Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 9 May 2024 18:54:17 +0100 | From | Al Viro <> | Subject | Re: [RFC] Mitigating unexpected arithmetic overflow |
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On Thu, May 09, 2024 at 08:38:28AM -0700, Linus Torvalds wrote:
> Going the other way is similar: > > all_bits = low_bits + ((u64) high_bits << 16) << 16); > > and again, the compiler will recognize this idiom and do the right > thing (and if 'all_bits' is only 32-bit, the compiler will optimize > the high bit noise away).
Umm... That would make sense if it was all_bits = low_bits + ((T) high_bits << 16) << 16); with possibly 32bit T. But the way you wrote that (with u64) it's pointless - u64 _can_ be shifted by 32 just fine.
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