llvm/test/DebugInfo/MIR/InstrRef/x86-drop-compare-inst.mir

# RUN: llc %s -o - -experimental-debug-variable-locations -run-pass=peephole-opt | FileCheck %s
#
# X86 initially produces subtract operations to perform comparisons, and then
# downgrades them into cmp instructions if nothing uses the result. It does this
# by calling setDesc on the instruction, mutating it from one sort to another,
# which makes any debug instruction numbers attached to the number invalid.
# This test tests that the relevant instruction number is dropped.
#
# CHECK-NOT: debug-instr-number
# CHECK:     CMP32rm
# CHECK-NOT: debug-instr-number
#
--- |
  ; ModuleID = '/fast/fs/build34llvm4/reduced.ll'
  target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
  target triple = "x86_64-unknown-linux-gnu"
  
  %"class.std::vector.534" = type { %"struct.std::_Vector_base.535" }
  %"struct.std::_Vector_base.535" = type { %"struct.std::_Vector_base<unsigned char, std::allocator<unsigned char>>::_Vector_impl" }
  %"struct.std::_Vector_base<unsigned char, std::allocator<unsigned char>>::_Vector_impl" = type { i8*, i8*, i8* }
  
  ; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
  declare void @llvm.dbg.declare(metadata, metadata, metadata) #0
  
  define hidden fastcc void @soup() unnamed_addr !dbg !3 {
  _ZN4llvm11raw_ostreamlsEPKc.exit2752:
    %0 = load %"class.std::vector.534"*, %"class.std::vector.534"** undef, align 8, !dbg !7
    %1 = load i8*, i8** undef, align 8, !dbg !7
    %_M_start.i2756 = getelementptr inbounds %"class.std::vector.534", %"class.std::vector.534"* %0, i64 undef, i32 0, i32 0, i32 0, !dbg !7
    %2 = load i8*, i8** %_M_start.i2756, align 8, !dbg !7
    %sub.ptr.lhs.cast.i2757 = ptrtoint i8* %1 to i64, !dbg !7
    %sub.ptr.rhs.cast.i2758 = ptrtoint i8* %2 to i64, !dbg !7
    %sub.ptr.sub.i2759 = sub i64 %sub.ptr.lhs.cast.i2757, %sub.ptr.rhs.cast.i2758, !dbg !7
    %conv373 = trunc i64 %sub.ptr.sub.i2759 to i32, !dbg !7
    call void @llvm.dbg.value(metadata i32 %conv373, metadata !8, metadata !DIExpression()), !dbg !7
    %cmp375.not2842 = icmp eq i32 %conv373, 0, !dbg !7
    br i1 %cmp375.not2842, label %for.cond.cleanup376, label %for.body377, !dbg !7
  
  for.cond.cleanup376:                              ; preds = %_ZN4llvm11raw_ostreamlsEPKc.exit2752
    ret void
  
  for.body377:                                      ; preds = %_ZN4llvm11raw_ostreamlsEPKc.exit2752
    ret void
  }
  
  ; Function Attrs: nofree nosync nounwind readnone speculatable willreturn
  declare void @llvm.dbg.value(metadata, metadata, metadata) #0
  
  attributes #0 = { nofree nosync nounwind readnone speculatable willreturn }
  
  !llvm.module.flags = !{!0}
  !llvm.dbg.cu = !{!1}
  
  !0 = !{i32 2, !"Debug Info Version", i32 3}
  !1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "beards", isOptimized: true, runtimeVersion: 4, emissionKind: FullDebug)
  !2 = !DIFile(filename: "bees.cpp", directory: "")
  !3 = distinct !DISubprogram(name: "nope", scope: !2, file: !2, line: 1, type: !4, spFlags: DISPFlagDefinition, unit: !1)
  !4 = !DISubroutineType(types: !5)
  !5 = !{!6}
  !6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
  !7 = !DILocation(line: 1, scope: !3)
  !8 = !DILocalVariable(name: "flannel", scope: !3)

...
---
name:            soup
alignment:       16
tracksRegLiveness: true
registers:
  - { id: 0, class: gr64 }
  - { id: 1, class: gr64 }
  - { id: 2, class: gr32 }
  - { id: 3, class: gr32 }
frameInfo:
  maxAlignment:    1
machineFunctionInfo: {}
body:             |
  bb.0._ZN4llvm11raw_ostreamlsEPKc.exit2752:
    successors: %bb.1(0x30000000), %bb.2(0x50000000)
  
    %1:gr64 = IMPLICIT_DEF
    %0:gr64 = MOV64rm killed %1, 1, $noreg, 0, $noreg, debug-location !7 :: (load (s64) from `i8** undef`)
    %2:gr32 = COPY %0.sub_32bit, debug-location !7
    %3:gr32 = SUB32rm %2, %0, 1, $noreg, 0, $noreg, implicit-def $eflags, debug-instr-number 1, debug-location !7 :: (load (s32) from %ir._M_start.i2756, align 8)
    DBG_INSTR_REF 1, 0, !8, !DIExpression(), debug-location !7
    JCC_1 %bb.2, 5, implicit $eflags, debug-location !7
    JMP_1 %bb.1, debug-location !7
  
  bb.1.for.cond.cleanup376:
    RET 0
  
  bb.2.for.body377:
    RET 0

...