Compilers: IBM XL C/C++ Version 13.1 for Linux
Compilers: IBM XL Fortran Version 15.1 for Linux
Libraries: IBM IBM Advance Toolchain 7
Operating systems: Red Hat Enterprise Linux Server release 7
Last updated: 16-June-2014
Selecting one of the following will take you directly to that section:
Perform optimizations for maximum performance. This includes maximum interprocedural analysis on all of the objects presented on the "link" step. This level of optimization will increase the compiler's memory usage and compile time requirements. -O5 Provides all of the functionality of the -O4 option, but also provides the functionality of the -qipa=level=2 option.
-O5 is equivalent to the following flagsPerform optimizations for maximum performance. This includes interprocedural analysis on all of the objects presented on the "link" step.
-O4 is equivalent to the following flagsProduces object code containing instructions that will run on the specified processors. "auto" selects the processor the compile is being done on. "pwr5x" is the POWER5+ processor.
Supported values for this flag are
Specifies the system architecture for which the executable program is optimized. This includes instruction scheduling and cache setting.
The supported values for suboption are
This option specifies that no functions are to be inlined.
This option inlines glue code that optimizes external function calls when compiling.
Performs high-order transformations on loops during optimization. The supported values for suboption are:
Specifying -qhot without suboptions implies -qhot=nosimd, -qhot=noarraypad, -qhot=vector and -qhot=level=1. The -qhot option is also implied by -O4, and -O5.
Enhances optimization by doing detailed analysis across procedures (interprocedural analysis or IPA). The level determines the amount of interprocedural analysis and optimization that is performed.
level=0 Does only minimal interprocedural analysis and optimization
level=1 turns on inlining , limited alias analysis, and limited call-site tailoring
level=2 turns on full interprocedural data flow and alias analysis
Suppresses interprocedural analysis (IPA), which is enabled by default at optimization levels -O4 and -O5.
The option used in the first pass of a profile directed feedback compile that causes pdf information to be generated. The profile directed feedback optimization gathers data on both execution path and data values. It does not use hardware counters, nor gather any data other than path and data values for PDF specific optimizations.
The option used in the second pass of a profile directed feedback compile that causes PDF information to be utilized during optimization.
The compiler generates additional symbol information for use by the "fdpr" binary optimization tool.
-qxlf90=<suboption>
Determines whether the compiler provides the
Fortran 90 or the Fortran 95 level of support for
certain aspects of the language. <suboption> can be
one of the following:
signedzero | nosignedzero
Determines how the SIGN(A,B) function handles
signed real 0.0. In addition, determines
whether negative internal values will be
prefixed with a minus when formatted output
would produce a negative sign zero.
autodealloc | noautodealloc
Determines whether the compiler deallocates
allocatable arrays that are declared locally
without either the SAVE or the STATIC
attribute and have a status of currently
allocated when the subprogram terminates.
oldpad | nooldpad
When the PAD=specifier is present in the
INQUIRE statement, specifying -qxlf90=nooldpad
returns UNDEFINED when there is no connection,
or when the connection is for unformatted I/O.
This behavior conforms with the Fortran 95
standard and above. Specifying -qxlf90=oldpad
preserves the Fortran 90 behavior.
Default:
o signedzero, autodealloc and nooldpad for the
xlf95, xlf95_r, xlf95_r7 and f95 invocation
commands.
o nosignedzero, noautodealloc and oldpad for
all other invocation commands.
Generates 64 bit ABI binaries. The default is to generate 32 bit ABI binaries.
Indicates that a program, designed to execute in a large page memory environment, can take advantage of large 16 MB pages provided on POWER4 and higher based systems.
Indicates that the compiler understands how to do alloca().
Causes the Fortran compiler to allocate dynamic arrays on the heap instead of the stack
Specifies that all local variables be treated as STATIC.
Enables the generation of vector instructions for processors that support them.
Enables the generation of vector instructions for processors that support them.
Specifies whether to use volatile or non-volatile vector registers. Volatile vector registers are registers whose value is not preserved across function calls so the compiler will not depend on values in them across function calls.
Link the mathematical acceleration subsystem libraries (MASS), which contain libraries of tuned mathematical intrinsic functions.
Link the Engineering and Scientific Subroutine Library (ESSL).
Specifies that, if either -lessl or -lesslsmp are also specified, then Engineering and Scientific Subroutine Library (ESSL) routines should be used in place of some Fortran 90 intrinsic procedures when there is a safe opportunity to do so.
Cause the C++ compiler to generate Run Time Type Identification code
qalias=ansi | noansi If ansi is specified, type-based aliasing is used during optimization, which restricts the lvalues that can be safely used to access a data object. The default is ansi for the xlc, xlC, and c89 commands. This option has no effect unless you also specify the -O option. qalias=std |nostd Indicates whether the compilation units contain any non-standard aliasing (see Compiler Reference for more information). If so, specify nostd.
