llvm/test/DebugInfo/MIR/InstrRef/phi-through-regalloc.mir

# RUN: llc %s -o - -mtriple=x86_64-unknown-unknown \
# RUN:    -experimental-debug-variable-locations \
# RUN:    -run-pass=phi-node-elimination,livedebugvars,greedy,virtregrewriter \
# RUN:    | FileCheck %s
#
# This test checks that for a very simple PHI, we produce a corresponding
# DBG_PHI instruction, that a DBG_INSTR_REF refers to. Tests the path through
# phi-node-elimination, live debug variables, and then placement after register
# allocation.
#
# Original code, compiled with only -mem2reg, then fed to llc -stop-before...
#
#    int ext(int);
#    int foo(int bar, int baz) {
#      int either = 0;
#      if (ext(0))
#        either = bar;
#      else
#        either = baz;
#
#      return either;
#    }
#

--- |
  ; ModuleID = 'promoted.ll'
  source_filename = "test.c"
  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"

  define dso_local i32 @foo(i32 %bar, i32 %baz) !dbg !7 {
  entry:
    call void @llvm.dbg.value(metadata i32 %bar, metadata !11, metadata !DIExpression()), !dbg !12
    call void @llvm.dbg.value(metadata i32 %baz, metadata !13, metadata !DIExpression()), !dbg !12
    call void @llvm.dbg.value(metadata i32 0, metadata !14, metadata !DIExpression()), !dbg !12
    %call = call i32 @ext(i32 0), !dbg !15
    %tobool = icmp ne i32 %call, 0, !dbg !15
    br i1 %tobool, label %if.end, label %if.else, !dbg !17

  if.else:                                          ; preds = %entry
    call void @llvm.dbg.value(metadata i32 %baz, metadata !14, metadata !DIExpression()), !dbg !12
    br label %if.end

  if.end:                                           ; preds = %entry, %if.else
    %either.0 = phi i32 [ %baz, %if.else ], [ %bar, %entry ], !dbg !18
    call void @llvm.dbg.value(metadata i32 %either.0, metadata !14, metadata !DIExpression()), !dbg !12
    ret i32 %either.0, !dbg !19
  }

  declare dso_local i32 @ext(i32)

  ; Function Attrs: nounwind readnone speculatable willreturn
  declare void @llvm.dbg.value(metadata, metadata, metadata)

  !llvm.dbg.cu = !{!0}
  !llvm.module.flags = !{!3, !4, !5}
  !llvm.ident = !{!6}

  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, splitDebugInlining: false, nameTableKind: None)
  !1 = !DIFile(filename: "test.c", directory: ".")
  !2 = !{}
  !3 = !{i32 7, !"Dwarf Version", i32 4}
  !4 = !{i32 2, !"Debug Info Version", i32 3}
  !5 = !{i32 1, !"wchar_size", i32 4}
  !6 = !{!"."}
  !7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, type: !8, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
  !8 = !DISubroutineType(types: !9)
  !9 = !{!10, !10, !10}
  !10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
  !11 = !DILocalVariable(name: "bar", arg: 1, scope: !7, file: !1, line: 2, type: !10)
  !12 = !DILocation(line: 0, scope: !7)
  !13 = !DILocalVariable(name: "baz", arg: 2, scope: !7, file: !1, line: 2, type: !10)
  !14 = !DILocalVariable(name: "either", scope: !7, file: !1, line: 3, type: !10)
  !15 = !DILocation(line: 4, column: 7, scope: !16)
  !16 = distinct !DILexicalBlock(scope: !7, file: !1, line: 4, column: 7)
  !17 = !DILocation(line: 4, column: 7, scope: !7)
  !18 = !DILocation(line: 0, scope: !16)
  !19 = !DILocation(line: 9, column: 3, scope: !7)

...
---
name:            foo
alignment:       16
tracksRegLiveness: true
registers:
  - { id: 0, class: gr32 }
  - { id: 1, class: gr32 }
  - { id: 2, class: gr32 }
  - { id: 3, class: gr32 }
  - { id: 4, class: gr32 }
liveins:
  - { reg: '$edi', virtual-reg: '%1' }
  - { reg: '$esi', virtual-reg: '%2' }
frameInfo:
  maxAlignment:    1
  hasCalls:        true
machineFunctionInfo: {}
body:             |
  bb.0.entry:
    successors: %bb.2(0x50000000), %bb.1(0x30000000)
    liveins: $edi, $esi

    DBG_VALUE $edi, $noreg, !11, !DIExpression(), debug-location !12
    DBG_VALUE $esi, $noreg, !13, !DIExpression(), debug-location !12
    %2:gr32 = COPY killed $esi
    %1:gr32 = COPY killed $edi
    DBG_VALUE 0, $noreg, !14, !DIExpression(), debug-location !12
    ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp, debug-location !15
    %3:gr32 = MOV32r0 implicit-def dead $eflags
    $edi = COPY killed %3, debug-location !15
    CALL64pcrel32 @ext, csr_64, implicit $rsp, implicit $ssp, implicit killed $edi, implicit-def $rsp, implicit-def $ssp, implicit-def $eax, debug-location !15
    ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp, debug-location !15
    %4:gr32 = COPY killed $eax, debug-location !15
    TEST32rr killed %4, %4, implicit-def $eflags, debug-location !15
    JCC_1 %bb.2, 5, implicit killed $eflags, debug-location !17
    JMP_1 %bb.1, debug-location !17

  bb.1.if.else:

    ; CHECK-LABEL: bb.2.if.end:
  bb.2.if.end:
    %0:gr32 = PHI %1, %bb.0, %2, %bb.1, debug-instr-number 1, debug-location !18
    DBG_INSTR_REF 1, 0, !14, !DIExpression(), debug-location !12
    ; CHECK:      DBG_PHI $ebp, 1
    ; CHECK:      DBG_INSTR_REF 1, 0
    $eax = COPY killed %0, debug-location !19
    ; Confirm that %0 is allocated in $ebp,
    ; CHECK:      $eax = COPY killed renamable $ebp
    RET 0, killed $eax, debug-location !19

...