https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92597
--- Comment #7 from Klaus Leppkes <leppkes at stce dot rwth-aachen.de> ---
1.) According to Jacob, g++ gives warning: ("Whether this PR is valid or
invalid is unclear, matching constraints for "m" are unsupported, we even warn
on "=m" (...) : "0" (...) which is the reason why "+m" is lowered to "=m" (...)
: "m" (...).").
Which flags to I need to specify to see such warnings? I tried the usual
suspects like -Wall -Wextra...
2.) I see 2 possibilities and how to proceed from here:
a) It's a non consistency in g++, the bug report should be marked as confirmed
and at some point it should be fixed.
b) The behavior is correct, google benchmark needs to be fixed. For now I just
overloaded DoNotOptimize for double and long double lvalues refs with "g"
instead of "m" and it seems to work fine. But I wonder if this effects other
cases, which then needs to be handled for gcc too.
