Miscompilation: missing assignment in function that might throw

Miscompilation: missing assignment in function that might throw

[Brian Green]

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I was unable to create an account in the gcc bugzilla, so I am trying to
report this here.

The following code should always exit with "5". Starting in g++ 12.1, it
will exit with "5" at "-O0" and with random garbage at "-O1" or "-O2".

https://godbolt.org/z/T3qTnheYW

struct Int {
  int value;
};

__attribute__((noipa)) Int always_throws() { throw 123; }

void foo(Int &x) {
  try {
    x = always_throws();
  } catch (...) {
  }
}

int main() {
  Int x;
  x.value = 5;
  foo(x);
  return x.value;
}

Re: Miscompilation: missing assignment in function that might throw

[Jonathan Wakely]

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On Wed, 30 Aug 2023, 18:39 Brian Green via Gcc-help, <gcc-help@gcc.gnu.org>
wrote:

> I was unable to create an account in the gcc bugzilla, so I am trying to
> report this here.
>

Please don't report bugs here. Did you send an email to get an account
created, as bugzilla says to do? Because I don't see any request from you.



> The following code should always exit with "5". Starting in g++ 12.1, it
> will exit with "5" at "-O0" and with random garbage at "-O1" or "-O2".
>
> https://godbolt.org/z/T3qTnheYW
>
> struct Int {
>   int value;
> };
>
> __attribute__((noipa)) Int always_throws() { throw 123; }
>
> void foo(Int &x) {
>   try {
>     x = always_throws();
>   } catch (...) {
>   }
> }
>
> int main() {
>   Int x;
>   x.value = 5;
>   foo(x);
>   return x.value;
> }
>

Re: Miscompilation: missing assignment in function that might throw

[Jonathan Wakely]

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On Wed, 30 Aug 2023, 20:23 Jonathan Wakely, <jwakely.gcc@gmail.com> wrote:

>
>
> On Wed, 30 Aug 2023, 18:39 Brian Green via Gcc-help, <gcc-help@gcc.gnu.org>
> wrote:
>
>> I was unable to create an account in the gcc bugzilla, so I am trying to
>> report this here.
>>
>
> Please don't report bugs here. Did you send an email to get an account
> created, as bugzilla says to do? Because I don't see any request from you.
>

Gah, it was in my spam folder, sorry. I'll get the account created now...




>
>
>> The following code should always exit with "5". Starting in g++ 12.1, it
>> will exit with "5" at "-O0" and with random garbage at "-O1" or "-O2".
>>
>> https://godbolt.org/z/T3qTnheYW
>>
>> struct Int {
>>   int value;
>> };
>>
>> __attribute__((noipa)) Int always_throws() { throw 123; }
>>
>> void foo(Int &x) {
>>   try {
>>     x = always_throws();
>>   } catch (...) {
>>   }
>> }
>>
>> int main() {
>>   Int x;
>>   x.value = 5;
>>   foo(x);
>>   return x.value;
>> }
>>
>