1. In a vector computer system having a plurality of processors connected to memory, wherein the memory includes one or more vector atomic memory operation (AMO) functional units and the processors include one or more vector functional units, a method of vectorizing an iterative loop, the method comprising: scanning program code, wherein scanning includes determining whether an operation is vectorizable; if an operation is vectorizable, determining whether the operation should be executed using a vector AMO instruction in one of the vector AMO functional units; if an operation is vectorizable and the operation should be executed using a vector AMO instruction in one of the vector AMO functional units, implement at least a portion of the operation as a vector AMO instruction; and if an operation is vectorizable and the operation should not be executed using a vector AMO instruction in one of the vector AMO functional units, implement at least a portion of the operation to execute in one or more vector functional units of one or more processors.