Re: Correct way to express to the compiler "this does not get clobbered"?

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To: Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx>
Subject: Re: Correct way to express to the compiler "this does not get clobbered"?
From: Andrea Corallo via Gcc-help <gcc-help@xxxxxxxxxxx>
Date: Fri, 04 Dec 2020 19:16:45 +0100
Cc: stefan@xxxxxxxxx, gcc-help@xxxxxxxxxxx
In-reply-to: <20201204172721.GM2672@gate.crashing.org> (Segher Boessenkool's message of "Fri, 4 Dec 2020 11:27:21 -0600")
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Reply-to: Andrea Corallo <andrea.corallo@xxxxxxx>
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Segher Boessenkool <segher@xxxxxxxxxxxxxxxxxxx> writes:

> On Fri, Dec 04, 2020 at 10:52:17AM +0100, Andrea Corallo via Gcc-help wrote:
>> stefan@xxxxxxxxx writes:
>> I might open a bug but my understanding is that const is generally
>> not used for optimizations.  Am I wrong?
>
> extern const int x = 42;
> int f(void) { return x; }
>
> The code generated for f does not load the value for x from memory: it
> returns 42 always.

Hi Segher,

Are you suggesting we should treat this as a bug?

  Andrea

Follow-Ups:
- Re: Correct way to express to the compiler "this does not get clobbered"?
  - From: Segher Boessenkool

References:
- Correct way to express to the compiler "this does not get clobbered"?
  - From: Andrea Corallo via Gcc-help
- Re: Correct way to express to the compiler "this does not get clobbered"?
  - From: David Brown
- Re: Correct way to express to the compiler "this does not get clobbered"?
  - From: Andrea Corallo via Gcc-help
- Re: Correct way to express to the compiler "this does not get clobbered"?
  - From: stefan
- Re: Correct way to express to the compiler "this does not get clobbered"?
  - From: Andrea Corallo via Gcc-help
- Re: Correct way to express to the compiler "this does not get clobbered"?
  - From: Segher Boessenkool

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