Specifies what aggregate alignment rules the
compiler uses for file compilation, where the
alignment options are:
bit_packed
The compiler uses the bit_packed alignment
rules.
full
The compiler uses the RISC System/6000
alignment rules. This is the same as power.
mac68k
The compiler uses the Macintosh alignment
rules. This suboption is valid only for 32-
bit compilations.
natural
The compiler maps structure members to their
natural boundaries.
packed
The compiler uses the packed alignment rules.
power
The compiler uses the RISC System/6000
alignment rules.
twobyte
The compiler uses the Macintosh alignment
rules. This suboption is valid only for 32-
bit compilations. The mac68k option is the
same as twobyte.
The default is -qalign=full.
qassert=refalign | norefalign Specifies that all pointers inside the compilation unit only point to data that is naturally aligned according to the length of the pointer types.
qprefetch=aggressive Aggressively prefetch data
The prefetch=dscr option causes the Data Streams Control Register to be set to the value specified when executing this program.
qrestrict TBD
Causes the compiler to automatically generate parallel code using OMP controls when possible.
Tell the compiler that OMP controls are used to identify parallel code.
Ensures that optimizations done by default at
optimization levels -O3 and higher, and, optionally
at -O2, do not alter the semantics of a program.
The -qstrict=all, -qstrict=precision,
-qstrict=exceptions, -qstrict=ieeefp, and
-qstrict=order suboptions and their negative forms
are group suboptions that affect multiple,
individual suboptions. Group suboptions act as if
either the positive or the no form of every
suboption of the group is specified.
Default:
o Always -qstrict or -qstrict=all when the
-qnoopt or -O0 optimization level is in effect
o -qstrict or -qstrict=all is the default when
the -O2 or -O optimization level is in effect
o -qnostrict or -qstrict=none is the default
when -O3 or a higher optimization level is in
effect
<suboptions_list> is a colon-separated list of one
or more of the following:
all | none
all disables all semantics-changing
transformations, including those controlled by
the ieeefp, order, library, precision, and
exceptions suboptions. none enables these
transformations.
precision | noprecision
precision disables all transformations that
are likely to affect floating-point precision,
including those controlled by the subnormals,
operationprecision, association,
reductionorder, and library suboptions.
noprecision enables these transformations.
exceptions | noexceptions
exceptions disables all transformations likely
to affect exceptions or be affected by them,
including those controlled by the nans,
infinities, subnormals, guards, and library
suboptions. noexceptions enables these
transformations.
ieeefp | noieeefp
ieeefp disables transformations that affect
IEEE floating-point compliance, including
those controlled by the nans, infinities,
subnormals, zerosigns, and operationprecision
suboptions. noieeefp enables these
transformations.
nans | nonans
nans disables transformations that may produce
incorrect results in the presence of, or that
may incorrectly produce IEEE floating-point
signaling NaN (not-a-number) values. nonans
enables these transformations.
infinities | noinfinities
infinities disables transformations that may
produce incorrect results in the presence of,
or that may incorrectly produce floating-point
infinities. noinfinities enables these
transformations.
subnormals | nosubnormals
subnormals disables transformations that may
produce incorrect results in the presence of,
or that may incorrectly produce IEEE
floating-point subnormals (formerly known as
denorms). nosubnormals enables these
transformations.
zerosigns | nozerosigns
zerosigns disables transformations that may
affect or be affected by whether the sign of a
floating-point zero is correct. nozerosigns
enables these transformations.
operationprecision | nooperationprecision
operationprecision disables transformations
that produce approximate results for
individual floating-point operations.
nooperationprecision enables these
transformations.
order | noorder
order disables all code reordering between
multiple operations that may affect results or
exceptions, including those controlled by the
association, reductionorder, and guards
suboptions. noorder enables code reordering.
association | noassociation
association disables reordering operations
within an expression. noassociation enables
reordering operations.
reductionorder | noreductionorder
reductionorder disables parallelizing
floating-point reductions. noreductionorder
enables these reductions.
guards | noguards
guards disables moving operations past guards
or calls which control whether the operation
should be executed or not. enables these
moving operations.
library | nolibrary
library disables transformations that affect
floating-point library functions. nolibrary
enables these transformations.
The inline option specifies the threshold and limit of inlined functions
The inline suboption specifies the threshold and limit of inlined functions
The partition suboption specifies the size of the program sections that are analysed together. Larger partitons may produce better analysis but require more storage. Default is medium.
The threads suboption allows the IPA optimizer to run portions of the optimization process in parallel threads, which can speed up the compilation process on multi-processor systems. All the available threads, or the number specified by N, may be used. N must be a positive integer. Specifying nothreads does not run any parallel threads; this is equivalent to running one serial thread. This option does not affect the code in the final binary created.
Link with tcmalloc's library for Linux on POWER. This is a library that optimizes calls to new, delete, malloc and free.
