[Bug c++/54710] New: moderately large tuple, with many gets, ballons compile time

[cppljevans at suddenlink dot net]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54710

             Bug #: 54710
           Summary: moderately large tuple, with many gets, ballons
                    compile time
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: cppljevans@suddenlink.net


Created attachment 28274
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28274
zip file containing source code, make files, make output, timing output

Using a multiple inheritance tuple implementation, and with many gets
to elements of tuple, compile time ballons from:
  0.5 * the compile time using clang

to:

  3.4 * the compile time using clang

when tuple size is 20.

The attached include a make file (suffix .mk) and the test driver
(suffix .cpp).  The time results are in the .txt files.
The time results show that as macro value LAST_LESS goes from
4 to 20, g++ compiles faster than clang, but as LAST_LESS
approaches TUPLE_SIZE, g++ slows down dramatically.

Could g++ be enhanced so that the compile times do no
increase so dramatically?

-regards,
Larry