Some source code reading revealed the answer. I thought that this was a deeper thing than it is. op_seq is zero before the peep-hole optimizer runs on some code and non-zero afterwards as a flag to prevent the optimizer from running again.

I now wonder how Simon got a handle to some code before the optimizer took hold of it. Hmm...

In reply to Re: When is an opcode's ->seq empty? by diotalevi
in thread When is an opcode's ->seq empty? by diotalevi

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