Revert "Fix signed-unsigned semantics in reduce_32"
This reverts commit aaf59b03.
This commit regressed the scaling-test unit test, by apparently allowing the compiler to emit fused multiply-add instructions in cases they wouldn't have been allowed before. While using gcc's -ffp-contract=... flag avoids the issue on amd64, it does not on at least aarch64 and ppc64.
This is unfortunate, because the commit being reverted resolved #43 (closed) so we will reintroduce this failure, but after more than a year without a fix for the unit test, I think it's time to bite the bullet.
Fixes: #49 (closed)