forked from OSchip/llvm-project
[DebugInfo][LSR] Limit the size of SCEV translated to DIExpression
SCEV-based salvaging will use excessive resources if it encounters very long SCEV expressions. This patch places a limit on the length of SCEV expression that salvaging will attempt to translate. Reviewed by: Orlando Differential Revision: https://reviews.llvm.org/D110558
This commit is contained in:
Chris Jackson
parent
b25f618857
commit
a61c0adba1
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@ -136,6 +136,12 @@ using namespace llvm;
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/// worst cases before LSR burns too much compile time and stack space.
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static const unsigned MaxIVUsers = 200;
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/// Limit the size of expression that SCEV-based salvaging will attempt to
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/// translate into a DIExpression.
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/// Choose a maximum size such that debuginfo is not excessively increased and
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/// the salvaging is not too expensive for the compiler.
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static const unsigned MaxSCEVSalvageExpressionSize = 64;
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// Temporary flag to cleanup congruent phis after LSR phi expansion.
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// It's currently disabled until we can determine whether it's truly useful or
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// not. The flag should be removed after the v3.0 release.
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@ -6152,6 +6158,9 @@ static void RewriteDVIUsingIterCount(DVIRecoveryRec CachedDVI,
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if (!Rec->isAffine())
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return;
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if (CachedDVI.SCEV->getExpressionSize() > MaxSCEVSalvageExpressionSize)
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return;
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// Initialise a new builder with the iteration count expression. In
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// combination with the value's SCEV this enables recovery.
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SCEVDbgValueBuilder RecoverValue(IterationCount);
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@ -6196,7 +6205,10 @@ DbgRewriteSalvageableDVIs(llvm::Loop *L, ScalarEvolution &SE,
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if (!IVAddRec->isAffine())
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return;
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// The iteratioun count is required to recover location values.
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if (IVAddRec->getExpressionSize() > MaxSCEVSalvageExpressionSize)
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return;
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// The iteration count is required to recover location values.
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SCEVDbgValueBuilder IterCountExpr;
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IterCountExpr.pushValue(LSRInductionVar);
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if (!IterCountExpr.SCEVToIterCountExpr(*IVAddRec, SE))
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@ -0,0 +1,142 @@
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; RUN: opt -loop-reduce -S %s | FileCheck %s
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;; This test ensures that no attempt is made to translate long SCEVs into
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;; DIExpressions. Attempting the translation can use excessive resources and
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;; result in crashes.
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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@c = dso_local local_unnamed_addr global i32 0, align 4, !dbg !0
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@b = dso_local local_unnamed_addr global i32 0, align 4, !dbg !9
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@a = dso_local local_unnamed_addr global i32 0, align 4, !dbg !5
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define dso_local i32 @d() local_unnamed_addr #0 !dbg !16 {
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entry:
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%b.promoted = load i32, i32* @b, align 4, !tbaa !29
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%mul = mul nsw i32 %b.promoted, %b.promoted, !dbg !33
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%mul.1 = mul nsw i32 %mul, %mul, !dbg !33
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%mul.2 = mul nsw i32 %mul.1, %mul.1, !dbg !33
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%mul.3 = mul nsw i32 %mul.2, %mul.2, !dbg !33
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%mul.4 = mul nsw i32 %mul.3, %mul.3, !dbg !33
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%mul.5 = mul nsw i32 %mul.4, %mul.4, !dbg !33
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%mul.6 = mul nsw i32 %mul.5, %mul.5, !dbg !33
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%mul.7 = mul nsw i32 %mul.6, %mul.6, !dbg !33
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%mul.8 = mul nsw i32 %mul.7, %mul.7, !dbg !33
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%mul.9 = mul nsw i32 %mul.8, %mul.8, !dbg !33
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%mul.10 = mul nsw i32 %mul.9, %mul.9, !dbg !33
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%mul.11 = mul nsw i32 %mul.10, %mul.10, !dbg !33
