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      1 ; REQUIRES: object-emission
      2 
      3 ; RUN: llc -mtriple=x86_64-apple-macosx10.10.0 -o %t %s
      4 
      5 ; Testcase generated from:
      6 ; #include <stdint.h>
      7 ; int foo(int a) {
      8 ;     int b = (int16_t)a + 8;
      9 ;     int c = (int16_t)b + 8;
     10 ;     int d = (int16_t)c + 8;
     11 ;     int e = (int16_t)d + 8;
     12 ;     int f = (int16_t)e + 8;
     13 ;     return f;
     14 ; }
     15 ; by emitting the IR and then manually applying mem2reg to it.
     16 
     17 ; This testcase would trigger the assert commited along with it if the
     18 ; fix of r221709 isn't applied. There is no other check except the successful
     19 ; run of llc.
     20 ; What happened before r221709, is that SDDbgInfo (the data structure helping
     21 ; SelectionDAG to keep track of dbg.values) kept a map keyed by SDNode pointers.
     22 ; This map was never purged when the SDNodes were deallocated and thus if a new
     23 ; SDNode was allocated in the same memory, it would have an entry in the SDDbgInfo
     24 ; map upon creation (Reallocation in the same memory can happen easily as
     25 ; SelectionDAG uses a Recycling allocator). This behavior could turn into a
     26 ; pathological memory consumption explosion if the DAG combiner hit the 'right'
     27 ; allocation patterns as could be seen in PR20893.
     28 ; By nature, this test could bitrot quite easily. If it doesn't trigger an assert
     29 ; when run with r221709 reverted, then it really doesn't test anything anymore.
     30 
     31 ; Function Attrs: nounwind ssp uwtable
     32 define i32 @foo(i32 %a) #0 !dbg !8 {
     33 entry:
     34   call void @llvm.dbg.value(metadata i32 %a, i64 0, metadata !16, metadata !17), !dbg !18
     35   %conv = trunc i32 %a to i16, !dbg !19
     36   %conv1 = sext i16 %conv to i32, !dbg !19
     37   %add = add nsw i32 %conv1, 8, !dbg !19
     38   call void @llvm.dbg.value(metadata i32 %add, i64 0, metadata !20, metadata !17), !dbg !21
     39   %conv2 = trunc i32 %add to i16, !dbg !22
     40   %conv3 = sext i16 %conv2 to i32, !dbg !22
     41   %add4 = add nsw i32 %conv3, 8, !dbg !22
     42   call void @llvm.dbg.value(metadata i32 %add4, i64 0, metadata !23, metadata !17), !dbg !24
     43   %conv5 = trunc i32 %add4 to i16, !dbg !25
     44   %conv6 = sext i16 %conv5 to i32, !dbg !25
     45   %add7 = add nsw i32 %conv6, 8, !dbg !25
     46   call void @llvm.dbg.value(metadata i32 %add7, i64 0, metadata !26, metadata !17), !dbg !27
     47   %conv8 = trunc i32 %add7 to i16, !dbg !28
     48   %conv9 = sext i16 %conv8 to i32, !dbg !28
     49   %add10 = add nsw i32 %conv9, 8, !dbg !28
     50   call void @llvm.dbg.value(metadata i32 %add10, i64 0, metadata !29, metadata !17), !dbg !30
     51   %conv11 = trunc i32 %add10 to i16, !dbg !31
     52   %conv12 = sext i16 %conv11 to i32, !dbg !31
     53   %add13 = add nsw i32 %conv12, 8, !dbg !31
     54   call void @llvm.dbg.value(metadata i32 %add13, i64 0, metadata !32, metadata !17), !dbg !33
     55   ret i32 %add13, !dbg !34
     56 }
     57 
     58 ; Function Attrs: nounwind readnone
     59 declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
     60 
     61 ; Function Attrs: nounwind readnone
     62 declare void @llvm.dbg.value(metadata, i64, metadata, metadata) #1
     63 
     64 attributes #0 = { nounwind ssp uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
     65 attributes #1 = { nounwind readnone }
     66 
     67 !llvm.dbg.cu = !{!0}
     68 !llvm.module.flags = !{!13, !14}
     69 !llvm.ident = !{!15}
     70 
     71 !0 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang version 3.6.0 ", isOptimized: false, emissionKind: 1, file: !1, enums: !2, retainedTypes: !3, subprograms: !7, globals: !2, imports: !2)
     72 !1 = !DIFile(filename: "ghost-sdnode-dbgvalues.c", directory: "/tmp")
     73 !2 = !{}
     74 !3 = !{!4}
     75 !4 = !DIDerivedType(tag: DW_TAG_typedef, name: "int16_t", line: 30, file: !5, baseType: !6)
     76 !5 = !DIFile(filename: "/usr/include/sys/_types/_int16_t.h", directory: "/tmp")
     77 !6 = !DIBasicType(tag: DW_TAG_base_type, name: "short", size: 16, align: 16, encoding: DW_ATE_signed)
     78 !7 = !{!8}
     79 !8 = distinct !DISubprogram(name: "foo", line: 3, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: false, scopeLine: 3, file: !1, scope: !9, type: !10, variables: !2)
     80 !9 = !DIFile(filename: "ghost-sdnode-dbgvalues.c", directory: "/tmp")
     81 !10 = !DISubroutineType(types: !11)
     82 !11 = !{!12, !12}
     83 !12 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
     84 !13 = !{i32 2, !"Dwarf Version", i32 2}
     85 !14 = !{i32 2, !"Debug Info Version", i32 3}
     86 !15 = !{!"clang version 3.6.0 "}
     87 !16 = !DILocalVariable(name: "a", line: 3, arg: 1, scope: !8, file: !9, type: !12)
     88 !17 = !DIExpression()
     89 !18 = !DILocation(line: 3, column: 13, scope: !8)
     90 !19 = !DILocation(line: 4, column: 5, scope: !8)
     91 !20 = !DILocalVariable(name: "b", line: 4, scope: !8, file: !9, type: !12)
     92 !21 = !DILocation(line: 4, column: 9, scope: !8)
     93 !22 = !DILocation(line: 5, column: 5, scope: !8)
     94 !23 = !DILocalVariable(name: "c", line: 5, scope: !8, file: !9, type: !12)
     95 !24 = !DILocation(line: 5, column: 9, scope: !8)
     96 !25 = !DILocation(line: 6, column: 5, scope: !8)
     97 !26 = !DILocalVariable(name: "d", line: 6, scope: !8, file: !9, type: !12)
     98 !27 = !DILocation(line: 6, column: 9, scope: !8)
     99 !28 = !DILocation(line: 7, column: 5, scope: !8)
    100 !29 = !DILocalVariable(name: "e", line: 7, scope: !8, file: !9, type: !12)
    101 !30 = !DILocation(line: 7, column: 9, scope: !8)
    102 !31 = !DILocation(line: 8, column: 5, scope: !8)
    103 !32 = !DILocalVariable(name: "f", line: 8, scope: !8, file: !9, type: !12)
    104 !33 = !DILocation(line: 8, column: 9, scope: !8)
    105 !34 = !DILocation(line: 9, column: 5, scope: !8)
    106