[Bug c++/41997] New: constant initializer_list not optimised

[chris at bubblescope dot net]

In C++0x, constant initializer_lists do not seem visible to the optimiser,
leading to sub-optimal code. Consider as a simple example:

#include <initializer_list>

int max_val(std::initializer_list<int> il)
{
        int i = *(il.begin());
        int j = *(il.begin() + 1);
        return (i > j ? i : j);
}

int main(void)
{
        return max_val({1,2});
}

I would expect 'main' to be reduced to just '2' at a suitable optimisation
level. At -O3 the body max_val is inlined the values {1,2} are not. Is there
some reason constant initalizer_lists cannot be made visible to optimisation?


-- 
           Summary: constant initializer_list not optimised
           Product: gcc
           Version: 4.5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: chris at bubblescope dot net
  GCC host triplet: i686-apple-darwin10


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41997