See through or/and in truthy-elision (#224)

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A loop test like (or (>= i cap) (> ... 4.0)) desugars to
(let* [g (>= i cap)] (if (truthy? g) g (> ... 4.0))) and the whole thing was
wrapped in jolt-truthy? because returns-scheme-bool? only looked at :const and
:invoke nodes, not the let*/if an or/and expands to. The wrapper defeats Chez's
branch inlining on the hot loop edge.

Make returns-scheme-bool? recursive over :if (both branches bool), :let (body
bool, tracking which bound locals hold a Scheme boolean), and :local (in that
set). or/and over bool-returning ops then read as Scheme booleans and the outer
wrapper drops. Still sound: eliding only when the value is provably #t/#f — a
jolt-nil is a truthy record in Chez, so a false positive would be a real bug, and
the recursion only proves bool-ness through ops already known to return one.

No bench regression; the win lands on hinted float loops where the branch, not
boxed arithmetic, is the cost.

Co-authored-by: Yogthos <yogthos@gmail.com>

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Dmitri Sotnikov 2026-06-26 06:11:35 +00:00 • committed by GitHub

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