path: root/gcc/common.opt

; Options for the language- and target-independent parts of the compiler.

; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012
; Free Software Foundation, Inc.
;
; This file is part of GCC.
;
; GCC is free software; you can redistribute it and/or modify it under
; the terms of the GNU General Public License as published by the Free
; Software Foundation; either version 3, or (at your option) any later
; version.
;
; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
; WARRANTY; without even the implied warranty of MERCHANTABILITY or
; FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
; for more details.
;
; You should have received a copy of the GNU General Public License
; along with GCC; see the file COPYING3.  If not see
; <http://www.gnu.org/licenses/>.

; See the GCC internals manual (options.texi) for a description of this file's format.

; Please try to keep this file in ASCII collating order.

Variable
int target_flags

Variable
int optimize

Variable
int optimize_size

Variable
int optimize_debug

; Not used directly to control optimizations, only to save -Ofast
; setting for "optimize" attributes.
Variable
int optimize_fast

; True if this is the lto front end.  This is used to disable gimple
; generation and lowering passes that are normally run on the output
; of a front end.  These passes must be bypassed for lto since they
; have already been done before the gimple was written.
Variable
bool in_lto_p = false

; 0 means straightforward implementation of complex divide acceptable.
; 1 means wide ranges of inputs must work for complex divide.
; 2 means C99-like requirements for complex multiply and divide.
Variable
int flag_complex_method = 1

; Nonzero if subexpressions must be evaluated from left-to-right.
Variable
int flag_evaluation_order = 0

; Language specific warning pass for unused results.
Variable
bool flag_warn_unused_result = false

Variable
int *param_values

; Nonzero if we should write GIMPLE bytecode for link-time optimization.
Variable
int flag_generate_lto

; True to warn about any objects definitions whose size is larger
; than N bytes.  Also want about function definitions whose returned
; values are larger than N bytes, where N is 'larger_than_size'.
Variable
bool warn_larger_than

Variable
HOST_WIDE_INT larger_than_size

; True to warn about any function whose frame size is larger
; than N bytes.
Variable
bool warn_frame_larger_than

Variable
HOST_WIDE_INT frame_larger_than_size

; Nonzero means we should be saving declaration info into a .X file.
Variable
int flag_gen_aux_info = 0

; Nonzero if we are compiling code for a shared library, zero for
; executable.
Variable
int flag_shlib

; These two are really VEC(char_p,heap) *.

Variable
void *flag_instrument_functions_exclude_functions

Variable
void *flag_instrument_functions_exclude_files

; Generic structs (e.g. templates not explicitly specialized)
; may not have a compilation unit associated with them, and so
; may need to be treated differently from ordinary structs.
;
; Structs only handled by reference (indirectly), will also usually
; not need as much debugging information.

Variable
enum debug_struct_file debug_struct_ordinary[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }

Variable
enum debug_struct_file debug_struct_generic[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }

; True if we should exit after parsing options.
Variable
bool exit_after_options

; Type(s) of debugging information we are producing (if any).  See
; flag-types.h for the definitions of the different possible types of
; debugging information.
Variable
enum debug_info_type write_symbols = NO_DEBUG

; Level of debugging information we are producing.  See flag-types.h
; for the definitions of the different possible levels.
Variable
enum debug_info_levels debug_info_level = DINFO_LEVEL_NONE

; Nonzero means use GNU-only extensions in the generated symbolic
; debugging information.  Currently, this only has an effect when
; write_symbols is set to DBX_DEBUG, XCOFF_DEBUG, or DWARF_DEBUG.
Variable
bool use_gnu_debug_info_extensions

; Original value of maximum field alignment in bytes, specified via
; -fpack-struct=<value>.
Variable
unsigned int initial_max_fld_align = TARGET_DEFAULT_PACK_STRUCT

; Type of stack check.
Variable
enum stack_check_type flag_stack_check = NO_STACK_CHECK

; True if stack usage information needs to be computed.
Variable
bool flag_stack_usage_info = false

; -dA causes debug commentary information to be produced in
; the generated assembly code (to make it more readable).  This option
; is generally only of use to those who actually need to read the
; generated assembly code (perhaps while debugging the compiler itself).
; Currently, this switch is only used by dwarf2out.c; however, it is intended
; to be a catchall for printing debug information in the assembler file.
Variable
int flag_debug_asm

; -dP causes the rtl to be emitted as a comment in assembly.
Variable
int flag_dump_rtl_in_asm

; Whether -da was passed (used only in handle_common_deferred_options).
Variable
bool flag_dump_all_passed

; Other flags saying which kinds of debugging dump have been requested.

Variable
int rtl_dump_and_exit

Variable
int flag_print_asm_name

; Name of top-level original source file (what was input to cpp).
; This comes from the #-command at the beginning of the actual input.
; If there isn't any there, then this is the cc1 input file name.
Variable
const char *main_input_filename

; Pointer to base name in main_input_filename, with directories and a
; single final extension removed, and the length of this base
; name.

Variable
const char *main_input_basename

Variable
int main_input_baselength

; Which options have been printed by --help.
Variable
char *help_printed

; Which enums have been printed by --help.  0 = not printed, no
; relevant options seen, 1 = relevant option seen, not yet printed, 2
; = printed.
Variable
char *help_enum_printed

; The number of columns for --help output.
Variable
unsigned int help_columns

; Whether this options structure has been through finish_options
Variable
bool flag_opts_finished

###
Driver

-assemble
Driver Alias(S)

-compile
Driver Alias(c)

-coverage
Driver Alias(coverage)

-debug
Common Alias(g)

-dump
Common Separate Alias(d)

-dump=
Common Joined Alias(d)

-dumpbase
Common Separate Alias(dumpbase)

-dumpdir
Common Separate Alias(dumpdir)

-entry
Driver Separate Alias(e)

-entry=
Driver Joined Alias(e)

-extra-warnings
Common Warning Alias(Wextra)

-for-assembler
Driver Separate Alias(Xassembler)

-for-assembler=
Driver JoinedOrMissing Alias(Xassembler)

-for-linker
Driver Separate Alias(Xlinker)

-for-linker=
Driver JoinedOrMissing Alias(Xlinker)

-force-link
Driver Separate Alias(u)

-force-link=
Driver Joined Alias(u)

-help
Common Driver Var(help_flag)
Display this information

-help=
Common Driver Report Joined
--help=<class>	Display descriptions of a specific class of options.  <class> is one or more of optimizers, target, warnings, undocumented, params

-language
Driver Separate Alias(x)

-language=
Driver Joined Alias(x)

-library-directory
Driver Separate Alias(L)

-library-directory=
Driver Joined Alias(L)

-no-canonical-prefixes
Driver Alias(no-canonical-prefixes)

-no-standard-libraries
Driver Alias(nostdlib)

-no-sysroot-suffix
Driver Var(no_sysroot_suffix)

-no-warnings
Common Alias(w)

-optimize
Common Alias(O)

-output
Common Driver Separate Alias(o) MissingArgError(missing filename after %qs)

-output=
Common Driver Joined Alias(o) MissingArgError(missing filename after %qs)

-pass-exit-codes
Driver Alias(pass-exit-codes)

-pedantic
Common Alias(Wpedantic)

-pedantic-errors
Common Alias(pedantic-errors)

-pie
Driver Alias(pie)

-pipe
Driver Alias(pipe)

-prefix
Driver Separate Alias(B)

-prefix=
Driver JoinedOrMissing Alias(B)

-preprocess
Driver Alias(E)

-print-file-name
Driver Separate Alias(print-file-name=)

-print-file-name=
Driver JoinedOrMissing Alias(print-file-name=)

-print-libgcc-file-name
Driver Alias(print-libgcc-file-name)

-print-multi-directory
Driver Alias(print-multi-directory)

-print-multi-lib
Driver Alias(print-multi-lib)

-print-multi-os-directory
Driver Alias(print-multi-os-directory)

-print-multiarch
Driver Alias(print-multiarch)

-print-prog-name
Driver Separate Alias(print-prog-name=)

-print-prog-name=
Driver JoinedOrMissing Alias(print-prog-name=)

-print-search-dirs
Driver Alias(print-search-dirs)

-print-sysroot
Driver Alias(print-sysroot)

-print-sysroot-headers-suffix
Driver Alias(print-sysroot-headers-suffix)

-profile
Common Alias(p)

-save-temps
Driver Alias(save-temps)

-shared
Driver Alias(shared)

-specs
Driver Separate Alias(specs=)

-specs=
Driver Joined Alias(specs=)

-static
Driver Alias(static)

-symbolic
Driver Alias(symbolic)

