@item -fno-asm
@opindex fno-asm
+@opindex fasm
Do not recognize @code{asm}, @code{inline} or @code{typeof} as a
keyword, so that code can use these words as identifiers. You can use
the keywords @code{__asm__}, @code{__inline__} and @code{__typeof__}
@item -fno-builtin
@itemx -fno-builtin-@var{function}
@opindex fno-builtin
+@opindex fbuiltin
@cindex built-in functions
Don't recognize built-in functions that do not begin with
@samp{__builtin_} as prefix. @xref{Other Builtins,,Other built-in
@item -fno-access-control
@opindex fno-access-control
+@opindex faccess-control
Turn off all access checking. This switch is mainly useful for working
around bugs in the access control code.
@item -fno-elide-constructors
@opindex fno-elide-constructors
+@opindex felide-constructors
The C++ standard allows an implementation to omit creating a temporary
that is only used to initialize another object of the same type.
Specifying this option disables that optimization, and forces G++ to
@item -fno-enforce-eh-specs
@opindex fno-enforce-eh-specs
+@opindex fenforce-eh-specs
Don't generate code to check for violation of exception specifications
at run time. This option violates the C++ standard, but may be useful
for reducing code size in production builds, much like defining
@item -fno-gnu-keywords
@opindex fno-gnu-keywords
+@opindex fgnu-keywords
Do not recognize @code{typeof} as a keyword, so that code can use this
word as an identifier. You can use the keyword @code{__typeof__} instead.
This option is implied by the strict ISO C++ dialects: @option{-ansi},
@item -fno-implicit-templates
@opindex fno-implicit-templates
+@opindex fimplicit-templates
Never emit code for non-inline templates that are instantiated
implicitly (i.e.@: by use); only emit code for explicit instantiations.
@xref{Template Instantiation}, for more information.
@item -fno-implicit-inline-templates
@opindex fno-implicit-inline-templates
+@opindex fimplicit-inline-templates
Don't emit code for implicit instantiations of inline templates, either.
The default is to handle inlines differently so that compiles with and
without optimization need the same set of explicit instantiations.
@item -fno-implement-inlines
@opindex fno-implement-inlines
+@opindex fimplement-inlines
To save space, do not emit out-of-line copies of inline functions
controlled by @code{#pragma implementation}. This causes linker
errors if these functions are not inlined everywhere they are called.
@item -fno-nonansi-builtins
@opindex fno-nonansi-builtins
+@opindex fnonansi-builtins
Disable built-in declarations of functions that are not mandated by
ANSI/ISO C@. These include @code{ffs}, @code{alloca}, @code{_exit},
@code{index}, @code{bzero}, @code{conjf}, and other related functions.
@item -fno-operator-names
@opindex fno-operator-names
+@opindex foperator-names
Do not treat the operator name keywords @code{and}, @code{bitand},
@code{bitor}, @code{compl}, @code{not}, @code{or} and @code{xor} as
synonyms as keywords.
@item -fno-optional-diags
@opindex fno-optional-diags
+@opindex foptional-diags
Disable diagnostics that the standard says a compiler does not need to
issue. Currently, the only such diagnostic issued by G++ is the one for
a name having multiple meanings within a class.
@item -fno-pretty-templates
@opindex fno-pretty-templates
+@opindex fpretty-templates
When an error message refers to a specialization of a function
template, the compiler normally prints the signature of the
template followed by the template arguments and any typedefs or
@item -fno-rtti
@opindex fno-rtti
+@opindex frtti
Disable generation of information about every class with virtual
functions for use by the C++ run-time type identification features
(@code{dynamic_cast} and @code{typeid}). If you don't use those parts
@item -fno-threadsafe-statics
@opindex fno-threadsafe-statics
+@opindex fthreadsafe-statics
Do not emit the extra code to use the routines specified in the C++
ABI for thread-safe initialization of local statics. You can use this
option to reduce code size slightly in code that doesn't need to be
@item -fno-use-cxa-get-exception-ptr
@opindex fno-use-cxa-get-exception-ptr
+@opindex fuse-cxa-get-exception-ptr
Don't use the @code{__cxa_get_exception_ptr} runtime routine. This
causes @code{std::uncaught_exception} to be incorrect, but is necessary
if the runtime routine is not available.