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%mul.12 = mul nsw i32 %mul.11, %mul.11, !dbg !33
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%mul.13 = mul nsw i32 %mul.12, %mul.12, !dbg !33
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%mul.14 = mul nsw i32 %mul.13, %mul.13, !dbg !33
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%mul.15 = mul nsw i32 %mul.14, %mul.14, !dbg !33
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%mul.16 = mul nsw i32 %mul.15, %mul.15, !dbg !33
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%mul.17 = mul nsw i32 %mul.16, %mul.16, !dbg !33
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%mul.18 = mul nsw i32 %mul.17, %mul.17, !dbg !33
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%mul.19 = mul nsw i32 %mul.18, %mul.18, !dbg !33
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%mul.20 = mul nsw i32 %mul.19, %mul.19, !dbg !33
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%mul.21 = mul nsw i32 %mul.20, %mul.20, !dbg !33
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%mul.22 = mul nsw i32 %mul.21, %mul.21, !dbg !33
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%mul.23 = mul nsw i32 %mul.22, %mul.22, !dbg !33
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%mul.24 = mul nsw i32 %mul.23, %mul.23, !dbg !33
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%mul.25 = mul nsw i32 %mul.24, %mul.24, !dbg !33
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%mul.26 = mul nsw i32 %mul.25, %mul.25, !dbg !33
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%mul.27 = mul nsw i32 %mul.26, %mul.26, !dbg !33
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%mul.28 = mul nsw i32 %mul.27, %mul.27, !dbg !33
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%mul.29 = mul nsw i32 %mul.28, %mul.28, !dbg !33
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%mul.30 = mul nsw i32 %mul.29, %mul.29, !dbg !33
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%mul.31 = mul nsw i32 %mul.30, %mul.30, !dbg !33
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%mul.32 = mul nsw i32 %mul.31, %mul.31, !dbg !33
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%mul.33 = mul nsw i32 %mul.32, %mul.32, !dbg !33
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%mul.34 = mul nsw i32 %mul.33, %mul.33, !dbg !33
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%mul.35 = mul nsw i32 %mul.34, %mul.34, !dbg !33
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%mul.36 = mul nsw i32 %mul.35, %mul.35, !dbg !33
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%mul.37 = mul nsw i32 %mul.36, %mul.36, !dbg !33
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%mul.38 = mul nsw i32 %mul.37, %mul.37, !dbg !33
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%mul.39 = mul nsw i32 %mul.38, %mul.38, !dbg !33
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%mul.40 = mul nsw i32 %mul.39, %mul.39, !dbg !33
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%mul.41 = mul nsw i32 %mul.40, %mul.40, !dbg !33
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%mul.42 = mul nsw i32 %mul.41, %mul.41, !dbg !33
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%mul.43 = mul nsw i32 %mul.42, %mul.42, !dbg !33
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%mul.44 = mul nsw i32 %mul.43, %mul.43, !dbg !33
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%mul.45 = mul nsw i32 %mul.44, %mul.44, !dbg !33
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%mul.46 = mul nsw i32 %mul.45, %mul.45, !dbg !33
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%mul.47 = mul nsw i32 %mul.46, %mul.46, !dbg !33
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store i32 49, i32* @c, align 4, !dbg !36, !tbaa !29
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store i32 %mul.47, i32* @b, align 4, !dbg !37, !tbaa !29
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%.pr = load i32, i32* @a, align 4, !dbg !38, !tbaa !29
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%tobool.not8 = icmp eq i32 %.pr, 0, !dbg !39
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br i1 %tobool.not8, label %for.end3, label %for.body2.preheader, !dbg !39
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for.body2.preheader: ; preds = %entry
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br label %for.body2, !dbg !39
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for.body2: ; preds = %for.body2.preheader, %for.body2
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%0 = phi i32 [ %sub, %for.body2 ], [ %.pr, %for.body2.preheader ]
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%sub = sub nsw i32 %0, %mul.47, !dbg !40
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; CHECK: call void @llvm.dbg.value(metadata !DIArgList(i32 undef, i32 %mul.47), metadata ![[VAR_e:[0-9]+]], metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_minus, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_LLVM_convert, 64, DW_ATE_signed, DW_OP_stack_value))
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call void @llvm.dbg.value(metadata i32 %sub, metadata !20, metadata !DIExpression(DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_LLVM_convert, 64, DW_ATE_signed, DW_OP_stack_value)), !dbg !41
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%tobool.not = icmp eq i32 %sub, 0, !dbg !39
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br i1 %tobool.not, label %for.cond1.for.end3_crit_edge, label %for.body2, !dbg !39, !llvm.loop !42
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for.cond1.for.end3_crit_edge: ; preds = %for.body2
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store i32 0, i32* @a, align 4, !dbg !40, !tbaa !29
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br label %for.end3, !dbg !39
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for.end3: ; preds = %for.cond1.for.end3_crit_edge, %entry
