Groups > comp.os.linux.misc > #81985

Re: For those arguing over languages...

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From	"Carlos E. R." <robin_listas@es.invalid>
Newsgroups	comp.os.linux.misc
Subject	Re: For those arguing over languages...
Date	Thu, 12 Feb 2026 15:14:57 +0100
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On 2026-02-12 13:38, The Natural Philosopher wrote:
> On 11/02/2026 22:24, Carlos E. R. wrote:
>> On 2026-02-11 19:50, Rich wrote:
>>> c186282 <c186282@nnada.net> wrote:
>>>> On 2/10/26 04:09, The Natural Philosopher wrote:
>>>>> ...more fuel on the fire...
>>>>>
>>>>> https://www.theregister.com/2026/02/09/compilers_undermine_encryption/
>>>>>
>>>>> GCC erases code whose delays obfuscates encryption delays because it
>>>>> doesn't do anything...
>>>>>
>>>>
>>>>    Very interesting ! How 'optimization' sometimes ISN'T.
>>>
>>> Nope.  As Richard Kettlewell has pointed out, what the encryption code
>>> writers want is "constant time execution, regardless of inputs" which
>>> is not a promised output from gcc, no matter the optimization level
>>> chosen.
>>>
>>> The compiler is "properly optimizing" given the meaning of
>>> "optimization" it uses ("make code run as fast as possible" or "make
>>> code as small as possible" -- with -Os).  But the compiler was not
>>> designed to create "constant time execution" code.  The writers were
>>> expecting a promise the compiler never promised.
>>
>> In the example posted:
>>
>>    The user types in a password, which gets checked against
>>    a database, character by character. Once the first character
>>    doesn't match, an error message is returned.
>>
>> ...the fault is not of the compiler, but of the programmer. He has to 
>> examine all characters even if he knows there is no point.
>>
>>
> I think the point is that the compiler knows that isn't necessary, and 
> doesnt bother.
> 

Then don't optimize. Optimization has always been somewhat problematic. 
Sometimes it introduced bugs that could not be debugged, because 
debugging altered the code, possibly removing the optimizations.

-- 
Cheers,
        Carlos E.R.

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Thread

For those arguing over languages... The Natural Philosopher <tnp@invalid.invalid> - 2026-02-10 09:09 +0000
  Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-10 13:11 +0000
  Re: For those arguing over languages... Farley Flud <ff@linux.rocks> - 2026-02-10 14:08 +0000
    Re: For those arguing over languages... Marc Haber <mh+usenetspam1118@zugschl.us> - 2026-02-10 15:16 +0100
      Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-10 16:19 +0000
        Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-10 18:20 +0000
      Re: For those arguing over languages... Chris Ahlstrom <OFeem1987@teleworm.us> - 2026-02-10 11:22 -0500
      Re: For those arguing over languages... John  <john@panix.com> - 2026-02-17 16:23 +0000
        Re: For those arguing over languages... Rich <rich@example.invalid> - 2026-02-19 19:26 +0000
          Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-22 09:28 +0000
    Re: For those arguing over languages... John Ames <commodorejohn@gmail.com> - 2026-02-10 08:24 -0800
      Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-10 18:16 +0000
  Re: For those arguing over languages... c186282 <c186282@nnada.net> - 2026-02-10 22:34 -0500
    Re: For those arguing over languages... Rich <rich@example.invalid> - 2026-02-11 18:50 +0000
      Re: For those arguing over languages... The Natural Philosopher <tnp@invalid.invalid> - 2026-02-11 19:28 +0000
        Re: For those arguing over languages... Rich <rich@example.invalid> - 2026-02-11 21:27 +0000
          Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-12 09:48 +0000
            Re: For those arguing over languages... c186282 <c186282@nnada.net> - 2026-02-12 20:48 -0500
      Re: For those arguing over languages... Chris Ahlstrom <OFeem1987@teleworm.us> - 2026-02-11 16:24 -0500
        Re: For those arguing over languages... Rich <rich@example.invalid> - 2026-02-11 22:45 +0000
          Re: For those arguing over languages... The Natural Philosopher <tnp@invalid.invalid> - 2026-02-12 12:42 +0000
      Re: For those arguing over languages... "Carlos E. R." <robin_listas@es.invalid> - 2026-02-11 23:24 +0100
        Re: For those arguing over languages... Lawrence D’Oliveiro <ldo@nz.invalid> - 2026-02-11 22:48 +0000
        Re: For those arguing over languages... Rich <rich@example.invalid> - 2026-02-11 22:49 +0000
        Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-12 09:55 +0000
          Re: For those arguing over languages... "Carlos E. R." <robin_listas@es.invalid> - 2026-02-12 11:49 +0100
          Re: For those arguing over languages... c186282 <c186282@nnada.net> - 2026-02-12 20:54 -0500
            Re: For those arguing over languages... Rich <rich@example.invalid> - 2026-02-13 03:20 +0000
              Re: For those arguing over languages... c186282 <c186282@nnada.net> - 2026-02-12 23:44 -0500
        Re: For those arguing over languages... The Natural Philosopher <tnp@invalid.invalid> - 2026-02-12 12:38 +0000
          Re: For those arguing over languages... "Carlos E. R." <robin_listas@es.invalid> - 2026-02-12 15:14 +0100
            Re: For those arguing over languages... Rich <rich@example.invalid> - 2026-02-12 17:23 +0000
              Re: For those arguing over languages... "Carlos E. R." <robin_listas@es.invalid> - 2026-02-12 19:52 +0100
                Re: For those arguing over languages... The Natural Philosopher <tnp@invalid.invalid> - 2026-02-13 10:11 +0000
                Re: For those arguing over languages... Richard Kettlewell <invalid@invalid.invalid> - 2026-02-13 10:20 +0000
            Re: For those arguing over languages... The Natural Philosopher <tnp@invalid.invalid> - 2026-02-13 10:10 +0000
              Re: For those arguing over languages... c186282 <c186282@nnada.net> - 2026-02-13 19:57 -0500
          Re: For those arguing over languages... c186282 <c186282@nnada.net> - 2026-02-12 20:56 -0500

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