@item -fno-weak
@opindex fno-weak
+@opindex fweak
Do not use weak symbol support, even if it is provided by the linker.
By default, G++ uses weak symbols if they are available. This
option exists only for testing, and should not be used by end-users;
@item -fno-nil-receivers
@opindex fno-nil-receivers
+@opindex fnil-receivers
Assume that all Objective-C message dispatches (@code{[receiver
message:arg]}) in this translation unit ensure that the receiver is
not @code{nil}. This allows for more efficient entry points in the
@item -fno-show-column
@opindex fno-show-column
+@opindex fshow-column
Do not print column numbers in diagnostics. This may be necessary if
diagnostics are being scanned by a program that does not understand the
column numbers, such as @command{dejagnu}.
@table @gcctabopt
@item -fno-defer-pop
@opindex fno-defer-pop
+@opindex fdefer-pop
For machines that must pop arguments after a function call, always pop
the arguments as soon as each function returns.
At levels @option{-O1} and higher, @option{-fdefer-pop} is the default;
@item -fno-inline
@opindex fno-inline
+@opindex finline
Do not expand any functions inline apart from those marked with
the @code{always_inline} attribute. This is the default when not
optimizing.
@item -fno-keep-inline-dllexport
@opindex fno-keep-inline-dllexport
+@opindex fkeep-inline-dllexport
This is a more fine-grained version of @option{-fkeep-inline-functions},
which applies only to functions that are declared using the @code{dllexport}
attribute or declspec. @xref{Function Attributes,,Declaring Attributes of
@item -fno-branch-count-reg
@opindex fno-branch-count-reg
+@opindex fbranch-count-reg
Disable the optimization pass that scans for opportunities to use
``decrement and branch'' instructions on a count register instead of
instruction sequences that decrement a register, compare it against zero, and
@item -fno-function-cse
@opindex fno-function-cse
+@opindex ffunction-cse
Do not put function addresses in registers; make each instruction that
calls a constant function contain the function's address explicitly.
@item -fno-zero-initialized-in-bss
@opindex fno-zero-initialized-in-bss
+@opindex fzero-initialized-in-bss
If the target supports a BSS section, GCC by default puts variables that
are initialized to zero into BSS@. This can save space in the resulting
code.
@item -fno-lifetime-dse
@opindex fno-lifetime-dse
+@opindex flifetime-dse
In C++ the value of an object is only affected by changes within its
lifetime: when the constructor begins, the object has an indeterminate
value, and any changes during the lifetime of the object are dead when
@item -fno-ira-share-save-slots
@opindex fno-ira-share-save-slots
+@opindex fira-share-save-slots
Disable sharing of stack slots used for saving call-used hard
registers living through a call. Each hard register gets a
separate stack slot, and as a result function stack frames are
@item -fno-ira-share-spill-slots
@opindex fno-ira-share-spill-slots
+@opindex fira-share-spill-slots
Disable sharing of stack slots allocated for pseudo-registers. Each
pseudo-register that does not get a hard register gets a separate
stack slot, and as a result function stack frames are larger.
@item -fno-sched-interblock
@opindex fno-sched-interblock
+@opindex fsched-interblock
Disable instruction scheduling across basic blocks, which
is normally enabled when scheduling before register allocation, i.e.@:
with @option{-fschedule-insns} or at @option{-O2} or higher.
@item -fno-sched-spec
@opindex fno-sched-spec
+@opindex fsched-spec
Disable speculative motion of non-load instructions, which
is normally enabled when scheduling before register allocation, i.e.@:
with @option{-fschedule-insns} or at @option{-O2} or higher.
