Chapter 4 Standard optimization features

This chapter discusses the standard optimization features available with the HP-UX compilers, including those inherent in optimization levels +O0 through +O2. This includes a discussion of the following topics:

“Constant folding”
“Partial evaluation of test conditions”
“Simple register assignment”
“Data alignment on natural boundaries”
“Branch optimization”
“Dead code elimination”
“Faster register allocation”
“Instruction scheduling”
“Peephole optimizations”
“Advanced constant folding and propagation”
“Common subexpression elimination”
“Global register allocation (GRA)”
“Loop-invariant code motion”, and unrolling
“Register reassociation”
“Software pipelining”
“Strength reduction of induction variables
and constants”
“Store and copy optimization”
“Unused definition elimination”

For more information as to specific command-line options, pragmas and directives for optimization, please see Chapter 7 “Controlling optimization”.

Chapter 4 Standard optimization features

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