gcc/c-family/c.opt

; Options for the C, ObjC, C++ and ObjC++ front ends.
; Copyright (C) 2003-2017 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 for a description of this file's format.

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

Language
C

Language
ObjC

Language
C++

Language
ObjC++

-all-warnings
C ObjC C++ ObjC++ Warning Alias(Wall)

-ansi
C ObjC C++ ObjC++ Alias(ansi)

-assert
C ObjC C++ ObjC++ Separate Alias(A) MissingArgError(assertion missing after %qs)

-assert=
C ObjC C++ ObjC++ Joined Alias(A) MissingArgError(assertion missing after %qs)

-comments
C ObjC C++ ObjC++ Alias(C)

-comments-in-macros
C ObjC C++ ObjC++ Alias(CC)

-define-macro
C ObjC C++ ObjC++ Separate Alias(D) MissingArgError(macro name missing after %qs)

-define-macro=
C ObjC C++ ObjC++ Joined Alias(D) MissingArgError(macro name missing after %qs)

-dependencies
C ObjC C++ ObjC++ Alias(M)

-dump
C ObjC C++ ObjC++ Separate Alias(d)

-dump=
C ObjC C++ ObjC++ Joined Alias(d)

-imacros
C ObjC C++ ObjC++ Separate Alias(imacros) MissingArgError(missing filename after %qs)

-imacros=
C ObjC C++ ObjC++ Joined Alias(imacros) MissingArgError(missing filename after %qs)

-include
C ObjC C++ ObjC++ Separate Alias(include) MissingArgError(missing filename after %qs)

-include=
C ObjC C++ ObjC++ Joined Alias(include) MissingArgError(missing filename after %qs)

-include-barrier
C ObjC C++ ObjC++ Alias(I, -)

-include-directory
C ObjC C++ ObjC++ Separate Alias(I) MissingArgError(missing path after %qs)

-include-directory=
C ObjC C++ ObjC++ Joined Alias(I) MissingArgError(missing path after %qs)

-include-directory-after
C ObjC C++ ObjC++ Separate Alias(idirafter) MissingArgError(missing path after %qs)

-include-directory-after=
C ObjC C++ ObjC++ Joined Alias(idirafter) MissingArgError(missing path after %qs)

-include-prefix
C ObjC C++ ObjC++ Separate Alias(iprefix)

-include-prefix=
C ObjC C++ ObjC++ JoinedOrMissing Alias(iprefix)

-include-with-prefix
C ObjC C++ ObjC++ Separate Alias(iwithprefix)

-include-with-prefix=
C ObjC C++ ObjC++ JoinedOrMissing Alias(iwithprefix)

-include-with-prefix-after
C ObjC C++ ObjC++ Separate Alias(iwithprefix)

-include-with-prefix-after=
C ObjC C++ ObjC++ JoinedOrMissing Alias(iwithprefix)

-include-with-prefix-before
C ObjC C++ ObjC++ Separate Alias(iwithprefixbefore)

-include-with-prefix-before=
C ObjC C++ ObjC++ JoinedOrMissing Alias(iwithprefixbefore)

-no-integrated-cpp
Driver Alias(no-integrated-cpp)

-no-line-commands
C ObjC C++ ObjC++ Alias(P)

-no-standard-includes
C ObjC C++ ObjC++ Alias(nostdinc)

-no-warnings
C ObjC C++ ObjC++ Alias(w)

-output
C ObjC C++ ObjC++ Separate Alias(o)

-output=
C ObjC C++ ObjC++ Joined Alias(o)

-output-pch=
C ObjC C++ ObjC++ Joined Separate

-pedantic
C ObjC C++ ObjC++ Alias(pedantic)

-preprocess
C ObjC C++ ObjC++ Undocumented Alias(E)

-print-missing-file-dependencies
C ObjC C++ ObjC++ Alias(MG)

-trace-includes
C ObjC C++ ObjC++ Alias(H)

-traditional
Driver Alias(traditional)

-traditional-cpp
C ObjC C++ ObjC++ Alias(traditional-cpp)

-trigraphs
C ObjC C++ ObjC++ Alias(trigraphs)

-undefine-macro
C ObjC C++ ObjC++ Separate Alias(U) MissingArgError(macro name missing after %qs)

-undefine-macro=
C ObjC C++ ObjC++ Joined Alias(U) MissingArgError(macro name missing after %qs)

-user-dependencies
C ObjC C++ ObjC++ Alias(MM)

-verbose
Common C ObjC C++ ObjC++ Alias(v)

-write-dependencies
C ObjC C++ ObjC++ NoDriverArg Separate Alias(MD) MissingArgError(missing filename after %qs)

-write-user-dependencies
C ObjC C++ ObjC++ NoDriverArg Separate Alias(MMD) MissingArgError(missing filename after %qs)

A
C ObjC C++ ObjC++ Joined Separate MissingArgError(assertion missing after %qs)
-A<question>=<answer>	Assert the <answer> to <question>.  Putting '-' before <question> disables the <answer> to <question>.

C
C ObjC C++ ObjC++
Do not discard comments.

CC
C ObjC C++ ObjC++
Do not discard comments in macro expansions.

D
C ObjC C++ ObjC++ Joined Separate MissingArgError(macro name missing after %qs)
-D<macro>[=<val>]	Define a <macro> with <val> as its value.  If just <macro> is given, <val> is taken to be 1.

E
C ObjC C++ ObjC++ Undocumented Var(flag_preprocess_only)

F
Driver C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-F <dir>	Add <dir> to the end of the main framework include path.

fgimple
C Var(flag_gimple) Init(0)
Enable parsing GIMPLE.

H
C ObjC C++ ObjC++
Print the name of header files as they are used.

I
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-I <dir>	Add <dir> to the end of the main include path.

M
C ObjC C++ ObjC++
Generate make dependencies.

MD
C ObjC C++ ObjC++ NoDriverArg Separate MissingArgError(missing filename after %qs)
Generate make dependencies and compile.

MF
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing filename after %qs)
-MF <file>	Write dependency output to the given file.

MG
C ObjC C++ ObjC++
Treat missing header files as generated files.

MM
C ObjC C++ ObjC++
Like -M but ignore system header files.

MMD
C ObjC C++ ObjC++ NoDriverArg Separate MissingArgError(missing filename after %qs)
Like -MD but ignore system header files.

MP
C ObjC C++ ObjC++
Generate phony targets for all headers.

MQ
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing makefile target after %qs)
-MQ <target>	Add a MAKE-quoted target.

MT
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing makefile target after %qs)
-MT <target>	Add an unquoted target.

P
C ObjC C++ ObjC++
Do not generate #line directives.

U
C ObjC C++ ObjC++ Joined Separate MissingArgError(macro name missing after %qs)
-U<macro>	Undefine <macro>.

Wabi
C ObjC C++ ObjC++ LTO Var(warn_abi) Warning
Warn about things that will change when compiling with an ABI-compliant compiler.

Wabi=
C ObjC C++ ObjC++ LTO Joined RejectNegative UInteger Warning
Warn about things that change between the current -fabi-version and the specified version.

Wabi-tag
C++ ObjC++ Var(warn_abi_tag) Warning
Warn if a subobject has an abi_tag attribute that the complete object type does not have.

Wpsabi
C ObjC C++ ObjC++ LTO Var(warn_psabi) Init(1) Warning Undocumented LangEnabledBy(C ObjC C++ ObjC++,Wabi)

Waddress
C ObjC C++ ObjC++ Var(warn_address) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about suspicious uses of memory addresses.

Enum
Name(warn_aligned_new_level) Type(int) UnknownError(argument %qs to %<-Waligned-new%> not recognized)

EnumValue
Enum(warn_aligned_new_level) String(none) Value(0)

EnumValue
Enum(warn_aligned_new_level) String(global) Value(1)

EnumValue
Enum(warn_aligned_new_level) String(all) Value(2)

Waligned-new
C++ ObjC++ Alias(Waligned-new=,global,none)
Warn about 'new' of type with extended alignment without -faligned-new.

Waligned-new=
C++ ObjC++ Var(warn_aligned_new) Enum(warn_aligned_new_level) Joined RejectNegative Warning LangEnabledBy(C++ ObjC++,Wall,1,0)
-Waligned-new=[none|global|all]	Warn even if 'new' uses a class member allocation function.

Wall
C ObjC C++ ObjC++ Warning
Enable most warning messages.

Walloca
C ObjC C++ ObjC++ Var(warn_alloca) Warning
Warn on any use of alloca.

Walloc-size-larger-than=
C ObjC C++ ObjC++ Var(warn_alloc_size_limit) Warning Joined
-Walloc-size-larger-than=<bytes> Warn for calls to allocation functions that
attempt to allocate objects larger than the specified number of bytes.

Walloc-zero
C ObjC C++ ObjC++ Var(warn_alloc_zero) Warning
-Walloc-zero Warn for calls to allocation functions that specify zero bytes.

