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bhimrazy
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bhimrazy
added this pull request to stack #2849
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Since torch 2.12, the fwd subgraph dynamo builds returns its outputs as a tuple, and the caller indexes it: return ((y,), (l_x_,)) getitem = autograd_function_apply[0] python_return(*sequencify(output)) unpacked a one-element tuple to the bare tensor, so [0] indexed into the tensor instead, and thunderfx returned a scalar where eager gives f32[2]. test_higher_order_inplace_alias_update: AssertionError: The values for attribute 'shape' do not match: torch.Size([]) != torch.Size([2]). Return the structure the graph produced. Bare and multi-element outputs are unchanged.
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What does this PR do?
Keeps the tuple that the
autograd_function_applyfwd graph returns, so thunderfx gives the right shape again.Problem: since torch 2.12, the fwd subgraph dynamo builds returns its outputs as a tuple, and the caller indexes it:
thunder's lookaside unpacked a one-element tuple to the bare tensor, so
[0]indexed into the tensor, and thunderfx returned a scalar where eager givesf32[2].Fix: return the structure the graph produced. Bare and multi-element outputs are unchanged.
Related CI:
test_higher_order_inplace_alias_update, the last failure in the core jobs on ubuntu, macOS and Windows.Error, torch 2.14, with the rest of this stack
Part 9 of the breakdown of #2832.