On Tue, 2024-07-09 at 16:33 -0700, Vineet Gupta wrote: > > > On 7/9/24 16:23, Jeff Law wrote: > > > > On 7/9/24 5:08 PM, Vineet Gupta wrote: > > > On 7/3/24 12:08, Xi Ruoyao wrote: > > > > On Fri, 2024-06-28 at 17:53 -0700, Vineet Gupta wrote: > > > > > I was also hoping to get __builtin_inf() done but unforutnately it > > > > > requires little more rtl foo/bar to implement a tri-modal return. > > > > Hmm do we really need to care the symbol? The generic __builtin_isinf > > > > does not care the symbol anyway: https://godbolt.org/z/bnnGf3a38 and the > > > > standards only require a non-zero return value if the input is infinite > > > > (positive or negative). > > > Not sure what you mean: are you saying the current flags based > > > implementation doesn't return tri-modal val. > > Me either. No idea what I was thinking/saying. Best to ignore whatever > > I asked/said on that topic ;-) > > Doh this was meant for Xi as he made this comment :-)
Yes I mean we don't need to do a tri-modal return. The linux man page describes the Glibc behavior, but it's not precisely what the standard mandates. In C23 draft (N3054) section 7.12.3.4 paragraph 3: The isinf macro returns a nonzero value if and only if its argument has an infinite value. And it says nothing about -1 or +1. GCC supports different libc implementations, and in the past days it never implemented try-modal return for __builtin_isinf, thus it seems we don't need to implement it. -- Xi Ruoyao <xry...@xry111.site> School of Aerospace Science and Technology, Xidian University
