Re: Floating-point constant folding in Emacs byte compiler

[Eli Zaretskii]

> From: Pip Cet <address@hidden>
> Date: Fri, 23 Mar 2018 20:52:52 +0000
> Cc: Emacs development discussions <address@hidden>
> 
> Is this really specific to floating-point expressions, though?
> 
> (byte-compile (lambda (x) (* #x10000 #x10000 #x10000 #x10000)))
> #[(x) "À\207" [0] 1]
> 
> (at least on this somewhat oudated version of Emacs). Note the 0 in
> the constant vector, which hardcodes the <65-bit-ness of fixnums.
> 
> I imagine that on a 32-bit version of emacs, (byte-compile (lambda (x)
> (* #x10000 #x10000))) similarly produces a constant-zero function,

The result depends on whether Emacs was build --with-wide-int.  If it
was, the result is #[(x) "\300\207" [4294967296] 1], if it wasn't, I
get #[(x) "\300\207" [0] 1].