-fno-inline -fno-math-errno -fno-peephole -fno-peephole2 @gol
-funsafe-math-optimizations -fno-trapping-math @gol
-fomit-frame-pointer -foptimize-register-move @gol
--foptimize-sibling-calls -freduce-all-givs @gol
+-foptimize-sibling-calls -fprefetch-loop-arrays -freduce-all-givs @gol
-fregmove -frename-registers @gol
-frerun-cse-after-loop -frerun-loop-opt @gol
-fschedule-insns -fschedule-insns2 @gol
@emph{i386 and x86-64 Options}
@gccoptlist{
--mcpu=@var{cpu-type} -march=@var{cpu-type} @gol
--mintel-syntax -mieee-fp -mno-fancy-math-387 @gol
+-mcpu=@var{cpu-type} -march=@var{cpu-type} -mfpmath=@var{unit} @gol
+-masm=@var{dialect} -mno-fancy-math-387 @gol
-mno-fp-ret-in-387 -msoft-float -msvr3-shlib @gol
-mno-wide-multiply -mrtd -malign-double @gol
-mpreferred-stack-boundary=@var{num} @gol
--mmmx -msse -m3dnow @gol
+-mmmx -msse -msse2 -msse-math -m3dnow @gol
-mthreads -mno-align-stringops -minline-all-stringops @gol
-mpush-args -maccumulate-outgoing-args -m128bit-long-double @gol
-m96bit-long-double -mregparm=@var{num} -momit-leaf-frame-pointer @gol
in many functions. @strong{It also makes debugging impossible on
some machines.}
-@ifset INTERNALS
-On some machines, such as the VAX, this flag has no effect, because
-the standard calling sequence automatically handles the frame pointer
-and nothing is saved by pretending it doesn't exist. The
-machine-description macro @code{FRAME_POINTER_REQUIRED} controls
-whether a target machine supports this flag. @xref{Registers}.
-@end ifset
-@ifclear INTERNALS
On some machines, such as the VAX, this flag has no effect, because
the standard calling sequence automatically handles the frame pointer
and nothing is saved by pretending it doesn't exist. The
machine-description macro @code{FRAME_POINTER_REQUIRED} controls
whether a target machine supports this flag. @xref{Registers,,Register
-Usage, gcc.info, Using and Porting GCC}.
-@end ifclear
+Usage, gccint, GNU Compiler Collection (GCC) Internals}.
@item -foptimize-sibling-calls
@opindex foptimize-sibling-calls
@option{-funroll-all-loops} implies the same options as
@option{-funroll-loops},
+@item -fprefetch-loop-arrays
+@opindex fprefetch-loop-arrays
+If supported by the target machine, generate instructions to prefetch
+memory to improve the performance of loops that access large arrays.
@item -fmove-all-movables
@opindex fmove-all-movables
structure of the generated code, so you must use the same source code
and the same optimization options for both compilations.
-@ifset INTERNALS
With @option{-fbranch-probabilities}, GCC puts a @samp{REG_EXEC_COUNT}
note on the first instruction of each basic block, and a
@samp{REG_BR_PROB} note on each @samp{JUMP_INSN} and @samp{CALL_INSN}.
used in one place: in @file{reorg.c}, instead of guessing which path a
branch is mostly to take, the @samp{REG_BR_PROB} values are used to
exactly determine which path is taken more often.
-@end ifset
@item -fno-guess-branch-probability
@opindex fno-guess-branch-probability
@}
@end example
-@ifset INTERNALS
Every language that wishes to perform language-specific alias analysis
should define a function that computes, given an @code{tree}
node, an alias set for the node. Nodes in different alias sets are not
allowed to alias. For an example, see the C front-end function
@code{c_get_alias_set}.
-@end ifset
@item -falign-functions
@itemx -falign-functions=@var{n}
@option{-nodefaultlibs} is @file{libgcc.a}, a library of internal subroutines
that GCC uses to overcome shortcomings of particular machines, or special
needs for some languages.
-@ifset INTERNALS
-(@xref{Interface,,Interfacing to GCC Output}, for more discussion of
-@file{libgcc.a}.)
-@end ifset
-@ifclear INTERNALS
-(@xref{Interface,,Interfacing to GCC Output,gcc.info,Porting GCC},
+(@xref{Interface,,Interfacing to GCC Output,gccint,GNU Compiler
+Collection (GCC) Internals},
for more discussion of @file{libgcc.a}.)
-@end ifclear
In most cases, you need @file{libgcc.a} even when you want to avoid
other standard libraries. In other words, when you specify @option{-nostdlib}
or @option{-nodefaultlibs} you should usually specify @option{-lgcc} as well.
This ensures that you have no unresolved references to internal GCC
library subroutines. (For example, @samp{__main}, used to ensure C++
-constructors will be called; @pxref{Collect2,,@command{collect2}}.)
+constructors will be called; @pxref{Collect2,,@code{collect2}, gccint,
+GNU Compiler Collection (GCC) Internals}.)
@item -s
@opindex s
options, usually for compatibility with other compilers on the same
platform.
-@ifset INTERNALS
These options are defined by the macro @code{TARGET_SWITCHES} in the
machine description. The default for the options is also defined by
that macro, which enables you to change the defaults.
-@end ifset
@menu
* M680x0 Options::
@samp{_flush_func} or @samp{__cpu_flush}.
@end table
-@ifset INTERNALS
These options are defined by the macro
@code{TARGET_SWITCHES} in the machine description. The default for the
options is also defined by that macro, which enables you to change the
defaults.
-@end ifset
@node i386 and x86-64 Options
@subsection Intel 386 and AMD x86-64 Options
@table @gcctabopt
@item -mcpu=@var{cpu-type}
@opindex mcpu
-Assume the defaults for the machine type @var{cpu-type} when scheduling
-instructions. The choices for @var{cpu-type} are @samp{i386},
-@samp{i486}, @samp{i586}, @samp{i686}, @samp{pentium},
-@samp{pentiumpro}, @samp{pentium4}, @samp{k6}, and @samp{athlon}
+Tune to @var{cpu-type} everything applicable about the generated code, except
+for the ABI and the set of available instructions. The choices for
+@var{cpu-type} are @samp{i386}, @samp{i486}, @samp{i586}, @samp{i686},
+@samp{pentium}, @samp{pentium-mmx}, @samp{pentiumpro}, @samp{pentium2},
+@samp{pentium3}, @samp{pentium4}, @samp{k6}, @samp{k6-2}, @samp{k6-3},
+@samp{athlon}, @samp{athlon-tbird}, @samp{athlon-4}, @samp{athlon-xp}
+and @samp{athlon-mp}.
While picking a specific @var{cpu-type} will schedule things appropriately
for that particular chip, the compiler will not generate any code that
@option{-mcpu=pentium}, and @option{-mcpu=pentiumpro} respectively.
These synonyms are deprecated.
-@item -mintel-syntax
-@opindex mintel-syntax
-Emit assembly using Intel syntax opcodes instead of AT&T syntax.
+@item -mfpmath=@var{unit}
+@opindex march
+generate floating point arithmetics for selected unit @var{unit}. the choices
+for @var{unit} are:
+
+@table @samp
+@item 387
+Use the standard 387 floating point coprocessor present majority of chips and
+emulated otherwise. Code compiled with this option will run almost everywhere.
+The temporary results are computed in 80bit precesion instead of precision
+specified by the type resulting in slightly different results compared to most
+of other chips. See @option{-ffloat-store} for more detailed description.
+
+This is the default choice for i386 compiler.
+
+@item sse
+Use scalar floating point instructions present in the SSE instruction set.
+This instruction set is supported by Pentium3 and newer chips, in the AMD line
+by Athlon-4, Athlon-xp and Athlon-mp chips. The earlier version of SSE
+instruction set supports only single precision arithmetics, thus the double and
+extended precision arithmetics is still done using 387. Later version, present
+only in Pentium4 and the future AMD x86-64 chips supports double precision
+arithmetics too.
+
+For i387 you need to use @option{-march=@var{cpu-type}}, @option{-msse} or
+@option{-msse2} switches to enable SSE extensions and make this option
+effective. For x86-64 compiler, these extensions are enabled by default.
+
+The resulting code should be considerably faster in majority of cases and avoid
+the numerical instability problems of 387 code, but may break some existing
+code that expects temporaries to be 80bit.
+
+This is the default choice for x86-64 compiler.
+
+@item sse,387
+Attempt to utilize both instruction sets at once. This effectivly double the
+amount of available registers and on chips with separate execution units for
+387 and SSE the execution resources too. Use this option with care, as it is
+still experimental, because gcc register allocator does not model separate
+functional units well resulting in instable performance.
+@end table
+
+@item -masm=@var{dialect}
+@opindex masm=@var{dialect}
+Output asm instructions using selected @var{dialect}. Supported choices are
+@samp{intel} or @samp{att} (the default one).
@item -mieee-fp
@itemx -mno-ieee-fp
@itemx -mno-mmx
@item -msse
@itemx -mno-sse
+@item -msse2
+@itemx -mno-sse2
@item -m3dnow
@itemx -mno-3dnow
@opindex mmmx
when searching for various kinds of files. Some are used to specify other
aspects of the compilation environment.
-@ifclear INTERNALS
-Note that you can also specify places to search using options such as
-@option{-B}, @option{-I} and @option{-L} (@pxref{Directory Options}). These
-take precedence over places specified using environment variables, which
-in turn take precedence over those specified by the configuration of GCC@.
-
-@end ifclear
-@ifset INTERNALS
Note that you can also specify places to search using options such as
@option{-B}, @option{-I} and @option{-L} (@pxref{Directory Options}). These
take precedence over places specified using environment variables, which
in turn take precedence over those specified by the configuration of GCC@.
-@xref{Driver}.
-@end ifset
+@xref{Driver,, Controlling the Compilation Driver @file{gcc}, gccint,
+GNU Compiler Collection (GCC) Internals}.
@table @env
@item LANG
OSDN Git Service
