FLAG DESCRIPTIONS
SUN C, C++ AND FORTRAN
Forte[tm] Developer 6 update 2, and Forte[tm] Developer 7 Early Access
11/5/01
Compiler Flags
Flag Description
-D Set definition for preprocessor.
-dalign Assume double-type data is double
aligned.
-dn Specify static binding.
-e Accept extended (132 character) input
source lines (FORTRAN).
-fast This is a convenience option for
selecting a set of optimizations for
performance, and it chooses:
o The -native best machine
characteristics option (-xarch=native,
-xchip=native, -xcache=native)
o Optimization level: -xO5
o A set of inline expansion templates
(-libmil)
o The -fsimple=2 option
o The -dalign option
o The -xalias_level=basic option (C
only)
o The -xlibmopt option
o The -xdepend option (FORTRAN only)
o The -xprefetch option (FORTRAN only)
o Options to turn off all trapping
(-fns -ftrap=%none)
-fixed Accept fixed-format input source files
(FORTRAN).
-fns Select non-standard floating point
mode.
This flag causes the nonstandard
floating point mode to be enabled when
a program begins execution. By default,
the nonstandard floating point mode
will not be enabled automatically.
On some SPARC systems, the nonstandard
floating point mode disables "gradual
underflow", causing tiny results to be
flushed to zero rather than producing
subnormal numbers. It also causes
subnormal operands to be silently
replaced by zero. On those SPARC
systems that do not support gradual
underflow and subnormal numbers in
hardware, use of this option can
significantly improve the performance
of some programs.
Warning: When nonstandard mode is
enabled, floating point arithmetic may
produce results that do not con- form
to the requirements of the IEEE 754
standard. See the Numerical Computation
Guide for more information.
-fsimple=0 Permits no simplifying assumptions.
Preserves strict IEEE 754 conformance.
-fsimple=1 With -fsimple=1, the optimizer can
assume the following:
o The IEEE 754 default
rounding/trapping modes do not change
after process initialization.
o Computations producing no visible
result other than potential
floating-point exceptions may be
deleted.
o Computations with Infinity or NaNs as
operands need not propagate NaNs to
their results. For example, x*0 may be
replaced by 0.
o Computations do not depend on sign of
zero.
-fsimple=2 Permits aggressive floating point
optimizations that may cause programs
to produce different numeric results
due to changes in rounding. Even with
-fsimple=2, the optimizer still is not
permitted to introduce a floating point
exception in a program that otherwise
produces none.
-fsimple[=n] Allows the compiler to make simplifying
assumptions concerning floating-point
arithmetic.
-ftrap=t Sets the IEEE 754 trapping mode in
effect at startup.
t is a comma-separated list that
consists of one or more of the
following: %all, %none, common,
[no%]invalid, [no%]overflow,
[no%]underflow, [no%]division,
[no%]inexact.
The default is -ftrap=%none.
This option sets the IEEE 754 trapping
modes that are established at program
initialization. Processing is
left-to-right. The common exceptions,
by definition, are invalid, division by
zero, and overflow.
o %none, the default, turns off all
trapping modes.
Do not use this option for programs
that depend on IEEE standard exception
handling; you can get different
numerical results, premature program
termination, or unexpected SIGFPE
signals.
-libmil Use inline expansion templates for
libm.
-library=iostream Use "classic" (pre 1998 C++ standard)
iostream library
Prior to the C++ standard (1998), there
was one iostream library, what is now
often called "classic" iostreams. The
C++ standard defines a different, but
similar, iostream library, which we
call "standard" iostreams. To get
classic iostreams in standard (default)
mode, you use the option
"-library=iostream".
-ll2amm Library containing chip specific memory
routines.
-lm Link with math library
-lmopt This chooses the math library that is
optimized for speed
-lprism32 Library to enable ISM (4MB page) usage.
-lsunperf Link with the Sun Performance Library
(netlib and SIAM routines)
-native Select native machine characteristics
for optimization.
-Qicache-chbab=1 Turn on optimization to reduce branch
after branch penalty
-Qoption <phase> <flags> Pass flags along to compiler phase:
f90comp Fortran first pass
iropt Global optimizer
cg Code generator
-Qoption cg <flags> See -Wc,<flags> below.
-Qoption cg Control irregular loop prefetching.
-Qlp=1-av=<nav>-t=<nt>-fa=1-fl=1
lp lp=1 turns on the module (default is
on for F90; off for C/C++)
fa fa=1 forces user settings to
override internally computed values.
fl fl=1 forces the optimization to be
turned on for all languages.
t Make <nt> attempts at prefetching.
av Sets the prefetch look ahead to
<nav>.