Link with libhugetlbfs.so. This enables heap to be backed by the 16 Megabyte pages.
| Parameter | Description | Executable name |
|---|---|---|
| a | Assembler | as |
| b | Low-level optimizer | xlfcode |
| c | Compiler front end | xlfentry |
| d | Disassembler | dis |
| F | C preprocessor | cpp |
| h | Array language optimizer | xlfhot |
| I | High-level optimizer, compile step | ipa |
| l | Linker | ld |
| z | Binder | bolt |
Instructs the linker to include every object file in the specified library, rather than searching the library for the required object files.
Instructs the linker to include libdl.a to enable dynamic linking loader.
Turn off the effect of the --whole-archive flag.
Instructs the linker to allow multiple definitions and the first definition will be used. Normally when a symbol is defined multiple times, the linker will report a fatal error.
Pass the --hugetlbfs-link=BDT flag to the linker so that the text, initialized data, and BSS segments of the application are backed by hugepages.
Pass the --hugetlbfs-align flag to the linker so that we can control (by environment variable HUGETLB_ELFMAP) which program segments are placed in hugepages.
Determines substitute path names for XL Fortran executables such as the compiler, assembler, linker, and preprocessor. It can be used in combination with the -t option, which determines which of these components are affected by -B.
Pass the -q flag to the linker causing the final executable to have the relocation information.
Link with the Apache C++ Standard Library ("stdcxx"). "libstd8d.so" is a 32-bit shared library with optimization enabled.
Adds the directory for the Apache C++ Standard Library to the search path at link time.
Specifies library search directory for the Apache C++ Standard Library for use by the runtime linker. The information is recorded in the object file and passed to the runtime linker.
Causes the compiler to treat "char" variables as signed instead of the default of unsigned.
Indicates that the input fortran source program is in fixed form.
Adds an underscore to global entities to match the C compiler ABI
Permits the usage of "//" to introduce a comment that lasts until the end of the current source line, as in C++.
Invoke the IBM XL C compiler. 32-bit binaries are produced by default. Link with the IBM Advanced Toolchain libraries.
Invoke the IBM XL C++ compiler. 32-bit binaries are produced by default. Link with the IBM Advanced Toolchain libraries.
Invoke the IBM XL Fortran compiler. 32-bit binaries are produced by default. Link with the IBM Advanced Toolchain libraries.
Allows most any c dialect.
Specifies whether to include standard object code in the object files. The noobject suboption can substantially reduce overall compilation time, by not generating object code during the first IPA phase. This option does not affect the code in the final binary created.
Specifies the size of the compiler's internal program storage areas, in bytes.
Causes the compiler to output a traceback if it abends.
Suppresses the message with the message number specified.
Suppresses informational, language-level, and warning messages. This option sets -qflag=e:e.
Usage:
- First we copied the original executable (baseexe) to baseexe.orig.
- Then, the executable is instrumented and its initial profile generated, as follows:
$ fdprpro -a instr baseexe
The output will be generated (by default) in baseexe.instr and its profile in baseexe.nprof.
- Next, run baseexe.instr using the training data. This will fill the profile file with information that characterizes the training workload.
- Finally, re-run FDPR-Pro with the profile file provided, as follows:
$ fdprpro -a opt -f baseexe.nprof [optimization options] baseexe
fdprpro [options] -f profile program
where -f specifies the profile run data. program is the name of the executable.
[options] can be one or more of the following:
Action Options:
-a/--action [action] Specifies customized actions
where [action] can be one of the following:
anl analyze program
instr generate instrumented program for profile gathering (same as -1)
opt generate optimized program (same as -3)
check_sign check fdpr signature in the input program
Action Options:
-anl, --analyze-program
Analyze the program but do not create a modified binary.
This option is used to generate profile/code coverage
reports in text format. When used with the -d option it
will generate the disassembly of the original program
-cci, --code-coverage-instrumentation
Instrument program in order to obtain code coverage
information. program must be compiled with line number
debug info
-pi, --profile-instrumentation
Instrument the program to obtain execution count profile
-ui, --user-instrumentation
Instrument program by insert calls to user supplied
functions compiled into shared library
Analysis Options:
-aawc/-noaawc, --analyze-assembly-written-csects/--noanalyze-assembly-written-csects
Analyze/Do not analyze objects written in Assembly.
