[Bug middle-end/114391] catch() and immediate throw; could be optimized to noop

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114391

Andrew Pinski  changed:

   What|Removed |Added

   Severity|normal  |enhancement
 CC||pinskia at gcc dot gnu.org

[Bug middle-end/114391] catch() and immediate throw; could be optimized to noop

[antoshkka at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114391

--- Comment #2 from Antony Polukhin  ---
> Is there something to optimize when foo() cannot be tail-called?

Yes. Just `catch (...) { throw; }`, no more restrictions. I do not even think,
that it should be the outer most EH region:


void foo();
void bar();

void test() {
try {
foo();
} catch (...) {
throw;
}
bar();
}


is fine to optimize to just


void test() {
foo();
bar();
}

[Bug middle-end/114391] catch() and immediate throw; could be optimized to noop

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114391

Richard Biener  changed:

   What|Removed |Added

   Last reconfirmed||2024-03-19
 Status|UNCONFIRMED |NEW
 Ever confirmed|0   |1

--- Comment #1 from Richard Biener  ---
Is there something to optimize when foo() cannot be tail-called?  IMO that
would be best done separately.  Consider

int foo();

int test() {
try {
return foo() + 1;
} catch (...) {
throw;
}
}

wouldn't it be valid to turn this into

int test() {
  return foo () + 1;
}

so the requirement is that the try {} catch (...) { throw; } is the
outermost EH handling region, nothing more?  And then we can elide it?