@item -fno-printf-return-value
@opindex fno-printf-return-value
+@opindex fprintf-return-value
Do not substitute constants for known return value of formatted output
functions such as @code{sprintf}, @code{snprintf}, @code{vsprintf}, and
@code{vsnprintf} (but not @code{printf} of @code{fprintf}). This
@item -fno-peephole
@itemx -fno-peephole2
@opindex fno-peephole
+@opindex fpeephole
@opindex fno-peephole2
+@opindex fpeephole2
Disable any machine-specific peephole optimizations. The difference
between @option{-fno-peephole} and @option{-fno-peephole2} is in how they
are implemented in the compiler; some targets use one, some use the
@item -fno-guess-branch-probability
@opindex fno-guess-branch-probability
+@opindex fguess-branch-probability
Do not guess branch probabilities using heuristics.
GCC uses heuristics to guess branch probabilities if they are
@item -fno-toplevel-reorder
@opindex fno-toplevel-reorder
+@opindex ftoplevel-reorder
Do not reorder top-level functions, variables, and @code{asm}
statements. Output them in the same order that they appear in the
input file. When this option is used, unreferenced static variables
@item -fno-math-errno
@opindex fno-math-errno
+@opindex fmath-errno
Do not set @code{errno} after calling math functions that are executed
with a single instruction, e.g., @code{sqrt}. A program that relies on
IEEE exceptions for math error handling may want to use this flag
@item -fno-signed-zeros
@opindex fno-signed-zeros
+@opindex fsigned-zeros
Allow optimizations for floating-point arithmetic that ignore the
signedness of zero. IEEE arithmetic specifies the behavior of
distinct +0.0 and @minus{}0.0 values, which then prohibits simplification
@item -fno-trapping-math
@opindex fno-trapping-math
+@opindex ftrapping-math
Compile code assuming that floating-point operations cannot generate
user-visible traps. These traps include division by zero, overflow,
underflow, inexact result and invalid operation. This option requires
@item -fno-fp-int-builtin-inexact
@opindex fno-fp-int-builtin-inexact
+@opindex ffp-int-builtin-inexact
Do not allow the built-in functions @code{ceil}, @code{floor},
@code{round} and @code{trunc}, and their @code{float} and @code{long
double} variants, to generate code that raises the ``inexact''
@item -fno-gnu-unique
@opindex fno-gnu-unique
+@opindex fgnu-unique
On systems with recent GNU assembler and C library, the C++ compiler
uses the @code{STB_GNU_UNIQUE} binding to make sure that definitions
of template static data members and static local variables in inline
@item -fno-common
@opindex fno-common
+@opindex fcommon
@cindex tentative definitions
In C code, this option controls the placement of global variables
defined without an initializer, known as @dfn{tentative definitions}
@item -fno-ident
@opindex fno-ident
+@opindex fident
Ignore the @code{#ident} directive.
@item -finhibit-size-directive
@item -fno-plt
@opindex fno-plt
+@opindex fplt
Do not use the PLT for external function calls in position-independent code.
Instead, load the callee address at call sites from the GOT and branch to it.
This leads to more efficient code by eliminating PLT stubs and exposing
@item -fno-jump-tables
@opindex fno-jump-tables
+@opindex fjump-tables
Do not use jump tables for switch statements even where it would be
more efficient than other code generation strategies. This option is
of use in conjunction with @option{-fpic} or @option{-fPIC} for
@item -mno-soft-cmpsf
@opindex mno-soft-cmpsf
+@opindex msoft-cmpsf
For single-precision floating-point comparisons, emit an @code{fsub} instruction
and test the flags. This is faster than a software comparison, but can
get incorrect results in the presence of NaNs, or when two different small
@item -mno-round-nearest
@opindex mno-round-nearest
+@opindex mround-nearest
Make the scheduler assume that the rounding mode has been set to
truncating. The default is @option{-mround-nearest}.