Walloca-larger-than=
C ObjC C++ LTO ObjC++ Var(warn_alloca_limit) Warning Joined RejectNegative UInteger
-Walloca-larger-than=<number>	Warn on unbounded uses of
alloca, and on bounded uses of alloca whose bound can be larger than
<number> bytes.

Warray-bounds
LangEnabledBy(C ObjC C++ ObjC++,Wall)
; in common.opt

Warray-bounds=
LangEnabledBy(C ObjC C++ ObjC++,Wall,1,0)
; in common.opt

Wassign-intercept
ObjC ObjC++ Var(warn_assign_intercept) Warning
Warn whenever an Objective-C assignment is being intercepted by the garbage collector.

Wbad-function-cast
C ObjC Var(warn_bad_function_cast) Warning
Warn about casting functions to incompatible types.

Wbool-compare
C ObjC C++ ObjC++ Var(warn_bool_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about boolean expression compared with an integer value different from true/false.

Wbool-operation
C ObjC C++ ObjC++ Var(warn_bool_op) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about certain operations on boolean expressions.

Wframe-address
C ObjC C++ ObjC++ Var(warn_frame_address) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn when __builtin_frame_address or __builtin_return_address is used unsafely.

Wbuiltin-declaration-mismatch
C ObjC C++ ObjC++ Var(warn_builtin_declaraion_mismatch) Init(1) Warning
Warn when a built-in function is declared with the wrong signature.

Wbuiltin-macro-redefined
C ObjC C++ ObjC++ CPP(warn_builtin_macro_redefined) CppReason(CPP_W_BUILTIN_MACRO_REDEFINED) Var(cpp_warn_builtin_macro_redefined) Init(1) Warning
Warn when a built-in preprocessor macro is undefined or redefined.

Wc90-c99-compat
C ObjC CPP(cpp_warn_c90_c99_compat) CppReason(CPP_W_C90_C99_COMPAT) Var(warn_c90_c99_compat) Init(-1) Warning
Warn about features not present in ISO C90, but present in ISO C99.

Wc99-c11-compat
C ObjC Var(warn_c99_c11_compat) Init(-1) Warning
Warn about features not present in ISO C99, but present in ISO C11.

Wc++-compat
C ObjC Var(warn_cxx_compat) CPP(warn_cxx_operator_names) CppReason(CPP_W_CXX_OPERATOR_NAMES) Init(0) Warning
Warn about C constructs that are not in the common subset of C and C++.

Wc++0x-compat
C++ ObjC++ Warning Alias(Wc++11-compat) Undocumented

Wc++11-compat
C++ ObjC++ Var(warn_cxx11_compat) Warning LangEnabledBy(C++ ObjC++,Wall) Init(0) CPP(cpp_warn_cxx11_compat) CppReason(CPP_W_CXX11_COMPAT)
Warn about C++ constructs whose meaning differs between ISO C++ 1998 and ISO C++ 2011.

Wc++14-compat
C++ ObjC++ Var(warn_cxx14_compat) Warning LangEnabledBy(C++ ObjC++,Wall)
Warn about C++ constructs whose meaning differs between ISO C++ 2011 and ISO C++ 2014.

Wc++1z-compat
C++ ObjC++ Var(warn_cxx1z_compat) Warning LangEnabledBy(C++ ObjC++,Wall)
Warn about C++ constructs whose meaning differs between ISO C++ 2014 and (forthcoming) ISO C++ 201z(7?).

Wc++17-compat
C++ ObjC++ Warning Alias(Wc++1z-compat) Undocumented

Wcast-qual
C ObjC C++ ObjC++ Var(warn_cast_qual) Warning
Warn about casts which discard qualifiers.

Wchar-subscripts
C ObjC C++ ObjC++ Var(warn_char_subscripts) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about subscripts whose type is \"char\".

Wchkp
C ObjC C++ ObjC++ Var(warn_chkp) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about memory access errors found by Pointer Bounds Checker.

Wclobbered
C ObjC C++ ObjC++ Var(warn_clobbered) Warning EnabledBy(Wextra)
Warn about variables that might be changed by \"longjmp\" or \"vfork\".

Wcomment
C ObjC C++ ObjC++ CPP(warn_comments) CppReason(CPP_W_COMMENTS) Var(cpp_warn_comment) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about possibly nested block comments, and C++ comments spanning more than one physical line.

Wcomments
C ObjC C++ ObjC++ Warning Alias(Wcomment)
Synonym for -Wcomment.

Wconditionally-supported
C++ ObjC++ Var(warn_conditionally_supported) Warning
Warn for conditionally-supported constructs.

Wconversion
C ObjC C++ ObjC++ Var(warn_conversion) Warning
Warn for implicit type conversions that may change a value.

Wconversion-null
C++ ObjC++ Var(warn_conversion_null) Init(1) Warning
Warn for converting NULL from/to a non-pointer type.

Wcpp
C ObjC C++ ObjC++ CppReason(CPP_W_WARNING_DIRECTIVE)
; Documented in common.opt

Wctor-dtor-privacy
C++ ObjC++ Var(warn_ctor_dtor_privacy) Warning
Warn when all constructors and destructors are private.

Wdangling-else
C ObjC C++ ObjC++ Var(warn_dangling_else) Warning LangEnabledBy(C ObjC C++ ObjC++,Wparentheses)
Warn about dangling else.

Wdate-time
C ObjC C++ ObjC++ CPP(warn_date_time) CppReason(CPP_W_DATE_TIME) Var(cpp_warn_date_time) Init(0) Warning
Warn about __TIME__, __DATE__ and __TIMESTAMP__ usage.

Wdeclaration-after-statement
C ObjC Var(warn_declaration_after_statement) Init(-1) Warning
Warn when a declaration is found after a statement.

Wdelete-incomplete
C++ ObjC++ Var(warn_delete_incomplete) Init(1) Warning
Warn when deleting a pointer to incomplete type.

Wdelete-non-virtual-dtor
C++ ObjC++ Var(warn_delnonvdtor) Warning LangEnabledBy(C++ ObjC++,Wall || Weffc++)
Warn about deleting polymorphic objects with non-virtual destructors.

Wdeprecated
C C++ ObjC ObjC++ CPP(cpp_warn_deprecated) CppReason(CPP_W_DEPRECATED) Var(warn_deprecated) Init(1) Warning
Warn if a deprecated compiler feature, class, method, or field is used.

Wdesignated-init
C ObjC Var(warn_designated_init) Init(1) Warning
Warn about positional initialization of structs requiring designated initializers.

Wdiscarded-array-qualifiers
C ObjC Var(warn_discarded_array_qualifiers) Init(1) Warning
Warn if qualifiers on arrays which are pointer targets are discarded.

Wdiscarded-qualifiers
C ObjC Var(warn_discarded_qualifiers) Init(1) Warning
Warn if type qualifiers on pointers are discarded.

Wdiv-by-zero
C ObjC C++ ObjC++ Var(warn_div_by_zero) Init(1) Warning
Warn about compile-time integer division by zero.

Wduplicated-branches
C ObjC C++ ObjC++ Var(warn_duplicated_branches) Init(0) Warning
Warn about duplicated branches in if-else statements.

Wduplicated-cond
C ObjC C++ ObjC++ Var(warn_duplicated_cond) Init(0) Warning
Warn about duplicated conditions in an if-else-if chain.

Weffc++
C++ ObjC++ Var(warn_ecpp) Warning
Warn about violations of Effective C++ style rules.

Wempty-body
C ObjC C++ ObjC++ Var(warn_empty_body) Warning EnabledBy(Wextra)
Warn about an empty body in an if or else statement.

Wendif-labels
C ObjC C++ ObjC++ CPP(warn_endif_labels) CppReason(CPP_W_ENDIF_LABELS) Var(cpp_warn_endif_labels) Init(1) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
Warn about stray tokens after #else and #endif.

Wenum-compare
C ObjC C++ ObjC++ Var(warn_enum_compare) Init(-1) Warning LangEnabledBy(C ObjC,Wall || Wc++-compat)
Warn about comparison of different enum types.

Werror
C ObjC C++ ObjC++
; Documented in common.opt

Werror-implicit-function-declaration
C ObjC RejectNegative Warning Alias(Werror=, implicit-function-declaration)
This switch is deprecated; use -Werror=implicit-function-declaration instead.

Wextra
C ObjC C++ ObjC++ Warning
; in common.opt

Wfloat-conversion
C ObjC C++ ObjC++ Var(warn_float_conversion) Warning LangEnabledBy(C ObjC C++ ObjC++,Wconversion)
Warn for implicit type conversions that cause loss of floating point precision.

Wfloat-equal
C ObjC C++ ObjC++ Var(warn_float_equal) Warning
Warn if testing floating point numbers for equality.

