Files
clang-p2996/clang/lib/CodeGen/CGLoopInfo.cpp
Ryotaro Kasuga 6c56a842b7 [clang][CodeGen] Generate follow-up metadata for loops in correct format (#131985)
When pragma of loop transformations is specified, follow-up metadata for
loops is generated after each transformation. On the LLVM side,
follow-up metadata is expected to be a list of properties, such as the
following:

```
!followup = !{!"llvm.loop.vectorize.followup_all", !mp, !isvectorized}
!mp = !{!"llvm.loop.mustprogress"}
!isvectorized = !{"llvm.loop.isvectorized"}
```

However, on the clang side, the generated metadata contains an MDNode
that has those properties, as shown below:

```
!followup = !{!"llvm.loop.vectorize.followup_all", !loop_id}
!loop_id = distinct !{!loop_id, !mp, !isvectorized}
!mp = !{!"llvm.loop.mustprogress"}
!isvectorized = !{"llvm.loop.isvectorized"}
```
According to the
[LangRef](https://llvm.org/docs/TransformMetadata.html#transformation-metadata-structure),
the LLVM side is correct. Due to this inconsistency, follow-up metadata
was not interpreted correctly, e.g., only one transformation is applied
when multiple pragmas are used.

This patch fixes clang side to emit followup metadata in correct format.
2025-03-27 20:29:37 +09:00

31 KiB