The default is @option{-mfp-mode=caller}
-@item -mnosplit-lohi
+@item -mno-split-lohi
@itemx -mno-postinc
@itemx -mno-postmodify
-@opindex mnosplit-lohi
+@opindex mno-split-lohi
+@opindex msplit-lohi
@opindex mno-postinc
+@opindex mpostinc
@opindex mno-postmodify
+@opindex mpostmodify
Code generation tweaks that disable, respectively, splitting of 32-bit
loads, generation of post-increment addresses, and generation of
post-modify addresses. The defaults are @option{msplit-lohi},
@item -mnovect-double
@opindex mno-vect-double
+@opindex mvect-double
Change the preferred SIMD mode to SImode. The default is
@option{-mvect-double}, which uses DImode as preferred SIMD mode.
@item -mno-mpy
@opindex mno-mpy
+@opindex mmpy
Do not generate @code{mpy}-family instructions for ARC700. This option is
deprecated.
@item -mno-sdata
@opindex mno-sdata
+@opindex msdata
Do not generate sdata references. This is the default for tool chains
built for @w{@code{arc-linux-uclibc}} and @w{@code{arceb-linux-uclibc}}
targets.
@item -mno-volatile-cache
@opindex mno-volatile-cache
+@opindex mvolatile-cache
Enable cache bypass for volatile references.
@end table
@item -mno-sched-prolog
@opindex mno-sched-prolog
+@opindex msched-prolog
Prevent the reordering of instructions in the function prologue, or the
merging of those instruction with the instructions in the function's
body. This means that all functions start with a recognizable set
@item -mno-specld-anomaly
@opindex mno-specld-anomaly
+@opindex mspecld-anomaly
Don't generate extra code to prevent speculative loads from occurring.
@item -mcsync-anomaly
@item -mno-csync-anomaly
@opindex mno-csync-anomaly
+@opindex mcsync-anomaly
Don't generate extra code to prevent CSYNC or SSYNC instructions from
occurring too soon after a conditional branch.
-@item -mlow-64k
-@opindex mlow-64k
+@item -mlow64k
+@opindex mlow64k
When enabled, the compiler is free to take advantage of the knowledge that
the entire program fits into the low 64k of memory.
-@item -mno-low-64k
-@opindex mno-low-64k
+@item -mno-low64k
+@opindex mno-low64k
Assume that the program is arbitrarily large. This is the default.
@item -mstack-check-l1
@item -mno-id-shared-library
@opindex mno-id-shared-library
+@opindex mid-shared-library
Generate code that doesn't assume ID-based shared libraries are being used.
This is the default.
@item -mno-leaf-id-shared-library
@opindex mno-leaf-id-shared-library
+@opindex mleaf-id-shared-library
Do not assume that the code being compiled won't link against any ID shared
libraries. Slower code is generated for jump and call insns.
@item -mno-sep-data
@opindex mno-sep-data
+@opindex msep-data
Generate code that assumes that the data segment follows the text segment.
This is the default.
@item -mno-side-effects
@opindex mno-side-effects
+@opindex mside-effects
Do not emit instructions with side effects in addressing modes other than
post-increment.
@item -mno-dword
@opindex mno-dword
+@opindex mdword
Do not use double word instructions.
@item -mno-optimize-membar
@opindex mno-optimize-membar
+@opindex moptimize-membar
This switch disables the automatic removal of redundant @code{membar}
instructions from the generated code.
@item -mno-exr
@opindex mno-exr
+@opindex mexr
Extended registers are not stored on stack before execution of function
with monitor attribute. Default option is @option{-mno-exr}.
This option is valid only for H8S targets.
@item -mno-space-regs
@opindex mno-space-regs
+@opindex mspace-regs
Generate code that assumes the target has no space registers. This allows
GCC to generate faster indirect calls and use unscaled index address modes.