Wformat
C ObjC C++ ObjC++ Warning Alias(Wformat=, 1, 0)
Warn about printf/scanf/strftime/strfmon format string anomalies.

Wformat-contains-nul
C ObjC C++ ObjC++ Var(warn_format_contains_nul) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 1, 0)
Warn about format strings that contain NUL bytes.

Wformat-extra-args
C ObjC C++ ObjC++ Var(warn_format_extra_args) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 1, 0)
Warn if passing too many arguments to a function for its format string.

Wformat-nonliteral
C ObjC C++ ObjC++ Var(warn_format_nonliteral) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 2, 0)
Warn about format strings that are not literals.

Wformat-overflow
C ObjC C++ LTO ObjC++ Warning Alias(Wformat-overflow=, 1, 0)
Warn about function calls with format strings that write past the end
of the destination region.  Same as -Wformat-overflow=1.

Wformat-security
C ObjC C++ ObjC++ Var(warn_format_security) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 2, 0)
Warn about possible security problems with format functions.

Wformat-signedness
C ObjC C++ ObjC++ Var(warn_format_signedness) Warning
Warn about sign differences with format functions.

Wformat-truncation
C ObjC C++ LTO ObjC++ Warning Alias(Wformat-truncation=, 1, 0)
Warn about calls to snprintf and similar functions that truncate output.
Same as -Wformat-truncation=1.

Wformat-y2k
C ObjC C++ ObjC++ Var(warn_format_y2k) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=,warn_format >= 2, 0)
Warn about strftime formats yielding 2-digit years.

Wformat-zero-length
C ObjC C++ ObjC++ Var(warn_format_zero_length) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=,warn_format >= 1, 0)
Warn about zero-length formats.

Wformat=
C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_format) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall, 1, 0)
Warn about printf/scanf/strftime/strfmon format string anomalies.

Wformat-overflow=
C ObjC C++ LTO ObjC++ Joined RejectNegative UInteger Var(warn_format_overflow) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 1, 0)
Warn about function calls with format strings that write past the end
of the destination region.

Wformat-truncation=
C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_format_trunc) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=, warn_format >= 1, 0)
Warn about calls to snprintf and similar functions that truncate output.

Wignored-qualifiers
C C++ Var(warn_ignored_qualifiers) Warning EnabledBy(Wextra)
Warn whenever type qualifiers are ignored.

Wignored-attributes
C C++ Var(warn_ignored_attributes) Init(1) Warning
Warn whenever attributes are ignored.

Wincompatible-pointer-types
C ObjC Var(warn_incompatible_pointer_types) Init(1) Warning
Warn when there is a conversion between pointers that have incompatible types.

Winit-self
C ObjC C++ ObjC++ Var(warn_init_self) Warning LangEnabledBy(C++ ObjC++,Wall)
Warn about variables which are initialized to themselves.

Wimplicit
C ObjC Var(warn_implicit) Warning LangEnabledBy(C ObjC,Wall)
Warn about implicit declarations.

Wimplicit-fallthrough=
LangEnabledBy(C ObjC C++ ObjC++,Wextra,3,0)
; in common.opt

Wdouble-promotion
C ObjC C++ ObjC++ Var(warn_double_promotion) Warning
Warn about implicit conversions from \"float\" to \"double\".

Wexpansion-to-defined
C ObjC C++ ObjC++ CPP(warn_expansion_to_defined) CppReason(CPP_W_EXPANSION_TO_DEFINED) Var(cpp_warn_expansion_to_defined) Init(0) Warning EnabledBy(Wextra || Wpedantic)
Warn if \"defined\" is used outside #if.

Wimplicit-function-declaration
C ObjC Var(warn_implicit_function_declaration) Init(-1) Warning LangEnabledBy(C ObjC,Wimplicit)
Warn about implicit function declarations.

Wimplicit-int
C ObjC Var(warn_implicit_int) Init(-1) Warning LangEnabledBy(C ObjC,Wimplicit)
Warn when a declaration does not specify a type.

Wimport
C ObjC C++ ObjC++ Undocumented Ignore

Winherited-variadic-ctor
C++ ObjC++ Var(warn_inh_var_ctor) Init(1) Warning
Warn about C++11 inheriting constructors when the base has a variadic constructor.

Wint-conversion
C ObjC Var(warn_int_conversion) Init(1) Warning
Warn about incompatible integer to pointer and pointer to integer conversions.

Wint-in-bool-context
C ObjC C++ ObjC++ Var(warn_int_in_bool_context) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn for suspicious integer expressions in boolean context.

Wint-to-pointer-cast
C ObjC C++ ObjC++ Var(warn_int_to_pointer_cast) Init(1) Warning
Warn when there is a cast to a pointer from an integer of a different size.

Winvalid-offsetof
C++ ObjC++ Var(warn_invalid_offsetof) Init(1) Warning
Warn about invalid uses of the \"offsetof\" macro.

Winvalid-pch
C ObjC C++ ObjC++ CPP(warn_invalid_pch) CppReason(CPP_W_INVALID_PCH) Var(cpp_warn_invalid_pch) Init(0) Warning
Warn about PCH files that are found but not used.

Wjump-misses-init
C ObjC Var(warn_jump_misses_init) Warning LangEnabledby(C ObjC,Wc++-compat)
Warn when a jump misses a variable initialization.

Wliteral-suffix
C++ ObjC++ CPP(warn_literal_suffix) CppReason(CPP_W_LITERAL_SUFFIX) Var(cpp_warn_literal_suffix) Init(1) Warning
Warn when a string or character literal is followed by a ud-suffix which does not begin with an underscore.

Wlogical-op
C ObjC C++ ObjC++ Var(warn_logical_op) Init(0) Warning
Warn when a logical operator is suspiciously always evaluating to true or false.

Wlogical-not-parentheses
C ObjC C++ ObjC++ Var(warn_logical_not_paren) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn when logical not is used on the left hand side operand of a comparison.

Wlong-long
C ObjC C++ ObjC++ CPP(cpp_warn_long_long) CppReason(CPP_W_LONG_LONG) Var(warn_long_long) Init(-1) Warning LangEnabledBy(C ObjC,Wc90-c99-compat)
Do not warn about using \"long long\" when -pedantic.

Wmain
C ObjC C++ ObjC++ Var(warn_main) Init(-1) Warning LangEnabledBy(C ObjC,Wall, 2, 0)
Warn about suspicious declarations of \"main\".

Wmain
LangEnabledBy(C ObjC C++ ObjC++,Wpedantic, 2, 0)
;

Wmemset-transposed-args
C ObjC C++ ObjC++ Var(warn_memset_transposed_args) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about suspicious calls to memset where the third argument is constant literal zero and the second is not.

Wmemset-elt-size
C ObjC C++ ObjC++ Var(warn_memset_elt_size) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about suspicious calls to memset where the third argument contains the number of elements not multiplied by the element size.

Wmisleading-indentation
C C++ Common Var(warn_misleading_indentation) Warning LangEnabledBy(C C++,Wall)
Warn when the indentation of the code does not reflect the block structure.

Wmissing-braces
C ObjC C++ ObjC++ Var(warn_missing_braces) Warning LangEnabledBy(C ObjC,Wall)
Warn about possibly missing braces around initializers.

Wmissing-declarations
C ObjC C++ ObjC++ Var(warn_missing_declarations) Warning
Warn about global functions without previous declarations.

Wmissing-field-initializers
C ObjC C++ ObjC++ Var(warn_missing_field_initializers) Warning EnabledBy(Wextra)
Warn about missing fields in struct initializers.

Wmultiple-inheritance
C++ ObjC++ Var(warn_multiple_inheritance) Warning
Warn on direct multiple inheritance.

Wnamespaces
C++ ObjC++ Var(warn_namespaces) Warning
Warn on namespace definition.

Wsized-deallocation
C++ ObjC++ Var(warn_sized_deallocation) Warning EnabledBy(Wextra)
Warn about missing sized deallocation functions.

Wsizeof-pointer-memaccess
C ObjC C++ ObjC++ Var(warn_sizeof_pointer_memaccess) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about suspicious length parameters to certain string functions if the argument uses sizeof.

Wsizeof-array-argument
C ObjC C++ ObjC++ Var(warn_sizeof_array_argument) Warning Init(1)
Warn when sizeof is applied on a parameter declared as an array.

Wstringop-overflow
C ObjC C++ ObjC++ Warning Alias(Wstringop-overflow=, 2, 0)
Warn about buffer overflow in string manipulation functions like memcpy
and strcpy.

Wstringop-overflow=
C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_stringop_overflow) Init(2) Warning
Under the control of Object Size type, warn about buffer overflow in string
manipulation functions like memcpy and strcpy.

Wsuggest-attribute=format
C ObjC C++ ObjC++ Var(warn_suggest_attribute_format) Warning
Warn about functions which might be candidates for format attributes.

