common.opt: Add description of the new -fgcse-after-reload flag.

[gcc.git] / gcc / common.opt

; Options for the language- and target-independent parts of the compiler.
; Copyright (C) 2003, 2004 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 2, 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 COPYING.  If not, write to the Free
; Software Foundation, 59 Temple Place - Suite 330, Boston, MA
; 02111-1307, USA.

; See c.opt for a description of this file's format.

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

-help
Common
Display this information

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

-target-help
Common

-version
Common

G
Common Joined Separate UInteger
-G<number>	Put global and static data smaller than <number> bytes into a special section (on some targets)

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

Os
Common
Optimize for space rather than speed

W
Common RejectNegative
This switch is deprecated; use -Wextra instead

Waggregate-return
Common
Warn about returning structures, unions or arrays

Wcast-align
Common
Warn about pointer casts which increase alignment

Wdeprecated-declarations
Common
Warn about uses of __attribute__((deprecated)) declarations

Wdisabled-optimization
Common
Warn when an optimization pass is disabled

Werror
Common
Treat all warnings as errors

Wextra
Common
Print extra (possibly unwanted) warnings

Winline
Common
Warn when an inlined function cannot be inlined

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

Wmissing-noreturn
Common
Warn about functions which might be candidates for __attribute__((noreturn))

Wpacked
Common
Warn when the packed attribute has no effect on struct layout

Wpadded
Common
Warn when padding is required to align structure members

Wshadow
Common
Warn when one local variable shadows another

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

Wswitch
Common
Warn about enumerated switches, with no default, missing a case

Wswitch-default
Common
Warn about enumerated switches missing a \"default:\" statement

Wswitch-enum
Common
Warn about all enumerated switches missing a specific case

Wsystem-headers
Common
Do not suppress warnings from system headers

Wuninitialized
Common
Warn about uninitialized automatic variables

Wunreachable-code
Common
Warn about code that will never be executed

Wunused
Common
Enable all -Wunused- warnings

Wunused-function
Common
Warn when a function is unused

Wunused-label
Common
Warn when a label is unused

Wunused-parameter
Common
Warn when a function parameter is unused

Wunused-value
Common
Warn when an expression value is unused

Wunused-variable
Common
Warn when a variable is unused

aux-info
Common Separate
-aux-info <file>	Emit declaration information into <file>

aux-info=
Common Joined

auxbase
Common Separate

auxbase-strip
Common Separate

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

dumpbase
Common Separate
-dumpbase <file>	Set the file basename to be used for dumps

fPIC
Common

fPIE
Common

fabi-version=
Common Joined UInteger

falign-functions
Common
Align the start of functions

falign-functions=
Common RejectNegative Joined UInteger

falign-jumps
Common
Align labels which are only reached by jumping

falign-jumps=
Common RejectNegative Joined UInteger

falign-labels
Common
Align all labels

falign-labels=
Common RejectNegative Joined UInteger

falign-loops
Common
Align the start of loops

falign-loops=
Common RejectNegative Joined UInteger

fargument-alias
Common
Specify that arguments may alias each other and globals

fargument-noalias
Common
Assume arguments may alias globals but not each other

fargument-noalias-global
Common
Assume arguments alias neither each other nor globals

fasynchronous-unwind-tables
Common
Generate unwind tables that are exact at each instruction boundary

fbounds-check
Common
Generate code to check bounds before indexing arrays

fbranch-count-reg
Common
Replace add, compare, branch with branch on count register

fbranch-probabilities
Common
Use profiling information for branch probabilities

fbranch-target-load-optimize
Common
Perform branch target load optimization before prologue / epilogue threading

fbranch-target-load-optimize2
Common
Perform branch target load optimization after prologue / epilogue threading

fbtr-bb-exclusive
Common
Restrict target load migration not to re-use registers in any basic block

fcall-saved-
Common Joined RejectNegative
-fcall-saved-<register>	Mark <register> as being preserved across functions

fcall-used-
Common Joined RejectNegative
-fcall-used-<register>	Mark <register> as being corrupted by function calls