-target-help
Common Driver
Alias for --help=target

-time
Driver Alias(time)

-verbose
Driver Alias(v)

;; The driver used to convert options such as --help into forms such
;; as -fhelp; the following four entries are for compatibility with
;; any direct uses of those (undocumented) -f forms
fhelp
Common Driver Alias(-help)

fhelp=
Common Driver Joined Alias(-help=)

ftarget-help
Common Driver Alias(-target-help)

fversion
Common Driver Alias(-version)

-param
Common Separate
--param <param>=<value>	Set parameter <param> to value.  See below for a complete list of parameters

-param=
Common Joined Alias(-param)

-sysroot
Driver Separate Alias(-sysroot=)

-sysroot=
Driver JoinedOrMissing

-version
Common Driver

B
Driver Joined Separate

E
Driver

L
Driver Joined Separate

N
Driver

O
Common JoinedOrMissing Optimization
-O<number>	Set optimization level to <number>

Os
Common Optimization
Optimize for space rather than speed

Ofast
Common Optimization
Optimize for speed disregarding exact standards compliance

Og
Common Optimization
Optimize for debugging experience rather than speed or size

Q
Driver

Qn
Driver Negative(Qy)

Qy
Driver Negative(Qn)

R
Driver Joined Separate

S
Driver

T
Driver Joined Separate

Tbss
Driver Separate

Tbss=
Driver Joined

Tdata
Driver Separate

Tdata=
Driver Joined

Ttext
Driver Separate

Ttext=
Driver Joined

W
Common RejectNegative Warning Alias(Wextra)
This switch is deprecated; use -Wextra instead

Wa,
Driver JoinedOrMissing

Wl,
Driver JoinedOrMissing

Wp,
Driver JoinedOrMissing

Waggregate-return
Common Var(warn_aggregate_return) Warning
Warn about returning structures, unions or arrays

Warray-bounds
Common Var(warn_array_bounds) Warning
Warn if an array is accessed out of bounds

Wattributes
Common Var(warn_attributes) Init(1) Warning
Warn about inappropriate attribute usage

Wcast-align
Common Var(warn_cast_align) Warning
Warn about pointer casts which increase alignment

Wcpp
Common Var(warn_cpp) Init(1) Warning
Warn when a #warning directive is encountered

Wdeprecated-declarations
Common Var(warn_deprecated_decl) Init(1) Warning
Warn about uses of __attribute__((deprecated)) declarations

Wdisabled-optimization
Common Var(warn_disabled_optimization) Warning
Warn when an optimization pass is disabled

Werror
Common Var(warnings_are_errors)
Treat all warnings as errors

Werror=
Common Joined
Treat specified warning as error

Wextra
Common Var(extra_warnings) Warning
Print extra (possibly unwanted) warnings

Wfatal-errors
Common Var(flag_fatal_errors)
Exit on the first error occurred

Wframe-larger-than=
Common RejectNegative Joined UInteger
-Wframe-larger-than=<number>	Warn if a function's stack frame requires more than <number> bytes

Wfree-nonheap-object
Common Var(warn_free_nonheap_object) Init(1) Warning
Warn when attempting to free a non-heap object

Winline
Common Var(warn_inline) Warning
Warn when an inlined function cannot be inlined

Winvalid-memory-model
Common Var(warn_invalid_memory_model) Init(1) Warning
Warn when an atomic memory model parameter is known to be outside the valid range.

Wlarger-than-
Common RejectNegative Joined Warning Undocumented Alias(Wlarger-than=)

Wlarger-than=
Common RejectNegative Joined UInteger Warning
-Wlarger-than=<number>	Warn if an object is larger than <number> bytes

Wunsafe-loop-optimizations
Common Var(warn_unsafe_loop_optimizations) Warning
Warn if the loop cannot be optimized due to nontrivial assumptions.

Wmissing-noreturn
Common Alias(Wsuggest-attribute=noreturn)

Woverflow
Common Var(warn_overflow) Init(1) Warning
Warn about overflow in arithmetic expressions

Wpacked
Common Var(warn_packed) Warning
Warn when the packed attribute has no effect on struct layout

Wpadded
Common Var(warn_padded) Warning
Warn when padding is required to align structure members

Wpedantic
Common Var(pedantic) Warning
Issue warnings needed for strict compliance to the standard

Wshadow
Common Var(warn_shadow) Warning
Warn when one local variable shadows another

Wstack-protector
Common Var(warn_stack_protect) Warning
Warn when not issuing stack smashing protection for some reason

Wstack-usage=
Common Joined RejectNegative UInteger Var(warn_stack_usage) Init(-1) Warning
Warn if stack usage might be larger than specified amount

Wstrict-aliasing
Common Warning
Warn about code which might break strict aliasing rules

Wstrict-aliasing=
Common Joined RejectNegative UInteger Var(warn_strict_aliasing) Warning
Warn about code which might break strict aliasing rules

Wstrict-overflow
Common Warning
Warn about optimizations that assume that signed overflow is undefined

Wstrict-overflow=
Common Joined RejectNegative UInteger Var(warn_strict_overflow) Warning
Warn about optimizations that assume that signed overflow is undefined

Wsuggest-attribute=const
Common Var(warn_suggest_attribute_const) Warning
Warn about functions which might be candidates for __attribute__((const))

Wsuggest-attribute=pure
Common Var(warn_suggest_attribute_pure) Warning
Warn about functions which might be candidates for __attribute__((pure))

Wsuggest-attribute=noreturn
Common Var(warn_suggest_attribute_noreturn) Warning
Warn about functions which might be candidates for __attribute__((noreturn))

Wsystem-headers
Common Var(warn_system_headers) Warning
Do not suppress warnings from system headers

Wtrampolines
Common Var(warn_trampolines) Warning
Warn whenever a trampoline is generated

Wtype-limits
Common Var(warn_type_limits) Warning EnabledBy(Wextra)
Warn if a comparison is always true or always false due to the limited range of the data type

Wuninitialized
Common Var(warn_uninitialized) Warning EnabledBy(Wextra)
Warn about uninitialized automatic variables

Wmaybe-uninitialized
Common Var(warn_maybe_uninitialized) Warning EnabledBy(Wuninitialized)
Warn about maybe uninitialized automatic variables

Wunreachable-code
Common Ignore
Does nothing. Preserved for backward compatibility.

Wunused
Common Var(warn_unused) Init(0) Warning
Enable all -Wunused- warnings

Wunused-but-set-parameter
Common Var(warn_unused_but_set_parameter) Warning EnabledBy(Wunused && Wextra)
Warn when a function parameter is only set, otherwise unused

Wunused-but-set-variable
Common Var(warn_unused_but_set_variable) Warning EnabledBy(Wunused)
Warn when a variable is only set, otherwise unused

Wunused-function
Common Var(warn_unused_function) Warning EnabledBy(Wunused)
Warn when a function is unused

Wunused-label
Common Var(warn_unused_label) Warning EnabledBy(Wunused)
Warn when a label is unused

Wunused-parameter
Common Var(warn_unused_parameter) Warning EnabledBy(Wunused && Wextra)
Warn when a function parameter is unused

Wunused-value
Common Var(warn_unused_value) Warning EnabledBy(Wunused)
Warn when an expression value is unused

Wunused-variable
Common Var(warn_unused_variable) Warning EnabledBy(Wunused)
Warn when a variable is unused

Wcoverage-mismatch
Common Var(warn_coverage_mismatch) Init(1) Warning
Warn in case profiles in -fprofile-use do not match

Wvector-operation-performance
Common Var(warn_vector_operation_performance) Warning
Warn when a vector operation is compiled outside the SIMD

Xassembler
Driver Separate

Xlinker
Driver Separate

Xpreprocessor
Driver Separate

Z
Driver

aux-info
Common Separate Var(aux_info_file_name)
-aux-info <file>	Emit declaration information into <file>

aux-info=
Common Joined Alias(aux-info)

auxbase
Common Separate RejectDriver Var(aux_base_name)

auxbase-strip
Common Separate RejectDriver

coverage
Driver

c
Driver

d
Common Joined
-d<letters>	Enable dumps from specific passes of the compiler

dumpbase
Common Separate Var(dump_base_name)
-dumpbase <file>	Set the file basename to be used for dumps

dumpdir
Common Separate Var(dump_dir_name)
-dumpdir <dir>	Set the directory name to be used for dumps

dumpmachine
Driver

dumpspecs
Driver

dumpversion
Driver

e
Driver Joined Separate

; This option has historically been passed down to the linker by an
; accident of a %{e*} spec, so ensure it continues to be passed down
; as a single option.  The supported option for this purpose is
; -rdynamic.  See PR 47390.
export-dynamic
Driver Undocumented

