[New-bugs-announce] [issue16956] Allow signed line number deltas in the code object's line number table

[Mark Shannon]

New submission from Mark Shannon:

The restriction that line numbers must be monotonically increasing w.r.t bytecode offset in the co_lnotab array prevents a number of beneficial transformations in the bytecode compiler.

This patch allows negative line number deltas and uses this capability to generate code for 'while' loops in standard text book fashion, putting the test *after* the body.

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hgrepos: 172
messages: 179887
nosy: Mark.Shannon
priority: normal
severity: normal
status: open
title: Allow signed line number deltas in the code object's  line number table

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue16956>
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