https://bugs.kde.org/show_bug.cgi?id=413330
Mark Wielaard <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |[email protected] Status|REPORTED |CONFIRMED Ever confirmed|0 |1 --- Comment #1 from Mark Wielaard <[email protected]> --- I am afraid rsqrtss is not like the other instructions in avx-1. The blog post you quote is very on topic: > (https://randomascii.wordpress.com/2013/07/16/floating-point-determinism/) The estimate instructions (rcpss, rcpps, rsqrtps, rsqrtss) are, as the name suggests, not expected to give a fully accurate result. They are supposed to provide estimates with bounded errors See also http://www-archive.xenproject.org/files/xensummit_germany09/AMD.pdf#page=15 So ideally we move these estimate instructions out of avx-1 and into their own testcase that checks the results are within the bounded error. Unfortunately I don't know of a good way to do that. Alternatively we might for now just assume there are only two implementations, the intel and amd one, and just print the results as we do now, but create two different .exp files for the new testcase. The test would then just pass if the result is either like the intel or the amd implementation. We can see what to do if another implementation pops up. -- You are receiving this mail because: You are watching all bug changes.
