[Bug c++/55986] RHS of logical operators may render LHS unevaluated in constant-expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55986 Andrew Pinski changed: What|Removed |Added Resolution|--- |FIXED Keywords||accepts-invalid Target Milestone|--- |6.0 Status|UNCONFIRMED |RESOLVED --- Comment #6 from Andrew Pinski --- Fixed in GCC 6 with r6-4886 (note this is expected because we delay simplifications until after semantics anlysis now).
[Bug c++/55986] RHS of logical operators may render LHS unevaluated in constant-expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55986
--- Comment #5 from Shafik Yaghmour ---
It looks like this case from this Stackoverflow question
http://stackoverflow.com/q/32920229/1708801 is possibly related:
int main(int argc, char**)
{
constexpr int a = argc * 0;
}
gcc treats `argc * 0` as a constant expression a comment indicates this is due
to constant folding and it seems possible that gcc is constant folding `i ||
true` as well.
[Bug c++/55986] RHS of logical operators may render LHS unevaluated in constant-expression
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55986 Shafik Yaghmour yaghmour.shafik at gmail dot com changed: What|Removed |Added CC||yaghmour.shafik at gmail dot com --- Comment #4 from Shafik Yaghmour yaghmour.shafik at gmail dot com --- This issue showed up recently in this Stackoverflow question: http://stackoverflow.com/q/31526278/1708801 As far as I can tell there should at least be a diagnostic when using -pedantic
[Bug c++/55986] RHS of logical operators may render LHS unevaluated in constant-expression
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55986 --- Comment #3 from David Krauss potswa at mac dot com 2013-01-15 08:02:55 UTC --- Likewise this is allowed: switch( 0 ) case i-i: ; I think this is a purposeful language extension, which could use a switch to disable. It would be nice if static_assert were always strict.
[Bug c++/55986] RHS of logical operators may render LHS unevaluated in constant-expression
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55986 --- Comment #1 from David Krauss potswa at mac dot com 2013-01-15 04:47:53 UTC --- Passing `-O2` additionally causes it to skip a condition like `(i == 0 || i != 0)`, so it looks like a general issue with expression simplification bypassing ODR-use.
[Bug c++/55986] RHS of logical operators may render LHS unevaluated in constant-expression
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55986 --- Comment #2 from David Krauss potswa at mac dot com 2013-01-15 04:48:47 UTC --- Passing `-O2` additionally causes it to skip a condition like `(i == 0 || i != 0)`, so it looks like a general issue with expression simplification bypassing use.
