select(c, a, select(c, b, d)) is select(c, a, d), and
select(c, select(c, a, b), d) is select(c, a, d). The recompiler leaves
these behind when a register is written more than once under the same
lane mask and when the f32 NaN selection tests the same source twice,
and nothing folded them. The constant folder now takes the inner arm
the outer condition already decides, then folds a select whose arms
became equal.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
