Abstract: Mechanisms for stable transitions in the presence of conditionals for an advanced dual-representation polyhedral loop transformation framework are provided. The mechanisms of the illustrative embodiments address the weaknesses of the known polyhedral loop transformation based approaches by providing mechanisms for performing code generation transformations on individual statement instances in an intermediate representation generated by the polyhedral loop transformation optimization of the source code. These code generation transformations have the important property that they do not change program order of the statements in the intermediate representation. This property allows the result of the code generation transformations to be provided back to the polyhedral loop transformation mechanisms in a program statement view, via a new re-entrance path of the illustrative embodiments, for additional optimization.

Abstract: Mechanisms for building approximate data dependences using a moving look-back window are provided. The mechanisms track dependence information for memory accesses over iterations of execution of a portion of code. The mechanisms receive a memory access of an iteration of the portion of code, the memory access having an address for access the memory and an access type indicating at least one of a read or a write access type. An entry in a moving look-back window data structure is generated corresponding to a memory location accessed by the memory access. The entry comprises at least an identification of the address, the access type, and an iteration number corresponding to the iteration of the memory access. The moving look-back window data structure is utilized to determine dependence information for memory accesses over a plurality of iterations of the portion of code.

Abstract: Mechanisms are provided for tracking dependencies of threads in a multi-threaded computer program execution. The mechanisms detect a dependency of a first thread's execution on results of a second thread's execution in an execution flow of the multi-threaded computer program. The mechanisms further store, in a hardware thread dependency vector storage associated with the first thread's execution, an identifier of the dependency by setting at least one bit in the hardware thread dependency vector storage corresponding to the second thread. Moreover, the mechanisms schedule tasks performed by the multi-threaded computer program based on the hardware thread dependency vector storage to minimize squashing of threads.

Abstract: A system and method for domain stretching for an advanced dual-representation polyhedral loop transformation framework are provided. The mechanisms of the illustrative embodiments address the weaknesses of the known polyhedral loop transformation based approaches by providing mechanisms for performing code generation transformations on individual statement instances in an intermediate representation generated by the polyhedral loop transformation optimization of the source code. These code generation transformations have the important property that they do not change program order of the statements in the intermediate representation. This property allows the result of the code generation transformations to be provided back to the polyhedral loop transformation mechanisms in a program statement view, via a new re-entrance path of the illustrative embodiments, for additional optimization.

Abstract: A system and method for advanced polyhedral loop transformations of source code in a compiler are provided. The mechanisms of the illustrative embodiments address the weaknesses of the known polyhedral loop transformation based approaches by providing mechanisms for performing code generation transformations on individual statement instances in an intermediate representation generated by the polyhedral loop transformation optimization of the source code. These code generation transformations have the important property that they do not change program order of the statements in the intermediate representation. This property allows the result of the code generation transformations to be provided back to the polyhedral loop transformation mechanisms in a program statement view, via a new re-entrance path of the illustrative embodiments, for additional optimization.

Abstract: A system and method for stable transitions in the presence of conditionals for an advanced dual-representation polyhedral loop transformation framework are provided. The mechanisms of the illustrative embodiments address the weaknesses of the known polyhedral loop transformation based approaches by providing mechanisms for performing code generation transformations on individual statement instances in an intermediate representation generated by the polyhedral loop transformation optimization of the source code. These code generation transformations have the important property that they do not change program order of the statements in the intermediate representation. This property allows the result of the code generation transformations to be provided back to the polyhedral loop transformation mechanisms in a program statement view, via a new re-entrance path of the illustrative embodiments, for additional optimization.

Abstract: A system and method for selective code generation optimization for an advanced dual-representation polyhedral loop transformation framework are provided. The mechanisms of the illustrative embodiments address the weaknesses of the known polyhedral loop transformation based approaches by providing mechanisms for performing code generation transformations on individual statement instances in an intermediate representation generated by the polyhedral loop transformation optimization of the source code. These code generation transformations have the important property that they do not change program order of the statements in the intermediate representation. This property allows the result of the code generation transformations to be provided back to the polyhedral loop transformation mechanisms in a program statement view, via a new re-entrance path of the illustrative embodiments, for additional optimization.

Abstract: Removal of invariant branches from nests of loops results in an optimized computer program with increased speed of execution. To accomplish this objective, each loop of a program is then examined, looking at inner loops before their containing outer loops, to locate conditional branch instructions which are loop invariant. Each conditional branch which is evaluated based upon loop invariant calculations is rewritten, outside the outermost loop for which this branch is invariant. The moved branch is modified to branch around the loop in which it was originally contained if its condition is evaluated false. A new copy of the loop is made in which the invariant branch is rewritten as an unconditional branch. In the original copy of the loop, the invariant branch is deleted, and a branch is inserted after the modified original loop to skip around the new copy when the original copy is executed.