Re: [PATCH] Change default to -fno-math-errno

2017-11-07 Thread Wilco Dijkstra
Joseph Myers wrote: On Mon, 30 Oct 2017, Wilco Dijkstra wrote: > The semantics of __*_finite definitely include finite-math-only, as they > aren't all just disabling the wrappers (e.g. sysdeps/i386/i686/fpu/e_log.S > has __log_finite separate from __ieee754_log). I only see a few cases where th

Re: [PATCH] Change default to -fno-math-errno

2017-10-30 Thread Joseph Myers
On Mon, 30 Oct 2017, Wilco Dijkstra wrote: > Richard Biener wrote: > > Should we also get the __ieee764_ entries used if the compiler sets > > __NO_MATH_ERRNO__?  That is, if the librari advertises not setting errno > > via math_errhandling is it still allowed to set/clobber errno anyways? > > Th

Re: [PATCH] Change default to -fno-math-errno

2017-10-30 Thread Wilco Dijkstra
Richard Biener wrote: > Should we also get the __ieee764_ entries used if the compiler sets > __NO_MATH_ERRNO__?  That is, if the librari advertises not setting errno > via math_errhandling is it still allowed to set/clobber errno anyways? That's a good question! I checked and the math wrappers cu

Re: [PATCH] Change default to -fno-math-errno

2017-10-30 Thread Joseph Myers
On Mon, 30 Oct 2017, Richard Biener wrote: > On Fri, Oct 27, 2017 at 6:28 PM, Joseph Myers wrote: > > No existing glibc version defines math_errhandling based on > > __NO_MATH_ERRNO__. I'd expect such a change to come with a glibc patch, > > and indeed a GCC execution test of the value of math_e

Re: [PATCH] Change default to -fno-math-errno

2017-10-30 Thread Richard Biener
On Fri, Oct 27, 2017 at 6:28 PM, Joseph Myers wrote: > No existing glibc version defines math_errhandling based on > __NO_MATH_ERRNO__. I'd expect such a change to come with a glibc patch, > and indeed a GCC execution test of the value of math_errhandling to make > sure the compiler's behavior is

Re: [PATCH] Change default to -fno-math-errno

2017-10-27 Thread Joseph Myers
No existing glibc version defines math_errhandling based on __NO_MATH_ERRNO__. I'd expect such a change to come with a glibc patch, and indeed a GCC execution test of the value of math_errhandling to make sure the compiler's behavior isn't contradicting what's declared by the runtime libraries

[PATCH] Change default to -fno-math-errno

2017-10-27 Thread Wilco Dijkstra
GCC currently defaults to -fmath-errno. This generates code assuming math functions set errno and the application checks errno. Very few applications test errno and various systems and math libraries no longer set errno since it is optional. GCC generates much faster code for simple math functio