fcaller-saves
Common
Save registers around function calls

fcommon
Common
Do not put uninitialized globals in the common section

fcprop-registers
Common
Perform a register copy-propagation optimization pass

fcrossjumping
Common
Perform cross-jumping optimization

fcse-follow-jumps
Common
When running CSE, follow jumps to their targets

fcse-skip-blocks
Common
When running CSE, follow conditional jumps

fdata-sections
Common
Place data items into their own section

fdefer-pop
Common
Defer popping functions args from stack until later

fdelayed-branch
Common
Attempt to fill delay slots of branch instructions

fdelete-null-pointer-checks
Common
Delete useless null pointer checks

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

fdump-unnumbered
Common
Suppress output of instruction numbers and line number notes in debugging dumps

feliminate-dwarf2-dups
Common
Perform DWARF2 duplicate elimination

feliminate-unused-debug-symbols
Common
Perform unused type elimination in debug info

feliminate-unused-debug-types
Common
Perform unused type elimination in debug info

fexceptions
Common
Enable exception handling

fexpensive-optimizations
Common
Perform a number of minor, expensive optimizations

ffast-math
Common

ffinite-math-only
Common
Assume no NaNs or infinities are generated

ffixed-
Common Joined RejectNegative
-ffixed-<register>	Mark <register> as being unavailable to the compiler

ffloat-store
Common
Do not store floats in registers

fforce-addr
Common
Copy memory address constants into registers before use

fforce-mem
Common
Copy memory operands into registers before use

ffunction-cse
Common
Allow function addresses to be held in registers

ffunction-sections
Common
Place each function into its own section

fgcse
Common
Perform global common subexpression elimination

fgcse-lm
Common
Perform enhanced load motion during global common subexpression elimination

fgcse-sm
Common
Perform store motion after global common subexpression elimination

fgcse-las
Common
Perform redundant load after store elimination in global common subexpression
elimination

fgcse-after-reload
Common
Perform global common subexpression elimination after register allocation
has finished.

fguess-branch-probability
Common
Enable guessing of branch probabilities

fident
Common
Process #ident directives

fif-conversion
Common
Perform conversion of conditional jumps to branchless equivalents

fif-conversion2
Common
Perform conversion of conditional jumps to conditional execution

finhibit-size-directive
Common
Do not generate .size directives

finline
Common
Pay attention to the \"inline\" keyword

finline-functions
Common
Integrate simple functions into their callers

finline-limit-
Common RejectNegative Joined UInteger

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

finstrument-functions
Common
Instrument function entry and exit with profiling calls

fkeep-inline-functions
Common
Generate code for functions even if they are fully inlined

fkeep-static-consts
Common
Emit static const variables even if they are not used

fleading-underscore
Common
Give external symbols a leading underscore

floop-optimize
Common
Perform loop optimizations

fmath-errno
Common
Set errno after built-in math functions

fmem-report
Common
Report on permanent memory allocation

fmerge-all-constants
Common
Attempt to merge identical constants and constant variables

fmerge-constants
Common
Attempt to merge identical constants across compilation units

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

fmove-all-movables
Common
Force all loop invariant computations out of loops

fnew-ra
Common
Use graph-coloring register allocation

fnon-call-exceptions
Common
Support synchronous non-call exceptions

fold-unroll-loops
Common
Perform loop unrolling when iteration count is known

fold-unroll-all-loops
Common
Perform loop unrolling for all loops

fomit-frame-pointer
Common
When possible do not generate stack frames

foptimize-register-move
Common
Do the full register move optimization pass

foptimize-sibling-calls
Common
Optimize sibling and tail recursive calls

fpack-struct
Common
Pack structure members together without holes

fpcc-struct-return
Common
Return small aggregates in memory, not registers

fpeel-loops
Common
Perform loop peeling

fpeephole
Common
Enable machine specific peephole optimizations

fpeephole2
Common
Enable an RTL peephole pass before sched2

fpic
Common
Generate position-independent code if possible

fpie
Common
Generate position-independent code for executables if possible

fprefetch-loop-arrays
Common
Generate prefetch instructions, if available, for arrays in loops

fprofile
Common
Enable basic program profiling code

fprofile-arcs
Common
Insert arc-based program profiling code

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

fprofile-use
Common
Enable common options for performing profile feedback directed optimizations

fprofile-values
Common
Insert code to profile values of expressions

frandom-seed
Common

frandom-seed=
Common Joined RejectNegative
-frandom-seed=<string>	Make compile reproducible using <string>

