[PyPy-issue] [issue640] Possible optimization in FOR_ITER on a constant tuple

[Alex Gaynor]

New submission from Alex Gaynor <alex.gaynor at gmail.com>:

Given:

for x in (1, 2, 3):
    i += x

We currently generate:

FOR_ITER to 47
guard(i5 is 1)
guard(guard_class(p7, 146344448))
p14 = ((pypy.objspace.std.iterobject.W_FastTupleIterObject)p7).inst_tupleitems
guard(guard_nonnull(p14))
i15 = ((pypy.objspace.std.iterobject.W_AbstractSeqIterObject)p7).inst_index
i16 = arraylen_gc(p14)
i17 = i15 >= i16
guard(i17 is false)
p18 = getarrayitem_gc(p14, i15)
i20 = i15 + 1


This is slightly inefficient in a few places, the getitem, for tupleitems, could
be eliminated, as could the arraylen.

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effort: ???
messages: 2155
nosy: agaynor, pypy-issue
priority: wish
release: ???
status: unread
title: Possible optimization in FOR_ITER on a constant tuple

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PyPy development tracker <pypy-dev-issue at codespeak.net>
<https://codespeak.net/issue/pypy-dev/issue640>
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