Wsuggest-override
C++ ObjC++ Var(warn_override) Warning
Suggest that the override keyword be used when the declaration of a virtual
function overrides another.

Wswitch
C ObjC C++ ObjC++ Var(warn_switch) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about enumerated switches, with no default, missing a case.

Wswitch-default
C ObjC C++ ObjC++ Var(warn_switch_default) Warning
Warn about enumerated switches missing a \"default:\" statement.

Wswitch-enum
C ObjC C++ ObjC++ Var(warn_switch_enum) Warning
Warn about all enumerated switches missing a specific case.

Wswitch-bool
C ObjC C++ ObjC++ Var(warn_switch_bool) Warning Init(1)
Warn about switches with boolean controlling expression.

Wtemplates
C++ ObjC++ Var(warn_templates) Warning
Warn on primary template declaration.

Wmissing-format-attribute
C ObjC C++ ObjC++ Warning Alias(Wsuggest-attribute=format)
;

Wmissing-include-dirs
C ObjC C++ ObjC++ CPP(warn_missing_include_dirs) CppReason(CPP_W_MISSING_INCLUDE_DIRS) Var(cpp_warn_missing_include_dirs) Init(0) Warning
Warn about user-specified include directories that do not exist.

Wmissing-parameter-type
C ObjC Var(warn_missing_parameter_type) Warning EnabledBy(Wextra)
Warn about function parameters declared without a type specifier in K&R-style functions.

Wmissing-prototypes
C ObjC Var(warn_missing_prototypes) Warning
Warn about global functions without prototypes.

Wmudflap
C ObjC C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

Wmultichar
C ObjC C++ ObjC++ CPP(warn_multichar) CppReason(CPP_W_MULTICHAR) Var(cpp_warn_multichar) Init(0) Warning
Warn about use of multi-character character constants.

Wnarrowing
C ObjC C++ ObjC++ Warning Var(warn_narrowing) Init(-1) LangEnabledBy(C++ ObjC++,Wall || Wc++11-compat)
Warn about narrowing conversions within { } that are ill-formed in C++11.

Wnested-externs
C ObjC Var(warn_nested_externs) Warning
Warn about \"extern\" declarations not at file scope.

Wnoexcept
C++ ObjC++ Var(warn_noexcept) Warning
Warn when a noexcept expression evaluates to false even though the expression can't actually throw.

Wnoexcept-type
C++ ObjC++ Warning Var(warn_noexcept_type) LangEnabledBy(C++ ObjC++,Wabi || Wc++1z-compat)
Warn if C++1z noexcept function type will change the mangled name of a symbol.

Wnon-template-friend
C++ ObjC++ Var(warn_nontemplate_friend) Init(1) Warning
Warn when non-templatized friend functions are declared within a template.

Wnon-virtual-dtor
C++ ObjC++ Var(warn_nonvdtor) Warning LangEnabledBy(C++ ObjC++,Weffc++)
Warn about non-virtual destructors.

Wnonnull
C ObjC C++ ObjC++ Var(warn_nonnull) Warning LangEnabledBy(C ObjC C++ ObjC++,Wformat=,warn_format >= 1,0)
Warn about NULL being passed to argument slots marked as requiring non-NULL.

Wnonnull
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
;

Wnonnull-compare
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
;

Wnormalized
C ObjC C++ ObjC++ Warning Alias(Wnormalized=,nfc,none)
;

Wnormalized=
C ObjC C++ ObjC++ RejectNegative Joined Warning CPP(warn_normalize) CppReason(CPP_W_NORMALIZE) Init(normalized_C) Var(cpp_warn_normalize) Enum(cpp_normalize_level)
-Wnormalized=[none|id|nfc|nfkc]	Warn about non-normalized Unicode strings.

; Required for these enum values.
SourceInclude
cpplib.h

Enum
Name(cpp_normalize_level) Type(int) UnknownError(argument %qs to %<-Wnormalized%> not recognized)

EnumValue
Enum(cpp_normalize_level) String(none) Value(normalized_none)

EnumValue
Enum(cpp_normalize_level) String(nfkc) Value(normalized_KC)

EnumValue
Enum(cpp_normalize_level) String(id) Value(normalized_identifier_C)

EnumValue
Enum(cpp_normalize_level) String(nfc) Value(normalized_C)

Wold-style-cast
C++ ObjC++ Var(warn_old_style_cast) Warning
Warn if a C-style cast is used in a program.

Wold-style-declaration
C ObjC Var(warn_old_style_declaration) Warning EnabledBy(Wextra)
Warn for obsolescent usage in a declaration.

Wold-style-definition
C ObjC Var(warn_old_style_definition) Warning
Warn if an old-style parameter definition is used.

Wopenmp-simd
C C++ Var(warn_openmp_simd) Warning LangEnabledBy(C C++,Wall)
Warn if a simd directive is overridden by the vectorizer cost model.

Woverlength-strings
C ObjC C++ ObjC++ Var(warn_overlength_strings) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
Warn if a string is longer than the maximum portable length specified by the standard.

Woverloaded-virtual
C++ ObjC++ Var(warn_overloaded_virtual) Warning
Warn about overloaded virtual function names.

Woverride-init
C ObjC Var(warn_override_init) Warning EnabledBy(Wextra)
Warn about overriding initializers without side effects.

Woverride-init-side-effects
C ObjC Var(warn_override_init_side_effects) Init(1) Warning
Warn about overriding initializers with side effects.

Wpacked-bitfield-compat
C ObjC C++ ObjC++ Var(warn_packed_bitfield_compat) Init(-1) Warning
Warn about packed bit-fields whose offset changed in GCC 4.4.

Wparentheses
C ObjC C++ ObjC++ Var(warn_parentheses) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about possibly missing parentheses.

Wpedantic
C ObjC C++ ObjC++ CPP(cpp_pedantic) CppReason(CPP_W_PEDANTIC) Warning
; Documented in common.opt

Wpmf-conversions
C++ ObjC++ Var(warn_pmf2ptr) Init(1) Warning
Warn when converting the type of pointers to member functions.

Wpointer-arith
C ObjC C++ ObjC++ Var(warn_pointer_arith) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
Warn about function pointer arithmetic.

Wpointer-sign
C ObjC Var(warn_pointer_sign) Warning LangEnabledBy(C ObjC,Wall || Wpedantic)
Warn when a pointer differs in signedness in an assignment.

Wpointer-compare
C ObjC C++ ObjC++ Var(warn_pointer_compare) Init(1) Warning
Warn when a pointer is compared with a zero character constant.

Wpointer-to-int-cast
C ObjC Var(warn_pointer_to_int_cast) Init(1) Warning
Warn when a pointer is cast to an integer of a different size.

Wpragmas
C ObjC C++ ObjC++ Var(warn_pragmas) Init(1) Warning
Warn about misuses of pragmas.

Wproperty-assign-default
ObjC ObjC++ Var(warn_property_assign_default) Init(1) Warning
Warn if a property for an Objective-C object has no assign semantics specified.

Wprotocol
ObjC ObjC++ Var(warn_protocol) Init(1) Warning
Warn if inherited methods are unimplemented.

Wplacement-new
C++ Warning Alias(Wplacement-new=, 1, 0)
Warn for placement new expressions with undefined behavior.

Wplacement-new=
C++ Joined RejectNegative UInteger Var(warn_placement_new) Init(-1) Warning
Warn for placement new expressions with undefined behavior.

Wredundant-decls
C ObjC C++ ObjC++ Var(warn_redundant_decls) Warning
Warn about multiple declarations of the same object.

Wregister
C++ ObjC++ Var(warn_register) Warning
Warn about uses of register storage specifier.

Wreorder
C++ ObjC++ Var(warn_reorder) Warning LangEnabledBy(C++ ObjC++,Wall)
Warn when the compiler reorders code.

Wreturn-type
C ObjC C++ ObjC++ Var(warn_return_type) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn whenever a function's return type defaults to \"int\" (C), or about inconsistent return types (C++).

Wscalar-storage-order
C ObjC C++ ObjC++ Init(1) Warning
Warn on suspicious constructs involving reverse scalar storage order.

Wselector
ObjC ObjC++ Var(warn_selector) Warning
Warn if a selector has multiple methods.

Wsequence-point
C ObjC C++ ObjC++ Var(warn_sequence_point) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about possible violations of sequence point rules.

Wshadow-ivar
ObjC ObjC++ Var(warn_shadow_ivar) EnabledBy(Wshadow) Init(1) Warning
Warn if a local declaration hides an instance variable.

Wshift-overflow
C ObjC C++ ObjC++ Warning Alias(Wshift-overflow=, 1, 0)
Warn if left shift of a signed value overflows.

Wshift-overflow=
C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_shift_overflow) Init(-1) Warning
Warn if left shift of a signed value overflows.

Wshift-count-negative
C ObjC C++ ObjC++ Var(warn_shift_count_negative) Init(1) Warning
Warn if shift count is negative.