-acf <analysis configuration file>, --analysis-configuration-file <analysis configuration file>
Provide a configuration file of analysis information
(advanced option)
-asd, --analyze-static-data
Analyze static data objects as distinct data elements
for data reordering (unsafe for certain compilers)
-esa, --extra-safe-analysis
Limit analysis phase to compiler generated code
-fca, --funcsect-analysis
Apply special analysis for an input executable that was
compiled with the -qfuncsect compiler option
-ff <string>, --file-format <string>
Input file format: can be LM (load module) or PO
(program object)
-ifl <file>, --ignored-function-list <file>
Set the ignored function list. The file contains names
of functions that considered as unsafe and thus are not
modified
-iinf, --ignore-info Ignore .info sections produced with the -qfdpr option
during compile time
Instrumentation Options:
-ccl <level>, --code-coverage-level <level>
Perform code coverage at the basic block level (BB) or
at the functions level (FUNC). default is BB
-ei, --embedded-instrumentation
Perform embedded instrumentation. The profile will be
collected into the application's global data area. When
the application terminates, the collected data will be
lost
-fd <Fdesc>, --file-descriptor <Fdesc>
Set the file descriptor number to be used when opening
the profile file. The default of <Fdesc> is set to the
maximum-allowed number of open files
-icsp, --instr-call-site-profiling
Instrument each basic block in order to collect each
caller context frequency
-icvp, --instr-call-value-profiling
instrument the values of parameters passed in function
calles
-imullX, --mullX-instrumentation
perform value profiling of RA and RB operands in mullX
instructions
-iderat, --derat-instrumentation
Perform value profiling of RA and RB operands in
load/store indexed instructions
-infp, --ignore-not-found-procedures
Ignore not found procedures defined in the
instrumentation directives file and do not exit with
error
-ipcr/-noipcr, --instrumentation-preserve-condition-register/--noinstrumentation-preserve-condition-register
Preserve/Do not preserve the condition register while
calling stubs
-ipctr/-noipctr, --instrumentation-preserve-count-register/--noinstrumentation-preserve-count-register
Preserve/Do not preserve the count register while
calling stubs
-ipe/-noipe, --instrumentation-preserve-environment/--noinstrumentation-preserve-environment
Do not preserve registers that are not overwritten while
calling stubs. -noipe implies -noipvr -noipspr
-iplr/-noiplr, --instrumentation-preserve-link-register/--noinstrumentation-preserve-link-register
Preserve/Do not preserve the link register while calling
stubs
-ipnvr, --instrumentation-preserve-non-volatile-registers
Preserve the non volatile registers while calling stubs.
-ipspr/-noipspr, --instrumentation-preserve-special-registers/--noinstrumentation-preserve-special-registers
Preserve/Do not preserve the special purpose registers
while calling stubs
-ipvr/-noipvr, --instrumentation-preserve-volatile-registers/--noinstrumentation-preserve-volatile-registers
Preserve/Do not preserve the volatile registers while
calling stubs. -noipvr implies -noipnvr and -nosfp
-ipxer/-noipxer, --instrumentation-preserve-fixed-point-exception-register/--noinstrumentation-preserve-fixed-point-exception-register
Preserve/Do not preserve the fixed-point exception
register while calling stubs
-issu, --instrumentation-safe-stack-usage
Ensure that additional stack space is properly allocated
for the instrumented run. Use this option if your
application uses the stack extensively (e.g., when the
program uses alloca()). Note that this option adds
extra overhead on instrumentation code
-iso <offset>, --instrumentation-stack-offset <offset>
Set the offset from the stack, a negative number, where
the instrumentation's area for saving registers is kept
at runtime. Use with care
-M <addr>, --profile-map <addr>
Set the shared memory segment address for profiling.
Alternative shared memory addresses are needed when the
instrumented program application creates a conflict
with the shared-memory addresses preserved for the
profiling. Typical alternative values are 0x40000000,
0x50000000, ... up to 0xC0000000. The default is set to
0x3000000
-ptm, --profile-to-memory
Use shared memory key instead of file mapping to obtain
a shared memory area for the profile data
-ri/-nori, --register-instrumentation/--noregister-instrumentation
Instrument/Do not instrument the input program file to
collect profile information about indirect branches via
registers. The default is set to collect the profile
information
-sfp/-nosfp, --save-floating-point-registers/--nosave-floating-point-registers
Save/Do not save floating point registers in
instrumented code. The default is set to save floating
point registers
-shmkey <key number>, --shared-memory-key <key number>
Specify a shared memory key to use when creating a
shared memory area for the profile. The default key is
created by hashing the profile file name (with ftok).
-spescr <0-127>, --spe-scratch-register <0-127>
Specify a global SPE scratch register, decreasing
instrumenation overhead, in order to minimize
possibility of local store overflow
Profile Files Options:
-af <prof_file>, --ascii-profile-file <prof_file>
Set the name of a text format profile file containing
profile information.
-aop, --accept-old-profile
Accept the old profile file collected on previous
versions of the input program file (requires the -f
flag)
-f <prof_file>, --profile-file <prof_file>
Set the profile file name. The profile file is created
during the instrumentation phase and read during the
optimization phase. The profile file is updated each
time you run the instrumented program
-fdir <prof_file_dir>, --profile-file-directory <prof_file_dir>
Set the run-time location of the profile file. The
profile will be search during the profiling phase at
this location. The default location is the path given
in the profile file name (-f option). Applicable only
at instrumentation phase
Optimization Options:
-A <alignment>, --align-code <alignment>
Specify code alignment strategy. 1: Use grouping rules
of target machine (default), 2: Same as 1 but consider
also hotness of branch targets. See -m for the selected
machine model.
-abb <factor>, --align-basic-blocks <factor>
Align basic blocks that are hotter than the average by a
given (float) <factor>. This is a lower-level
machine-specific alignment compared to --align-code.
