Abstract: Control flow information and data flow information associated with a program containing a upc_forall loop are built. A shared reference map data structure using the control flow information and the data flow information is created. All local shared accesses are hashed to facilitate a constant access stride after being rewritten. All local shared references in a hash entry having a longest list are privatized. The upc_forall loop is rewritten into a for loop. Responsive to a determination that an unprocessed upc_forall loop does not exist, dead store elimination is run. The control flow information and the data flow information associated with the program containing the for loop is rebuilt.

Abstract: A process for check pointing in speculative execution frameworks, identifies calls to a set of setjmp/longjmp instructions to form identified calls to setjmp/longjmp, determines a control flow path between a call to a setjmp and a longjmp pair of instructions in the identified calls to setjmp/longjmp and replaces calls to the setjmp/longjmp pair of instructions with calls to an improved_setjmp and improved_longjmp instruction pair. The process creates a context data structure in memory, computes a non-volatile save/restore set and replaces the call to improved_setjmp of the setjmp/longjmp pair of instructions with instructions to save all required non-volatile and special purpose registers and replaces a call to improved_longjmp of the setjmp/longjmp pair of instructions with instructions to restore all required non-volatile and special purpose registers and to branch to an instruction immediately following a block of code containing the call to improved_setjmp.

Abstract: Optimizing program code in a static compiler by determining the live ranges of variables and determining which live ranges are candidates for moving code from the use site to the definition site of source code. Live ranges for variables in a flow graph are determined. Selected live ranges are determined as candidates in which code will be moved from a use site within the source code to a definition site within the source code. Optimization opportunities within the source code are identified based on the code motion.

Abstract: Control flow information and data flow information associated with a program containing a upc_forall loop are built. A shared reference map data structure using the control flow information and the data flow information is created. All local shared accesses are hashed to facilitate a constant access stride after being rewritten. All local shared references in a hash entry having a longest list are privatized. The upc_forall loop is rewritten into a for loop. Responsive to a determination that an unprocessed upc_forall loop does not exist, dead store elimination is run. The control flow information and the data flow information associated with the program containing the for loop is rebuilt.

Abstract: A method and system of auto parallelization of zero-trip loops that substitutes a nested basic linear induction variable by exploiting a parallelizing compiler is provided. Provided is a use of a max{0,N} variable for loop iterations in case of no information is known about the value of N, for a typical loop iterating from 1 to N, in which N is the loop invariant. For the nested basic induction variables, an induction variable substitution process is applied to the nested loops starting from the innermost loop to the outermost one. Then a removal of the max operator afterwards through a copy propagation pass of the IBM compiler is provided. In doing so, the loop dependency on the induction variable is eliminated and an opportunity for a parallelizing compiler to parallel the outermost loop is provided.

Abstract: Computer implemented method, system and computer usable program code for cache management. A cache is provided, wherein the cache is viewed as a sorted array of data elements, wherein a top position of the array is a most recently used position of the array and a bottom position of the array is a least recently used position of the array. A memory access sequence is provided, and a training operation is performed with respect to a memory access of the memory access sequence to determine a type of memory access operation to be performed with respect to the memory access. Responsive to a result of the training operation, a cache replacement operation is performed using the determined memory access operation with respect to the memory access.

Abstract: A computer implemented method for facilitating debugging of source code. The source code is scanned to identify a candidate region. A procedure control descriptor is generated, wherein the procedure control descriptor corresponds to the candidate region. The procedure control descriptor identifies, for the candidate region, a condition which, if true at runtime means that the candidate region can be specialized. Responsive to a determination during compile time that satisfaction of at least one condition will be known only at runtime, the procedure control descriptor is used to specialize the candidate region at compile time to create a first version of the candidate region for execution in a case where the condition is true and a second version of the candidate region for execution in a case where the condition is false, and further generate code to correctly select one of the first region and the second region at runtime.

Abstract: A method of compiling source code. The method includes converting pointer-based access in the source code to array-based access in the source code in a first pass compilation of the source code. Information is collected for objects in the source code during the first pass compilation. Candidate objects in the source code are selected based on the collected information to form selected candidate objects. Global stride variables are created for the selected candidate objects. Memory allocation operations are updated for the selected candidate objects in a second pass compilation of the source code. Multiple-level pointer indirect references are replaced in the source code with multi-dimensional array indexed references for the selected candidate objects in the second pass compilation of the source code.

Abstract: Inter-procedural strength reduction is provided by a mechanism of the present invention to optimize software program. During a forward pass, the present invention collects information of global variables and analyzes the information to select candidate computations for optimization. During a backward pass, the present invention replaces costly computations with less costly or weaker computations using pre-computed values and inserts store operations of new global variables to pre-compute the costly computations at definition points of the global variables used in the costly computations.

Abstract: A mechanism for folding all the data dependencies in a loop into a single, conservative dependence. This mechanism leads to one pair of synchronization primitives per loop. This mechanism does not require complicated, multi-stage compile time analysis. This mechanism considers only the data dependence information in the loop. The low synchronization cost balances the loss in parallelism due to the reduced overlap between iterations. Additionally, a novel scheme is presented to implement required synchronization to enforce data dependences in a DOACROSS loop. The synchronization is based on an iteration vector, which identifies a spatial position in the iteration space of the loop. Multiple iterations executing in parallel have their own iteration vector for synchronization where they update their position in the iteration space. As no sequential updates to the synchronization variable exist, this method exploits a greater degree of parallelism.

