On 2018-02-06 10:49:48 +0100, Matthias Klose wrote: > I have seen some issues with mpfr 4.0.0 on 32bit platforms, however > not in GCC itself yet. These are all fixed in 4.0.1 rc2, so maybe > document 4.0.1 instead of 4.0.0 once it is released.
The issues were also present on 64-bit platforms and were due to a bug in mpfr_div_ui, which has always been present, since 1999. With MPFR 4.0.0, they are also visible with mpfr_div just because mpfr_div now uses mpfr_div_ui in some simple cases. I don't think that GCC could be affected because AFAIK, a failure can only occur when the input and output precisions are different, or is this possible with GCC? Now, I've just found a "regression" when comparing Sipe results with MPFR results, but it is the Sipe result with SIPE_FLOAT equal to 1 (float) or 2 (double) that is incorrect, 3 (long double) being OK. Bug triggered with -O2 -march=native on an Intel Xeon E5-2609 v3 machine. At least from 4.9 to 8.0.1 20180124 [trunk revision 257009] are affected. I'll try to find a simple test case for a bug report. I suspect that the regression comes from the fact this is a new machine + the use (as in the past) of -march=native. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