Wshift-count-overflow
C ObjC C++ ObjC++ Var(warn_shift_count_overflow) Init(1) Warning
Warn if shift count >= width of type.

Wshift-negative-value
C ObjC C++ ObjC++ Var(warn_shift_negative_value) Init(-1) Warning
Warn if left shifting a negative value.

Wsign-compare
C ObjC C++ ObjC++ Var(warn_sign_compare) Warning LangEnabledBy(C++ ObjC++,Wall)
Warn about signed-unsigned comparisons.

Wsign-compare
C ObjC C++ ObjC++ EnabledBy(Wextra)
;

Wsign-conversion
C ObjC C++ ObjC++ Var(warn_sign_conversion) Warning LangEnabledBy(C ObjC,Wconversion)
Warn for implicit type conversions between signed and unsigned integers.

Wsign-promo
C++ ObjC++ Var(warn_sign_promo) Warning
Warn when overload promotes from unsigned to signed.

Wstrict-null-sentinel
C++ ObjC++ Warning Var(warn_strict_null_sentinel)
Warn about uncasted NULL used as sentinel.

Wstrict-prototypes
C ObjC Var(warn_strict_prototypes) Warning
Warn about unprototyped function declarations.

Wstrict-aliasing=
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall, 3, 0)
;

Wstrict-overflow=
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall, 1, 0)
;

Wstrict-selector-match
ObjC ObjC++ Var(warn_strict_selector_match) Warning
Warn if type signatures of candidate methods do not match exactly.

Wsync-nand
C C++ Var(warn_sync_nand) Init(1) Warning
Warn when __sync_fetch_and_nand and __sync_nand_and_fetch built-in functions are used.

Wsynth
C++ ObjC++ Var(warn_synth) Warning
Deprecated.  This switch has no effect.

Wsystem-headers
C ObjC C++ ObjC++ Warning
; Documented in common.opt

Wtautological-compare
C ObjC C++ ObjC++ Var(warn_tautological_compare) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn if a comparison always evaluates to true or false.

Wterminate
C++ ObjC++ Warning Var(warn_terminate) Init(1)
Warn if a throw expression will always result in a call to terminate().

Wtraditional
C ObjC CPP(cpp_warn_traditional) CppReason(CPP_W_TRADITIONAL) Var(warn_traditional) Init(0) Warning
Warn about features not present in traditional C.

Wtraditional-conversion
C ObjC Var(warn_traditional_conversion) Warning
Warn of prototypes causing type conversions different from what would happen in the absence of prototype.

Wtrigraphs
C ObjC C++ ObjC++ CPP(warn_trigraphs) CppReason(CPP_W_TRIGRAPHS) Var(cpp_warn_trigraphs) Init(2) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn if trigraphs are encountered that might affect the meaning of the program.

Wundeclared-selector
ObjC ObjC++ Var(warn_undeclared_selector) Warning
Warn about @selector()s without previously declared methods.

Wundef
C ObjC C++ ObjC++ CPP(warn_undef) CppReason(CPP_W_UNDEF) Var(cpp_warn_undef) Init(0) Warning
Warn if an undefined macro is used in an #if directive.

Wuninitialized
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
;

Wmaybe-uninitialized
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
;

Wunknown-pragmas
C ObjC C++ ObjC++ Warning Var(warn_unknown_pragmas) LangEnabledBy(C ObjC C++ ObjC++,Wall, 1, 0)
Warn about unrecognized pragmas.

Wunsuffixed-float-constants
C ObjC Var(warn_unsuffixed_float_constants) Warning
Warn about unsuffixed float constants.

Wunused
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wall)
; documented in common.opt

Wunused-local-typedefs
C ObjC C++ ObjC++ Var(warn_unused_local_typedefs) Warning EnabledBy(Wunused)
Warn when typedefs locally defined in a function are not used.

Wunused-macros
C ObjC C++ ObjC++ CppReason(CPP_W_UNUSED_MACROS) Var(cpp_warn_unused_macros) Warning
Warn about macros defined in the main file that are not used.

Wunused-result
C ObjC C++ ObjC++ Var(warn_unused_result) Init(1) Warning
Warn if a caller of a function, marked with attribute warn_unused_result, does not use its return value.

Wunused-variable
C ObjC C++ ObjC++ LangEnabledBy(C ObjC C++ ObjC++,Wunused)
; documented in common.opt

Wunused-const-variable
C ObjC C++ ObjC++ Warning Alias(Wunused-const-variable=, 2, 0)
Warn when a const variable is unused.

Wunused-const-variable=
C ObjC C++ ObjC++ Joined RejectNegative UInteger Var(warn_unused_const_variable) Warning LangEnabledBy(C ObjC,Wunused-variable, 1, 0)
Warn when a const variable is unused.

Wvariadic-macros
C ObjC C++ ObjC++ CPP(warn_variadic_macros) CppReason(CPP_W_VARIADIC_MACROS) Var(cpp_warn_variadic_macros) Init(0) Warning LangEnabledBy(C ObjC C++ ObjC++,Wpedantic || Wtraditional)
Warn about using variadic macros.

Wvarargs
C ObjC C++ ObjC++ Warning Var(warn_varargs) Init(1)
Warn about questionable usage of the macros used to retrieve variable arguments.

Wvla
C ObjC C++ ObjC++ Var(warn_vla) Init(-1) Warning
Warn if a variable length array is used.

Wvla-larger-than=
C ObjC C++ ObjC++ Var(warn_vla_limit) Warning Joined RejectNegative UInteger
-Wvla-larger-than=<number>	Warn on unbounded uses of variable-length arrays, and
on bounded uses of variable-length arrays whose bound can be
larger than <number> bytes.

Wvolatile-register-var
C ObjC C++ ObjC++ Var(warn_volatile_register_var) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn when a register variable is declared volatile.

Wvirtual-inheritance
C++ ObjC++ Var(warn_virtual_inheritance) Warning
Warn on direct virtual inheritance.

Wvirtual-move-assign
C++ ObjC++ Var(warn_virtual_move_assign) Warning Init(1)
Warn if a virtual base has a non-trivial move assignment operator.

Wwrite-strings
C ObjC C++ ObjC++ Var(warn_write_strings) Warning
In C++, nonzero means warn about deprecated conversion from string literals to 'char *'.  In C, similar warning, except that the conversion is of course not deprecated by the ISO C standard.

Wzero-as-null-pointer-constant
C++ ObjC++ Var(warn_zero_as_null_pointer_constant) Warning
Warn when a literal '0' is used as null pointer.

Wuseless-cast
C++ ObjC++ Var(warn_useless_cast) Warning
Warn about useless casts.

Wsubobject-linkage
C++ ObjC++ Var(warn_subobject_linkage) Warning Init(1)
Warn if a class type has a base or a field whose type uses the anonymous namespace or depends on a type with no linkage.

Wduplicate-decl-specifier
C ObjC Var(warn_duplicate_decl_specifier) Warning LangEnabledBy(C ObjC,Wall)
Warn when a declaration has duplicate const, volatile, restrict or _Atomic specifier.

Wrestrict
C ObjC C++ ObjC++ Var(warn_restrict) Warning LangEnabledBy(C ObjC C++ ObjC++)
Warn when an argument passed to a restrict-qualified parameter aliases with
another argument.

ansi
C ObjC C++ ObjC++
A synonym for -std=c89 (for C) or -std=c++98 (for C++).

; This should really just be C++/ObjC++ but we (NetBSD) use it when
; calling C and ObjC compilers as well.
cxx-isystem
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-cxx-isystem <dir>	Add <dir> to the start of the C++ system include path

d
C ObjC C++ ObjC++ Joined
; Documented in common.opt.  FIXME - what about -dI, -dD, -dN and -dD?

fabi-compat-version=
C++ ObjC++ Joined RejectNegative UInteger Var(flag_abi_compat_version) Init(-1)
The version of the C++ ABI used for -Wabi warnings and link compatibility aliases.

faccess-control
C++ ObjC++ Var(flag_access_control) Init(1)
Enforce class member access control semantics.

fada-spec-parent=
C ObjC C++ ObjC++ RejectNegative Joined Var(ada_specs_parent)
-fada-spec-parent=unit  Dump Ada specs as child units of given parent.

faligned-new
C++ ObjC++ Alias(faligned-new=,1,0)
Support C++17 allocation of over-aligned types.

faligned-new=
C++ ObjC++ Joined RejectNegative Var(aligned_new_threshold) UInteger Init(-1)
-faligned-new=<N> Use C++17 over-aligned type allocation for alignments greater than N.

fall-virtual
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fallow-parameterless-variadic-functions
C ObjC Var(flag_allow_parameterless_variadic_functions)
Allow variadic functions without named parameter.

falt-external-templates
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)
No longer supported.

fasm
C ObjC C++ ObjC++ Var(flag_no_asm, 0)
Recognize the \"asm\" keyword.