; The version of the C++ ABI in use.  The following values are allowed:
;
; 0: The version of the ABI believed most conformant with the C++ ABI
;    specification.  This ABI may change as bugs are discovered and fixed.
;    Therefore, 0 will not necessarily indicate the same ABI in different
;    versions of G++.
;
; 1: The version of the ABI first used in G++ 3.2.
;
; 2: The version of the ABI first used in G++ 3.4 (and current default).
;
; 3: The version of the ABI that fixes the missing underscore
;    in template non-type arguments of pointer type.
;
; 4: The version of the ABI that introduces unambiguous mangling of
;    vector types.  First selectable in G++ 4.5.
;
; 5: The version of the ABI that ignores attribute const/noreturn
;    in function pointer mangling, and corrects mangling of decltype and
;    function parameters used in other parameters and the return type.
;    First selectable in G++ 4.6.
;
; 6: The version of the ABI that doesn't promote scoped enums to int and
;    changes the mangling of template argument packs, const/static_cast,
;    prefix ++ and --, and a class scope function used as a template
;    argument.
;    First selectable in G++ 4.7.
;
; 7: The version of the ABI that treats nullptr_t as a builtin type.
;    First selectable in G++ 4.8.
; Additional positive integers will be assigned as new versions of
; the ABI become the default version of the ABI.
fabi-version=
Common Joined RejectNegative UInteger Var(flag_abi_version) Init(2)

falign-functions
Common Report Var(align_functions,0) Optimization UInteger
Align the start of functions

falign-functions=
Common RejectNegative Joined UInteger Var(align_functions)

falign-jumps
Common Report Var(align_jumps,0) Optimization UInteger
Align labels which are only reached by jumping

falign-jumps=
Common RejectNegative Joined UInteger Var(align_jumps)

falign-labels
Common Report Var(align_labels,0) Optimization UInteger
Align all labels

falign-labels=
Common RejectNegative Joined UInteger Var(align_labels)

falign-loops
Common Report Var(align_loops,0) Optimization UInteger
Align the start of loops

falign-loops=
Common RejectNegative Joined UInteger Var(align_loops)

fargument-alias
Common Ignore
Does nothing. Preserved for backward compatibility.

fargument-noalias
Common Ignore
Does nothing. Preserved for backward compatibility.

fargument-noalias-global
Common Ignore
Does nothing. Preserved for backward compatibility.

fargument-noalias-anything
Common Ignore
Does nothing. Preserved for backward compatibility.

fsanitize=address
Common Report Var(flag_asan)
Enable AddressSanitizer, a memory error detector

fsanitize=thread
Common Report Var(flag_tsan)
Enable ThreadSanitizer, a data race detector

fasynchronous-unwind-tables
Common Report Var(flag_asynchronous_unwind_tables) Optimization
Generate unwind tables that are exact at each instruction boundary

fauto-inc-dec
Common Report Var(flag_auto_inc_dec) Init(1)
Generate auto-inc/dec instructions

; -fcheck-bounds causes gcc to generate array bounds checks.
; For C, C++ and ObjC: defaults off.
; For Java: defaults to on.
; For Fortran: defaults to off.
fbounds-check
Common Report Var(flag_bounds_check)
Generate code to check bounds before indexing arrays

fbranch-count-reg
Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
Replace add, compare, branch with branch on count register

fbranch-probabilities
Common Report Var(flag_branch_probabilities) Optimization
Use profiling information for branch probabilities

fbranch-target-load-optimize
Common Report Var(flag_branch_target_load_optimize) Optimization
Perform branch target load optimization before prologue / epilogue threading

fbranch-target-load-optimize2
Common Report Var(flag_branch_target_load_optimize2) Optimization
Perform branch target load optimization after prologue / epilogue threading

fbtr-bb-exclusive
Common Report Var(flag_btr_bb_exclusive) Optimization
Restrict target load migration not to re-use registers in any basic block

fcall-saved-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fcall-saved-<register>	Mark <register> as being preserved across functions

fcall-used-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fcall-used-<register>	Mark <register> as being corrupted by function calls

; Nonzero for -fcaller-saves: allocate values in regs that need to
; be saved across function calls, if that produces overall better code.
; Optional now, so people can test it.
fcaller-saves
Common Report Var(flag_caller_saves) Optimization
Save registers around function calls

fcheck-data-deps
Common Report Var(flag_check_data_deps)
Compare the results of several data dependence analyzers.

fcombine-stack-adjustments
Common Report Var(flag_combine_stack_adjustments) Optimization
Looks for opportunities to reduce stack adjustments and stack references.

fcommon
Common Report Var(flag_no_common,0) Optimization
Do not put uninitialized globals in the common section

fcompare-debug
Driver
; Converted by the driver to -fcompare-debug= options.

fcompare-debug=
Common Driver JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
-fcompare-debug[=<opts>]	Compile with and without e.g. -gtoggle, and compare the final-insns dump

fcompare-debug-second
Common Driver RejectNegative Var(flag_compare_debug)
Run only the second compilation of -fcompare-debug

fcompare-elim
Common Report Var(flag_compare_elim_after_reload) Optimization
Perform comparison elimination after register allocation has finished

fconserve-stack
Common Var(flag_conserve_stack) Optimization
Do not perform optimizations increasing noticeably stack usage

fcprop-registers
Common Report Var(flag_cprop_registers) Optimization
Perform a register copy-propagation optimization pass

fcrossjumping
Common Report Var(flag_crossjumping) Optimization
Perform cross-jumping optimization

fcse-follow-jumps
Common Report Var(flag_cse_follow_jumps) Optimization
When running CSE, follow jumps to their targets

fcse-skip-blocks
Common Ignore
Does nothing.  Preserved for backward compatibility.

fcx-limited-range
Common Report Var(flag_cx_limited_range) Optimization SetByCombined
Omit range reduction step when performing complex division

fcx-fortran-rules
Common Report Var(flag_cx_fortran_rules) Optimization
Complex multiplication and division follow Fortran rules

fdata-sections
Common Report Var(flag_data_sections) Optimization
Place data items into their own section

fdbg-cnt-list
Common Report Var(common_deferred_options) Defer
List all available debugging counters with their limits and counts.

fdbg-cnt=
Common RejectNegative Joined Var(common_deferred_options) Defer
-fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...]	Set the debug counter limit.   

fdebug-prefix-map=
Common Joined RejectNegative Var(common_deferred_options) Defer
Map one directory name to another in debug information

fdebug-types-section
Common Report Var(flag_debug_types_section) Init(0)
Output .debug_types section when using DWARF v4 debuginfo.

; Nonzero for -fdefer-pop: don't pop args after each function call
; instead save them up to pop many calls' args with one insns.
fdefer-pop
Common Report Var(flag_defer_pop) Optimization
Defer popping functions args from stack until later

fdelayed-branch
Common Report Var(flag_delayed_branch) Optimization
Attempt to fill delay slots of branch instructions

fdelete-dead-exceptions
Common Report Var(flag_delete_dead_exceptions) Init(0)
Delete dead instructions that may throw exceptions

fdelete-null-pointer-checks
Common Report Var(flag_delete_null_pointer_checks) Init(1) Optimization
Delete useless null pointer checks

fdevirtualize
Common Report Var(flag_devirtualize) Optimization
Try to convert virtual calls to direct ones.

fdiagnostics-show-location=
Common Joined RejectNegative Enum(diagnostic_prefixing_rule)
-fdiagnostics-show-location=[once|every-line]	How often to emit source location at the beginning of line-wrapped diagnostics

; Required for these enum values.
SourceInclude
pretty-print.h

Enum
Name(diagnostic_prefixing_rule) Type(int)

EnumValue
Enum(diagnostic_prefixing_rule) String(once) Value(DIAGNOSTICS_SHOW_PREFIX_ONCE)