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ret i32 undef, !dbg !45
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}
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declare void @llvm.dbg.value(metadata, metadata, metadata) #1
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!llvm.dbg.cu = !{!2}
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!llvm.module.flags = !{!11, !12, !13, !14}
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!llvm.ident = !{!15}
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!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
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!1 = distinct !DIGlobalVariable(name: "c", scope: !2, file: !7, line: 2, type: !8, isLocal: false, isDefinition: true)
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!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 14.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, globals: !4, splitDebugInlining: false, nameTableKind: None)
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!3 = !DIFile(filename: "test.c", directory: "/test")
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!4 = !{!5, !9, !0}
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!5 = !DIGlobalVariableExpression(var: !6, expr: !DIExpression())
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!6 = distinct !DIGlobalVariable(name: "a", scope: !2, file: !7, line: 2, type: !8, isLocal: false, isDefinition: true)
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!7 = !DIFile(filename: "./test.c", directory: "/test")
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!8 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!9 = !DIGlobalVariableExpression(var: !10, expr: !DIExpression())
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!10 = distinct !DIGlobalVariable(name: "b", scope: !2, file: !7, line: 2, type: !8, isLocal: false, isDefinition: true)
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!11 = !{i32 7, !"Dwarf Version", i32 4}
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!12 = !{i32 2, !"Debug Info Version", i32 3}
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!13 = !{i32 1, !"wchar_size", i32 4}
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!14 = !{i32 7, !"uwtable", i32 1}
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!15 = !{!"clang version 14.0.0"}
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!16 = distinct !DISubprogram(name: "d", scope: !7, file: !7, line: 3, type: !17, scopeLine: 3, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !19)
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!17 = !DISubroutineType(types: !18)
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!18 = !{!8}
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!19 = !{!20}
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; CHECK: ![[VAR_e]] = !DILocalVariable(name: "e", scope: !21, file: !7, line: 8, type: !24)
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!20 = !DILocalVariable(name: "e", scope: !21, file: !7, line: 8, type: !24)
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!21 = distinct !DILexicalBlock(scope: !22, file: !7, line: 7, column: 14)
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!22 = distinct !DILexicalBlock(scope: !23, file: !7, line: 7, column: 3)
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!23 = distinct !DILexicalBlock(scope: !16, file: !7, line: 7, column: 3)
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!24 = !DIDerivedType(tag: DW_TAG_typedef, name: "uint64_t", file: !25, line: 27, baseType: !26)
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!25 = !DIFile(filename: "/usr/include/x86_64-linux-gnu/bits/stdint-uintn.h", directory: "")
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!26 = !DIDerivedType(tag: DW_TAG_typedef, name: "__uint64_t", file: !27, line: 44, baseType: !28)
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!27 = !DIFile(filename: "/usr/include/x86_64-linux-gnu/bits/types.h", directory: "")
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!28 = !DIBasicType(name: "long unsigned int", size: 64, encoding: DW_ATE_unsigned)
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!29 = !{!30, !30, i64 0}
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!30 = !{!"int", !31, i64 0}
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!31 = !{!"omnipotent char", !32, i64 0}
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!32 = !{!"Simple C/C++ TBAA"}
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!33 = !DILocation(line: 6, column: 7, scope: !34)
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!34 = distinct !DILexicalBlock(scope: !35, file: !7, line: 5, column: 3)
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!35 = distinct !DILexicalBlock(scope: !16, file: !7, line: 5, column: 3)
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!36 = !DILocation(line: 0, scope: !16)
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!37 = !DILocation(line: 0, scope: !34)
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!38 = !DILocation(line: 7, column: 10, scope: !22)
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!39 = !DILocation(line: 7, column: 3, scope: !23)
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!40 = !DILocation(line: 8, column: 20, scope: !21)
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!41 = !DILocation(line: 0, scope: !21)
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!42 = distinct !{!42, !39, !43, !44}
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!43 = !DILocation(line: 9, column: 3, scope: !23)
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!44 = !{!"llvm.loop.mustprogress"}
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!45 = !DILocation(line: 10, column: 1, scope: !16)
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