Re: Keep compiler silence (clang 10, implicit conversion from 'long'to 'double' ) - Mailing list pgsql-hackers

From Thomas Munro
Subject Re: Keep compiler silence (clang 10, implicit conversion from 'long'to 'double' )
Date
Msg-id CA+hUKGJrLQs7Q8ff-6DYySX2LSxtDEP-nk7zDfZFFBuyj6Xpww@mail.gmail.com
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In response to Re: Keep compiler silence (clang 10, implicit conversion from 'long'to 'double' )  (Yuya Watari <watari.yuya@gmail.com>)
Responses Re: Keep compiler silence (clang 10, implicit conversion from 'long' to 'double' )  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Wed, Nov 6, 2019 at 3:33 PM Yuya Watari <watari.yuya@gmail.com> wrote:
> However, this behavior depends on the platform architecture. As you
> have said, C language does not always follow IEEE-754. I think adding
> explicit checking of NaN is necessary.

I'm curious about this point.  C may not require IEEE 754 (for
example, on current IBM mainframe and POWER hardware you can opt for
IBM hex floats, and on some IBM platforms that is the default, and the
C compiler isn't breaking any rules by doing that; the only other
floating point format I've heard of is VAX format, long gone, but
perhaps allowed by C).  But PostgreSQL effectively requires IEEE 754
since commit 02ddd499322ab6f2f0d58692955dc9633c2150fc, right?



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