PIX: Numbering pass fails with /Od when subroutines are used

Repro:
Run the pix file mentioned in PIX bug 26308011.
Attempt to recompile the shader in question with /Od.
(Ask jeffnn/jeffno for details on how to do this)

This assert hits:

!dbg attachment points at wrong subprogram for function
!78 = !DISubprogram(name: "ClusterAirprobeVolumesCS", scope: !79, file: !79, line: 153, type: !80, isLocal: false, isDefinition: true, scopeLine: 154, flags: DIFlagPrototyped, isOptimized: false, function: void ()* @ClusterAirprobeVolumesCS)
void ()* @ClusterAirprobeVolumesCS
call void @llvm.dbg.declare(metadata [1 x float]* %126, metadata !964, metadata !604), !dbg !970
!970 = !DILocation(line: 96, column: 1, scope: !965)
!965 = distinct !DILexicalBlock(scope: !966, file: !79, line: 90, column: 3)
!109 = !DISubprogram(name: "CullAirprobeVolumes", linkageName: "\01?CullAirprobeVolumes@@YA?AV?$vector@I$03@@Y07V?$vector@M$02@@@Z", scope: !79, file: !79, line: 71, type: !110, isLocal: false, isDefinition: true, scopeLine: 72, flags: DIFlagPrototyped, isOptimized: false)
Exception thrown at 0x00007FFE881C361C in WinPixEngineHost.exe: Microsoft C++ exception: std::exception at memory location 0x00000074B87FCFD8.