@item -mlong-calls
@opindex mno-long-calls
+@opindex mlong-calls
Generate code that uses long call sequences. This ensures that a call
is always able to reach linker generated stubs. The default is to generate
long calls only when the distance from the call site to the beginning
@item -mno-inline-int-divide
@opindex mno-inline-int-divide
+@opindex minline-int-divide
Do not generate inline code for divides of integer values.
@item -minline-sqrt-min-latency
The @code{rtd} instruction is supported by the 68010, 68020, 68030,
68040, 68060 and CPU32 processors, but not by the 68000 or 5200.
-@item -mno-rtd
-@opindex mno-rtd
-Do not use the calling conventions selected by @option{-mrtd}.
-This is the default.
+The default is @option{-mno-rtd}.
@item -malign-int
@itemx -mno-align-int
instructions if the target is the @samp{AM33} or later. This is the
default. This option defines the preprocessor macro @code{__LIW__}.
-@item -mnoliw
-@opindex mnoliw
+@item -mno-liw
+@opindex mno-liw
Do not allow the compiler to generate @emph{Long Instruction Word}
instructions. This option defines the preprocessor macro
@code{__NO_LIW__}.
instructions if the target is the @samp{AM33} or later. This is the
default. This option defines the preprocessor macro @code{__SETLB__}.
-@item -mnosetlb
-@opindex mnosetlb
+@item -mno-setlb
+@opindex mno-setlb
Do not allow the compiler to generate @emph{SETLB} or @emph{Lcc}
instructions. This option defines the preprocessor macro
@code{__NO_SETLB__}.
Do not generate conditional move instructions.
@item -mext-perf
-@opindex mperf-ext
+@opindex mext-perf
Generate performance extension instructions.
@item -mno-ext-perf
-@opindex mno-perf-ext
+@opindex mno-ext-perf
Do not generate performance extension instructions.
@item -mext-perf2
-@opindex mperf-ext
+@opindex mext-perf2
Generate performance extension 2 instructions.
@item -mno-ext-perf2
-@opindex mno-perf-ext
+@opindex mno-ext-perf2
Do not generate performance extension 2 instructions.
@item -mext-string
-@opindex mperf-ext
+@opindex mext-string
Generate string extension instructions.
@item -mno-ext-string
-@opindex mno-perf-ext
+@opindex mno-ext-string
Do not generate string extension instructions.
@item -mv3push
@item -mno-fp-ret-in-387
@opindex mno-fp-ret-in-387
+@opindex mfp-ret-in-387
Do not use the FPU registers for return values of functions.
The usual calling convention has functions return values of types
@item -mno-fancy-math-387
@opindex mno-fancy-math-387
+@opindex mfancy-math-387
Some 387 emulators do not support the @code{sin}, @code{cos} and
@code{sqrt} instructions for the 387. Specify this option to avoid
generating those instructions.
@item -mno-align-stringops
@opindex mno-align-stringops
+@opindex malign-stringops
Do not align the destination of inlined string operations. This switch reduces
code size and improves performance in case the destination is already aligned,
but GCC doesn't know about it.
@item -mno-red-zone
@opindex mno-red-zone
+@opindex mred-zone
Do not use a so-called ``red zone'' for x86-64 code. The red zone is mandated
by the x86-64 ABI; it is a 128-byte area beyond the location of the
stack pointer that is not modified by signal or interrupt handlers
@item -fno-set-stack-executable
@opindex fno-set-stack-executable
+@opindex fset-stack-executable
This option is available for MinGW targets. It specifies that
the executable flag for the stack used by nested functions isn't
set. This is necessary for binaries running in kernel mode of
@item -fwritable-relocated-rdata
@opindex fno-writable-relocated-rdata
+@opindex fwritable-relocated-rdata
This option is available for MinGW and Cygwin targets. It specifies
that relocated-data in read-only section is put into the @code{.data}
section. This is a necessary for older runtimes not supporting
projects / gcc.git / commitdiff