EnumValue
Enum(diagnostic_prefixing_rule) String(every-line) Value(DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE)

fdiagnostics-show-caret
Common Var(flag_diagnostics_show_caret) Init(1)
Show the source line with a caret indicating the column

fdiagnostics-show-option
Common Var(flag_diagnostics_show_option) Init(1)
Amend appropriate diagnostic messages with the command line option that controls them

fdisable-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fdisable-[tree|rtl|ipa]-<pass>=range1+range2 disables an optimization pass

fenable-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fenable-[tree|rtl|ipa]-<pass>=range1+range2 enables an optimization pass

fdump-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fdump-<type>	Dump various compiler internals to a file

fdump-final-insns
Driver RejectNegative

fdump-final-insns=
Common RejectNegative Joined Var(flag_dump_final_insns)
-fdump-final-insns=filename	Dump to filename the insns at the end of translation

fdump-go-spec=
Common RejectNegative Joined Var(flag_dump_go_spec)
-fdump-go-spec=filename	Write all declarations to file as Go code

fdump-noaddr
Common Report Var(flag_dump_noaddr)
Suppress output of addresses in debugging dumps

fdump-passes
Common Var(flag_dump_passes) Init(0)
Dump optimization passes

fdump-unnumbered
Common Report Var(flag_dump_unnumbered)
Suppress output of instruction numbers, line number notes and addresses in debugging dumps

fdump-unnumbered-links
Common Report Var(flag_dump_unnumbered_links)
Suppress output of previous and next insn numbers in debugging dumps

fdwarf2-cfi-asm
Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
Enable CFI tables via GAS assembler directives.

fearly-inlining
Common Report Var(flag_early_inlining) Init(1) Optimization
Perform early inlining

feliminate-dwarf2-dups
Common Report Var(flag_eliminate_dwarf2_dups)
Perform DWARF2 duplicate elimination

fipa-sra
Common Report Var(flag_ipa_sra) Init(0) Optimization
Perform interprocedural reduction of aggregates

feliminate-unused-debug-symbols
Common Report Var(flag_debug_only_used_symbols)
Perform unused type elimination in debug info

feliminate-unused-debug-types
Common Report Var(flag_eliminate_unused_debug_types) Init(1)
Perform unused type elimination in debug info

femit-class-debug-always
Common Report Var(flag_emit_class_debug_always) Init(0)
Do not suppress C++ class debug information.

fexceptions
Common Report Var(flag_exceptions) Optimization
Enable exception handling

fexpensive-optimizations
Common Report Var(flag_expensive_optimizations) Optimization
Perform a number of minor, expensive optimizations

fexcess-precision=
Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision_cmdline) Init(EXCESS_PRECISION_DEFAULT)
-fexcess-precision=[fast|standard]	Specify handling of excess floating-point precision

Enum
Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess precision style %qs)

EnumValue
Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)

EnumValue
Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)

ffast-math
Common

ffat-lto-objects
Common Var(flag_fat_lto_objects) Init(1)
Output lto objects containing both the intermediate language and binary output.

ffinite-math-only
Common Report Var(flag_finite_math_only) Optimization SetByCombined
Assume no NaNs or infinities are generated

ffixed-
Common Joined RejectNegative Var(common_deferred_options) Defer
-ffixed-<register>	Mark <register> as being unavailable to the compiler

ffloat-store
Common Report Var(flag_float_store) Optimization
Don't allocate floats and doubles in extended-precision registers

fforce-addr
Common Ignore
Does nothing.  Preserved for backward compatibility.

fforward-propagate
Common Report Var(flag_forward_propagate) Optimization
Perform a forward propagation pass on RTL

ffp-contract=
Common Joined RejectNegative Enum(fp_contract_mode) Var(flag_fp_contract_mode) Init(FP_CONTRACT_FAST)
-ffp-contract=[off|on|fast] Perform floating-point expression contraction.

Enum
Name(fp_contract_mode) Type(enum fp_contract_mode) UnknownError(unknown floating point contraction style %qs)

EnumValue
Enum(fp_contract_mode) String(off) Value(FP_CONTRACT_OFF)

; Not implemented, fall back to conservative FP_CONTRACT_OFF.
EnumValue
Enum(fp_contract_mode) String(on) Value(FP_CONTRACT_OFF)

EnumValue
Enum(fp_contract_mode) String(fast) Value(FP_CONTRACT_FAST)

; Nonzero means don't put addresses of constant functions in registers.
; Used for compiling the Unix kernel, where strange substitutions are
; done on the assembly output.
ffunction-cse
Common Report Var(flag_no_function_cse,0)
Allow function addresses to be held in registers

ffunction-sections
Common Report Var(flag_function_sections)
Place each function into its own section

fgcse
Common Report Var(flag_gcse) Optimization
Perform global common subexpression elimination

fgcse-lm
Common Report Var(flag_gcse_lm) Init(1) Optimization
Perform enhanced load motion during global common subexpression elimination

fgcse-sm
Common Report Var(flag_gcse_sm) Init(0) Optimization
Perform store motion after global common subexpression elimination

fgcse-las
Common Report Var(flag_gcse_las) Init(0) Optimization
Perform redundant load after store elimination in global common subexpression
elimination

fgcse-after-reload
Common Report Var(flag_gcse_after_reload) Optimization
Perform global common subexpression elimination after register allocation
has finished

; This option is not documented yet as its semantics will change.
fgraphite
Common Report Var(flag_graphite)
Enable in and out of Graphite representation

fgraphite-identity
Common Report Var(flag_graphite_identity) Optimization
Enable Graphite Identity transformation

fhoist-adjacent-loads
Common Report Var(flag_hoist_adjacent_loads) Optimization
Enable hoisting adjacent loads to encourage generating conditional move
instructions

floop-parallelize-all
Common Report Var(flag_loop_parallelize_all) Optimization
Mark all loops as parallel

floop-strip-mine
Common Report Var(flag_loop_strip_mine) Optimization
Enable Loop Strip Mining transformation

floop-interchange
Common Report Var(flag_loop_interchange) Optimization
Enable Loop Interchange transformation

floop-block
Common Report Var(flag_loop_block) Optimization
Enable Loop Blocking transformation

fgnu-tm
Common Report Var(flag_tm)
Enable support for GNU transactional memory

floop-flatten
Common Ignore
Does nothing. Preserved for backward compatibility.

floop-nest-optimize
Common Report Var(flag_loop_optimize_isl) Optimization
Enable the ISL based loop nest optimizer

fstrict-volatile-bitfields
Common Report Var(flag_strict_volatile_bitfields) Init(-1)
Force bitfield accesses to match their type width

fguess-branch-probability
Common Report Var(flag_guess_branch_prob) Optimization
Enable guessing of branch probabilities

; Nonzero means ignore `#ident' directives.  0 means handle them.
; Generate position-independent code for executables if possible
; On SVR4 targets, it also controls whether or not to emit a
; string identifying the compiler.
fident
Common Report Var(flag_no_ident,0)
Process #ident directives

fif-conversion
Common Report Var(flag_if_conversion) Optimization
Perform conversion of conditional jumps to branchless equivalents

fif-conversion2
Common Report Var(flag_if_conversion2) Optimization
Perform conversion of conditional jumps to conditional execution

fstack-reuse=
Common Joined RejectNegative Enum(stack_reuse_level) Var(flag_stack_reuse) Init(SR_ALL)
-fstack-reuse=[all|named_vars|none] Set stack reuse level for local variables.

Enum
Name(stack_reuse_level) Type(enum stack_reuse_level) UnknownError(unknown Stack Reuse Level %qs)

EnumValue
Enum(stack_reuse_level) String(all) Value(SR_ALL)

EnumValue
Enum(stack_reuse_level) String(named_vars) Value(SR_NAMED_VARS)

EnumValue
Enum(stack_reuse_level) String(none) Value(SR_NONE)

ftree-loop-if-convert
Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
Convert conditional jumps in innermost loops to branchless equivalents

ftree-loop-if-convert-stores
Common Report Var(flag_tree_loop_if_convert_stores) Optimization
Also if-convert conditional jumps containing memory writes

; -finhibit-size-directive inhibits output of .size for ELF.
; This is used only for compiling crtstuff.c,
; and it may be extended to other effects
; needed for crtstuff.c on other systems.
finhibit-size-directive
Common Report Var(flag_inhibit_size_directive)
Do not generate .size directives

findirect-inlining
Common Report Var(flag_indirect_inlining)
Perform indirect inlining

; General flag to enable inlining.  Specifying -fno-inline will disable
; all inlining apart from always-inline functions.
finline
Common Report Var(flag_no_inline,0) Init(0) Optimization
Enable inlining of function declared \"inline\", disabling disables all inlining

finline-small-functions
Common Report Var(flag_inline_small_functions) Optimization
Integrate functions into their callers when code size is known not to grow

finline-functions
Common Report Var(flag_inline_functions) Optimization
Integrate functions not declared \"inline\" into their callers when profitable

finline-functions-called-once
Common Report Var(flag_inline_functions_called_once) Optimization
Integrate functions only required by their single caller

finline-limit-
Common RejectNegative Joined Alias(finline-limit=)

finline-limit=
Common RejectNegative Joined UInteger
-finline-limit=<number>	Limit the size of inlined functions to <number>

finline-atomics
Common Report Var(flag_inline_atomics) Init(1) Optimization
Inline __atomic operations when a lock free instruction sequence is available.

