[PATCH] D31573: [Builtins] Add IEEE 754 support for __fixunsxfti

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

There are two kinds of systems with 80-bit long double: 64-bit x86, and 32-bit x86.  On 32-bit x86 with 80-bit long double, CRT_HAS_128BIT is false, and `__LDBL_MANT_DIG__` is 64.  On 64-bit x86 with 80-bit long double, CRT_HAS_128BIT is true, and `__LDBL_MANT_DIG__` is 64.

For the 80-bit long double tests which don't use 128-bit integers, you want to run them for all systems where __LDBL_MANT_DIG__ is 64.  For the 80-bit long double tests which do use 128-bit integers, you want to run them only on systems where CRT_HAS_128BIT is set and `__LDBL_MANT_DIG__` is 64.


https://reviews.llvm.org/D31573