Missing Continue in Assembly Optimizations

[ritzdorf]

Version Information

• vyper Version (output of vyper --version OR linkable commit hash vyperlang/vyper@): b43ffac

Issue Description

_stack_peephole_opts() tries to perform 5 different optimizations at
each index i of the assembly using a while loop. However, the last two
optimizations, when performed do not continue the loop, which means
that:

• i is incremented by 1, leading to skipping the next instruction
  and potentially missing an optimization.
• If both optimizations are performed for a given i, it might be
  that the second one tries accessing an index that is out of range
  given that the first one removed the 2 last elements of the array
  and the check for the index is not performed in between the two
  optimizations.