finstrument-functions
Common Report Var(flag_instrument_function_entry_exit)
Instrument function entry and exit with profiling calls

finstrument-functions-exclude-function-list=
Common RejectNegative Joined
-finstrument-functions-exclude-function-list=name,...  Do not instrument listed functions

finstrument-functions-exclude-file-list=
Common RejectNegative Joined
-finstrument-functions-exclude-file-list=filename,...  Do not instrument functions listed in files

fipa-cp
Common Report Var(flag_ipa_cp) Optimization
Perform Interprocedural constant propagation

fipa-cp-clone
Common Report Var(flag_ipa_cp_clone) Optimization
Perform cloning to make Interprocedural constant propagation stronger

fipa-profile
Common Report Var(flag_ipa_profile) Init(0) Optimization
Perform interprocedural profile propagation

fipa-pta
Common Report Var(flag_ipa_pta) Init(0) Optimization
Perform interprocedural points-to analysis

fipa-pure-const
Common Report Var(flag_ipa_pure_const) Init(0) Optimization
Discover pure and const functions

fipa-reference
Common Report Var(flag_ipa_reference) Init(0) Optimization
Discover readonly and non addressable static variables

fipa-matrix-reorg
Common Ignore
Does nothing. Preserved for backward compatibility.

fipa-struct-reorg
Common Ignore
Does nothing. Preserved for backward compatibility.

fira-algorithm=
Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB)
-fira-algorithm=[CB|priority] Set the used IRA algorithm

Enum
Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)

EnumValue
Enum(ira_algorithm) String(CB) Value(IRA_ALGORITHM_CB)

EnumValue
Enum(ira_algorithm) String(priority) Value(IRA_ALGORITHM_PRIORITY)

fira-region=
Common Joined RejectNegative Enum(ira_region) Var(flag_ira_region) Init(IRA_REGION_AUTODETECT)
-fira-region=[one|all|mixed] Set regions for IRA

Enum
Name(ira_region) Type(enum ira_region) UnknownError(unknown IRA region %qs)

EnumValue
Enum(ira_region) String(one) Value(IRA_REGION_ONE)

EnumValue
Enum(ira_region) String(all) Value(IRA_REGION_ALL)

EnumValue
Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)

fira-hoist-pressure
Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
Use IRA based register pressure calculation
in RTL hoist optimizations.

fira-loop-pressure
Common Report Var(flag_ira_loop_pressure)
Use IRA based register pressure calculation
in RTL loop optimizations.

fira-share-save-slots
Common Report Var(flag_ira_share_save_slots) Init(1)
Share slots for saving different hard registers.

fira-share-spill-slots
Common Report Var(flag_ira_share_spill_slots) Init(1)
Share stack slots for spilled pseudo-registers.

fira-verbose=
Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
-fira-verbose=<number>	Control IRA's level of diagnostic messages.

fivopts
Common Report Var(flag_ivopts) Init(1) Optimization
Optimize induction variables on trees

fjump-tables
Common Var(flag_jump_tables) Init(1) Optimization
Use jump tables for sufficiently large switch statements

fkeep-inline-functions
Common Report Var(flag_keep_inline_functions)
Generate code for functions even if they are fully inlined

fkeep-static-consts
Common Report Var(flag_keep_static_consts) Init(1)
Emit static const variables even if they are not used

fleading-underscore
Common Report Var(flag_leading_underscore) Init(-1)
Give external symbols a leading underscore

floop-optimize
Common Ignore
Does nothing.  Preserved for backward compatibility.

flto
Common
Enable link-time optimization.

flto=
Common RejectNegative Joined Var(flag_lto)
Link-time optimization with number of parallel jobs or jobserver.

flto-partition=1to1
Common Var(flag_lto_partition_1to1)
Partition symbols and vars at linktime based on object files they originate from

flto-partition=balanced
Common Var(flag_lto_partition_balanced)
Partition functions and vars at linktime into approximately same sized buckets

flto-partition=max
Common Var(flag_lto_partition_max)
Put every symbol into separate partition

flto-partition=none
Common Var(flag_lto_partition_none)
Disable partioning and streaming

; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
flto-compression-level=
Common Joined RejectNegative UInteger Var(flag_lto_compression_level) Init(-1)
-flto-compression-level=<number>	Use zlib compression level <number> for IL

flto-report
Common Report Var(flag_lto_report) Init(0)
Report various link-time optimization statistics

fmath-errno
Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
Set errno after built-in math functions

fmax-errors=
Common Joined RejectNegative UInteger Var(flag_max_errors)
-fmax-errors=<number>	Maximum number of errors to report

fmem-report
Common Report Var(mem_report)
Report on permanent memory allocation

fmem-report-wpa
Common Report Var(mem_report_wpa)
Report on permanent memory allocation in WPA only

; This will attempt to merge constant section constants, if 1 only
; string constants and constants from constant pool, if 2 also constant
; variables.
fmerge-all-constants
Common Report Var(flag_merge_constants,2) Init(1) Optimization
Attempt to merge identical constants and constant variables

fmerge-constants
Common Report Var(flag_merge_constants,1) Optimization
Attempt to merge identical constants across compilation units

fmerge-debug-strings
Common Report Var(flag_merge_debug_strings) Init(1)
Attempt to merge identical debug strings across compilation units

fmessage-length=
Common RejectNegative Joined UInteger
-fmessage-length=<number>	Limit diagnostics to <number> characters per line.  0 suppresses line-wrapping

fmodulo-sched
Common Report Var(flag_modulo_sched) Optimization
Perform SMS based modulo scheduling before the first scheduling pass

fmodulo-sched-allow-regmoves
Common Report Var(flag_modulo_sched_allow_regmoves)
Perform SMS based modulo scheduling with register moves allowed

fmove-loop-invariants
Common Report Var(flag_move_loop_invariants) Init(1) Optimization
Move loop invariant computations out of loops

fdce
Common Var(flag_dce) Init(1) Optimization
Use the RTL dead code elimination pass

fdse
Common Var(flag_dse) Init(1) Optimization
Use the RTL dead store elimination pass

freschedule-modulo-scheduled-loops
Common Report Var(flag_resched_modulo_sched) Optimization
Enable/Disable the traditional scheduling in loops that already passed modulo scheduling

fnon-call-exceptions
Common Report Var(flag_non_call_exceptions) Optimization
Support synchronous non-call exceptions

fomit-frame-pointer
Common Report Var(flag_omit_frame_pointer) Optimization
When possible do not generate stack frames

fopt-info
Common Report Var(flag_opt_info) Optimization
Enable all optimization info dumps on stderr

fopt-info-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fopt-info[-<type>=filename]	Dump compiler optimization details

foptimize-register-move
Common Report Var(flag_regmove) Optimization
Do the full register move optimization pass

foptimize-sibling-calls
Common Report Var(flag_optimize_sibling_calls) Optimization
Optimize sibling and tail recursive calls

fpartial-inlining
Common Report Var(flag_partial_inlining)
Perform partial inlining

fpre-ipa-mem-report
Common Report Var(pre_ipa_mem_report)
Report on memory allocation before interprocedural optimization

fpost-ipa-mem-report
Common Report Var(post_ipa_mem_report)
Report on memory allocation before interprocedural optimization

fpack-struct
Common Report Var(flag_pack_struct) Optimization
Pack structure members together without holes

fpack-struct=
Common RejectNegative Joined UInteger Optimization
-fpack-struct=<number>	Set initial maximum structure member alignment

fpcc-struct-return
Common Report Var(flag_pcc_struct_return,1) Init(DEFAULT_PCC_STRUCT_RETURN)
Return small aggregates in memory, not registers

fpeel-loops
Common Report Var(flag_peel_loops) Optimization
Perform loop peeling

fpeephole
Common Report Var(flag_no_peephole,0) Optimization
Enable machine specific peephole optimizations

fpeephole2
Common Report Var(flag_peephole2) Optimization
Enable an RTL peephole pass before sched2

fPIC
Common Report Var(flag_pic,2) Negative(fPIE)
Generate position-independent code if possible (large mode)

fPIE
Common Report Var(flag_pie,2) Negative(fpic)
Generate position-independent code for executables if possible (large mode)

fpic
Common Report Var(flag_pic,1) Negative(fpie)
Generate position-independent code if possible (small mode)

fpie
Common Report Var(flag_pie,1) Negative(fPIC)
Generate position-independent code for executables if possible (small mode)

fplugin=
Common Joined RejectNegative Var(common_deferred_options) Defer
Specify a plugin to load

fplugin-arg-
Common Joined RejectNegative Var(common_deferred_options) Defer
-fplugin-arg-<name>-<key>[=<value>]	Specify argument <key>=<value> for plugin <name>

fpredictive-commoning
Common Report Var(flag_predictive_commoning) Optimization
Run predictive commoning optimization.

