1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008
4 ; Free Software Foundation, Inc.
6 ; This file is part of GCC.
8 ; GCC is free software; you can redistribute it and/or modify it under
9 ; the terms of the GNU General Public License as published by the Free
10 ; Software Foundation; either version 3, or (at your option) any later
13 ; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 ; WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 ; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 ; You should have received a copy of the GNU General Public License
19 ; along with GCC; see the file COPYING3. If not see
20 ; <http://www.gnu.org/licenses/>.
22 ; See the GCC internals manual (options.texi) for a description of this file's format.
24 ; Please try to keep this file in ASCII collating order.
28 Display this information
32 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params
36 Alias for --help=target
38 ;; The following three entries are to work around the gcc driver
39 ;; program's insatiable desire to turn options starting with a
40 ;; double dash (--) into options starting with a dash f (-f).
52 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
58 Common Joined Separate UInteger
59 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
62 Common JoinedOrMissing
63 -O<number> Set optimization level to <number>
67 Optimize for space rather than speed
71 This switch is deprecated; use -Wextra instead
74 Common Var(warn_aggregate_return) Warning
75 Warn about returning structures, unions or arrays
78 Common Var(warn_array_bounds) Warning
79 Warn if an array is accessed out of bounds
82 Common Var(warn_attributes) Init(1) Warning
83 Warn about inappropriate attribute usage
86 Common Var(warn_cast_align) Warning
87 Warn about pointer casts which increase alignment
89 Wdeprecated-declarations
90 Common Var(warn_deprecated_decl) Init(1) Warning
91 Warn about uses of __attribute__((deprecated)) declarations
93 Wdisabled-optimization
94 Common Var(warn_disabled_optimization) Warning
95 Warn when an optimization pass is disabled
98 Common Var(warnings_are_errors)
99 Treat all warnings as errors
103 Treat specified warning as error
107 Print extra (possibly unwanted) warnings
110 Common Var(flag_fatal_errors)
111 Exit on the first error occurred
114 Common RejectNegative Joined UInteger
115 -Wframe-larger-than=@var{len} Warn whenever a function's stack frame requires
116 more than @var{len} bytes. The computation done to determine
117 the stack frame size is approximate and not conservative.
118 The actual requirements may be somewhat greater than @var{len}
119 even if you do not get a warning. In addition, any space allocated
120 via @code{alloca}, variable-length arrays, or related constructs
121 is not included by the compiler when determining
122 whether or not to issue a warning.
