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[RFA] libstdc++/22203, aka PowerPC vs numeric_limits<integer>::traps


Hi,

submitter maintains that PowerPC integer divide does not trap and
therefore, according to this comment in std_limits.h:

// GCC only intrinsicly supports modulo integral types.  The only remaining
// integral exceptional values is division by zero.  Only targets that
do not
// signal division by zero in some "hard to ignore" way should use false.
#ifndef __glibcxx_integral_traps
# define __glibcxx_integral_traps true
#endif

we should define __glibcxx_integral_traps to false for powerpc-*.

Today I verified the substance of the PR with Ulrich Weigand, and I'd
like to double check with you all that indeed for libstdc++-v3 it's
appropriate defining __glibcxx_integral_traps to false. That would
require a bit of configury, likely a new empty
config/cpu/generic/cpu_defines.h, included by c++config.h (and therefore
by std_limits.h), and specialized in config/cpu/powerpc/, not a big
deal, overall.

Paolo.


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