Abstract: A computer implemented method, computer usable program code, and a system for parallelizing a loop. A parameter that will be used to limit parallelization of the loop is identified to limit parallelization of the loop. The parameter specifies a minimum number of loop iterations that a thread should execute. The parameter can be adjusted based on a parallel performance factor. A parallel performance factor is a factor that influences the performance of parallel code. A number of threads from a plurality of threads is selected for processing iterations of the loop based on the parameter. The number of threads is selected prior to execution of the first iteration of the loop.

Abstract: A process for check pointing in speculative execution frameworks, identifies calls to a set of setjmp/longjmp instructions to form identified calls to setjmp/longjmp, determines a control flow path between a call to a setjmp and a longjmp pair of instructions in the identified calls to setjmp/longjmp and replaces calls to the setjmp/longjmp pair of instructions with calls to an improved_setjmp and improved_longjmp instruction pair. The process creates a context data structure in memory, computes a non-volatile save/restore set and replaces the call to improved_setjmp of the setjmp/longjmp pair of instructions with instructions to save all required non-volatile and special purpose registers and replaces a call to improved_longjmp of the setjmp/longjmp pair of instructions with instructions to restore all required non-volatile and special purpose registers and to branch to an instruction immediately following a block of code containing the call to improved_setjmp.

Abstract: A computer implemented method, system, and computer usable program code for simplifying compiler-generated software code by creating a stub routine for checking storage contiguity. A stub routine is generated for a subroutine. The stub routine is used to determine whether data is contiguous for the subroutine. A subroutine call in the code is replaced with a stub routine call for the stub routine. The subroutine call has at least one argument. The stub routine call includes each argument for the subroutine call. The code is executed. The stub routine is called by the stub routine call to determine whether data is contiguous for the subroutine.

Abstract: Optimizing program code in a static compiler by determining the live ranges of variables and determining which live ranges are candidates for moving code from the use site to the definition site of source code. Live ranges for variables in a flow graph are determined. Selected live ranges are determined as candidates in which code will be moved from a use site within the source code to a definition site within the source code. Optimization opportunities within the source code are identified based on the code motion.

Abstract: Computer implemented method, system and computer usable program code for cache management. A cache is provided, wherein the cache is viewed as a sorted array of data elements, wherein a top position of the array is a most recently used position of the array and a bottom position of the array is a least recently used position of the array. A memory access sequence is provided, and a training operation is performed with respect to a memory access of the memory access sequence to determine a type of memory access operation to be performed with respect to the memory access. Responsive to a result of the training operation, a cache replacement operation is performed using the determined memory access operation with respect to the memory access.

Abstract: Inter-procedural strength reduction is provided by a mechanism of the present invention to improve data cache performance. During a forward pass, the present invention collects information of global variables and analyzes the usage pattern of global objects to select candidate computations for optimization. During a backward pass, the present invention remaps global objects into smaller size new global objects and generates more cache efficient code by replacing candidate computations with indirect or indexed reference of smaller global objects and inserting store operations to the new global objects for each computation that references the candidate global objects.

Abstract: A method and system of auto parallelization of zero-trip loops that substitutes a nested basic linear induction variable by exploiting a parallelizing compiler is provided. Provided is a use of a max{0,N} variable for loop iterations in case of no information is known about the value of N, for a typical loop iterating from 1 to N, in which N is the loop invariant. For the nested basic induction variables, an induction variable substitution process is applied to the nested loops starting from the innermost loop to the outermost one. Then a removal of the max operator afterwards through a copy propagation pass of the IBM compiler is provided. In doing so, the loop dependency on the induction variable is eliminated and an opportunity for a parallelizing compiler to parallel the outermost loop is provided.

Abstract: Inter-procedural strength reduction is provided by a mechanism of the present invention to optimize software program. During a forward pass, the present invention collects information of global variables and analyzes the information to select candidate computations for optimization. During a backward pass, the present invention replaces costly computations with less costly or weaker computations using pre-computed values and inserts store operations of new global variables to pre-compute the costly computations at definition points of the global variables used in the costly computations.

Abstract: A mechanism for folding all the data dependencies in a loop into a single, conservative dependence. This mechanism leads to one pair of synchronization primitives per loop. This mechanism does not require complicated, multi-stage compile time analysis. This mechanism considers only the data dependence information in the loop. The low synchronization cost balances the loss in parallelism due to the reduced overlap between iterations. Additionally, a novel scheme is presented to implement required synchronization to enforce data dependences in a DOACROSS loop. The synchronization is based on an iteration vector, which identifies a spatial position in the iteration space of the loop. Multiple iterations executing in parallel have their own iteration vector for synchronization where they update their position in the iteration space. As no sequential updates to the synchronization variable exist, this method exploits a greater degree of parallelism.

Abstract: A method, system and apparatus for barrier synchronization using distributed counters and a centralized sensor. The system can include multiple distributed counters coupled to corresponding application processes in a computing application. The barrier synchronization system further can include a centralized sensor coupled for observation by the application processes. Preferably, the application processes can be separate threads of execution in the computing application. The barrier synchronization centralized sensor yet further can be managed by a designated master one of the application processes. Moreover, preferably the system further can include a backup sensor coupled for observation by the application processes and managed by the designated master one of the application processes.