# RUN: llc -O1 -start-after register-coalescer -o - %s -experimental-debug-variable-locations=true | FileCheck %s

--- |
  target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
  target triple = "x86_64-pc-linux-gnu"

  define i16 @foo(i8 %zzz) !dbg !4 {
  entry:
    ret i16 1
  }

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

  !llvm.dbg.cu = !{!0}
  !llvm.module.flags = !{!3}

  !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, retainedTypes: !2)
  !1 = !DIFile(filename: "test.c", directory: "")
  !2 = !{}
  !3 = !{i32 1, !"Debug Info Version", i32 3}
  !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0)
  !5 = !DISubroutineType(types: !6)
  !6 = !{null}
  !7 = !DILocalVariable(name: "zzz", arg: 1, scope: !4, file: !1, line: 3, type: !8)
  !8 = !DIBasicType(name: "char", size: 8, align: 8, encoding: DW_ATE_signed)
  !9 = !DILocation(line: 0, scope: !4)
  !10 = !DILocation(line: 4, column: 22, scope: !11)
  !11 = distinct !DILexicalBlock(scope: !4, file: !1, line: 3, column: 19)

...
---
name:            foo
tracksRegLiveness: true
debugInstrRef: true
debugValueSubstitutions:
  - { srcinst: 2, srcop: 0, dstinst: 1, dstop: 0, subreg: 2 }
body:             |
  bb.0:
    %0:gr16_abcd = MOV16ri 1, debug-instr-number 1, debug-location !9

  bb.1:
    DBG_INSTR_REF !7, !DIExpression(DW_OP_LLVM_arg, 0), dbg-instr-ref(2, 0), debug-location !9
    %1:gr16 = COPY %0, debug-location !9
    %2:gr16 = COPY %0

  bb.2:
    $ax = COPY %1, debug-location !9
    $dx = COPY %2
    RET64 killed $ax, killed $dx, debug-location !9
...

# This test is an instruction-referencing flavour of the
# dbg-value-superreg-copy.mir test. Over there, we ran into difficulties where
# register coalescing would transform DBG_VALUEs of subregisters such as:
#
#   DBG_VALUE %0.sub_8bit_hi, $noreg,
#
# Into references to larger registers, potentially with the wrong offset. We
# can't refer to vregs in instruction referencing mode, so this test replicates
# the same scenario in a new test. The defining storing load gets an instruction
# number, and we encode which subregister we want through a substitution. Check
# that it comes out the other end of regalloc through coalescing still in a
# high register.
#
# CHECK-NOT:    #DEBUG_VALUE:
# CHECK:        #DEBUG_VALUE: foo:zzz <- ${{[abcd]+}}h
# CHECK-NOT:    #DEBUG_VALUE: