Fix fbcode CI torch.compile fusion with newer PyTorch#2567
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oulgen
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| _scheduler_node_has_aliasing_or_mutation = SchedulerNode.has_aliasing_or_mutation | ||
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| def _helion_scheduler_node_has_aliasing_or_mutation( | ||
| self: SchedulerNode, | ||
| ) -> bool: | ||
| if isinstance(self.node, HelionTemplateBuffer): | ||
| return False | ||
| return _scheduler_node_has_aliasing_or_mutation(self) | ||
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| # Inductor's generic template prologue check rejects any template with mutation | ||
| # outputs. Helion already limits prologue fusion to non-mutated inputs via | ||
| # allowed_prologue_inps, so non-mutated pointwise producers can still fuse safely. | ||
| SchedulerNode.has_aliasing_or_mutation = ( # pyrefly: ignore[bad-assignment] | ||
| _helion_scheduler_node_has_aliasing_or_mutation | ||
| ) |
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what's going on here? this code looks very suspicious
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Yep it was too broad. Addressed now.
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| # Inductor has no template hook for the prologue-fusion mutation gate. Route | ||
| # Helion templates through the narrower check above while leaving every other | ||
| # SchedulerNode on Inductor's implementation. | ||
| SchedulerNode.has_aliasing_or_mutation = ( # pyrefly: ignore[bad-assignment] |
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Can we fix this on the PyTorch side rather than monkey patching?
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Fix Helion torch.compile fusion failures seen in fbcode CI with a newer PyTorch/Inductor version.
Newer Inductor rejects template prologue fusion when the template scheduler node reports mutation. PyTorch PR pytorch/pytorch#185317 adds a template hook for that gate, and this Helion change implements the hook instead of monkey patching SchedulerNode.
Helion allows independent non-mutated prologue producers while still blocking aliases, real mutations, direct mutation inputs, and producers that read mutated inputs through allowed_prologue_inps.
Also refreshes Inductor range-tree symbol mappings after fusion hook setup to fix
Unregistered range symbolfailures from renamed prologue/epilogue range variables.Adds a regression test for the allowed and blocked prologue-fusion cases.