Supporting Function Variants in OpenMP.

Although the OpenMP API is supported across a wide and diverse set of architectures, different models of programming -and in extreme cases, different programs altogether -may be required to achieve high levels of performance on different platforms. We reduce the complexity of maintaining multiple implementations through a proposed extension to the OpenMP API that enables developers to specify that different code paths should be executed under certain compile-time conditions, including properties of: active OpenMP constructs; the targeted device; and available OpenMP runtime extensions. Our proposal directly addresses the complexities of modern applications, allowing for OpenMP contextual information to be passed across function call boundaries, translation units and library interfaces. This can greatly simplify the task of developing and maintaining a code with specializations that address performance for distinct platforms and environments.