[Mingw-users] Known performance bottlenecks on C++ applications?

[Óscar F. <of...@wa...>]

On a CPU-intensive C++ application, I found a 3x slowdown on executables
compiled with MinGW compared with Visual Studio.

It is not the core compiler, because the same g++ version on Linux does
a job as good as VS, if not better. It is not exception handling code
either, because disabling exceptions makes just a bit of a difference.
Finally, I also discarded memory handling as a cause. There is no
multithreading nor any OS-intensive work.

The C++ application is a JIT compiler. The compilation part is slower
than VC by a 1.1 factor. That is acceptable. But while executing the
generated bytecode the slowdown factor is larger than 3. The compiler
creates an array of funcion pointers and the interpreter just walks the
array calling those functions. Each function does a fairly simple job
(like "take 2 numbers from the stack, add them and put the result on the
stack".)

The obvious suspect is some Windows-specific compiler intrinsic that
could be implemented on a suboptimal way.

Which areas are known to be performance sinks?