freduce-all-givs
Common
Strength reduce all loop general induction variables

freg-struct-return
Common
Return small aggregates in registers

fregmove
Common
Enables a register move optimization

frename-registers
Common
Perform a register renaming optimization pass

freorder-blocks
Common
Reorder basic blocks to improve code placement

freorder-functions
Common
Reorder functions to improve code placement

frerun-cse-after-loop
Common
Add a common subexpression elimination pass after loop optimizations

frerun-loop-opt
Common
Run the loop optimizer twice

frounding-math
Common
Disable optimizations that assume default FP rounding behavior

fsched-interblock
Common
Enable scheduling across basic blocks

fsched-spec
Common
Allow speculative motion of non-loads

fsched-spec-load
Common
Allow speculative motion of some loads

fsched-spec-load-dangerous
Common
Allow speculative motion of more loads

fsched-verbose=
Common RejectNegative Joined
-fsched-verbose=<number>	Set the verbosity level of the scheduler

fsched2-use-superblocks
Common
If scheduling post reload, do superblock scheduling

fsched2-use-traces
Common
If scheduling post reload, do trace scheduling

fschedule-insns
Common
Reschedule instructions before register allocation

fschedule-insns2
Common
Reschedule instructions after register allocation

fsched-stalled-insns
Common
Allow premature scheduling of queued insns

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

fsched-stalled-insns-dep
Common
Set dependence distance checking in premature scheduling of queued insns

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

fshared-data
Common
Mark data as shared rather than private

fsignaling-nans
Common
Disable optimizations observable by IEEE signaling NaNs

fsingle-precision-constant
Common
Convert floating point constants to single precision constants

fstack-check
Common
Insert stack checking code into the program

fstack-limit
Common

fstack-limit-register=
Common RejectNegative Joined
-fstack-limit-register=<register>	Trap if the stack goes past <register>

fstack-limit-symbol=
Common RejectNegative Joined
-fstack-limit-symbol=<name>	Trap if the stack goes past symbol <name>

fstrength-reduce
Common
Perform strength reduction optimizations

fstrict-aliasing
Common
Assume strict aliasing rules apply

fsyntax-only
Common
Check for syntax errors, then stop

ftest-coverage
Common
Create data files needed by \"gcov\"

fthread-jumps
Common
Perform jump threading optimizations

ftime-report
Common
Report the time taken by each compiler pass

ftls-model=
Common Joined RejectNegative
-ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec]	Set the default thread-local storage code generation model

ftracer
Common
Perform superblock formation via tail duplication

ftrapping-math
Common
Assume floating-point operations can trap

ftrapv
Common
Trap for signed overflow in addition, subtraction and multiplication

funit-at-a-time
Common
Compile whole compilation unit at a time

funroll-loops
Common
Perform loop unrolling when iteration count is known

funroll-all-loops
Common
Perform loop unrolling for all loops

funsafe-math-optimizations
Common
Allow math optimizations that may violate IEEE or ISO standards

funswitch-loops
Common
Perform loop unswitching

funwind-tables
Common
Just generate unwind tables for exception handling

fvar-tracking
Common
Perform variable tracking

fverbose-asm
Common
Add extra commentary to assembler output

fvpt
Common
Use expression value profiles in optimizations

fweb
Common
Construct webs and split unrelated uses of single variable

fwrapv
Common
Assume signed arithmetic overflow wraps around

fzero-initialized-in-bss
Common
Put zero initialized data in the bss section

g
Common JoinedOrMissing
Generate debug information in default format

gcoff
Common JoinedOrMissing
Generate debug information in COFF format

gdwarf-2
Common JoinedOrMissing
Generate debug information in DWARF v2 format

ggdb
Common JoinedOrMissing
Generate debug information in default extended format

gstabs
Common JoinedOrMissing
Generate debug information in STABS format

gstabs+
Common JoinedOrMissing
Generate debug information in extended STABS format

gvms
Common JoinedOrMissing
Generate debug information in VMS format

gxcoff
Common JoinedOrMissing
Generate debug information in XCOFF format

gxcoff+
Common JoinedOrMissing
Generate debug information in extended XCOFF format

m
Common Joined

o
Common Joined Separate
-o <file>	Place output into <file>

p
Common
Enable function profiling

pedantic
Common
Issue warnings needed for strict compliance to the standard

pedantic-errors
Common
Like -pedantic but issue them as errors

quiet
Common
Do not display functions compiled or elapsed time

version
Common
Display the compiler's version

w
Common
Suppress warnings

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