Re: math tests failed when the argument is out of domain

[Szabolcs Nagy <szabolcs.nagy@arm.com>]

The 10/11/2022 20:25, Yu-Chien Peter Lin wrote:
> Hi all, 
> 
> We run the glibc testsuite on RISC-V targets and got some 
> common failure of following test in math subdir. 
> 
> FAIL: math/test-double-acos
> FAIL: math/test-double-asin
> FAIL: math/test-float64-acos
> FAIL: math/test-float64-asin
> FAIL: math/test-float32x-acos
> FAIL: math/test-float32x-asin
> 
> The return values and errno of acos and asin are correct, but
> they don't raise "Invalid operation" exception when the argument
> is inf, -inf, 1.125, -1.125, max_value and -max_value.


fwiw i saw this on aarch64 with some version of gcc-10 when
'return INFINITY/INFINITY;' is optimized to 'return NAN;'
so the fenv exception is not set.

this could be fixed via a more robust arithmetic to set nan
e.g. (x-x)/(x-x) or ensuring gcc takes exceptions into account
when const folding float operations.

> 
> These failed cases are listed test results [1] since glibc 2.33,
> but it seems not a reported bug on sourceware bugzilla. so I want
> to know the status on this issue.
> 
> [1] https://sourceware.org/glibc/wiki/Release/2.35#RISC-V_.28rv64imafdc.2Flp64d.29
> 
> These tests run at below environments.
> - glibc 2.35
> - gcc 10.2.1
> - binutils 2.38
> - Linux 5.4
> 
> Best Regards,
> Peter Lin