Value of -1 (the default) disables this option
-bh <factor>, --branch-hint <factor>
add branch hints to basic blocks that are hotter then
the average by given (float) <factor>. This is a SPE
specific optimization. Value of -1 (the default)
disables this option
-ccc <threshold>, --cold-code-connector <threshold>
Preserves original order for code which is less
frequently executed than given threshold
-bldcg, --build-dcg Build a Data Connectivity Graph (DCG) for enhanced data
reordering (applicable only with the -RD flag)
-cbpth, --cold-branch-prediction-threshold
Set the Cold Branch Prediction Threshold for branch
prediction optimization. Branches whose execution count
relative to the average is below this value will be
statically predicted. Allowed values are between (0,1).
Default is -1 - optimization is not applied.
(Applicable only with the -bp flag)
-bpth, --branch-prediction-threshold
Set threshold for event based branch prediction
optimization
-pbp, --preserve-branch-predication
Preserve branch predication pattern (bc+8) and avoid
code reordering and branch prediction
-btcar, --branch-table-csect-anchor-removal
Eliminate load instructions used when accessing branch
tables
-cbsi, --chain-based-selective-inline
Perform selective inlining of functions that produce
long hot chains of code
-cbtd, --convert-bss-to-data
Convert BSS section into a data section. This is useful
for more aggressive tocload and RD optimizations
-cib-opt, --convert-indirect-branches-optimization
Convert indirect branch to direct branch
-cRD, --conservativeRD
Perform conservative static data reordering by packing
together all frequently referenced static variables
-dce, --dead-code-elimination
Eliminate instructions related to unused local variables
within frequently executed functions. This is useful
mainly after applying function inlining optimization
-dp, --data-prefetch Insert data-cache prefetch instructions to improve
data-cache performance
-dpht <threshold>, --data-placement-hotness-threshold <threshold>
Set data placement algorithm hotness threshold between
(0,1), where 0 reorders the static variables in large
groups based on the control flow, and 1 reorders the
variables in very small groups based on their access
frequency. (This is applicable only with the -RD flag)
-dpnf <factor>, --data-placement-normalization-factor <factor>
Set data placement algorithm normalization factor
between (0,1), where 0 causes static variables to be
reordered regardless of their size, and 1 locates only
small sized variables first. (applicable only with the
-RD flag)
-ece, --epilog-code-eliminate
Reduce code size by grouping common instructions in
function epilogs, into a single unified code
-fatc <num_of_bytes>, --fat-const <num_of_bytes>
Inflate constant areas in code section by adding
<num_of_bytes> (entire set to 255) to each constant
area
-fatd <num_of_bytes>, --fat-data <num_of_bytes>
Inflate data section by adding <num_of_bytes> (entire
set to 255) to each data basic unit
-fatn <num_of_nops>, --fat-nop <num_of_nops>
Inflate code secion by adding <num_of_nop> to each code
basic block
-bined < binary_editor>, --binary-editor < binary_editor>
Edit existing binary code (advanced option)
-fc, --function-cloning
Enable function cloning phase only during function
inlining optimizations (applicable only with function
inlining flags: -i, -si, -ihf, -isf, -shci)
-hr, --hco-reschedule Relocate instructions from frequently executed code to
rarely executed code areas, when possible
-hrf <factor>, --hco-resched-factor <factor>
Set the aggressiveness of the -hr optimization option
according to a factor value between (0,1), where 0 is
the least aggressive factor (applicable only with the
-hr option)
-tasr, --toc-anchor-store-reschedule
Relocate TOC store instructions from frequently executed
code to rarely executed code areas, when possible
-i, --inline Same as --selective-inline with --inline-small-funcs 12
-ia, --indirect-analysis
Perform indirect branch target analysis
-icm-opt, --icm-optimization
Replace a sequence of l/ltr or ly/ltr instructions with
and icm or icmy instruction respectively
-ihf <pct>, --inline-hot-functions <pct>
Inline all function call sites to functions that have a
frequency count greater than the given <pct> frequency
percentage
-iplte, --inline-plt-entries
Replaces the call to a PLT entry with the PLT entry code
itself, by inlining the first part of the entry
-isf <size>, --inline-small-funcs <size>
Inline all functions that are smaller than or equal to
the given <size> in bytes
-kr, --killed-registers
Eliminate stores and restores of registers that are
killed (overwritten) after frequently executed function
calls
-lal-opt, --load-after-load-optimization
Replace two load instruction from the same memory
location to one load instruction and one placement
instruction
-lap, --load-address-propagation
Eliminate load instructions of variable addresses by
re-using pre-loaded addresses of adjacent variables
-larl-opt, --larl-optimization
Replace a sequence of bras/const area/llgt instructions
with a single lalr instruction
-las, --load-after-store
Add NOP instructions to place each load instruction
further apart following a store instruction that
references the same memory address
-plas, --pattern-based-load-after-store
Optimizes inefficient memory access patterns in order to
avoid load-after-store events.
