Re: Bignum speedup patch causes crash at startup

[Paul Eggert]

Eli Zaretskii wrote:
> I don't understand why it prefers GMP calls to a simple double
> division, when both arguments are fixnums.  What am I missing?

First, converting a fixnum to a double can lose info. Second, the double 
division could round, which would mean the result would be double-rounded. We're 
already suffering from double-rounding when either argument is floating-point, 
and we don't want that bug to also infect integer division. So even the Emacs 26 
code (which doesn't have bignums) must use integer division here, not double 
division.

This is worth commenting so I installed the attached. While writing the comment 
I noticed there's a bug when one argument is a bignum and the other is a float, 
so I fixed that in the attached too.

0001-Fix-round-FLOAT-BIGNUM-bug.patch
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