Abstract: Calling a function may include: determining whether a call is a direct or an indirect call. In response to determining that the call is an indirect call, a first address stored in a function pointer may be obtained, wherein the function pointer is stored at a first address in a stack frame of a calling function. Whether to execute a nested function call code sequence may be determined based on whether a tag bit in the first address stored in the function pointer is set. In response to determining that the tag bit in the first address is set, a second address stored at a nested function address location may be obtained, wherein the nested function address location is at the first address, and control may be transferred to a called function, wherein the called function is stored at the second address.

Abstract: Systems, methods and computer products for compiler support for aggressive safe load speculation. Exemplary embodiments include a method for aggressive safe load speculation for a compiler in a computer system, the method including building a control flow graph, identifying both countable and non-countable loops, gathering a set of candidate loops for load speculation, and for each candidate loop in the set of candidate loops gathered for load speculation, computing an estimate of the iteration count, delay cycles, and code size, performing a profitability analysis and determining an unroll factor based on the delay cycles and the code size, transforming the loop by generating a prologue loop to achieve data alignment and an unrolled main loop with loop directives, indicating which loads can safely be executed speculatively and performing low-level instruction scheduling on the generated unrolled main loop.

Abstract: Systems, methods and computer products for compiler support for aggressive safe load speculation. Exemplary embodiments include a method for aggressive safe load speculation for a compiler in a computer system, the method including building a control flow graph, identifying both countable and non-countable loops, gathering a set of candidate loops for load speculation, for each candidate loop in the set of candidate loops gathered for load speculation performing computing an estimate of the iteration count, delay cycles, and code size, performing a profitability analysis and determine an unroll factor based on the delay cycles and the code size, transforming the loop by generating a prologue loop to achieve data alignment and an unrolled main loop with loop directives, indicating which loads can safely be executed speculatively and performing low-level instruction on the generated unrolled main loop.