diff --git a/llvm/include/llvm/Support/GenericLoopInfo.h b/llvm/include/llvm/Support/GenericLoopInfo.h index d560ca648132c9..f4b50367bf93d7 100644 --- a/llvm/include/llvm/Support/GenericLoopInfo.h +++ b/llvm/include/llvm/Support/GenericLoopInfo.h @@ -44,6 +44,8 @@ #include "llvm/ADT/PostOrderIterator.h" #include "llvm/ADT/STLExtras.h" #include "llvm/ADT/SetOperations.h" +#include "llvm/IR/IntrinsicInst.h" +#include "llvm/IR/ValueHandle.h" #include "llvm/Support/Allocator.h" #include "llvm/Support/GenericDomTree.h" @@ -75,6 +77,13 @@ template class LoopBase { const LoopBase & operator=(const LoopBase &) = delete; + // Induction variable exit value and its debug users, preserved by the + // 'indvars' pass, when it detects that the loop can be deleted and the + // there are no PHIs to be rewritten. + // For now, we only preserve single induction variables. + Value *IndVarFinalValue = nullptr; + SmallVector IndVarDebugUsers; + public: /// Return the nesting level of this loop. An outer-most loop has depth 1, /// for consistency with loop depth values used for basic blocks, where depth @@ -251,6 +260,21 @@ template class LoopBase { [&](BlockT *Pred) { return contains(Pred); }); } + /// Preserve the induction variable exit value and its debug users by the + /// 'indvars' pass if the loop can deleted. Those debug users will be used + /// by the 'loop-delete' pass. + void preserveDebugInductionVariableInfo( + Value *FinalValue, SmallVector DbgUsers) { + IndVarFinalValue = FinalValue; + for (DbgVariableIntrinsic *DebugUser : DbgUsers) + IndVarDebugUsers.push_back(DebugUser); + } + + Value *getDebugInductionVariableFinalValue() { return IndVarFinalValue; } + SmallVector &getDebugInductionVariableDebugUsers() { + return IndVarDebugUsers; + } + //===--------------------------------------------------------------------===// // APIs for simple analysis of the loop. // diff --git a/llvm/include/llvm/Transforms/Utils/LoopUtils.h b/llvm/include/llvm/Transforms/Utils/LoopUtils.h index 187ace3a0cbedf..736f4a630c7b3e 100644 --- a/llvm/include/llvm/Transforms/Utils/LoopUtils.h +++ b/llvm/include/llvm/Transforms/Utils/LoopUtils.h @@ -477,6 +477,12 @@ int rewriteLoopExitValues(Loop *L, LoopInfo *LI, TargetLibraryInfo *TLI, ReplaceExitVal ReplaceExitValue, SmallVector &DeadInsts); +/// Assign exit values to variables that use this loop variable during the loop. +void addDebugValuesToIncomingValue(BasicBlock *Successor, Value *IndVar, + PHINode *PN); +void addDebugValuesToLoopVariable(BasicBlock *Successor, Value *ExitValue, + PHINode *PN); + /// Set weights for \p UnrolledLoop and \p RemainderLoop based on weights for /// \p OrigLoop and the following distribution of \p OrigLoop iteration among \p /// UnrolledLoop and \p RemainderLoop. \p UnrolledLoop receives weights that diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp index 002bc90c9b5677..1ffd390ea5accc 100644 --- a/llvm/lib/Transforms/Utils/LoopUtils.cpp +++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp @@ -31,6 +31,7 @@ #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h" #include "llvm/Analysis/ScalarEvolutionExpressions.h" #include "llvm/IR/DIBuilder.h" +#include "llvm/IR/DebugInfo.h" #include "llvm/IR/Dominators.h" #include "llvm/IR/Instructions.h" #include "llvm/IR/IntrinsicInst.h" @@ -607,6 +608,17 @@ void llvm::deleteDeadLoop(Loop *L, DominatorTree *DT, ScalarEvolution *SE, llvm::SmallVector DeadDPValues; if (ExitBlock) { + if (ExitBlock->phis().empty()) { + // As the loop is deleted, replace the debug users with the preserved + // induction variable final value recorded by the 'indvar' pass. + Value *FinalValue = L->getDebugInductionVariableFinalValue(); + SmallVector &DbgUsers = L->getDebugInductionVariableDebugUsers(); + for (WeakVH &DebugUser : DbgUsers) + if (DebugUser) + cast(DebugUser)->replaceVariableLocationOp( + 0u, FinalValue); + } + // Given LCSSA form is satisfied, we should not have users of instructions // within the dead loop outside of the loop. However, LCSSA doesn't take // unreachable uses into account. We handle them here. @@ -1412,6 +1424,36 @@ static bool checkIsIndPhi(PHINode *Phi, Loop *L, ScalarEvolution *SE, return InductionDescriptor::isInductionPHI(Phi, L, SE, ID); } +void llvm::addDebugValuesToIncomingValue(BasicBlock *Successor, Value *IndVar, + PHINode *PN) { + SmallVector DbgUsers; + findDbgUsers(DbgUsers, IndVar); + for (auto *DebugUser : DbgUsers) { + // Skip debug-users with variadic variable locations; they will not, + // get updated, which is fine as that is the existing behaviour. + if (DebugUser->hasArgList()) + continue; + auto *Cloned = cast(DebugUser->clone()); + Cloned->replaceVariableLocationOp(0u, PN); + Cloned->insertBefore(*Successor, Successor->getFirstNonPHIIt()); + } +} + +void llvm::addDebugValuesToLoopVariable(BasicBlock *Successor, Value *ExitValue, + PHINode *PN) { + SmallVector DbgUsers; + findDbgUsers(DbgUsers, PN); + for (auto *DebugUser : DbgUsers) { + // Skip debug-users with variadic variable locations; they will not, + // get updated, which is fine as that is the existing behaviour. + if (DebugUser->hasArgList()) + continue; + auto *Cloned = cast(DebugUser->clone()); + Cloned->replaceVariableLocationOp(0u, ExitValue); + Cloned->insertBefore(*Successor, Successor->getFirstNonPHIIt()); + } +} + int llvm::rewriteLoopExitValues(Loop *L, LoopInfo *LI, TargetLibraryInfo *TLI, ScalarEvolution *SE, const TargetTransformInfo *TTI, @@ -1553,6 +1595,10 @@ int llvm::rewriteLoopExitValues(Loop *L, LoopInfo *LI, TargetLibraryInfo *TLI, (isa(Inst) || isa(Inst)) ? &*Inst->getParent()->getFirstInsertionPt() : Inst; RewritePhiSet.emplace_back(PN, i, ExitValue, InsertPt, HighCost); + + // Add debug values for the candidate PHINode incoming value. + if (BasicBlock *Successor = ExitBB->getSingleSuccessor()) + addDebugValuesToIncomingValue(Successor, PN->getIncomingValue(i), PN); } } } @@ -1611,11 +1657,30 @@ int llvm::rewriteLoopExitValues(Loop *L, LoopInfo *LI, TargetLibraryInfo *TLI, // Replace PN with ExitVal if that is legal and does not break LCSSA. if (PN->getNumIncomingValues() == 1 && LI->replacementPreservesLCSSAForm(PN, ExitVal)) { + addDebugValuesToLoopVariable(PN->getParent(), ExitVal, PN); PN->replaceAllUsesWith(ExitVal); PN->eraseFromParent(); } } + // If the loop can be deleted and there are no PHIs to be rewritten (there + // are no loop live-out values), record debug variables corresponding to the + // induction variable with their constant exit-values. Those values will be + // inserted by the 'deletion loop' logic. + if (LoopCanBeDel && RewritePhiSet.empty()) { + if (auto *IndVar = L->getInductionVariable(*SE)) { + const SCEV *PNSCEV = SE->getSCEVAtScope(IndVar, L->getParentLoop()); + if (auto *Const = dyn_cast(PNSCEV)) { + Value *FinalIVValue = Const->getValue(); + if (L->getUniqueExitBlock()) { + SmallVector DbgUsers; + findDbgUsers(DbgUsers, IndVar); + L->preserveDebugInductionVariableInfo(FinalIVValue, DbgUsers); + } + } + } + } + // The insertion point instruction may have been deleted; clear it out // so that the rewriter doesn't trip over it later. Rewriter.clearInsertPoint(); diff --git a/llvm/test/Transforms/IndVarSimplify/pr51735-1.ll b/llvm/test/Transforms/IndVarSimplify/pr51735-1.ll new file mode 100644 index 00000000000000..356217985fed11 --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/pr51735-1.ll @@ -0,0 +1,129 @@ +; RUN: opt -passes="loop(indvars)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --check-prefix=CHECK %s +; RUN: opt -passes="loop(indvars,loop-deletion)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --check-prefix=CHECK %s + +; Make sure that when we delete the loop, that the variable Index has +; the 777 value. + +; As this test case does fire the 'indvars' transformation, the debug values +; are added to the 'for.end' exit block. No debug values are preserved by the +; pass to be used by the 'loop-deletion' pass. + +; CHECK: for.cond: +; CHECK: call void @llvm.dbg.value(metadata i32 %[[SSA_INDEX_0:.+]], metadata ![[DBG:[0-9]+]], {{.*}} + +; CHECK: for.extra: +; CHECK: %[[SSA_CALL_0:.+]] = call noundef i32 @"?nop@@YAHH@Z"(i32 noundef %[[SSA_INDEX_0]]), {{.*}} +; CHECK: br i1 %[[SSA_CMP_0:.+]], label %for.cond, label %if.else, {{.*}} + +; CHECK: if.then: +; CHECK: call void @llvm.dbg.value(metadata i32 777, metadata ![[DBG]], {{.*}} +; CHECK: call void @llvm.dbg.value(metadata i32 %[[SSA_VAR_1:.+]], metadata ![[VAR:[0-9]+]], {{.*}} +; CHECK: br label %for.end, {{.*}} + +; CHECK: if.else: +; CHECK: call void @llvm.dbg.value(metadata i32 %[[SSA_VAR_2:.+]], metadata ![[VAR:[0-9]+]], {{.*}} +; CHECK: br label %for.end, {{.*}} + +; CHECK: for.end: +; CHECK: call void @llvm.dbg.value(metadata i32 777, metadata ![[DBG]], {{.*}} + +; CHECK-DAG: ![[DBG]] = !DILocalVariable(name: "Index"{{.*}}) +; CHECK-DAG: ![[VAR]] = !DILocalVariable(name: "Var"{{.*}}) + +define dso_local noundef i32 @"?nop@@YAHH@Z"(i32 noundef %Param) !dbg !11 { +entry: + %Param.addr = alloca i32, align 4 + store i32 %Param, ptr %Param.addr, align 4 + call void @llvm.dbg.declare(metadata ptr %Param.addr, metadata !32, metadata !DIExpression()), !dbg !35 + ret i32 0, !dbg !36 +} + +define dso_local void @_Z3barv() local_unnamed_addr #1 !dbg !12 { +entry: + call void @llvm.dbg.value(metadata i32 777, metadata !16, metadata !DIExpression()), !dbg !17 + call void @llvm.dbg.value(metadata i32 27, metadata !18, metadata !DIExpression()), !dbg !17 + call void @llvm.dbg.value(metadata i32 1, metadata !19, metadata !DIExpression()), !dbg !17 + call void @llvm.dbg.value(metadata i32 1, metadata !30, metadata !DIExpression()), !dbg !17 + br label %for.cond, !dbg !20 + +for.cond: ; preds = %for.cond, %entry + %Index.0 = phi i32 [ 27, %entry ], [ %inc, %for.extra ], !dbg !17 + call void @llvm.dbg.value(metadata i32 %Index.0, metadata !18, metadata !DIExpression()), !dbg !17 + %cmp = icmp ult i32 %Index.0, 777, !dbg !21 + %inc = add nuw nsw i32 %Index.0, 1, !dbg !24 + call void @llvm.dbg.value(metadata i32 %inc, metadata !18, metadata !DIExpression()), !dbg !17 + br i1 %cmp, label %for.extra, label %if.then, !dbg !25, !llvm.loop !26 + +for.extra: + %call.0 = call noundef i32 @"?nop@@YAHH@Z"(i32 noundef %Index.0), !dbg !21 + %cmp.0 = icmp ult i32 %Index.0, %call.0, !dbg !21 + br i1 %cmp.0, label %for.cond, label %if.else, !dbg !25, !llvm.loop !26 + +if.then: ; preds = %for.cond + %Var.1 = add nsw i32 %Index.0, 1, !dbg !20 + call void @llvm.dbg.value(metadata i32 %Var.1, metadata !19, metadata !DIExpression()), !dbg !20 + br label %for.end, !dbg !20 + +if.else: + %Var.2 = add nsw i32 %Index.0, 2, !dbg !20 + call void @llvm.dbg.value(metadata i32 %Var.2, metadata !19, metadata !DIExpression()), !dbg !20 + br label %for.end, !dbg !20 + +for.end: ; preds = %if.else, %if.then + %Zeta.0 = phi i32 [ %Var.1, %if.then ], [ %Var.2, %if.else ], !dbg !20 + call void @llvm.dbg.value(metadata i32 %Zeta.0, metadata !30, metadata !DIExpression()), !dbg !20 + %Var.3 = add nsw i32 %Index.0, 1, !dbg !20 + call void @llvm.dbg.value(metadata i32 %Var.3, metadata !19, metadata !DIExpression()), !dbg !20 + %call = call noundef i32 @"?nop@@YAHH@Z"(i32 noundef %Index.0), !dbg !37 + ret void, !dbg !29 +} + +declare void @llvm.dbg.value(metadata, metadata, metadata) +declare void @llvm.dbg.declare(metadata, metadata, metadata) + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8} +!llvm.ident = !