-Qoption f90comp Enable padding of f90 arrays by n.
-array_pad_rows,<n>
-Qoption f90comp -expansion Enable f90 array expansion.
-qoption f90comp -O3 This reduces the optimization level of
the f90 front/middle end to O3. The
effect is to turn off loop cloning and
unrolling (Note that it has no effect
on cg's loop unrolling).
-Qoption iropt <flags> See -W2,<flags> below.
-Qoption iropt -Adata_access enable optimizations based on data
access patterns
-Qoption iropt -Addint:sf=9 Set memory store operation weight for
loop interchange to 9
-Qoption iropt -Amemopt See -W2,-Amemopt
-Qoption iropt -Ma<n> See -W2,-Ma<n>
-Qoption iropt -Mm<n> See -W2,-Mm<n>
-Qoption iropt -MR Do not inline calls when parameters are
arrays and actual array dimensions and
formal array dimensions are mismatched
-Qoption iropt -Mr<n> See -W2,-Mr<n>
-Qoption iropt -O4+scalarrep disable scalar replacement optimization
-Qoption iropt -Rscalarrep,-MR Same as -Qoption iropt -Rscalarrep plus
-Qoption iropt -MR
-Qoption iropt -whole See -W2,-whole
-stackvar Allocate routine local variables on
stack (FORTRAN).
-W<phase>,<flags> Pass flags along to compiler phase
(2=optimizer, c=code generator)
-W2,-Abopt Enable aggressive optimizations of all
branches.
-W2,-Adata_access Enable optimizations based on data
access patterns.
-W2,-Aheap Allows the compiler to recognize
malloc-like memory allocation
functions.
-W2,-Ainline Perform IPA-based inlining.
-W2,-Aivel:duplicate_loops More aggresive strength reduction by
replicating loops.
-W2,-Amemopt Memory access optimization. This does
whole-program mode inter-procedural
memory access analysis, merges memory
allocations, and performs cache
conscious data layout program
transformations.
-W2,-Amemopt:arrayloc Reconstruct array subscripts during
memory allocation merging and data
layout program transformation
-W2,-Ashort_ldst Convert multiple short memory
operations into single long memory
operations.
-W2,-Aunroll Enables outer-loop unrolling.
-W2,-crit Enable optimization of critical control
paths
-W2,-Ma<n> Enable inlining of routines with frame
size up to n.
-W2,-Mm<n> Maximum module increase limit for
inlining.
-W2,-Mp<n> Procedures with entry counts equal or
greater than n become candidates for
inlining.
-W2,-Mr<n> Maximum code increase due to inlining
is limited to n triples.
-W2,-Ms<n> Maximum level of recursive inlining.
-W2,-Mt<n> The maximum size of a routine body
eligible for inlining is limited to n
triples.
-W2,-O4+restrict_g Assume that different global pointer
variables point to their own memory
locations.
-W2,-reroll=1 Turns on loop rerolling.
-W2,-whole Do whole program optimizations.
-Wc,-Qdepgraph-early_cross_call=1 Enable early cross-call instruction
scheduling.
-Wc,-Qeps:do_spec_load=1 Allow generating speculative load
during EPS.
-Wc,-Qeps:enabled=1 Use enhanced pipeline scheduling(EPS)
and selective scheduling algorithms for
instruction scheduling.
-Wc,-Qeps:rp_filtering_margin=100 Turn off register pressure heuristic in
EPS.
-Wc,-Qgsched-T4 Sets the aggressiveness of the trace
formation.
-Wc,-Qgsched-trace_late=1 Turns on the late trace scheduler.
-Wc,-Qgsched-trace_spec_load=1 Turns on the conversion of loads to
non-faulting loads inside the trace.
-Wc,-Qinline_memcpy=<n> Inline calls to memcpy with n bytes or
fewer being copied
-Wc,-Qipa:valueprediction Use profile feedback data to predict
values and attempt to generate faster
code along these control paths, even at
the expense of possibly slower code
along paths leading to different
values. Correct code is generated for
both paths.
-Wc,-Qiselect-funcalign=<n> Do function entry alignment at n-byte
boundaries.
-Wc,-Qiselect-sw_pf_tbl_th=<n> Peels the most frequent test
branches/cases off a switch until the
branch probability reaches less than
1/n. This is effective only when
profile feedback is used
-Wc,-Qms_pipe+intdivusefp Use fp divide for signed integer
division
-Wc,-Qms_pipe-pref Turn off prefetching within modulo
scheduling
-Wc,-Qpeep-Sh0 Disables the max live base registers
algorithm for sethi hoisting.
