Intel® C++ Compiler 16.0 User and Reference Guide
This topic only applies to Intel® 64 and IA-32 architectures targeting Intel® Graphics Technology.
The compiler supports several syntax forms to express vector reductions in the target code:
#pragma simd reduction
built-in reduction functions for Intel® Cilk™ Plus array notation, such as __sec_reduce_add or __sec_reduce_all_zero
some reduction loop patterns
In these cases, the compiler tries to generate a code sequence optimized for the target.