{!9} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None) +!1 = !DIFile(filename: "test.cpp", directory: "") +!2 = !{i32 7, !"Dwarf Version", i32 5} +!3 = !{i32 2, !"Debug Info Version", i32 3} +!4 = !{i32 1, !"wchar_size", i32 4} +!5 = !{i32 8, !"PIC Level", i32 2} +!6 = !{i32 7, !"PIE Level", i32 2} +!7 = !{i32 7, !"uwtable", i32 2} +!8 = !{i32 7, !"frame-pointer", i32 2} +!9 = !{!"clang version 18.0.0"} +!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!11 = distinct !DISubprogram(name: "nop", linkageName: "?nop@@YAHH@Z", scope: !1, file: !1, line: 1, type: !33, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !31) +!12 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 5, type: !13, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !15) +!13 = !DISubroutineType(types: !14) +!14 = !{null} +!15 = !{} +!16 = !DILocalVariable(name: "End", scope: !12, file: !1, line: 6, type: !10) +!17 = !DILocation(line: 0, scope: !12) +!18 = !DILocalVariable(name: "Index", scope: !12, file: !1, line: 7, type: !10) +!19 = !DILocalVariable(name: "Var", scope: !12, file: !1, line: 8, type: !10) +!20 = !DILocation(line: 9, column: 3, scope: !12) +!21 = !DILocation(line: 9, column: 16, scope: !22) +!22 = distinct !DILexicalBlock(scope: !23, file: !1, line: 9, column: 3) +!23 = distinct !DILexicalBlock(scope: !12, file: !1, line: 9, column: 3) +!24 = !DILocation(line: 9, column: 23, scope: !22) +!25 = !DILocation(line: 9, column: 3, scope: !23) +!26 = distinct !{!26, !25, !27, !28} +!27 = !DILocation(line: 10, column: 5, scope: !23) +!28 = !{!"llvm.loop.mustprogress"} +!29 = !DILocation(line: 12, column: 1, scope: !12) +!30 = !DILocalVariable(name: "Zeta", scope: !12, file: !1, line: 8, type: !10) +!31 = !{!32} +!32 = !DILocalVariable(name: "Param", arg: 1, scope: !11, file: !1, line: 1, type: !10) +!33 = !DISubroutineType(types: !34) +!34 = !{!10, !10} +!35 = !DILocation(line: 1, scope: !11) +!36 = !DILocation(line: 2, scope: !11) +!37 = !DILocation(line: 20, scope: !12) diff --git a/llvm/test/Transforms/IndVarSimplify/pr51735-2.ll b/llvm/test/Transforms/IndVarSimplify/pr51735-2.ll new file mode 100644 index 00000000000000..58cc9932e04ca8 --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/pr51735-2.ll @@ -0,0 +1,128 @@ +; RUN: opt -passes="loop(indvars)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --implicit-check-not="call void @llvm.dbg" \ +; RUN: --check-prefix=ALL-CHECK --check-prefix=PRE-CHECK %s +; RUN: opt -passes="loop(indvars,loop-deletion)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --implicit-check-not="call void @llvm.dbg" \ +; RUN: --check-prefix=ALL-CHECK --check-prefix=POST-CHECK %s + +; Check what happens to a modified but otherwise unused variable in a loop +; that gets deleted. The assignment in the loop is 'forgotten' by LLVM and +; doesn't appear in the debugging information. This behaviour is suboptimal, +; but we want to know if it changes + +; For all cases, LLDB shows +; Var = + +; 1 __attribute__((optnone)) int nop() { +; 2 return 0; +; 3 } +; 4 +; 5 void bar() { +; 6 int End = 777; +; 7 int Index = 27; +; 8 char Var = 1; +; 9 for (; Index < End; ++Index) { +; 10 if (Index == 666) { +; 11 ++Var; +; 12 } +; 13 } +; 14 nop(); +; 15 } + +; ALL-CHECK: entry: +; ALL-CHECK: call void @llvm.dbg.value(metadata i32 1, metadata ![[DBG:[0-9]+]], {{.