| commit | 4159fd819a89cb18e03a91576372ae257ee5fbc7 | [log] [tgz] |
|---|---|---|
| author | Abid Qadeer <haqadeer@amd.com> | Fri Aug 29 16:56:26 2025 +0100 |
| committer | GitHub <noreply@github.com> | Fri Aug 29 16:56:26 2025 +0100 |
| tree | 0fc1e8d9846077f427c4575889fe4fba6eda87d5 | |
| parent | 260ee975fcb43621c1979848dc02ebad7bece350 [diff] |
[OMPIRBuilder] Avoid crash in BasicBlock::splice. (#154987)
Calling `BasicBlock::splice` in `spliceBB` when both `Old` and `New` are
empty is a `nop` currently but it can cause a crash once debug records
are used instead of debug intrinsics. This PR makes the call conditional
on at least one of `Old` or `New` being non-empty.
Consider the following mlir:
```
omp.target map_entries() {
llvm.intr.dbg.declare ...
llvm.intr.dbg.declare ...
omp.teams ...
...
}
```
Current code would translate llvm.intr Ops to llvm intrinsics. Old is
the BasicBlock where they were get inserted and it will have 2 llvm
debug intrinsics by the time the implementation of `omp.teams` starts.
This implementation creates many BasicBlocks by calling `splitBB`. The
`New` is the just created BasicBlock which is empty.
In the new scheme (using debug records), there will be no instruction in
the `Old` BB after llvm.intr Ops get translated but just 2 trailing
debug records. So both `Old` and `New` are empty. When control reaches
`BasicBlock::splice`, it calls `spliceDebugInfoEmptyBlock`. This
function expects that in this case (`Src` is empty but has trailing
debug records), the `ToIt` is valid and it can call `adoptDbgRecords` on
it. This assumption is not true in this case as `New` is empty and
`ToIt` is pointing to end(). The fix is to only call
`BasicBlock::splice` when at least of `Old` or `New` is not empty.
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