; Define extra predefined macros for use in libgcc.
fbuilding-libgcc
C ObjC C++ ObjC++ Undocumented Var(flag_building_libgcc)

fbuiltin
C ObjC C++ ObjC++ Var(flag_no_builtin, 0)
Recognize built-in functions.

fbuiltin-
C ObjC C++ ObjC++ Joined

fcanonical-system-headers
C ObjC C++ ObjC++
Where shorter, use canonicalized paths to systems headers.

fcheck-pointer-bounds
C ObjC C++ ObjC++ LTO Report Var(flag_check_pointer_bounds)
Add Pointer Bounds Checker instrumentation.  fchkp-* flags are used to
control instrumentation.  Currently available for C, C++ and ObjC.

fchkp-check-incomplete-type
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_incomplete_type) Init(1)
Generate pointer bounds checks for variables with incomplete type.

fchkp-zero-input-bounds-for-main
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_zero_input_bounds_for_main) Init(0)
Use zero bounds for all incoming arguments in 'main' function.  It helps when
instrumented binaries are used with legacy libs.

fchkp-first-field-has-own-bounds
C ObjC C++ ObjC++ LTO RejectNegative Report Var(flag_chkp_first_field_has_own_bounds)
Forces Pointer Bounds Checker to use narrowed bounds for address of the first
field in the structure.  By default pointer to the first field has the same
bounds as pointer to the whole structure.

fchkp-narrow-bounds
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_narrow_bounds) Init(1)
Control how Pointer Bounds Checker handle pointers to object fields.  When
narrowing is on, field bounds are used.  Otherwise full object bounds are used.

fchkp-narrow-to-innermost-array
C ObjC C++ ObjC++ LTO RejectNegative Report Var(flag_chkp_narrow_to_innermost_arrray)
Forces Pointer Bounds Checker to use bounds of the innermost arrays in case of
nested static arrays access.  By default outermost array is used.

fchkp-flexible-struct-trailing-arrays
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_flexible_struct_trailing_arrays)
Forces Pointer Bounds Checker to treat all trailing arrays in structures as
possibly flexible.  By default only arrays fields with zero length or that are
marked with attribute bnd_variable_size are treated as flexible.

fchkp-optimize
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_optimize) Init(-1)
Allow Pointer Bounds Checker optimizations.  By default allowed
on optimization levels >0.

fchkp-use-fast-string-functions
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_use_fast_string_functions) Init(0)
Allow to use *_nobnd versions of string functions by Pointer Bounds Checker.

fchkp-use-nochk-string-functions
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_use_nochk_string_functions) Init(0)
Allow to use *_nochk versions of string functions by Pointer Bounds Checker.

fchkp-use-static-bounds
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_use_static_bounds) Init(1)
Use statically initialized variable for vars bounds instead of
generating them each time it is required.

fchkp-use-static-const-bounds
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_use_static_const_bounds) Init(-1)
Use statically initialized variable for constant bounds instead of
generating them each time it is required.

fchkp-treat-zero-dynamic-size-as-infinite
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_zero_dynamic_size_as_infinite) Init(0)
With this option zero size obtained dynamically for objects with
incomplete type will be treated as infinite.

fchkp-check-read
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_check_read) Init(1)
Generate checks for all read accesses to memory.

fchkp-check-write
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_check_write) Init(1)
Generate checks for all write accesses to memory.

fchkp-store-bounds
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_store_bounds) Init(1)
Generate bounds stores for pointer writes.

fchkp-instrument-calls
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_instrument_calls) Init(1)
Generate bounds passing for calls.

fchkp-instrument-marked-only
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_instrument_marked_only) Init(0)
Instrument only functions marked with bnd_instrument attribute.

fchkp-use-wrappers
C ObjC C++ ObjC++ LTO Report Var(flag_chkp_use_wrappers) Init(1)
Transform instrumented builtin calls into calls to wrappers.

static-libmpx
Driver

static-libmpxwrappers
Driver

fcilkplus
C ObjC C++ ObjC++ LTO Report Var(flag_cilkplus) Init(0)
Enable Cilk Plus.

fconcepts
C++ ObjC++ Var(flag_concepts)
Enable support for C++ concepts.

fcond-mismatch
C ObjC C++ ObjC++
Allow the arguments of the '?' operator to have different types.

fconserve-space
C++ ObjC++ Var(flag_conserve_space)
Does nothing.  Preserved for backward compatibility.

fconstant-string-class=
ObjC ObjC++ Joined MissingArgError(no class name specified with %qs)
-fconst-string-class=<name>	Use class <name> for constant strings.

fconstexpr-depth=
C++ ObjC++ Joined RejectNegative UInteger Var(max_constexpr_depth) Init(512)
-fconstexpr-depth=<number>	Specify maximum constexpr recursion depth.

fconstexpr-loop-limit=
C++ ObjC++ Joined RejectNegative UInteger Var(constexpr_loop_limit) Init(262144)
-fconstexpr-loop-limit=<number>	Specify maximum constexpr loop iteration count.

fdebug-cpp
C ObjC C++ ObjC++
Emit debug annotations during preprocessing.

fdeduce-init-list
C++ ObjC++ Var(flag_deduce_init_list) Init(0)
-fdeduce-init-list	enable deduction of std::initializer_list for a template type parameter from a brace-enclosed initializer-list.

fdeclone-ctor-dtor
C++ ObjC++ Var(flag_declone_ctor_dtor) Init(-1)
Factor complex constructors and destructors to favor space over speed.

fdefault-inline
C++ ObjC++ Ignore
Does nothing.  Preserved for backward compatibility.

fdirectives-only
C ObjC C++ ObjC++
Preprocess directives only.

fdollars-in-identifiers
C ObjC C++ ObjC++
Permit '$' as an identifier character.

fdump-ada-spec
C ObjC C++ ObjC++ RejectNegative Var(flag_dump_ada_spec)
Write all declarations as Ada code transitively.

fdump-ada-spec-slim
C ObjC C++ ObjC++ RejectNegative Var(flag_dump_ada_spec_slim)
Write all declarations as Ada code for the given file only.

felide-constructors
C++ ObjC++ Var(flag_elide_constructors) Init(1)

fenforce-eh-specs
C++ ObjC++ Var(flag_enforce_eh_specs) Init(1)
Generate code to check exception specifications.

fenum-int-equiv
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fexec-charset=
C ObjC C++ ObjC++ Joined RejectNegative
-fexec-charset=<cset>	Convert all strings and character constants to character set <cset>.

fextended-identifiers
C ObjC C++ ObjC++
Permit universal character names (\\u and \\U) in identifiers.

finput-charset=
C ObjC C++ ObjC++ Joined RejectNegative
-finput-charset=<cset>	Specify the default character set for source files.

fextern-tls-init
C++ ObjC++ Var(flag_extern_tls_init) Init(-1)
Support dynamic initialization of thread-local variables in a different translation unit.

fexternal-templates
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

ffor-scope
C++ ObjC++ Var(flag_new_for_scope) Init(1)
Scope of for-init-statement variables is local to the loop.

ffreestanding
C ObjC C++ ObjC++
Do not assume that standard C libraries and \"main\" exist.

fgnu-keywords
C++ ObjC++ Var(flag_no_gnu_keywords, 0)
Recognize GNU-defined keywords.

fgnu-runtime
ObjC ObjC++ LTO Report RejectNegative Var(flag_next_runtime,0) Init(NEXT_OBJC_RUNTIME)
Generate code for GNU runtime environment.

fgnu89-inline
C ObjC Var(flag_gnu89_inline) Init(-1)
Use traditional GNU semantics for inline functions.

fguiding-decls
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fhandle-exceptions
C++ ObjC++ Optimization Alias(fexceptions) Warn({-fhandle-exceptions has been renamed -fexceptions (and is now on by default)})

fhonor-std
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fhosted
C ObjC
Assume normal C execution environment.

fhuge-objects
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)
No longer supported.

fimplement-inlines
C++ ObjC++ Var(flag_implement_inlines) Init(1)
Export functions even if they can be inlined.

fimplicit-inline-templates
C++ ObjC++ Var(flag_implicit_inline_templates) Init(1)
Emit implicit instantiations of inline templates.

fimplicit-templates
C++ ObjC++ Var(flag_implicit_templates) Init(1)
Emit implicit instantiations of templates.

fnew-inheriting-ctors
C++ ObjC++ Var(flag_new_inheriting_ctors) Init(1)
Implement C++17 inheriting constructor semantics.

ffriend-injection
C++ ObjC++ Var(flag_friend_injection)
Inject friend functions into enclosing namespace.

fkeep-inline-dllexport
C C++ ObjC ObjC++ Var(flag_keep_inline_dllexport) Init(1) Report Condition(TARGET_DLLIMPORT_DECL_ATTRIBUTES)
Don't emit dllexported inline functions unless needed.