*}} + +; Only the 'indvars' pass is executed. +; PRE-CHECK: for.cond: +; PRE-CHECK: call void @llvm.dbg.value(metadata i32 %[[SSA_VAR_0:.+]], metadata ![[DBG]], {{.*}} +; PRE-CHECK: call void @llvm.dbg.value(metadata !DIArgList{{.*}} + +; PRE-CHECK: for.body: +; PRE-CHECK: {{.*}} = icmp eq i32 %[[SSA_INDEX_0:.+]], 666 +; PRE-CHECK: {{.*}} = add nsw i32 %[[SSA_VAR_0]], 1 +; PRE-CHECK: {{.*}} = select i1 {{.*}}, i32 {{.*}}, i32 %[[SSA_VAR_0]] +; PRE-CHECK: call void @llvm.dbg.value(metadata i32 {{.*}}, metadata ![[DBG]], {{.*}} +; PRE-CHECK: br label %for.cond + +; PRE-CHECK: for.end: +; PRE-CHECK: ret void +; PRE-CHECK-DAG: ![[DBG]] = !DILocalVariable(name: "Var"{{.*}}) + +; The 'indvars' and 'loop-deletion' passes are executed. +; POST-CHECK: for.end: +; POST-CHECK: call void @llvm.dbg.value(metadata i32 undef, metadata ![[DBG:[0-9]+]], {{.*}} +; POST-CHECK: ret void +; POST-CHECK-DAG: ![[DBG]] = !DILocalVariable(name: "Var"{{.*}}) + +define dso_local void @_Z3barv() local_unnamed_addr !dbg !18 { +entry: + call void @llvm.dbg.value(metadata i32 1, metadata !24, metadata !DIExpression()), !dbg !22 + br label %for.cond, !dbg !25 + +for.cond: ; preds = %for.cond, %entry + %Index.0 = phi i32 [ 27, %entry ], [ %inc2, %for.body ], !dbg !22 + %Var.0 = phi i32 [ 1, %entry ], [ %spec.select, %for.body ], !dbg !22 + call void @llvm.dbg.value(metadata i32 %Var.0, metadata !24, metadata !DIExpression()), !dbg !22 + %cmp = icmp ult i32 %Index.0, 777, !dbg !26 + call void @llvm.dbg.value(metadata !DIArgList(i32 poison, i32 %Index.0), metadata !24, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_constu, 666, DW_OP_eq, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_plus, DW_OP_stack_value)), !dbg !22 + %inc2 = add nuw nsw i32 %Index.0, 1, !dbg !29 + br i1 %cmp, label %for.body, label %for.end, !dbg !30, !llvm.loop !31 + +for.body: ; preds = %for.cond + %cmp1 = icmp eq i32 %Index.0, 666, !dbg !30 + %inc = add nsw i32 %Var.0, 1 + %spec.select = select i1 %cmp1, i32 %inc, i32 %Var.0, !dbg !32 + call void @llvm.dbg.value(metadata i32 %spec.select, metadata !24, metadata !DIExpression()), !dbg !22 + br label %for.cond, !dbg !34, !llvm.loop !35 + +for.end: ; preds = %for.cond + ret void, !dbg !35 +} + +declare void @llvm.dbg.value(metadata, metadata, metadata) + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8} +!llvm.ident = !{!9} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None) +!1 = !DIFile(filename: "test-b.cpp", directory: "") +!2 = !{i32 7, !"Dwarf Version", i32 5} +!3 = !{i32 2, !"Debug Info Version", i32 3} +!4 = !{i32 1, !"wchar_size", i32 4} +!5 = !{i32 8, !"PIC Level", i32 2} +!6 = !{i32 7, !"PIE Level", i32 2} +!7 = !{i32 7, !"uwtable", i32 2} +!8 = !{i32 7, !"frame-pointer", i32 2} +!9 = !{!"clang version 19.0.0"} +!10 = distinct !DISubprogram(name: "nop", linkageName: "_Z3nopi", scope: !1, file: !1, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !14) +!11 = !DISubroutineType(types: !12) +!12 = !{!13, !13} +!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!14 = !{} +!15 = !DILocalVariable(name: "Param", arg: 1, scope: !10, file: !1, line: 1, type: !13) +!16 = !DILocation(line: 1, column: 38, scope: !10) +!17 = !DILocation(line: 2, column: 3, scope: !10) +!18 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 5, type: !19, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !14) +!19 = !DISubroutineType(types: !20) +!20 = !