Horton

Re: Bug fix for glibc broke freebsd build in REL_11_STABLE

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Gierth <andrew@tao11.riddles.org.uk>
Cc: Andres Freund <andres@anarazel.de>, Victor Wagner <vitus@wagner.pp.ru>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2018-09-04T21:46:29Z
Lists: pgsql-hackers 
Andrew Gierth <andrew@tao11.riddles.org.uk> writes:
> The reason it behaves oddly is this: on i387 FPU (and NOT on arm32 or on
> 32-bit i386 with a modern architecture specified to the compiler), the
> result of 1e200 * 1e180 is not in fact infinite, because it fits in an
> 80-bit long double. So __builtin_isinf reports that it is finite; but if
> it gets stored to memory as a double (e.g. to pass as a parameter to a
> function), it then becomes infinite.

Ah-hah.  Can we fix it by explicitly casting the argument of isinf
to double?

			regards, tom lane

Commits

  1. Error out for clang on x86-32 without SSE2 support, no -fexcess-precision.

  2. Fix 8a934d677 for libc++ and make more include order resistant.