flabels-ok
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

flax-vector-conversions
C ObjC C++ ObjC++ Var(flag_lax_vector_conversions)
Allow implicit conversions between vectors with differing numbers of subparts and/or differing element types.

fms-extensions
C ObjC C++ ObjC++ Var(flag_ms_extensions)
Don't warn about uses of Microsoft extensions.

fmudflap
C ObjC C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fmudflapth
C ObjC C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fmudflapir
C ObjC C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fname-mangling-version-
C++ ObjC++ Joined Ignore Warn(switch %qs is no longer supported)

fnew-abi
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fnew-ttp-matching
C++ ObjC++ Var(flag_new_ttp)
Implement resolution of DR 150 for matching of template template arguments.

fnext-runtime
ObjC ObjC++ LTO Report RejectNegative Var(flag_next_runtime)
Generate code for NeXT (Apple Mac OS X) runtime environment.

fnil-receivers
ObjC ObjC++ Var(flag_nil_receivers) Init(1)
Assume that receivers of Objective-C messages may be nil.

flocal-ivars
ObjC ObjC++ Var(flag_local_ivars) Init(1)
Allow access to instance variables as if they were local declarations within instance method implementations.

fivar-visibility=
ObjC ObjC++ Joined RejectNegative Enum(ivar_visibility) Var(default_ivar_visibility) Init(IVAR_VISIBILITY_PROTECTED)
-fvisibility=[private|protected|public|package]	Set the default symbol visibility.

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

EnumValue
Enum(ivar_visibility) String(private) Value(IVAR_VISIBILITY_PRIVATE)

EnumValue
Enum(ivar_visibility) String(protected) Value(IVAR_VISIBILITY_PROTECTED)

EnumValue
Enum(ivar_visibility) String(public) Value(IVAR_VISIBILITY_PUBLIC)

EnumValue
Enum(ivar_visibility) String(package) Value(IVAR_VISIBILITY_PACKAGE)

fnonansi-builtins
C++ ObjC++ Var(flag_no_nonansi_builtin, 0)

fnonnull-objects
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fnothrow-opt
C++ ObjC++ Optimization Var(flag_nothrow_opt)
Treat a throw() exception specification as noexcept to improve code size.

fobjc-abi-version=
ObjC ObjC++ LTO Joined Report RejectNegative UInteger Var(flag_objc_abi)
Specify which ABI to use for Objective-C family code and meta-data generation.

; Generate special '- .cxx_construct' and '- .cxx_destruct' methods
; to initialize any non-POD ivars in Objective-C++ classes.
fobjc-call-cxx-cdtors
ObjC++ Var(flag_objc_call_cxx_cdtors)
Generate special Objective-C methods to initialize/destroy non-POD C++ ivars, if needed.

fobjc-direct-dispatch
ObjC ObjC++ Var(flag_objc_direct_dispatch)
Allow fast jumps to the message dispatcher.

; Nonzero means that we will allow new ObjC exception syntax (@throw,
; @try, etc.) in source code.
fobjc-exceptions
ObjC ObjC++ Var(flag_objc_exceptions)
Enable Objective-C exception and synchronization syntax.

fobjc-gc
ObjC ObjC++ LTO Var(flag_objc_gc)
Enable garbage collection (GC) in Objective-C/Objective-C++ programs.

fobjc-nilcheck
ObjC ObjC++ Var(flag_objc_nilcheck,1)
Enable inline checks for nil receivers with the NeXT runtime and ABI version 2.

; Nonzero means that we generate NeXT setjmp based exceptions.
fobjc-sjlj-exceptions
ObjC ObjC++ Var(flag_objc_sjlj_exceptions) Init(-1)
Enable Objective-C setjmp exception handling runtime.

fobjc-std=objc1
ObjC ObjC++ Var(flag_objc1_only)
Conform to the Objective-C 1.0 language as implemented in GCC 4.0.

fopenacc
C ObjC C++ ObjC++ LTO Var(flag_openacc)
Enable OpenACC.

fopenacc-dim=
C ObjC C++ ObjC++ LTO Joined Var(flag_openacc_dims)
Specify default OpenACC compute dimensions.

fopenmp
C ObjC C++ ObjC++ LTO Var(flag_openmp)
Enable OpenMP (implies -frecursive in Fortran).

fopenmp-simd
C ObjC C++ ObjC++ Var(flag_openmp_simd)
Enable OpenMP's SIMD directives.

foperator-names
C++ ObjC++
Recognize C++ keywords like \"compl\" and \"xor\".

foptional-diags
C++ ObjC++ Ignore
Does nothing.  Preserved for backward compatibility.

fpch-deps
C ObjC C++ ObjC++

fpch-preprocess
C ObjC C++ ObjC++
Look for and use PCH files even when preprocessing.

fpermissive
C++ ObjC++ Var(flag_permissive)
Downgrade conformance errors to warnings.

fplan9-extensions
C ObjC Var(flag_plan9_extensions)
Enable Plan 9 language extensions.

fpreprocessed
C ObjC C++ ObjC++
Treat the input file as already preprocessed.

ftrack-macro-expansion
C ObjC C++ ObjC++ JoinedOrMissing RejectNegative UInteger
; converted into ftrack-macro-expansion=

ftrack-macro-expansion=
C ObjC C++ ObjC++ JoinedOrMissing RejectNegative UInteger
-ftrack-macro-expansion=<0|1|2>  Track locations of tokens coming from macro expansion and display them in error messages.

fpretty-templates
C++ ObjC++ Var(flag_pretty_templates) Init(1)
-fno-pretty-templates Do not pretty-print template specializations as the template signature followed by the arguments.

fprintf-return-value
C ObjC C++ ObjC++ LTO Optimization Var(flag_printf_return_value) Init(1)
Treat known sprintf return values as constants.

freplace-objc-classes
ObjC ObjC++ LTO Var(flag_replace_objc_classes)
Used in Fix-and-Continue mode to indicate that object files may be swapped in at runtime.

frepo
C++ ObjC++
Enable automatic template instantiation.

frtti
C++ ObjC++ Optimization Var(flag_rtti) Init(1)
Generate run time type descriptor information.

fshort-enums
C ObjC C++ ObjC++ LTO Optimization Var(flag_short_enums)
Use the narrowest integer type possible for enumeration types.

fshort-wchar
C ObjC C++ ObjC++ LTO Optimization Var(flag_short_wchar)
Force the underlying type for \"wchar_t\" to be \"unsigned short\".

fsigned-bitfields
C ObjC C++ ObjC++ Var(flag_signed_bitfields) Init(1)
When \"signed\" or \"unsigned\" is not given make the bitfield signed.

fsigned-char
C ObjC C++ ObjC++ LTO Var(flag_signed_char)
Make \"char\" signed by default.

fsized-deallocation
C++ ObjC++ Var(flag_sized_deallocation) Init(-1)
Enable C++14 sized deallocation support.

fsquangle
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fsso-struct=
C ObjC Joined RejectNegative Enum(sso_struct) Var(default_sso) Init(SSO_NATIVE)
-fsso-struct=[big-endian|little-endian|native]	Set the default scalar storage order.

Enum
Name(sso_struct) Type(enum scalar_storage_order_kind) UnknownError(unrecognized scalar storage order value %qs)

EnumValue
Enum(sso_struct) String(big-endian) Value(SSO_BIG_ENDIAN)

EnumValue
Enum(sso_struct) String(little-endian) Value(SSO_LITTLE_ENDIAN)

EnumValue
Enum(sso_struct) String(native) Value(SSO_NATIVE)

fstats
C++ ObjC++ Var(flag_detailed_statistics)
Display statistics accumulated during compilation.

fstrict-enums
C++ ObjC++ Optimization Var(flag_strict_enums)
Assume that values of enumeration type are always within the minimum range of that type.

fstrict-prototype
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fstrong-eval-order
C++ ObjC++ Common Alias(fstrong-eval-order=, all, none)
Follow the C++17 evaluation order requirements for assignment expressions,
shift, member function calls, etc.

fstrong-eval-order=
C++ ObjC++ Common Var(flag_strong_eval_order) Joined Enum(strong_eval_order) RejectNegative Init(-1)
Follow the C++17 evaluation order requirements for assignment expressions,
shift, member function calls, etc.