{null} +!22 = !DILocation(line: 0, scope: !18) +!24 = !DILocalVariable(name: "Var", scope: !18, file: !1, line: 8, type: !13) +!25 = !DILocation(line: 9, column: 3, scope: !18) +!26 = !DILocation(line: 9, column: 16, scope: !27) +!27 = distinct !DILexicalBlock(scope: !28, file: !1, line: 9, column: 3) +!28 = distinct !DILexicalBlock(scope: !18, file: !1, line: 9, column: 3) +!29 = !DILocation(line: 9, column: 23, scope: !27) +!30 = !DILocation(line: 9, column: 3, scope: !28) +!31 = distinct !{!31, !30, !32, !33} +!32 = !DILocation(line: 11, column: 9, scope: !28) +!33 = !{!"llvm.loop.mustprogress"} +!34 = !DILocation(line: 12, column: 3, scope: !18) +!35 = !DILocation(line: 13, column: 1, scope: !18) +!36 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 15, type: !37, scopeLine: 15, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0) +!37 = !DISubroutineType(types: !38) +!38 = !{!13} +!39 = !DILocation(line: 16, column: 3, scope: !36) +!40 = !DILocation(line: 17, column: 1, scope: !36) diff --git a/llvm/test/Transforms/IndVarSimplify/pr51735-3.ll b/llvm/test/Transforms/IndVarSimplify/pr51735-3.ll new file mode 100644 index 00000000000000..ac9964743e0ffc --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/pr51735-3.ll @@ -0,0 +1,131 @@ +; RUN: opt -passes="loop(indvars)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --implicit-check-not="call void @llvm.dbg" \ +; RUN: --check-prefix=ALL-CHECK --check-prefix=PRE-CHECK %s +; RUN: opt -passes="loop(indvars,loop-deletion)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --implicit-check-not="call void @llvm.dbg" \ +; RUN: --check-prefix=ALL-CHECK --check-prefix=POST-CHECK %s + +; Check what happens to a modified but otherwise unused variable in a loop +; that gets deleted. The assignment in the loop is 'forgotten' by LLVM and +; doesn't appear in the debugging information. This behaviour is suboptimal, +; but we want to know if it changes + +; For all cases, LLDB shows +; Var = + +; 1 __attribute__((optnone)) int nop() { +; 2 return 0; +; 3 } +; 4 +; 5 void bar() { +; 6 int End = 777; +; 7 int Index = 27; +; 8 char Var = 1; +; 9 for (; Index < End; ++Index) { +; 10 if (Index == 666) { +; 11 Var = 555; +; 12 } +; 13 } +; 14 nop(); +; 15 } + +; ALL-CHECK: entry: +; ALL-CHECK: call void @llvm.dbg.value(metadata i32 1, metadata ![[DBG:[0-9]+]], {{.*}} + +; Only the 'indvars' pass is executed. +; PRE-CHECK: if.then: +; PRE-CHECK: call void @llvm.dbg.value(metadata i32 555, metadata ![[DBG]], {{.*}} + +; PRE-CHECK: for.inc: +; PRE-CHECK: %[[SSA_VAR_0:.+]] = phi i32 [ 1, %for.body ], [ 555, %if.then ] +; PRE-CHECK: call void @llvm.dbg.value(metadata i32 %[[SSA_VAR_0]], metadata ![[DBG]], {{.*}} +; PRE-CHECK: {{.*}} = add nuw nsw i32 %[[SSA_INDEX_0:.+]], 1 +; PRE-CHECK: br label %for.cond + +; PRE-CHECK: for.end: +; PRE-CHECK: ret void +; PRE-CHECK-DAG: ![[DBG]] = !DILocalVariable(name: "Var"{{.*}}) + +; The 'indvars' and 'loop-deletion' passes are executed. +; POST-CHECK: for.end: +; POST-CHECK: call void @llvm.dbg.value(metadata i32 555, metadata ![[DBG]], {{.*}} +; POST-CHECK: ret void +; POST-CHECK-DAG: ![[DBG]] = !DILocalVariable(name: "Var"{{.*}}) + +define dso_local void @_Z3barv() local_unnamed_addr !dbg !18 { +entry: + call void @llvm.dbg.value(metadata i32 1, metadata !24, metadata !DIExpression()), !dbg !22 + br label %for.cond, !dbg !25 + +for.cond: ; preds = %for.inc, %entry + %Index.0 = phi i32 [ 27, %entry ], [ %inc, %for.inc ], !dbg !22 + %cmp = icmp ult i32 %Index.0, 777, !dbg !26 + br i1 %cmp, label %for.body, label %for.end, !dbg !30, !llvm.loop !29 + +for.body: ; preds = %for.cond + %cmp1 = icmp eq i32 %Index.0, 666, !dbg !30 + br i1 %cmp1, label %if.then, label %for.inc, !dbg !32 + +if.then: ; preds = %for.body + call void @llvm.dbg.value(metadata i32 555, metadata !24, metadata !DIExpression()), !dbg !22 + br label %for.inc, !dbg !34, !llvm.loop !32 + +for.inc: ; preds = %for.body, %if.then + %Var.0 = phi i32 [ 1, %for.body ], [ 555, %if.then ], !dbg !22 + call void @llvm.dbg.value(metadata i32 %Var.0, metadata !24, metadata !DIExpression()), !dbg !22 + %inc = add nuw nsw i32 %Index.0, 1, !dbg !29 + br label %for.cond, !dbg !34, !llvm.loop !35 + +for.end: ; preds = %for.cond + ret void, !dbg !35 +} + +declare void @llvm.dbg.value(metadata, metadata, metadata) + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8} +!llvm.ident = !{!9} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None) +!1 = !DIFile(filename: "test-c.cpp", directory: "") +!2 = !{i32 7, !"Dwarf Version", i32 5} +!3 = !{i32 2, !"Debug Info Version", i32 3} +!4 = !{i32 1, !"wchar_size", i32 4} +!5 = !{i32 8, !"PIC Level", i32 2} +!6 = !{i32 7, !"PIE Level", i32 2} +!7 = !{i32 7, !"uwtable", i32 2} +!8 = !{i32 7, !"frame-pointer", i32 2} +!9 = !{!"clang version 19.0.0"} +!10 = distinct !DISubprogram(name: "nop", linkageName: "_Z3nopi", scope: !1, file: !1, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !14) +!11 = !DISubroutineType(types: !12) +!12 = !{!13, !13} +!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!14 = !{} +!15 = !DILocalVariable(name: "Param", arg: 1, scope: !10, file: !1, line: 1, type: !13) +!16 = !DILocation(line: 1, column: 38, scope: !10) +!17 = !DILocation(line: 2, column: 3, scope: !10) +!18 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 5, type: !19, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !14) +!19 = !DISubroutineType(types: !20) +!20 = !{null} +!21 = !DILocalVariable(name: "End", scope: !18, file: !1, line: 6, type: !13) +!22 = !DILocation(line: 0, scope: !18) +!23 = !DILocalVariable(name: "Index", scope: !18, file: !1, line: 7, type: !13) +!24 = !DILocalVariable(name: "Var", scope: !18, file: !1, line: 8, type: !13) +!25 = !DILocation(line: 9, column: 3, scope: !18) +!26 = !DILocation(line: 9, column: 16, scope: !27) +!27 = distinct !DILexicalBlock(scope: !28, file: !1, line: 9, column: 3) +!28 = distinct !DILexicalBlock(scope: !18, file: !1, line: 9, column: 3) +!29 = !DILocation(line: 9, column: 23, scope: !27) +!30 = !DILocation(line: 9, column: 3, scope: !28) +!31 = distinct !{!31, !30, !32, !33} +!32 = !DILocation(line: 11, column: 13, scope: !28) +!33 = !{!"llvm.loop.mustprogress"} +!34 = !DILocation(line: 12, column: 3, scope: !18) +!35 = !DILocation(line: 13, column: 1, scope: !18) +!36 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 15, type: !37, scopeLine: 15, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0) +!37 = !DISubroutineType(types: !38) +!38 = !{!13} +!39 = !DILocation(line: 16, column: 3, scope: !36) +!40 = !DILocation(line: 17, column: 1, scope: !36) diff --git a/llvm/test/Transforms/IndVarSimplify/pr51735.ll b/llvm/test/Transforms/IndVarSimplify/pr51735.ll new file mode 100644 index 00000000000000..3014b3467852d1 --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/pr51735.ll @@ -0,0 +1,104 @@ +; RUN: opt -passes="loop(indvars)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --check-prefix=PRE-CHECK %s +; RUN: opt -passes="loop(indvars,loop-deletion)" \ +; RUN: --experimental-debuginfo-iterators=false -S -o - < %s | \ +; RUN: FileCheck --check-prefix=POST-CHECK %s + +; Make sure that when we delete the loop in the code below, that the variable +; Index has the 777 value. + +; 1 __attribute__((optnone)) int nop() { +; 2 return 0; +; 3 } +; 4 +; 5 void bar() { +; 6 int End = 777; +; 7 int Index = 27; +; 8 char Var = 1; +; 9 for (; Index < End; ++Index) +; 10 ; +; 11 nop(); +; 12 } +; 13 +; 14 int main () { +; 15 bar(); +; 16 } + +; Only the 'indvars' pass is executed. +; As this test case does not fire the 'indvars' transformation, no debug values +; are preserved and or added. + +; PRE-CHECK: for.cond: +; PRE-CHECK: call void @llvm.dbg.value(metadata i32 poison, metadata ![[DBG_1:[0-9]+]], {{.