Hewlett-packard Company

Daryl K Odnert

Vatsa Santhanam

Dale Calvin Morris

William R Bryg

Jerome C Huck

Ruby B Lee

Stephen G Burger

Michael J Mahon

Vivek S Pendharkar

Optimization techniques are implemented by means of a program analyzer used in connection with a program compiler to optimize usage of limited register resources in a computer processor. The first optimization technique, called interprocedural global variable promotion allows the global variables of a program to be accessed in common registers across a plurality of procedures. Moreover, a single common register can be used for different global variables in distinct regions of a program call graph. This is realized by identifying subgraphs, of the program call graph, called webs, where the variable is used. The second optimization technique, called spill code motion, involves the identification of regions of the call graph, called clusters, that facilitate the movement of spill instructions to procedures which are executed relatively less often. This decreases the overhead of register saves and restores which must be executed for procedure calls.

Method and apparatus for compiling computer programs with

A method for operating a digital computer in response to the occurrence of an exception is disclosed. The method provides for the examination both of the contents of a predetermined computer location and of the instruction code for the instruction causing the exception. The computer then utilizes the result of those examinations to determine the dismissibility of the exception. The computer transfers control to the next instruction after the instruction which caused the exception if that instruction is dismissible.

Software method for implementing dismissible instructions on a computer

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Palo Alto, CA, United States of America

Daryl K Odnert