fprefetch-loop-arrays
Common Report Var(flag_prefetch_loop_arrays) Init(-1) Optimization
Generate prefetch instructions, if available, for arrays in loops

fprofile
Common Report Var(profile_flag)
Enable basic program profiling code

fprofile-arcs
Common Report Var(profile_arc_flag)
Insert arc-based program profiling code

fprofile-dir=
Common Joined RejectNegative Var(profile_data_prefix)
Set the top-level directory for storing the profile data.
The default is 'pwd'.

fprofile-correction
Common Report Var(flag_profile_correction)
Enable correction of flow inconsistent profile data input

fprofile-generate
Common
Enable common options for generating profile info for profile feedback directed optimizations

fprofile-generate=
Common Joined RejectNegative
Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=

fprofile-use
Common Var(flag_profile_use)
Enable common options for performing profile feedback directed optimizations

fprofile-use=
Common Joined RejectNegative
Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=

fprofile-values
Common Report Var(flag_profile_values)
Insert code to profile values of expressions

fprofile-report
Common Report Var(profile_report)
Report on consistency of profile

frandom-seed
Common Var(common_deferred_options) Defer

frandom-seed=
Common Joined RejectNegative Var(common_deferred_options) Defer
-frandom-seed=<string>	Make compile reproducible using <string>

; This switch causes the command line that was used to create an
; object file to be recorded into the object file.  The exact format
; of this recording is target and binary file format dependent.
; It is related to the -fverbose-asm switch, but that switch only
; records information in the assembler output file as comments, so
; they never reach the object file.
frecord-gcc-switches
Common Report Var(flag_record_gcc_switches)
Record gcc command line switches in the object file.

freg-struct-return
Common Report Var(flag_pcc_struct_return,0) Optimization
Return small aggregates in registers

fregmove
Common Report Var(flag_regmove) Optimization
Enables a register move optimization

frename-registers
Common Report Var(flag_rename_registers) Init(2) Optimization
Perform a register renaming optimization pass

freorder-blocks
Common Report Var(flag_reorder_blocks) Optimization
Reorder basic blocks to improve code placement

freorder-blocks-and-partition
Common Report Var(flag_reorder_blocks_and_partition) Optimization
Reorder basic blocks and partition into hot and cold sections

freorder-functions
Common Report Var(flag_reorder_functions) Optimization
Reorder functions to improve code placement

frerun-cse-after-loop
Common Report Var(flag_rerun_cse_after_loop) Optimization
Add a common subexpression elimination pass after loop optimizations

frerun-loop-opt
Common Ignore
Does nothing.  Preserved for backward compatibility.

frounding-math
Common Report Var(flag_rounding_math) Optimization SetByCombined
Disable optimizations that assume default FP rounding behavior

fsched-interblock
Common Report Var(flag_schedule_interblock) Init(1) Optimization
Enable scheduling across basic blocks

fsched-pressure
Common Report Var(flag_sched_pressure) Init(0) Optimization
Enable register pressure sensitive insn scheduling

fsched-spec
Common Report Var(flag_schedule_speculative) Init(1) Optimization
Allow speculative motion of non-loads

fsched-spec-load
Common Report Var(flag_schedule_speculative_load) Optimization
Allow speculative motion of some loads

fsched-spec-load-dangerous
Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
Allow speculative motion of more loads

fsched-verbose=
Common RejectNegative Joined UInteger Var(sched_verbose_param)
-fsched-verbose=<number>	Set the verbosity level of the scheduler

fsched2-use-superblocks
Common Report Var(flag_sched2_use_superblocks) Optimization
If scheduling post reload, do superblock scheduling

fsched2-use-traces
Common Ignore
Does nothing.  Preserved for backward compatibility.

fschedule-insns
Common Report Var(flag_schedule_insns) Optimization
Reschedule instructions before register allocation

fschedule-insns2
Common Report Var(flag_schedule_insns_after_reload) Optimization
Reschedule instructions after register allocation

; This flag should be on when a target implements non-trivial
; scheduling hooks, maybe saving some information for its own sake.
; On IA64, for example, this is used for correct bundling. 
fselective-scheduling
Common Report Var(flag_selective_scheduling) Optimization
Schedule instructions using selective scheduling algorithm

fselective-scheduling2
Common Report Var(flag_selective_scheduling2) Optimization 
Run selective scheduling after reload

fsel-sched-pipelining
Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
Perform software pipelining of inner loops during selective scheduling

fsel-sched-pipelining-outer-loops
Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
Perform software pipelining of outer loops during selective scheduling

fsel-sched-reschedule-pipelined
Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
Reschedule pipelined regions without pipelining

; sched_stalled_insns means that insns can be moved prematurely from the queue
; of stalled insns into the ready list.
fsched-stalled-insns
Common Report Var(flag_sched_stalled_insns) Optimization UInteger
Allow premature scheduling of queued insns

fsched-stalled-insns=
Common RejectNegative Joined UInteger
-fsched-stalled-insns=<number>	Set number of queued insns that can be prematurely scheduled

; sched_stalled_insns_dep controls how many recently scheduled cycles will
; be examined for a dependency on a stalled insn that is candidate for
; premature removal from the queue of stalled insns into the ready list (has
; an effect only if the flag 'sched_stalled_insns' is set).
fsched-stalled-insns-dep
Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
Set dependence distance checking in premature scheduling of queued insns

fsched-stalled-insns-dep=
Common RejectNegative Joined UInteger
-fsched-stalled-insns-dep=<number>	Set dependence distance checking in premature scheduling of queued insns

fsched-group-heuristic
Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
Enable the group heuristic in the scheduler

fsched-critical-path-heuristic
Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
Enable the critical path heuristic in the scheduler

fsched-spec-insn-heuristic
Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
Enable the speculative instruction heuristic in the scheduler

fsched-rank-heuristic
Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
Enable the rank heuristic in the scheduler

fsched-last-insn-heuristic
Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
Enable the last instruction heuristic in the scheduler

fsched-dep-count-heuristic
Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
Enable the dependent count heuristic in the scheduler

fsection-anchors
Common Report Var(flag_section_anchors) Optimization
Access data in the same section from shared anchor points

fsee
Common Ignore
Does nothing.  Preserved for backward compatibility.

fzee
Common Ignore
Does nothing.  Preserved for backward compatibility.

free
Common Report Var(flag_ree) Init(0)
Turn on Redundant Extensions Elimination pass.

fshow-column
Common Report Var(flag_show_column) Init(1)
Show column numbers in diagnostics, when available.  Default on

fshrink-wrap
Common Report Var(flag_shrink_wrap) Optimization
Emit function prologues only before parts of the function that need it,
rather than at the top of the function.

fsignaling-nans
Common Report Var(flag_signaling_nans) Optimization SetByCombined
Disable optimizations observable by IEEE signaling NaNs

fsigned-zeros
Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
Disable floating point optimizations that ignore the IEEE signedness of zero

fsingle-precision-constant
Common Report Var(flag_single_precision_constant) Optimization
Convert floating point constants to single precision constants

fsplit-ivs-in-unroller
Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
Split lifetimes of induction variables when loops are unrolled

fsplit-stack
Common Report Var(flag_split_stack) Init(-1)
Generate discontiguous stack frames

fsplit-wide-types
Common Report Var(flag_split_wide_types) Optimization
Split wide types into independent registers

fvariable-expansion-in-unroller
Common Report Var(flag_variable_expansion_in_unroller) Optimization
Apply variable expansion when loops are unrolled

fstack-check=
Common Report RejectNegative Joined
-fstack-check=[no|generic|specific]	Insert stack checking code into the program

fstack-check
Common Alias(fstack-check=, specific, no)
Insert stack checking code into the program.  Same as -fstack-check=specific

fstack-limit
Common Var(common_deferred_options) Defer

fstack-limit-register=
Common RejectNegative Joined Var(common_deferred_options) Defer
-fstack-limit-register=<register>	Trap if the stack goes past <register>

fstack-limit-symbol=
Common RejectNegative Joined Var(common_deferred_options) Defer
-fstack-limit-symbol=<name>	Trap if the stack goes past symbol <name>

fstack-protector
Common Report Var(flag_stack_protect, 1)
Use propolice as a stack protection method

fstack-protector-all
Common Report RejectNegative Var(flag_stack_protect, 2)
Use a stack protection method for every function

fstack-usage
Common RejectNegative Var(flag_stack_usage)
Output stack usage information on a per-function basis

fstrength-reduce
Common Ignore
Does nothing.  Preserved for backward compatibility.

