Prior to 18.104.22.168, the following
(compile nil '(lambda (x)
(declare (type (single-float 0.0 1.0) x)
(optimize speed (safety 0)))
(values (truncate (* x 1000.0)))))
compiles without notes to straight-line FPU code. In current HEAD, the
same compiles to a full call to %UNARY-TRUNCATE/SINGLE-FLOAT. If I had
to guess, based on the compiler notes generated, I'd guess that the type
derivation information from TRUNCATE gets lost along the way.
Since I think this isn't actually a regression from the previous
release, I'm not going to hold the release for it, but I will accept a
tested and reviewed patch if someone produces one.