-ebplas, --event-based-pattern-based-load-after-store
Optimizes inefficient memory access patterns in order to
avoid load-after-store events. The optimization is
possible if PM_MRK_LSU_REJECT_LHS profile is available
-rcl, --remove-constant-load
Reduces the number of load instructions used to bring
constant values into registers. The parameter is used
to control which version of optimization is applied,
versions from 0 to 3 are available.
-ldce, --local-dead-code-optimization
Local dead code elimination (basic block scope only) -
needless when using -dce
-ldp-opt, --long-displacement-optimization
Replace an instruction which has long displacement with
the matching insturction which has short displacement,
according to the displacement operand (e.g. ay-->a,
oy-->o, xy-->x, etc.)
-lgfr-opt, --lgfr-optimization
Replace when can a 32 bit instruction with its matching
64 bit instruction
-llgh-opt, --llgh-optimization
Replace a sequence of lh/nilh/llgfr instructions with a
single llgh instruction
-fce, --fix-cobol-entries
An optimization for COBOL code - fixes entries of
CSECTs. Needed for HLR optimizations.
-pvgc <mode>, --print-visual-graph-csect <mode>
Print a .dot file with CFG information for each csect.
Mode 0 is for a graph containing full instructions list
for each node, 1 is for a graph with short nodes
description.
-pvgf <mode>, --print-visual-graph-func <mode>
Print a .dot file with CFG information for each
function. Mode 0 is for a graph containing full
instructions list for each node, 1 is for a graph with
short nodes description.
-lro, --link-register-optimization
Eliminate saves and restores of the link register in
frequently-executed functions
-lu <aggressiveness_factor>, --loop-unroll <aggressiveness_factor>
Unroll short loops containing one to several basic
blocks according to an aggressiveness factor between
(1,9), where 1 is the least aggressive unrolling option
for very hot and short loops
-lun <unrolling_number>, --loop-unrolling-number <unrolling_number>
Set the number of unrolled iterations in each unrolled
loop. The allowed range is between (2,50). Default is
set to 2. (Applicable only with the -lu flag)
-lux <unrolling_factor>, --loop-unroll-extended <unrolling_factor>
Unroll hot loops using given unrolling factor. The
allowed values are integer numbers that are power of 2.
Value -1 disables the optimization, value 1 calculates
the unrolling factor automatically, given a machine
model
-mvc-opt, --mvc-optimization
Replace an mvc instruction with lg/stg instructions
-nillr15-opt, --nillr15-optimization
Remove a nill r15,0xfffe instruction if followed by an
stmg r14,r12,8(r13) instruction
-sls, --store-load-on-stack-opt
Optimize store load on stack pattern
-fmrx, --fmr-to-xxlor Replace FMR instructions from reordered code with XXLOR
instruction
-xscpx, --xscpsgndp-to-xxlor
Replace Xscpsgndp instructions from reordered code with
XXLOR instruction
-dir, --dependant-instr-resched
Put NOP between dependant instructions
-O Switch on basic optimizations only. Same as -RC -nop -bp
-bf
-O2 Switch on less aggressive optimization flags. Same as -O
-hr -pto -isf 8 -tlo -kr -see 0
-O3 Switch on aggressive optimization flags. Same as -O2 -RD
-isf 12 -si -lro -las -vro -btcar (for XCOFF files) -lu
9 -rt 0 -so -see 1 -oderat
-O4 Switch on aggressive optimization flags together with
aggressive function inlining. Same as -O3 -sidf 50 -ihf
20 -sdp 9 -shci 90 and -bldcg (for XCOFF files)
-ocvp, --opt-call-value-profiling
specialize function calls according to the values of
their passed parameters
-ocsp, --opt-call-site-profiling
Cluster functions with simliar behaviour according to
calling context
-omullX, --mullX-optimization
Optimize mullX instructions by adding a run-time check
on RA and RB and performing equivalent operations with
lower penalty. The optimization requires the use of
-imullX in the instrumentation phase
-oderat, --derat-optimization
Optimize load/store indexed instructions by adding a
run-time check on RA and RB and performing equivalent
operations with lower penalty. The optimization
requires the use of -iderat in the instrumentation
phase
-pbsi, --path-based-selective-inline
Perform selective inlining of dominant hot function
calls based on the control flow paths leading to hot
functions
-pc, --preserve-csects
Preserve CSects' boundaries in reordered code
-pca, --propagate-constant-area
Relocate the constant variables area to the top of the
code section when possible
-pfb, --preserve-first-bb
Preserve original location of the entry point basic
block in program
-pp, --preserve-functions
Preserve functions' boundaries in reordered code
-pr/-nopr, --ptrgl-r11/--noptrgl-r11
Perform/Do not perform removal of R11 load instruction
in _ptrgl csect (the default is to perform the
optimization)
-pto, --ptrgl-optimization
Perform optimization of indirect call instructions via
registers by replacing them with conditional direct
jumps
-ptoht <heatness_threshold>, --ptrgl-optimization-heatness-threshold <heatness_threshold>
Set the frequency threshold for indirect calls that are
to be optimized by -pto optimization. Allowed range
between 0 and 1. Default is set to 0.8. (Applicable
only with -pto flag)
-ptosl <limit_size>, --ptrgl-optimization-size-limit <limit_size>
Set the limit of the number of conditional statements
generated by -pto optimization. Allowed values are
between 1 and 100. Default value is set to 3.