*}} +; PRE-CHECK: call void @llvm.dbg.value(metadata i32 poison, metadata ![[DBG_1]], {{.*}} +; PRE-CHECK: br i1 false, label %for.cond, label %for.end + +; PRE-CHECK: for.end: +; PRE-CHECK-NOT: call void @llvm.dbg.value +; PRE-CHECK: ret void +; PRE-CHECK-DAG: ![[DBG_1]] = !DILocalVariable(name: "Index"{{.*}}) + +; The 'indvars' and 'loop-deletion' passes are executed. +; The loop is deleted and the debug values collected by 'indvars' are used by +; 'loop-deletion' to add the induction variable debug value. + +; POST-CHECK: for.end: +; POST-CHECK: call void @llvm.dbg.value(metadata i32 777, metadata ![[DBG_2:[0-9]+]], {{.*}} +; POST-CHECK: ret void +; POST-CHECK-DAG: ![[DBG_2]] = !DILocalVariable(name: "Index"{{.*}}) + +define dso_local void @_Z3barv() local_unnamed_addr #1 !dbg !15 { +entry: + call void @llvm.dbg.value(metadata i32 777, metadata !19, metadata !DIExpression()), !dbg !20 + call void @llvm.dbg.value(metadata i32 27, metadata !21, metadata !DIExpression()), !dbg !20 + call void @llvm.dbg.value(metadata i32 1, metadata !22, metadata !DIExpression()), !dbg !20 + br label %for.cond, !dbg !23 + +for.cond: ; preds = %for.cond, %entry + %Index.0 = phi i32 [ 27, %entry ], [ %inc, %for.cond ], !dbg !20 + call void @llvm.dbg.value(metadata i32 %Index.0, metadata !21, metadata !DIExpression()), !dbg !20 + %cmp = icmp ult i32 %Index.0, 777, !dbg !24 + %inc = add nuw nsw i32 %Index.0, 1, !dbg !27 + call void @llvm.dbg.value(metadata i32 %inc, metadata !21, metadata !DIExpression()), !dbg !20 + br i1 %cmp, label %for.cond, label %for.end, !dbg !28, !llvm.loop !29 + +for.end: ; preds = %for.cond + ret void, !dbg !33 +} + +declare void @llvm.dbg.value(metadata, metadata, metadata) + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8} +!llvm.ident = !{!9} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None) +!1 = !DIFile(filename: "test.cpp", directory: "") +!2 = !{i32 7, !"Dwarf Version", i32 5} +!3 = !{i32 2, !"Debug Info Version", i32 3} +!4 = !{i32 1, !"wchar_size", i32 4} +!5 = !{i32 8, !"PIC Level", i32 2} +!6 = !{i32 7, !"PIE Level", i32 2} +!7 = !{i32 7, !"uwtable", i32 2} +!8 = !{i32 7, !"frame-pointer", i32 2} +!9 = !{!"clang version 18.0.0"} +!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!15 = distinct !DISubprogram(name: "bar", linkageName: "_Z3barv", scope: !1, file: !1, line: 5, type: !16, scopeLine: 5, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !18) +!16 = !DISubroutineType(types: !17) +!17 = !{null} +!18 = !{} +!19 = !DILocalVariable(name: "End", scope: !15, file: !1, line: 6, type: !13) +!20 = !DILocation(line: 0, scope: !15) +!21 = !DILocalVariable(name: "Index", scope: !15, file: !1, line: 7, type: !13) +!22 = !DILocalVariable(name: "Var", scope: !15, file: !1, line: 8, type: !13) +!23 = !DILocation(line: 9, column: 3, scope: !15) +!24 = !DILocation(line: 9, column: 16, scope: !25) +!25 = distinct !DILexicalBlock(scope: !26, file: !1, line: 9, column: 3) +!26 = distinct !DILexicalBlock(scope: !15, file: !1, line: 9, column: 3) +!27 = !DILocation(line: 9, column: 23, scope: !25) +!28 = !DILocation(line: 9, column: 3, scope: !26) +!29 = distinct !{!29, !28, !30, !31} +!30 = !DILocation(line: 10, column: 5, scope: !26) +!31 = !{!"llvm.loop.mustprogress"} +!33 = !DILocation(line: 12, column: 1, scope: !15)