; Nonzero if we should do (language-dependent) alias analysis.
; Typically, this analysis will assume that expressions of certain
; types do not alias expressions of certain other types.  Only used
; if alias analysis (in general) is enabled.
fstrict-aliasing
Common Report Var(flag_strict_aliasing) Optimization
Assume strict aliasing rules apply

fstrict-overflow
Common Report Var(flag_strict_overflow)
Treat signed overflow as undefined

fsync-libcalls
Common Report Var(flag_sync_libcalls) Init(1)
Implement __atomic operations via libcalls to legacy __sync functions

fsyntax-only
Common Report Var(flag_syntax_only)
Check for syntax errors, then stop

ftest-coverage
Common Report Var(flag_test_coverage)
Create data files needed by \"gcov\"

fthread-jumps
Common Report Var(flag_thread_jumps) Optimization
Perform jump threading optimizations

ftime-report
Common Report Var(time_report)
Report the time taken by each compiler pass

ftls-model=
Common Joined RejectNegative Enum(tls_model) Var(flag_tls_default) Init(TLS_MODEL_GLOBAL_DYNAMIC)
-ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec]	Set the default thread-local storage code generation model

Enum
Name(tls_model) Type(enum tls_model) UnknownError(unknown TLS model %qs)

EnumValue
Enum(tls_model) String(global-dynamic) Value(TLS_MODEL_GLOBAL_DYNAMIC)

EnumValue
Enum(tls_model) String(local-dynamic) Value(TLS_MODEL_LOCAL_DYNAMIC)

EnumValue
Enum(tls_model) String(initial-exec) Value(TLS_MODEL_INITIAL_EXEC)

EnumValue
Enum(tls_model) String(local-exec) Value(TLS_MODEL_LOCAL_EXEC)

ftoplevel-reorder
Common Report Var(flag_toplevel_reorder) Init(2) Optimization
Reorder top level functions, variables, and asms

ftracer
Common Report Var(flag_tracer)
Perform superblock formation via tail duplication

; Zero means that floating-point math operations cannot generate a
; (user-visible) trap.  This is the case, for example, in nonstop
; IEEE 754 arithmetic.
ftrapping-math
Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
Assume floating-point operations can trap

ftrapv
Common Report Var(flag_trapv) Optimization
Trap for signed overflow in addition, subtraction and multiplication

ftree-ccp
Common Report Var(flag_tree_ccp) Optimization
Enable SSA-CCP optimization on trees

ftree-bit-ccp
Common Report Var(flag_tree_bit_ccp) Optimization
Enable SSA-BIT-CCP optimization on trees

ftree-store-ccp
Common Ignore
Does nothing.  Preserved for backward compatibility.

ftree-ch
Common Report Var(flag_tree_ch) Optimization
Enable loop header copying on trees

ftree-coalesce-inlined-vars
Common Report Var(flag_ssa_coalesce_vars,1) Init(2) RejectNegative Optimization
Enable coalescing of copy-related user variables that are inlined

ftree-coalesce-vars
Common Report Var(flag_ssa_coalesce_vars,2) Optimization
Enable coalescing of all copy-related user variables

ftree-copyrename
Common Report Var(flag_tree_copyrename) Optimization
Replace SSA temporaries with better names in copies

ftree-copy-prop
Common Report Var(flag_tree_copy_prop) Optimization
Enable copy propagation on trees

ftree-store-copy-prop
Common Ignore
Does nothing.  Preserved for backward compatibility.

ftree-cselim
Common Report Var(flag_tree_cselim) Init(2) Optimization
Transform condition stores into unconditional ones

ftree-switch-conversion
Common Report Var(flag_tree_switch_conversion) Optimization
Perform conversions of switch initializations.

ftree-dce
Common Report Var(flag_tree_dce) Optimization
Enable SSA dead code elimination optimization on trees

ftree-dominator-opts
Common Report Var(flag_tree_dom) Optimization
Enable dominator optimizations

ftree-tail-merge
Common Report Var(flag_tree_tail_merge) Optimization
Enable tail merging on trees

ftree-dse
Common Report Var(flag_tree_dse) Optimization
Enable dead store elimination

ftree-forwprop
Common Report Var(flag_tree_forwprop) Init(1) Optimization
Enable forward propagation on trees

ftree-fre
Common Report Var(flag_tree_fre) Optimization
Enable Full Redundancy Elimination (FRE) on trees

foptimize-strlen
Common Report Var(flag_optimize_strlen) Optimization
Enable string length optimizations on trees

ftree-loop-distribution
Common Report Var(flag_tree_loop_distribution) Optimization
Enable loop distribution on trees

ftree-loop-distribute-patterns
Common Report Var(flag_tree_loop_distribute_patterns) Optimization
Enable loop distribution for patterns transformed into a library call

ftree-loop-im
Common Report Var(flag_tree_loop_im) Init(1) Optimization
Enable loop invariant motion on trees

ftree-loop-linear
Common Alias(floop-interchange)
Enable loop interchange transforms.  Same as -floop-interchange

ftree-loop-ivcanon
Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
Create canonical induction variables in loops

ftree-loop-optimize
Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
Enable loop optimizations on tree level

ftree-parallelize-loops=
Common Report Joined RejectNegative UInteger Var(flag_tree_parallelize_loops) Init(1)
Enable automatic parallelization of loops

ftree-phiprop
Common Report Var(flag_tree_phiprop) Init(1) Optimization
Enable hoisting loads from conditional pointers.

ftree-pre
Common Report Var(flag_tree_pre) Optimization
Enable SSA-PRE optimization on trees

ftree-partial-pre
Common Report Var(flag_tree_partial_pre) Optimization
In SSA-PRE optimization on trees, enable partial-partial redundancy elimination

ftree-pta
Common Report Var(flag_tree_pta) Init(1) Optimization
Perform function-local points-to analysis on trees.

ftree-reassoc
Common Report Var(flag_tree_reassoc) Init(1) Optimization
Enable reassociation on tree level

ftree-salias
Common Ignore
Does nothing.  Preserved for backward compatibility.

ftree-sink
Common Report Var(flag_tree_sink) Optimization
Enable SSA code sinking on trees

ftree-slsr
Common Report Var(flag_tree_slsr) Optimization
Perform straight-line strength reduction

ftree-sra
Common Report Var(flag_tree_sra) Optimization
Perform scalar replacement of aggregates

ftree-ter
Common Report Var(flag_tree_ter) Optimization
Replace temporary expressions in the SSA->normal pass

ftree-lrs
Common Report Var(flag_tree_live_range_split) Optimization
Perform live range splitting during the SSA->normal pass

ftree-vrp
Common Report Var(flag_tree_vrp) Init(0) Optimization
Perform Value Range Propagation on trees

funit-at-a-time
Common Report Var(flag_unit_at_a_time) Init(1) Optimization
Compile whole compilation unit at a time

funroll-loops
Common Report Var(flag_unroll_loops) Optimization
Perform loop unrolling when iteration count is known

funroll-all-loops
Common Report Var(flag_unroll_all_loops) Optimization
Perform loop unrolling for all loops

; Nonzero means that loop optimizer may assume that the induction variables
; that control loops do not overflow and that the loops with nontrivial
; exit condition are not infinite
funsafe-loop-optimizations
Common Report Var(flag_unsafe_loop_optimizations) Optimization
Allow loop optimizations to assume that the loops behave in normal way

fassociative-math
Common Report Var(flag_associative_math) SetByCombined
Allow optimization for floating-point arithmetic which may change the
result of the operation due to rounding.

freciprocal-math
Common Report Var(flag_reciprocal_math) SetByCombined
Same as -fassociative-math for expressions which include division.

