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Date: Mon, 14 Jan 2019 08:42:00 -0000
From: Jakub Jelinek <jakub@redhat.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: Jonathan Wakely <jwakely.gcc@gmail.com>, libstdc++ <libstdc++@gcc.gnu.org>,        GCC Patches <gcc-patches@gcc.gnu.org>,        Marc Glisse <marc.glisse@inria.fr>
Subject: Re: [PATCH] Use __builtin_is_constant_evaluated in std::less etc. (PR tree-optimization/88775)
Message-ID: <20190114084237.GA30353@tucnak>
Reply-To: Jakub Jelinek <jakub@redhat.com>
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On Mon, Jan 14, 2019 at 09:29:03AM +0100, Richard Biener wrote:
> So why is this not just
> 
>   return (__UINTPTR_TYPE__)__x > (__UINTPTR_TYPE__)__y;
> 
> or with the casts elided?  Does the C++ standard say pointers are
> to be compared unsigned here?  Or do all targets GCC support
> lay out the address space in a way that this is correct for pointers
> into distinct objects?

See PR78420 for details on why it is done that way.

	Jakub