Displaying 4 results from an estimated 4 matches for "except_behavior".
2020 Jan 27
11
Floating point semantic modes
...find a home for it in the clang documentation, but I'd like to start by getting input on whether everyone agrees with my judgment on how these things should work and whether I've missed anything.
Here's what I've got.
======================
FP semantic modes
======================
except_behavior { ignore, strict, may_trap }
fenv_access { on, off }
rounding_mode { dynamic, tonearest, downward, upward, towardzero }
contract { on, off, fast }
denormal_fp_math { IEEE, PreserveSign, PositiveZero }
denormal_fp32_math { IEEE, PreserveSign, PositiveZero }
support_math_errno { on, off }
no_honor_na...
2020 Jan 29
2
Floating point semantic modes
...FENV_ACCESS as a fully strict mode of operation, but what you’re suggesting aligns with what Cameron suggested and even some of my own reasoning on other points. So, let me amend my previous proposal to say:
STDC FENV_ACCESS {ON|OFF}
Patch in progress. I think ON should force the following:
except_behavior { strict }
fenv_access { on }
rounding_mode { dynamic }
Other modes should be unchanged.
Thanks,
Andy
From: Serge Pavlov <sepavloff at gmail.com>
Sent: Wednesday, January 29, 2020 9:34 AM
To: Kaylor, Andrew <andrew.kaylor at intel.com>
Cc: cfe-dev at lists.llvm.org; LLVM Dev...
2020 Jan 29
3
Floating point semantic modes
...if we have any code in the optimizer that introduces access to or modification of errno in the user's program. The library calls that test should always act as barriers to one another.
> ideally there would be a way to support snan too. (e.g. isnan(x) cannot be turned into x!=x then)
The except_behavior mode is supposed to handle this. The LLVM support for constrained intrinsics is considering all manner of FP exceptions that could be raised, including the distinction between QNaN and SNaN. The default LLVM IR definition does not support this distinction.
We seem to have an issue with isnan() in...
2020 Jan 28
3
Floating point semantic modes
...gs should work
> and whether I've missed anything.
> >
> > Here's what I've got.
> >
>
> i'm not an llvm/clang dev, i hope this mail wont bounce.
>
> > ======================
> > FP semantic modes
> > ======================
> > except_behavior { ignore, strict, may_trap } fenv_access { on, off }
> > rounding_mode { dynamic, tonearest, downward, upward, towardzero }
> > contract { on, off, fast } denormal_fp_math { IEEE, PreserveSign,
> > PositiveZero } denormal_fp32_math { IEEE, PreserveSign, PositiveZero }
> > su...