you can use:
__declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;
This will select the high performance GPU as long as no profile exists that assigns the application to another GPU.
Please make sure to use a 13.35 or newer driver. Older drivers do not support this.
We tested it out (with the 14.12 driver), and it works as expected. Thanks!
I cross-posted your answer to the related forum question (Force high performance GPU programmatically on Switchable Graphics) and also on StackOverflow (gpu - AMD equivalent to NvOptimusEnablement - Stack Overflow).