, + ++MachineBasicBlock::iterator(DbgMI)); + } +} + /// SinkInstruction - Determine whether it is safe to sink the specified machine /// instruction out of its current block into a successor. bool MachineSinking::SinkInstruction(MachineInstr &MI, bool &SawStore, @@ -866,30 +897,7 @@ bool MachineSinking::SinkInstruction(MachineInstr &MI, bool &SawStore, while (InsertPos != SuccToSinkTo->end() && InsertPos->isPHI()) ++InsertPos; - // collect matching debug values. - SmallVector<MachineInstr *, 2> DbgValuesToSink; - collectDebugValues(MI, DbgValuesToSink); - - // Merge or erase debug location to ensure consistent stepping in profilers - // and debuggers. - if (!SuccToSinkTo->empty() && InsertPos != SuccToSinkTo->end()) - MI.setDebugLoc(DILocation::getMergedLocation(MI.getDebugLoc(), - InsertPos->getDebugLoc())); - else - MI.setDebugLoc(DebugLoc()); - - - // Move the instruction. - SuccToSinkTo->splice(InsertPos, ParentBlock, MI, - ++MachineBasicBlock::iterator(MI)); - - // Move previously adjacent debug value instructions to the insert position. - for (SmallVectorImpl<MachineInstr *>::iterator DBI = DbgValuesToSink.begin(), - DBE = DbgValuesToSink.end(); DBI != DBE; ++DBI) { - MachineInstr *DbgMI = *DBI; - SuccToSinkTo->splice(InsertPos, ParentBlock, DbgMI, - ++MachineBasicBlock::iterator(DbgMI)); - } + performSink(MI, *SuccToSinkTo, InsertPos); // Conservatively, clear any kill flags, since it's possible that they are no // longer correct. @@ -1118,6 +1126,9 @@ bool PostRAMachineSinking::tryToSinkCopy(MachineBasicBlock &CurBB, MachineInstr *MI = &*I; ++I; + if (MI->isDebugInstr()) + continue; + // Do not move any instruction across function call. if (MI->isCall()) return false; @@ -1158,7 +1169,7 @@ bool PostRAMachineSinking::tryToSinkCopy(MachineBasicBlock &CurBB, // block. clearKillFlags(MI, CurBB, UsedOpsInCopy, UsedRegUnits, TRI); MachineBasicBlock::iterator InsertPos = SuccBB->getFirstNonPHI(); - SuccBB->splice(InsertPos, &CurBB, MI); + performSink(*MI, *SuccBB, InsertPos); updateLiveIn(MI, SuccBB, UsedOpsInCopy, DefedRegsInCopy); Changed = true; diff --git a/llvm/test/CodeGen/X86/postra-ignore-dbg-instrs.mir b/llvm/test/CodeGen/X86/postra-ignore-dbg-instrs.mir new file mode 100644 index 00000000000..0286e6e68bf --- /dev/null +++ b/llvm/test/CodeGen/X86/postra-ignore-dbg-instrs.mir @@ -0,0 +1,88 @@ +# RUN: llc -mtriple=x86_64-none-linux-gnu -run-pass=postra-machine-sink -verify-machineinstrs -o - %s | FileCheck %s +# +# This test was originally generated from the following sample: +# +# int x0; +# extern void x3(int, int); +# void x1(int x2) { +# if (x0) +# x3(0, x2); +# } +# +# The code generates a COPY instruction which the PostRA Machine Sink pass will +# try to sink. Earlier versions were not performing the sink due to a +# DBG_VALUE instruction confusing the sinking algorithm. + +--- | + @x0 = common dso_local global i32 0, align 4, !dbg !0 + + define dso_local void @x1(i32) !dbg !11 { + %2 = alloca i32, align 4 + store i32 %0, i32* %2, align 4 + call void @llvm.dbg.declare(metadata i32* %2, metadata !14, metadata !DIExpression()), !dbg !16 + %3 = load i32, i32* @x0, align 4, !dbg !16 + %4 = icmp ne i32 %3, 0, !dbg !16 + br i1 %4, label %5, label %7, !dbg !16 + + ; <label>:5: ; preds = %1 + %6 = load i32, i32* %2, align 4, !dbg !16 + call void @x3(i32 0, i32 %6), !dbg !16 + br label %7, !dbg !16 + + ; <label>:7: ; preds = %5, %1 + ret void, !dbg !16 + } + + declare void @llvm.dbg.declare(metadata, metadata, metadata) + declare dso_local void @x3(i32, i32) + + !llvm.dbg.cu = !{!2} + !llvm.module.flags = !{!7, !8} + + !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) + !1 = distinct !DIGlobalVariable(name: "x0", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true) + !2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5) + !3 = !DIFile(filename: "test.c", directory: "") + !4 = !{} + !5 = !{!0} + !6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) + !7 = !{i32 2, !"Dwarf Version", i32 4} + !8 = !{i32 2, !"Debug Info Version", i32 3} + !11 = distinct !DISubprogram(name: "x1", scope: !3, file: !3, line: 3, type: !12, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, unit: !2) + !12 = !DISubroutineType(types: !13) + !13 = !{null, !6} + !14 = !DILocalVariable(name: "x2", arg: 1, scope: !11, file: !3, line: 3, type: !6) + !15 = distinct !DILexicalBlock(scope: !11, file: !3, line: 4, column: 7) + !16 = !DILocation(line: 4, column: 7, scope: !15) + +... +--- +# CHECK: name: x1 +# CHECK: bb.0: +# CHECK-NOT: $eax = COPY $edi +# CHECK: bb.1: +# CHECK: renamable $eax = COPY $edi +# CHECK-NEXT: DBG_VALUE debug-use $eax, +# CHECK: bb.2: +name: x1 +alignment: 4 +tracksRegLiveness: true +body: | + bb.0: + successors: %bb.2, %bb.1; %bb.2, %bb.1 + liveins: $edi + DBG_VALUE debug-use $edi, debug-use $noreg, !14, !DIExpression(), debug-location !16 + renamable $eax = COPY $edi + DBG_VALUE debug-use $eax, debug-use $noreg, !14, !DIExpression(), debug-location !16 + CMP32mi8 $rip, 1, $noreg, @x0, $noreg, 0, implicit-def $eflags, debug-location !16 + JE_1 %bb.2, implicit killed $eflags, debug-location !16 + JMP_1 %bb.1, debug-location !16 + + bb.1: + liveins: $eax + $edi = MOV32r0 implicit-def dead $eflags, debug-location !16 + $esi = COPY killed renamable $eax, debug-location !16 + + bb.2: + RET 0, debug-location !16 +... |
