[C++ PATCH] Don't promote bitfields in last arg of __builtin_*_overflow_p

Martin Sebor msebor@gmail.com
Thu Jun 16 02:24:00 GMT 2016


On 06/15/2016 01:51 PM, Jakub Jelinek wrote:
> On Wed, Jun 15, 2016 at 08:08:22AM -0600, Martin Sebor wrote:
>> I like the idea of being able to use the built-ins for this, but
>> I think it would be confusing for them to follow subtly different
>> rules for C than for C++.  Since the value of the last argument
>
> Here is incremental patch to the patch I've posted earlier today,
> which doesn't promote the last argument of __builtin_*_overflow_p
> and thus for bitfields it behaves pretty much like the C FE.

Looks fine to me.  The bit-field handling should be explained
in the manual.  Though useful, it's unusual enough that I don't
think people will expect it (there have been bug reports or
questions in the past about the C handling of bit-fields from
users familiar with the C++ semantics).

Martin



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