Mehdi Amini 5c06541fb8 [mlir][CFGToSCF] Fix crash when region contains unconvertible multi-successor op (#183935) ...

`transformCFGToSCF` would crash with a use-list assertion when it
encountered an op like `spirv.BranchConditional` that implements
`BranchOpInterface` (passing the existing precondition checks) but is
not handled by `createStructuredBranchRegionOp`. The algorithm mutated
the IR significantly before discovering the op was unsupported, leaving
it in a corrupt half-transformed state that triggered the assertion on
teardown.

Fix by adding `canConvertBranchOp` to `CFGToSCFInterface` (default:
accept all ops) and calling it inside `checkTransformationPreconditions`
for every block with more than one successor, before any IR
modifications are made. `ControlFlowToSCFTransformation` overrides the
method to accept only `cf.cond_br` and `cf.switch`.

Fixes #173566

Assisted-by: Claude Code

2026-03-24 19:09:40 +00:00

7.4 KiB

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