[llvm-dev] Commit history duplicated, seeing weird diffusion activity (Was: [Diffusion] rG67c416dc9a5a: [DebugInfo] Allow spill slots in call site parameter descriptions)

[Vedant Kumar via llvm-dev]

I just got a Diffusion notification about a change of mine being reverted by Fangrui, but I'm not sure that's actually what happened and am confused and concerned.

My commit was "[DebugInfo] Allow spill slots in call site parameter descriptions", and it appears in the history under two hashes: 1ee84e and 67c416. The first commit contains the actual change. The second touches something in yaml2obj, which I promise I did not do:

```
$ g show 67c416dc9a5aeda034d46bdcb3b63fffa462d28e
commit 67c416dc9a5aeda034d46bdcb3b63fffa462d28e
Author: Vedant Kumar <vsk at apple.com>
Date:   Thu Nov 14 09:20:58 2019

    [DebugInfo] Allow spill slots in call site parameter descriptions
    
    [snip]

diff --git a/llvm/test/tools/yaml2obj/coff-xrelocs.yaml b/llvm/test/tools/yaml2obj/COFF/xrelocs.yaml
similarity index 100%
rename from llvm/test/tools/yaml2obj/coff-xrelocs.yaml
rename to llvm/test/tools/yaml2obj/COFF/xrelocs.yaml
```

Does anyone know what happened?

thanks,
vedant

> On Nov 15, 2019, at 10:06 AM, Fangrui Song via Phabricator <reviews at reviews.llvm.org> wrote:
> 
> MaskRay committed rG67c416dc9a5a: [DebugInfo] Allow spill slots in call site parameter descriptions (authored by vsk).
> MaskRay added a reverted change: rGeb4c98ca3d25: [DebugInfo] Exclude memory location values as parameter entry values.
> 
> [DebugInfo] Allow spill slots in call site parameter descriptions
> 
> Allow call site paramter descriptions to reference spill slots. Spill
> slots are not visible to high-level LLVM IR, so they can safely be
> referenced during entry value evaluation (as they cannot be clobbered by
> some other function).
> 
> This gives a 5% increase in the number of call site parameter DIEs in an
> LTO x86_64 build of the xnu kernel.
> 
> This reverts commit eb4c98ca3d2590bad9f6542afbf3a7824d2b53fa (
> [DebugInfo] Exclude memory location values as parameter entry values),
> effectively reintroducing the portion of D60716 <https://reviews.llvm.org/D60716> which dealt with memory
> locations (authored by Djordje, Nikola, Ananth, and Ivan).
> 
> This partially addresses llvm.org/PR43343. However, not all memory
> operands forwarded to callees live in spill slots. In the xnu build, it
> may be possible to use an escape analysis to increase the number of call
> site parameter by another 15% (more details in PR43343).
> 
> Differential Revision: https://reviews.llvm.org/D70254
> 
> 
> BRANCHES
>  master
> 
> Files:
>  /llvm/test/tools/yaml2obj/COFF/
>  /llvm/test/tools/yaml2obj/COFF/xrelocs.yaml
>  /llvm/test/tools/yaml2obj/coff-xrelocs.yaml
> 
> PATCH
> 
> diff --git a/llvm/test/tools/yaml2obj/coff-xrelocs.yaml b/llvm/test/tools/yaml2obj/COFF/xrelocs.yaml
> similarity index 100%
> rename from llvm/test/tools/yaml2obj/coff-xrelocs.yaml
> rename to llvm/test/tools/yaml2obj/COFF/xrelocs.yaml
> 
> Users:
>  vsk (Author)
>  MaskRay (Committer)
> 
> https://reviews.llvm.org/rG67c416dc9a5a
> 
> 
>