(Applicable only with the -pto flag)
-rcaf <aggressiveness_factor>, --reorder-code-aggressivenes-factor <aggressiveness_factor>
Set the aggressiveness of code reordering optimization.
Allowed values are [0 | 1 | 2], where 0 preserves then
original code order and 2 is the most aggressive.
Default is set to 1. (Applicable only with the -RC
flag)
-rccrf <reversal_factor>, --reorder-code-condition-reversal-factor <reversal_factor>
Set the threshold fraction that determines when to
enable condition reversal for each conditional branch
during code reordering. Allowed input range is between
0.0 and 1.0 where 0.0 tries to preserve original
condition direction and 1.0 ignores it. Default is set
to 0.8 (Applicable only with the -RC flag)
-rcctf <termination_factor>, --reorder-code-chain-termination-factor <termination_factor>
Set the threshold fraction that determines when to
terminate each chain of basic blocks during code
reordering. Allowed input range is between 0.0 and 1.0
where 0.0 generates long chains and 1.0 creates single
basic block chains. Default is set to 0.05. (Applicable
only with the -RC flag)
-RD, --reorder-data Perform static data reordering
-ippcf, --instrument-for-path-profiling
Perform cross function path profiling instrumentation
-ppcf, --optimize-with-path-profiling
Perform cross function path profiling optimization
-rmte, --remove-multiple-toc-entries
Remove multiple TOC entries pointing to the same
location in the input program file
-rt <removal_factor>, --reduce-toc <removal_factor>
Perform removal of TOC entries according to a removal
factor between (0,1), where 0 removes non-accessed TOC
entries only and 1 removes all possible TOC entries
-rtb, --remove-traceback-tables
Remove traceback tables in reordered code
-rcs, --remove-csect-symbols
Remove csect symbols
-sal-opt, --store-after-load-optimization
Remove store after load when there is no change
-scca <level>, --safe-calling-conventions-analysis <level>
Determine how conservative must FDPR be when analysing a
function that may break calling conventions
-sdp <aggressiveness_factor>, --stride-data-prefetch <aggressiveness_factor>
Perform data prefetching within frequently executed
loops based on stride analysis, according to an
aggressiveness factor between (1,9), where 1 is the
least aggressive
-sdpila <instructions_number>, --stride-data-prefetch-instruction-look-ahead <instructions_number>
Set the number of instructions for which data is
prefetched into the cache ahead of time. Default value
is platform dependant. (Applicable only with the -sdp
flag)
-sdpms <stride_min_size>, --stride-data-prefetch-min-size <stride_min_size>
Set the minimal stride size in bytes, for which data
will be considered a candidate for prefetching. Default
value is set to 128 bytes. (Applicable only with the
-sdp flag)
-ebp <evt_based_prefetch>, --event-based-prefetch <evt_based_prefetch>
Perform data prefetching based on the events file
-ebpla <instructions_number>, --event-based-prefetch-look-ahead <instructions_number>
Set the number of instructions for which event based
prefetch is performed. Default value is platform
dependant. (Applicable only with the -ebp flag)
-see <level> Use simplified prolog/epilog for functions that perform
conditional early-exit. Use basic optimization with
<level>=0 and maximal with <level>=1
-shci <pct>, --selective-hot-code-inline <pct>
Perform selective inlining of functions in order to
decrease the total number of execution counts, so that
only functions with hotness above the given percentage
are inlined
-si, --selective-inline
Perform selective inlining of dominant hot function
calls
-sidf <percentage_factor>, --selective-inline-dominant-factor <percentage_factor>
Set a dominant factor percentage for selective inline
optimization. The allowed range is between 0 and 100.
Default is set to 80. (Applicable only with the -si and
-pbsi flags)
-siht <frequency_factor>, --selective-inline-hotness-threshold <frequency_factor>
Set a hotness threshold factor percentage for selective
inline optimization to inline all dominant function
calls that have a frequency count greater than the
given frequency percentage. Default is set to 100.
