100x -O0 Compile Time Regression {3.2,3.3} -> {3.4,3.5}

[Zack Weinberg]

John Vickers <John@xza5.com> writes:

> Hello.
>
> We've got some generated C++ which compiles in about 10s (on a P4
> 2800) at -O0 with gcc-3.2 or 3.3.2, but takes about 1000s with 3.4.0
> or 3.5.0.  -ftime-report says that the parser time has gone from
> 8.04s (gcc-3.3.2) to 958.19s (gcc-3.4.0)

The most efficient way to track this down is probably to apply a
function-level profiler (oprofile is convenient as it doesn't require
recompiling anything; gprof also works; I can supply instructions for
building the compiler with gprof instrumentation if you like)

> Any suggestions as to where to start digging ?  I can supply
> preprocessed source to anyone interested.

Please file a bug report and attach the preprocessed source to that.

zw