Intel Corporation

Intle Corporation

Jayashankar Bharadwaj

Sara S Baghsorkhi

Albert Hartono

Nalini Vasudevan

Victor W Lee

Daehyun Kim

Tin-Fook Ngai

Robert Valentine

Mark Jay Charney

Christopher J Hughes

Ali-Reza Adl-Tabatabai

Milind Baburao Girkar

Tatiana Shpeisman

Ravi Narayanaswamy

Chris M McKinsey

Kim Daehyun

Christopher M McKinsey

Methods and systems to convert a scalar computer program loop having loop-carried dependences into a vector computer program loop are disclosed. One such method includes, at runtime, identifying, by executing an instruction with one or more processors, a first loop iteration that cannot be executed in parallel with a second loop iteration due to a set of conflicting scalar loop operations. The first loop iteration is executed after the second loop iteration. The method also includes sectioning, by executing an instruction with one or more processors, a vector loop into vector partitions including a first vector partition. The first vector partition executes consecutive loop iterations in parallel and the consecutive loop iterations start at the second loop iteration and end before the first loop iteration.

Methods and systems to vectorize scalar computer program loops having loop-carried dependences

Embodiments of systems, apparatuses, and methods for performing in a computer processor generation of a predicate mask based on vector comparison in response to a single instruction are described.

Systems, apparatuses, and methods for setting an output mask in a destination writemask register from a source write mask register using an input writemask and immediate

A vector reduction instruction with non-unit strided access pattern is received and executed by the execution circuitry of a processor. In response to the instruction, the execution circuitry performs an associative reduction operation on data elements of a first vector register. Based on values of the mask register and a current element position being processed, the execution circuitry sequentially sets one or more data elements of the first vector register to a result, which is generated by the associative reduction operation applied to both a previous data element of the first vector register and a data clement of a third vector register. The previous data element is located more than one element position away from the current element position.

Instruction to reduce elements in a vector register with strided access pattern

Loop vectorization methods and apparatus are disclosed. An example method includes prior to executing an original loop having iterations, analyzing, via a processor, the iterations of the original loop, identifying a dependency between a first one of the iterations of the original loop and a second one of the iterations of the original loop, after identifying the dependency, vectorizing a first group of the iterations of the original loop based on the identified dependency to form a vectorization loop, and setting a dynamic adjustment value of the vectorization loop based on the identified dependency.

Loop vectorization methods and apparatus

Embodiments of systems, apparatuses, and methods of performing in a computer processor dependency index vector calculation in response to an instruction that includes a first and second source writemask register operands, a destination vector register operand, and an opcode are described.

Systems, apparatuses, and methods for generating a dependency vector based on two source writemask registers

An apparatus and method for propagating conditionally evaluated values are disclosed. For example, a method according to one embodiment comprises: reading each value contained in an input mask register, each value being a true value or a false value and having a bit position associated therewith; for each true value read from the input mask register, generating a first result containing the bit position of the true value; for each false value read from the input mask register following the first true value, adding the vector length of the input mask register to a bit position of the last true value read from the input mask register to generate a second result; and storing each of the first results and second results in bit positions of an output register corresponding to the bit positions read from the input mask register.

Apparatus and method for propagating conditionally evaluated values in SIMD/vector execution using an input mask register

Methods and systems to convert a scalar computer program loop having loop-carried dependences into a vector computer program loop are disclosed. One such method includes, replacing the scalar recurrence operation in the scalar computer program loop with a first vector summing operation and a first vector recurrence operation. The first vector summing operation is to generate a first running sum and the first vector recurrence operation is to generate a first vector. In some examples, the first vector recurrence operation is based on the scalar recurrence operation. Disclosed methods also include inserting: 1) a renaming operation to rename the first vector, 2) a second vector summing operation that is to generate a second running sum; and 3) a second vector recurrence operation to generate a second vector based on the renamed first vector.

An apparatus and method are described for detecting and responding to fault conditions in a processor. For example, one embodiment of a method comprises: reading each active element in succession from a first vector register, each active element specifying an address for a gather or load operation; detecting one or more fault conditions associated with one or more of the active elements; for each active element read in succession prior to a detected fault condition on an element other than the first active element, storing the data loaded from an address associated with the active element in a first output vector register; and for each active element associated with the detected fault condition and following the detected fault condition, setting a bit in an output mask register to indicate the detected fault condition.

Apparatus and method for vectorization with speculation support

Methods and systems to convert scalar computer program loops having loop carried dependences to vector computer program loops are disclosed. One example method and system generates a first predicate set associated with a first conditionally executed statement. The first predicate set contains a first set of predicates that cause a variable to be defined in a scalar computer program loop at or before the variable is defined by the first conditionally executed statement. The method and system also generates a second predicate set associated with the first conditionally executed statement. The second predicate set contains a second set of predicates that cause the variable to be used in the scalar computer program loop at or before the variable is defined by the first conditionally executed statement. The method and system determines whether the second predicate set is a subset of the first predicate set and, based on the determination, propagates a vector value in an element of a vector of the variable to a subsequent element of the vector.

Loop vectorization methods and apparatus are disclosed. An example method includes setting a dynamic adjustment value of a vectorization loop; executing the vectorization loop to vectorize a loop by grouping iterations of the loop into one or more vectors; identifying a dependency between iterations of the loop as; and setting the dynamic adjustment value based on the identified dependency.

According to one embodiment, a processor includes an instruction decoder to decode an instruction to read a plurality of data elements from memory, the instruction having a first operand specifying a storage location, a second operand specifying a bitmask having one or more bits, each bit corresponding to one of the data elements, and a third operand specifying a memory address storing a plurality of data elements. The processor further includes an execution unit coupled to the instruction decoder, in response to the instruction, to read one or more data elements speculatively, based on the bitmask specified by the second operand, from a memory location based on the memory address indicated by the third operand, and to store the one or more data elements in the storage location indicated by the first operand.

Speculative non-faulting loads and gathers

A method and apparatus for a read barrier mechanism are described. According to an embodiment, a method comprises receiving an access request for a program object; performing a combined check for a null reference or for a read barrier for the program object; and if the combined check is affirmative, performing a recovery operation.

Program object read barrier

The present disclosure relates to the allocation of registers the scheduling of instructions, and, more specifically, to the classifying of operands and allocation of registers to local operands.

Growing community of inventors

Saratoga, CA, United States of America

Jayashankar Bharadwaj