Enum
Name(strong_eval_order) Type(int)

EnumValue
Enum(strong_eval_order) String(none) Value(0)

EnumValue
Enum(strong_eval_order) String(some) Value(1)

EnumValue
Enum(strong_eval_order) String(all) Value(2)

ftabstop=
C ObjC C++ ObjC++ Joined RejectNegative UInteger
-ftabstop=<number>	Distance between tab stops for column reporting.

ftemplate-backtrace-limit=
C++ ObjC++ Joined RejectNegative UInteger Var(template_backtrace_limit) Init(10)
Set the maximum number of template instantiation notes for a single warning or error.

ftemplate-depth-
C++ ObjC++ Joined RejectNegative Undocumented Alias(ftemplate-depth=)

ftemplate-depth=
C++ ObjC++ Joined RejectNegative UInteger
-ftemplate-depth=<number>	Specify maximum template instantiation depth.

fthis-is-variable
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)

fthreadsafe-statics
C++ ObjC++ Optimization Var(flag_threadsafe_statics) Init(1)
-fno-threadsafe-statics	Do not generate thread-safe code for initializing local statics.

funsigned-bitfields
C ObjC C++ ObjC++ Var(flag_signed_bitfields, 0)
When \"signed\" or \"unsigned\" is not given make the bitfield unsigned.

funsigned-char
C ObjC C++ ObjC++ LTO Var(flag_signed_char, 0)
Make \"char\" unsigned by default.

fuse-cxa-atexit
C++ ObjC++ Var(flag_use_cxa_atexit) Init(DEFAULT_USE_CXA_ATEXIT)
Use __cxa_atexit to register destructors.

fuse-cxa-get-exception-ptr
C++ ObjC++ Var(flag_use_cxa_get_exception_ptr) Init(2)
Use __cxa_get_exception_ptr in exception handling.

fvisibility-inlines-hidden
C++ ObjC++
Marks all inlined functions and methods as having hidden visibility.

fvisibility-ms-compat
C++ ObjC++ Var(flag_visibility_ms_compat)
Changes visibility to match Microsoft Visual Studio by default.

fvtable-gc
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)
No longer supported.

fvtable-thunks
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)
No longer supported.

fweak
C++ ObjC++ Var(flag_weak) Init(1)
Emit common-like symbols as weak symbols.

fwide-exec-charset=
C ObjC C++ ObjC++ Joined RejectNegative
-fwide-exec-charset=<cset>	Convert all wide strings and character constants to character set <cset>.

fworking-directory
C ObjC C++ ObjC++ Var(flag_working_directory) Init(-1)
Generate a #line directive pointing at the current working directory.

fxref
C++ ObjC++ Ignore Warn(switch %qs is no longer supported)
No longer supported.

fzero-link
ObjC ObjC++ Var(flag_zero_link)
Generate lazy class lookup (via objc_getClass()) for use in Zero-Link mode.

gen-decls
ObjC ObjC++ Driver Var(flag_gen_declaration)
Dump declarations to a .decl file.

femit-struct-debug-baseonly
C ObjC C++ ObjC++
-femit-struct-debug-baseonly	Aggressive reduced debug info for structs.

femit-struct-debug-reduced
C ObjC C++ ObjC++
-femit-struct-debug-reduced	Conservative reduced debug info for structs.

femit-struct-debug-detailed=
C ObjC C++ ObjC++ Joined
-femit-struct-debug-detailed=<spec-list>	Detailed reduced debug info for structs.

fext-numeric-literals
C++ ObjC++ Var(flag_ext_numeric_literals) Init(1)
Interpret imaginary, fixed-point, or other gnu number suffix as the corresponding
number literal rather than a user-defined number literal.

idirafter
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-idirafter <dir>	Add <dir> to the end of the system include path.

imacros
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing filename after %qs)
-imacros <file>	Accept definition of macros in <file>.

imultilib
C ObjC C++ ObjC++ Joined Separate
-imultilib <dir>	Set <dir> to be the multilib include subdirectory.

include
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing filename after %qs)
-include <file>	Include the contents of <file> before other files.

iprefix
C ObjC C++ ObjC++ Joined Separate
-iprefix <path>	Specify <path> as a prefix for next two options.

isysroot
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-isysroot <dir>	Set <dir> to be the system root directory.

isystem
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-isystem <dir>	Add <dir> to the start of the system include path.

iquote
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-iquote <dir>	Add <dir> to the end of the quote include path.

iremap
C ObjC C++ ObjC++ Joined Separate MissingArgError(missing path after %qs)
-iremap <src:dst>	Convert <src> to <dst> if it occurs as prefix in __FILE__.

iwithprefix
C ObjC C++ ObjC++ Joined Separate
-iwithprefix <dir>	Add <dir> to the end of the system include path.

iwithprefixbefore
C ObjC C++ ObjC++ Joined Separate
-iwithprefixbefore <dir>	Add <dir> to the end of the main include path.

lang-asm
C Undocumented RejectDriver

no-integrated-cpp
Driver

nostdinc
C ObjC C++ ObjC++
Do not search standard system include directories (those specified with -isystem will still be used).

nostdinc++
C++ ObjC++
Do not search standard system include directories for C++.

o
C ObjC C++ ObjC++ Joined Separate
; Documented in common.opt

pedantic
C ObjC C++ ObjC++ Alias(Wpedantic)
; Documented in common.opt

print-objc-runtime-info
ObjC ObjC++
Generate C header of platform-specific features.

remap
C ObjC C++ ObjC++
Remap file names when including files.

std=c++98
C++ ObjC++
Conform to the ISO 1998 C++ standard revised by the 2003 technical corrigendum.

std=c++03
C++ ObjC++ Alias(std=c++98)
Conform to the ISO 1998 C++ standard revised by the 2003 technical corrigendum.

std=c++11
C++ ObjC++
Conform to the ISO 2011 C++ standard.

std=c++0x
C++ ObjC++ Alias(std=c++11) Undocumented
Deprecated in favor of -std=c++11.

std=c++1y
C++ ObjC++ Alias(std=c++14) Undocumented
Deprecated in favor of -std=c++14.

std=c++14
C++ ObjC++
Conform to the ISO 2014 C++ standard.

std=c++1z
C++ ObjC++
Conform to the ISO 2017(?) C++ draft standard (experimental and incomplete support).

std=c++17
C++ ObjC++ Alias(std=c++1z) Undocumented

std=c11
C ObjC
Conform to the ISO 2011 C standard.

std=c1x
C ObjC Alias(std=c11)
Deprecated in favor of -std=c11.

std=c89
C ObjC Alias(std=c90)
Conform to the ISO 1990 C standard.

std=c90
C ObjC
Conform to the ISO 1990 C standard.

std=c99
C ObjC
Conform to the ISO 1999 C standard.

std=c9x
C ObjC Alias(std=c99)
Deprecated in favor of -std=c99.

std=gnu++98
C++ ObjC++
Conform to the ISO 1998 C++ standard revised by the 2003 technical
corrigendum with GNU extensions.

std=gnu++03
C++ ObjC++ Alias(std=gnu++98)
Conform to the ISO 1998 C++ standard revised by the 2003 technical
corrigendum with GNU extensions.

std=gnu++11
C++ ObjC++
Conform to the ISO 2011 C++ standard with GNU extensions.

std=gnu++0x
C++ ObjC++ Alias(std=gnu++11) Undocumented
Deprecated in favor of -std=gnu++11.

std=gnu++1y
C++ ObjC++ Alias(std=gnu++14) Undocumented
Deprecated in favor of -std=gnu++14.

std=gnu++14
C++ ObjC++
Conform to the ISO 2014 C++ standard with GNU extensions.

std=gnu++1z
C++ ObjC++
Conform to the ISO 201z(7?) C++ draft standard with GNU extensions (experimental and incomplete support).

std=gnu++17
C++ ObjC++ Alias(std=gnu++1z) Undocumented

std=gnu11
C ObjC
Conform to the ISO 2011 C standard with GNU extensions.

std=gnu1x
C ObjC Alias(std=gnu11)
Deprecated in favor of -std=gnu11.

std=gnu89
C ObjC Alias(std=gnu90)
Conform to the ISO 1990 C standard with GNU extensions.

std=gnu90
C ObjC
Conform to the ISO 1990 C standard with GNU extensions.

std=gnu99
C ObjC
Conform to the ISO 1999 C standard with GNU extensions.

std=gnu9x
C ObjC Alias(std=gnu99)
Deprecated in favor of -std=gnu99.

std=iso9899:1990
C ObjC Alias(std=c90)
Conform to the ISO 1990 C standard.

std=iso9899:199409
C ObjC
Conform to the ISO 1990 C standard as amended in 1994.

std=iso9899:1999
C ObjC Alias(std=c99)
Conform to the ISO 1999 C standard.

std=iso9899:199x
C ObjC Alias(std=c99)
Deprecated in favor of -std=iso9899:1999.

std=iso9899:2011
C ObjC Alias(std=c11)
Conform to the ISO 2011 C standard.

traditional
Driver

traditional-cpp
C ObjC C++ ObjC++
Enable traditional preprocessing.

trigraphs
C ObjC C++ ObjC++
-trigraphs	Support ISO C trigraphs.

undef
C ObjC C++ ObjC++ Var(flag_undef)
Do not predefine system-specific and GCC-specific macros.

v
C ObjC C++ ObjC++
; Documented in common.opt

w
C ObjC C++ ObjC++
; Documented in common.opt

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