-Xa Assume ANSI C conformance, allow K & R
extensions. (default mode)
-xalias_level=<a> Allows compiler to perform type-based
alias analysis at the given alias
level.
basic assume ISO C9X aliasing rules for
basic types only.
std assume ISO C9X aliasing rules.
strong assume all pointers are type
safe (strongly typed).
-xarch=<a> Limit the set of instructions the
compiler may use.
-Xc Assume strict ANSI C conformance.
-xcache=<c> Defines the cache properties for use by
the optimizer.
c must be one of the following:
o native (set parameters for the host
environment)
o s1/l1/a1
o s1/l1/a1:s2/l2/a2
o s1/l1/a1:s2/l2/a2:s3/l3/a3
The si/li/ai are defined as follows:
si The size of the data cache at level
i, in kilobytes.
li The line size of the data cache at
level i, in bytes.
ai The associativity of the data cache
at level i.
-xchip=<c> Specifies the target processor for use
by the optimizer. c must be one of:
generic, generic64, native, native64,
old, super, super2, micro, micro2,
hyper, hyper2, powerup, ultra, ultra2,
ultra2i, ultra3, 386, 486, pentium,
pentium_pro, 603, 604.
-xcrossfile Enable cross-file inlining.
-xdepend Analyze loops for data dependencies.
-xF Allow function reordering by the
WorkShop Performance Analyzer
-xinline= Turn off inlining
-xipo=n Performs optimizations across all
object files in the link step: 0=off,
1=on, 2=performs whole-program
detection and analysis
-xlibmopt This chooses the math library that is
optimized for speed.
-xO1 Does basic local optimization
(peephole).
-xO2 xO1 and more local and global
optimizations.
-xO3 Besides what xO2 does, it optimizes
references or definitions for external
variables. Loop unrolling and software
pipelining are also performed.
-xO4 xO3 plus function inlining.
-xO5 Besides what xO4 does, it enables
speculative code motion.
-xpad=common[:<n>] Pad common block variables, for better
use of cache. n specifies the amount of
padding to apply. If no parameter is
specified then the compiler selects one
automatically.
-xpad=local[:<n>] Pad local variables only, for better
use of cache. n specifies the amount of
padding to apply. If no parameter is
specified then the compiler selects one
automatically.
-xparallel Use parallel processing to improve
performance.
-xprefetch[=value] Enable prefetch instructions on those
architectures that support prefetch,
such as UltraSPARC II (-xarch=v8plus,
v8plusa, v9plusb, v9, v9a, or v9b)
auto
Enable automatic generation of prefetch
instructions
no%auto
Disable automatic generation of
prefetch instructions
explicit
Enable explicit prefetch macros
no%explicit
Disable explicit prefetch macros
yes
-xprefetch=yes is the same as
-xprefetch=auto,explicit
no
-xprefetch=no is the same as
-xprefetch=no%auto,no%explicit
Defaults
If -xprefetch is not specified,
-xprefetch=no%auto,explicit is assumed.
If only -xprefetch is specified,
-xprefetch=auto,explicit is assumed.
-xprofile=collect Collect profile data for feedback
directed optimizations.
-xprofile=use Use data collected for profile
feedback.
-xreduction Parallelize loops containing
reductions.
-xregs=syst Allows use of the system reserved
registers %g6 and %g7, and %g5 if not
already allowed by -xarch value.
-xrestrict[=f1,...,f2,%all, Treat pointer-valued function
%none] parameters as restricted pointers. The
default is %none. Specifying -xrestrict
is equivalent to specifying
-xrestrict=%all.
-xsafe=mem Enables the use of non-faulting loads
when used in conjunction with
-xarch=v8plus. Assumes that no memory
based traps will occur.
-xsfpconst Represents unsuffixed floating-point
constants as single precision
-Xt Assume K & R conformance, allow ANSI C.
-xtarget=native Same as -native
------------------------------------------------------------------
Kernel Parameters
Flag Description
shmsys:shminfo_shmmin Minimum size of system V shared memory
segment that can be created.
shmsys:shminfo_shmmax Maximum size of system V shared memory
segment that can be created. This
parameter is an upper limit that is
checked before the system sees if it
actually has the physical resources to
create the requested memory segment.
shmsys:shminfo_shmmni System wide limit on number of shared
memory segments that can be created.
shmsys:shminfo_shmseg Limit on the number of shared memory
segments that any one process can
create.
------------------------------------------------------------------
Environment Variables
Flag Description
PRISM_HEAP=<n> Set the heap size limit for large pages
PRISM_MODE=2 Large page mode: Attempt to put text,
data and heap all into large pages.