[Transform] Preserve all reachable functions in FuseTIR #16471
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@slyubomirsky Would this resolve the problem encountered in #16462 ? I think this would avoid throwing out the in-place updates, and would also allow handling of context-dependent fusions, depending on whether the call site could support an in-place operation. |
Prior to this commit, the `FuseTIR` pass had custom logic to determine whether a `PrimFunc` should be kept in the output `IRModule`. This commit replaces this check in `FuseTIR` with a post-processing by `DeadCodeElimination`.
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| tir::PrimFunc fused_tir = FusedTIRConstructor::GetFusedTIR(orig_mod_, old_gvar); |
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Are you sure we aren't likely to call this more than once per global var? As long as it's not likely or costly, this approach is probably fine.
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It probably would be called several times. The fused Relax function is generated once per pattern match in FuseOpsByPattern, and is then de-duplicated, leaving many calls to a single kPrimitive function. This would generate the fused TIR function once per callsite, after which the resulting functions would be de-duplicated. Whether that is good or bad would probably depend on the usefulness for call_tir_inplace, so I'll take a look at #16487.
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Oh so there's probably no issue with calling it more often than in the current way the pass is written. That seems good to me.
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See 16487, the in-place case will be handled. |
Sounds good. I think I still like having this change overall, as it avoids having duplicate logic for DCE. When 16487, I'll rebase this PR on top of it. |
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Prior to this commit, the
FuseTIRpass had custom logic to determine whether aPrimFuncshould be kept in the outputIRModule. This commit replaces this check inFuseTIRwith a post-processing byDeadCodeElimination.