125 Common Var(warn_inline) Warning
126 Warn when an inlined function cannot be inlined
129 Common RejectNegative Joined UInteger Warning
132 Common RejectNegative Joined UInteger Warning
133 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
136 Common Warning Var(warn_logical_op)
137 Warn when a logical operator is suspicously always evaluating to true or false
139 Wunsafe-loop-optimizations
140 Common Var(warn_unsafe_loop_optimizations) Warning
141 Warn if the loop cannot be optimized due to nontrivial assumptions.
144 Common Var(warn_missing_noreturn) Warning
145 Warn about functions which might be candidates for __attribute__((noreturn))
148 Common Var(warn_mudflap) Init(1) Warning
149 Warn about constructs not instrumented by -fmudflap
152 Common Var(warn_overflow) Init(1) Warning
153 Warn about overflow in arithmetic expressions
156 Common Var(warn_packed) Warning
157 Warn when the packed attribute has no effect on struct layout
160 Common Var(warn_padded) Warning
161 Warn when padding is required to align structure members
164 Common Var(warn_shadow) Warning
165 Warn when one local variable shadows another
168 Common Var(warn_stack_protect) Warning
169 Warn when not issuing stack smashing protection for some reason
173 Warn about code which might break strict aliasing rules
176 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
177 Warn about code which might break strict aliasing rules
181 Warn about optimizations that assume that signed overflow is undefined
184 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
185 Warn about optimizations that assume that signed overflow is undefined
188 Common Var(warn_switch) Warning
189 Warn about enumerated switches, with no default, missing a case
192 Common Var(warn_switch_default) Warning
193 Warn about enumerated switches missing a \"default:\" statement
196 Common Var(warn_switch_enum) Warning
197 Warn about all enumerated switches missing a specific case
200 Common Var(warn_system_headers) Warning
201 Do not suppress warnings from system headers
204 Common Var(warn_type_limits) Init(-1) Warning
205 Warn if a comparison is always true or always false due to the limited range of the data type
208 Common Var(warn_uninitialized) Warning
209 Warn about uninitialized automatic variables
212 Common Var(warn_notreached) Warning
213 Warn about code that will never be executed
217 Enable all -Wunused- warnings
220 Common Var(warn_unused_function) Warning
221 Warn when a function is unused
224 Common Var(warn_unused_label) Warning
225 Warn when a label is unused
228 Common Var(warn_unused_parameter) Warning
229 Warn when a function parameter is unused
232 Common Var(warn_unused_value) Warning
233 Warn when an expression value is unused
236 Common Var(warn_unused_variable) Warning
237 Warn when a variable is unused
240 Common RejectNegative Var(warn_coverage_mismatch) Warning
241 Warn instead of error in case profiles in -fprofile-use do not match
245 -aux-info <file> Emit declaration information into <file>
258 -d<letters> Enable dumps from specific passes of the compiler
262 -dumpbase <file> Set the file basename to be used for dumps
264 ; The version of the C++ ABI in use. The following values are allowed:
266 ; 0: The version of the ABI believed most conformant with the C++ ABI
267 ; specification. This ABI may change as bugs are discovered and fixed.
268 ; Therefore, 0 will not necessarily indicate the same ABI in different
271 ; 1: The version of the ABI first used in G++ 3.2.
273 ; 2: The version of the ABI first used in G++ 3.4.
275 ; Additional positive integers will be assigned as new versions of
276 ; the ABI become the default version of the ABI.
278 Common Joined UInteger Var(flag_abi_version) Init(2)
281 Common Report Var(align_functions,0)
282 Align the start of functions
285 Common RejectNegative Joined UInteger
288 Common Report Var(align_jumps,0) Optimization
289 Align labels which are only reached by jumping
292 Common RejectNegative Joined UInteger
295 Common Report Var(align_labels,0) Optimization
299 Common RejectNegative Joined UInteger
302 Common Report Var(align_loops) Optimization
303 Align the start of loops
306 Common RejectNegative Joined UInteger
308 ; This flag is only tested if alias checking is enabled.
309 ; 0 if pointer arguments may alias each other. True in C.
310 ; 1 if pointer arguments may not alias each other but may alias
312 ; 2 if pointer arguments may not alias each other and may not
313 ; alias global variables.
314 ; 3 if pointer arguments may not alias anything. True in Fortran.
315 ; Set by the front end.
317 Common Report Var(flag_argument_noalias,0) Optimization
318 Specify that arguments may alias each other and globals
321 Common Report Var(flag_argument_noalias,1) VarExists Optimization
322 Assume arguments may alias globals but not each other
324 fargument-noalias-global
325 Common Report Var(flag_argument_noalias,2) VarExists Optimization
326 Assume arguments alias neither each other nor globals
328 fargument-noalias-anything
329 Common Report Var(flag_argument_noalias,3) VarExists Optimization
330 Assume arguments alias no other storage
332 fasynchronous-unwind-tables
333 Common Report Var(flag_asynchronous_unwind_tables) Optimization
334 Generate unwind tables that are exact at each instruction boundary
337 Common Report Var(flag_auto_inc_dec) Init(1)
338 Generate auto-inc/dec instructions
340 ; -fcheck-bounds causes gcc to generate array bounds checks.
341 ; For C, C++ and ObjC: defaults off.
342 ; For Java: defaults to on.
343 ; For Fortran: defaults to off.