(Applicable only with the -si -pbsi flags)
-slbp, --spinlock-branch-prediction
Perform branch prediction bit setting for conditional
branches in spinlock code containing l*arx and st*cx
instructions. (Applicable after -bp flag)
-sldp, --spinlock-data-prefetch
Perform data prefetching for memory access instructions
preceding spinlock code containing l*arx and st*cx
instructions
-sll <Lib1:Prof1,...,LibN:ProfN>, --static-link-libraries <Lib1:Prof1,...,LibN:ProfN>
Statically link hot code from specified dynamically
linked libraries to the input program. The parameter
consists of a comma-separated list of libraries and
their profiles. IMPORTANT: Licensing rights of
specified libraries should be observed when applying
this copying optimization
-sllht <hotness_threshold>, --static-link-libraries-hotness-threshold <hotness_threshold>
Set hotness threshold for the --static-link-libraries
optimization. The allowed input range is between 0
(least aggressive) and 1, or -1, which does not require
a profile and selects all code that might be called by
the input program from the given libraries. Default is
set at 0.5
-so, --stack-optimization
Reduce the stack frame size of functions that are called
with a small number of arguments
-spc, --shortcut-plt-calls
Shortcut PLT calls in shared libraries to local
functions if they exist. Note: Resolving to external
symbols is disabled for such calls
-stf, --stack-flattening
Merge the stack frames of inlined functions with the
frames of the calling functions
-tb, --preserve-traceback-tables
Force the restructuring of traceback tables in reordered
code. If -tb option is omitted, traceback tables are
automatically included only for C++ applications that
use the Try & Catch mechanism
-tlo, --tocload-optimization
Replace each load instruction that references the TOC
with a corresponding add-immediate instruction via the
TOC anchor register, where possible
-ucde, --unreachable-code-data-elimination
Remove unreachable code and non-accessed static data
-vro, --volatile-registers-optimization
Eliminate stores and restores of non-volatile registers
in frequently executed functions by using available
volatile registers
-vrox, --volatile-registers-extended-optimization
Eliminate stores and restores of non-volatile registers
in frequently executed functions by using available
volatile registers, the extended version supports FP
registers and transparency
Output Options:
-bcdf <file>, --binary-code-dump-file <file>
Create a binary dump of the code (opcodes) with
annotations of addresses.
-ccgi <mode>, --code-coverage-generate-info <mode>
Produce coverage information in a file based on profile
information. Use <mode>=XML for an XML output and
<mode>=FLAT for a formatted text file. The generated
file is <output file>.cci[.xml]
-cep, --complement-edge-profile
Complements partial profile information given for the
basic blocks' frequencies by adding missing basic
block-to-basic block edge counts
-d, --disassemble-text
Print the disassembled text section of the output
program into <output_file>.dis_text file
-dap, --dump-ascii-profile
Dump profile information in ASCII format into
<program>.aprof (requires the -f flag).
-db, --disassemble-bss
Print the disassembled bss section of the output program
into <output_file>.dis_bss file
-dd, --disassemble-data
Print the disassembled data section of the output
program into <output_file>.dis_data file
-diap, --dump-initial-ascii-profile
Dump the given profile information in ASCII format into
<program>.aprof.init (requires the -f flag)
-dim, --dump-instruction-mix
Dump instruction mix statistics based on gathered
profile information
-dm, --dump-mapper Print a map of basic blocks and static variables with
their respective new -> old addresses into a
<program>.mapper file
-enc, --encapsulate Encapsulate SPE executables present in the PPE input
(see --spe-directory)
-o <output_file>, --output-file <output_file>
Set the name of the output file. The default
instrumented file is <program>.instr. The default
optimized file is <program>.fdpr
-scl, --show-constant-load
Adds annotaions in fdpr disassembly on load instructions
used to bring constant values into registers (requires
-d flag)
-pds, --preserve-debug-symbols
Preserve debug symbols
-plc, --preserve-linkage-conventions
Preserve linkage conventions
-ppcf, --print-prof-counts-file
Print a text format of the profiling counters into a
<program>.counts file (requires the -f flag).
-sf, --strip-file Strip the output file
-simo, --single-input-multiple-outputs
Optimize in parallel into multiple outputs as specified
by option sets read from stdin
-spedir <directory>, --spe-directory <directory>
Set the directory into which SPE executables will be
extracted and from which they will be encapsulated
General Options:
-cell, --cell-supervisor
Integrated PPE/SPE processing. Perform SPE extraction,
processing, and encapsulation automatically prior to
PPE processing
-h, --help Print the online help
-j <jour_file>, --journal <jour_file>
Output optimization journal information to <jour_file>
-smt, --smt_mode set SMT mode (1:ST, 2: (SMT2-shared, SMT2-split),
4:SMT4, 8:SMT8)
-m <machine-model>, --machine <machine-model>
Generate code for the specified machine model. Target
machine can be one of the following models: power2,
power3, ppc405, ppc440, power4, ppc970, power5, power6,
power7, power8, ppe, spe, spe_edp, z10, z9.
Default is power7
-q, --quiet Set the output mode to quiet, suppressing informational
messages
-st <stat_file>, --statistics <stat_file>
Output statistics information to <stat_file>. If
<stat_file> is '-', the output goes to the standard
output. See --verbose for the default
-v <level>, --verbose <level>
Set verbose output mode level. When set, various
statistics about the output program are printed into
the file <program>.stat. Allowed level range is between
0 and 3. Default is set to 0
-V, --version Print the version number
-w <level>, --warning-level <level>
Set the warning level so only errors of this level and
below will be printed. The levels are: 1: errors, 2:
warnings, 3: debug warning, 4: debug information.
Default is 2
-armember For archive files - list of archive members to be
optimized, if -armember is not specified, all members
will be optimized