O

object files

compile only, 3.4.7 –c

name, 3.4.72 –o name

object library search directories, 3.4.49 –Lpath

obsolete command-line options, 3.3.4 Obsolete Option Flags

octal, 4.2.1.2 Alternate Forms of Boolean Constants

one-trip DO loops, 3.4.73 –onetrip

OpenMP, 2.3.2.1 OpenMP Parallelization Directives

directives summary, C.3 Fortran OpenMP Directives

OPT directive, 2.3.1.5 The OPT Directive

-xmaxopt option, 3.4.146 –xmaxopt[=n]

optimization

across source files

3.4.119 –xcrossfile[={1|0}]

3.4.131 –xipo[={0|1|2}]

aliasing, 3.4.108 –xalias[=keywords]

floating-point, 3.4.35 –fsimple[={1|2|0}]

inline user-written routines, 3.4.44 –inline=[%auto][[,][no%]f1,…[no%]fn]

interprocedural, 3.4.131 –xipo[={0|1|2}]

levels, 3.4.65 –O[n]

link-time, 3.4.144 –xlinkopt[={1|2|0}]

loop unrolling, 3.4.99 –unroll=n

loop unrolling by directive, 2.3.1.3 The UNROLL Directive

math library, 3.4.141 –xlibmopt

OPT directive

2.3.1.5 The OPT Directive

3.4.146 –xmaxopt[=n]

PIPELOOP directive, 2.3.1.6 The PIPELOOP[=n] Directive

PREFETCH directive, 2.3.1.7 The PREFETCH Directives

specify cache, 3.4.114 –xcache=c

specify instruction set architecture, 3.4.110 –xarch=isa

specify processor, 3.4.116 –xchip=c

target hardware, 3.4.57 –native

vector library transformations with -xvector, 3.4.179 –xvector[= [[no%]lib, [no%]simd, %none] ]

with -fast, 3.4.24 –fast

with debugging, 3.4.39 –g

options, See command-line options

order of, functions, 3.4.122 –xF

order of processing, options, 3.2 Options Syntax

overflow

stack, 3.4.91 –stackvar

trap on floating-point, 3.4.37 –ftrap=t

overindexing, aliasing, 3.4.108 –xalias[=keywords]