[llvm] [InferAttrs] Mark ceil and round as memory(none) (PR #170694)

[Nikita Popov via llvm-commits]

https://github.com/nikic approved this pull request.

LGTM

>From the man page of round:

> POSIX.1-2001  contains  text  about  overflow  (which might set errno to
       ERANGE, or raise an FE_OVERFLOW exception).   In  practice,  the  result
       cannot overflow on any current machine, so this error-handling stuff was
       just nonsense.  (More precisely, overflow can happen only when the maxi‐
       mum  value  of the exponent is smaller than the number of mantissa bits.
       For the IEEE-754 standard 32-bit and 64-bit floating-point  numbers  the
       maximum  value of the exponent is 127 (respectively, 1023), and the num‐
       ber of mantissa bits including the implicit  bit  is  24  (respectively,
       53).)  This was removed in POSIX.1-2008.

https://github.com/llvm/llvm-project/pull/170694