; Nonzero means that unsafe floating-point math optimizations are allowed
; for the sake of speed.  IEEE compliance is not guaranteed, and operations
; are allowed to assume that their arguments and results are "normal"
; (e.g., nonnegative for SQRT).
funsafe-math-optimizations
Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
Allow math optimizations that may violate IEEE or ISO standards

funswitch-loops
Common Report Var(flag_unswitch_loops) Optimization
Perform loop unswitching

funwind-tables
Common Report Var(flag_unwind_tables) Optimization
Just generate unwind tables for exception handling

fuse-ld=bfd
Common Negative(fuse-ld=gold)
Use the bfd linker instead of the default linker

fuse-ld=gold
Common Negative(fuse-ld=bfd)
Use the gold linker instead of the default linker

fuse-linker-plugin
Common Undocumented

; Positive if we should track variables, negative if we should run
; the var-tracking pass only to discard debug annotations, zero if
; we're not to run it.  When flag_var_tracking == 2 (AUTODETECT_VALUE) it
; will be set according to optimize, debug_info_level and debug_hooks
; in process_options ().
fvar-tracking
Common Report Var(flag_var_tracking) Init(2) Optimization
Perform variable tracking

; Positive if we should track variables at assignments, negative if
; we should run the var-tracking pass only to discard debug
; annotations.  When flag_var_tracking_assignments ==
; AUTODETECT_VALUE it will be set according to flag_var_tracking.
fvar-tracking-assignments
Common Report Var(flag_var_tracking_assignments) Init(2) Optimization
Perform variable tracking by annotating assignments

; Nonzero if we should toggle flag_var_tracking_assignments after
; processing options and computing its default.  */
fvar-tracking-assignments-toggle
Common Report Var(flag_var_tracking_assignments_toggle) Optimization
Toggle -fvar-tracking-assignments

; Positive if we should track uninitialized variables, negative if
; we should run the var-tracking pass only to discard debug
; annotations.  When flag_var_tracking_uninit == AUTODETECT_VALUE it
; will be set according to flag_var_tracking.
fvar-tracking-uninit
Common Report Var(flag_var_tracking_uninit) Optimization
Perform variable tracking and also tag variables that are uninitialized

ftree-vectorize
Common Report Var(flag_tree_vectorize) Optimization
Enable loop vectorization on trees

ftree-vectorizer-verbose=
Common RejectNegative Joined UInteger Var(common_deferred_options) Defer
-ftree-vectorizer-verbose=<number>	This switch is deprecated. Use -fopt-info instead.

ftree-slp-vectorize
Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
Enable basic block vectorization (SLP) on trees

fvect-cost-model
Common Report Var(flag_vect_cost_model) Optimization
Enable use of cost model in vectorization

ftree-vect-loop-version
Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
Enable loop versioning when doing loop vectorization on trees

ftree-scev-cprop
Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
Enable copy propagation of scalar-evolution information.

; -fverbose-asm causes extra commentary information to be produced in
; the generated assembly code (to make it more readable).  This option
; is generally only of use to those who actually need to read the
; generated assembly code (perhaps while debugging the compiler itself).
; -fno-verbose-asm, the default, causes the extra information
; to not be added and is useful when comparing two assembler files.
fverbose-asm
Common Report Var(flag_verbose_asm)
Add extra commentary to assembler output

fvisibility=
Common Joined RejectNegative Enum(symbol_visibility) Var(default_visibility) Init(VISIBILITY_DEFAULT)
-fvisibility=[default|internal|hidden|protected]	Set the default symbol visibility

Enum
Name(symbol_visibility) Type(enum symbol_visibility) UnknownError(unrecognized visibility value %qs)

EnumValue
Enum(symbol_visibility) String(default) Value(VISIBILITY_DEFAULT)

EnumValue
Enum(symbol_visibility) String(internal) Value(VISIBILITY_INTERNAL)

EnumValue
Enum(symbol_visibility) String(hidden) Value(VISIBILITY_HIDDEN)

EnumValue
Enum(symbol_visibility) String(protected) Value(VISIBILITY_PROTECTED)

fvpt
Common Report Var(flag_value_profile_transformations) Optimization
Use expression value profiles in optimizations

fweb
Common Report Var(flag_web) Init(2) Optimization
Construct webs and split unrelated uses of single variable

ftree-builtin-call-dce
Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
Enable conditional dead code elimination for builtin calls

fwhole-program
Common Report Var(flag_whole_program) Init(0) Optimization
Perform whole program optimizations

fwrapv
Common Report Var(flag_wrapv) Optimization
Assume signed arithmetic overflow wraps around

fzero-initialized-in-bss
Common Report Var(flag_zero_initialized_in_bss) Init(1)
Put zero initialized data in the bss section

g
Common JoinedOrMissing
Generate debug information in default format

gcoff
Common JoinedOrMissing Negative(gdwarf-)
Generate debug information in COFF format

gdwarf-
Common Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
Generate debug information in DWARF v2 (or later) format

ggdb
Common JoinedOrMissing
Generate debug information in default extended format

gno-pubnames
Common RejectNegative Var(debug_generate_pub_sections, 0) Init(-1)
Don't generate DWARF pubnames and pubtypes sections.

gpubnames
Common RejectNegative Var(debug_generate_pub_sections, 1)
Generate DWARF pubnames and pubtypes sections.

gno-record-gcc-switches
Common RejectNegative Var(dwarf_record_gcc_switches,0) Init(1)
Don't record gcc command line switches in DWARF DW_AT_producer.

grecord-gcc-switches
Common RejectNegative Var(dwarf_record_gcc_switches,1)
Record gcc command line switches in DWARF DW_AT_producer.

gno-split-dwarf
Common Driver RejectNegative Var(dwarf_split_debug_info,0) Init(0)
Don't generate debug information in separate .dwo files

gsplit-dwarf
Common Driver RejectNegative Var(dwarf_split_debug_info,1)
Generate debug information in separate .dwo files

gstabs
Common JoinedOrMissing Negative(gstabs+)
Generate debug information in STABS format

gstabs+
Common JoinedOrMissing Negative(gvms)
Generate debug information in extended STABS format

gno-strict-dwarf
Common RejectNegative Var(dwarf_strict,0) Init(0)
Emit DWARF additions beyond selected version

gstrict-dwarf
Common Report RejectNegative Var(dwarf_strict,1)
Don't emit DWARF additions beyond selected version

gtoggle
Common Report Var(flag_gtoggle)
Toggle debug information generation

gvms
Common JoinedOrMissing Negative(gxcoff)
Generate debug information in VMS format

gxcoff
Common JoinedOrMissing Negative(gxcoff+)
Generate debug information in XCOFF format

gxcoff+
Common JoinedOrMissing Negative(gcoff)
Generate debug information in extended XCOFF format

h
Driver Joined Separate

iplugindir=
Common Joined Var(plugindir_string) Init(0)
-iplugindir=<dir>	Set <dir> to be the default plugin directory

imultiarch
Common Joined Separate RejectDriver Var(imultiarch) Init(0)
-imultiarch <dir>	Set <dir> to be the multiarch include subdirectory

l
Driver Joined Separate

n
Driver

no-canonical-prefixes
Driver

nodefaultlibs
Driver

nostartfiles
Driver

nostdlib
Driver

o
Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs)
-o <file>	Place output into <file>

p
Common Var(profile_flag)
Enable function profiling

pass-exit-codes
Driver Var(pass_exit_codes)

pedantic
Common Alias(Wpedantic)

pedantic-errors
Common Var(flag_pedantic_errors)
Like -pedantic but issue them as errors

pg
Driver

pipe
Driver Var(use_pipes)

print-file-name=
Driver JoinedOrMissing Var(print_file_name)

print-libgcc-file-name
Driver

print-multi-directory
Driver Var(print_multi_directory)

print-multi-lib
Driver Var(print_multi_lib)

print-multi-os-directory
Driver Var(print_multi_os_directory)
 
print-multiarch
Driver Var(print_multiarch)

print-prog-name=
Driver JoinedOrMissing Var(print_prog_name)

print-search-dirs
Driver Var(print_search_dirs)

print-sysroot
Driver Var(print_sysroot)

print-sysroot-headers-suffix
Driver Var(print_sysroot_headers_suffix)

quiet
Common Var(quiet_flag) RejectDriver
Do not display functions compiled or elapsed time

r
Driver

s
Driver

save-temps
Driver

save-temps=
Driver Joined

t
Driver

time
Driver Var(report_times)

time=
Driver JoinedOrMissing

u
Driver Joined Separate

undef
Driver
; C option, but driver must not handle as "-u ndef".

v
Common Driver Var(verbose_flag)
Enable verbose output

version
Common Var(version_flag) RejectDriver
Display the compiler's version

w
Common Var(inhibit_warnings)
Suppress warnings

wrapper
Driver Separate Var(wrapper_string)

x
Driver Joined Separate

shared
Driver RejectNegative Negative(pie)
Create a shared library

shared-libgcc
Driver

specs
Driver Separate Alias(specs=)

specs=
Driver Joined

static
Driver

static-libgcc
Driver

static-libgfortran
Driver
; Documented for Fortran, but always accepted by driver.

static-libstdc++
Driver

static-libgo
Driver
; Documented for Go, but always accepted by driver.

static-libasan
Driver

static-libtsan
Driver

symbolic
Driver

pie
Driver RejectNegative Negative(shared)
Create a position independent executable

z
Driver Joined Separate

; This comment is to ensure we retain the blank line above.