345 Common Report Var(flag_bounds_check)
346 Generate code to check bounds before indexing arrays
349 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
350 Replace add, compare, branch with branch on count register
352 fbranch-probabilities
353 Common Report Var(flag_branch_probabilities) Optimization
354 Use profiling information for branch probabilities
356 fbranch-target-load-optimize
357 Common Report Var(flag_branch_target_load_optimize) Optimization
358 Perform branch target load optimization before prologue / epilogue threading
360 fbranch-target-load-optimize2
361 Common Report Var(flag_branch_target_load_optimize2) Optimization
362 Perform branch target load optimization after prologue / epilogue threading
365 Common Report Var(flag_btr_bb_exclusive) Optimization
366 Restrict target load migration not to re-use registers in any basic block
369 Common Joined RejectNegative
370 -fcall-saved-<register> Mark <register> as being preserved across functions
373 Common Joined RejectNegative
374 -fcall-used-<register> Mark <register> as being corrupted by function calls
376 ; Nonzero for -fcaller-saves: allocate values in regs that need to
377 ; be saved across function calls, if that produces overall better code.
378 ; Optional now, so people can test it.
380 Common Report Var(flag_caller_saves) Optimization
381 Save registers around function calls
384 Common Report Var(flag_check_data_deps)
385 Compare the results of several data dependence analyzers.
388 Common Report Var(flag_no_common,0) Optimization
389 Do not put uninitialized globals in the common section
392 Common Report Var(flag_cprop_registers) Optimization
393 Perform a register copy-propagation optimization pass
396 Common Report Var(flag_crossjumping) Optimization
397 Perform cross-jumping optimization
400 Common Report Var(flag_cse_follow_jumps) Optimization
401 When running CSE, follow jumps to their targets
404 Common Report Var(flag_cse_skip_blocks) Optimization
405 When running CSE, follow conditional jumps
408 Common Report Var(flag_cx_limited_range) Optimization
409 Omit range reduction step when performing complex division
412 Common Report Var(flag_cx_fortran_rules) Optimization
413 Complex multiplication and division follow Fortran rules
416 Common Report Var(flag_data_sections) Optimization
417 Place data items into their own section
421 List all available debugging counters with their limits and counts.
424 Common RejectNegative Joined
425 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
428 Common Joined RejectNegative
429 Map one directory name to another in debug information
431 ; Nonzero for -fdefer-pop: don't pop args after each function call
432 ; instead save them up to pop many calls' args with one insns.
434 Common Report Var(flag_defer_pop) Optimization
435 Defer popping functions args from stack until later
438 Common Report Var(flag_delayed_branch) Optimization
439 Attempt to fill delay slots of branch instructions
441 fdelete-null-pointer-checks
442 Common Report Var(flag_delete_null_pointer_checks) Optimization
443 Delete useless null pointer checks
445 fdiagnostics-show-location=
446 Common Joined RejectNegative
447 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
449 fdiagnostics-show-option
451 Amend appropriate diagnostic messages with the command line option that controls them
454 Common Joined RejectNegative
455 -fdump-<type> Dump various compiler internals to a file
458 Common Report Var(flag_dump_noaddr)
459 Suppress output of addresses in debugging dumps
462 Common Report Var(flag_dump_unnumbered) VarExists
463 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
466 Common Report Var(flag_early_inlining) Init(1) Optimization
467 Perform early inlining
469 feliminate-dwarf2-dups
470 Common Report Var(flag_eliminate_dwarf2_dups)
471 Perform DWARF2 duplicate elimination
473 feliminate-unused-debug-symbols
474 Common Report Var(flag_debug_only_used_symbols)
475 Perform unused type elimination in debug info
477 feliminate-unused-debug-types
478 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
479 Perform unused type elimination in debug info
481 femit-class-debug-always
482 Common Report Var(flag_emit_class_debug_always) Init(0)
483 Do not suppress C++ class debug information.
486 Common Report Var(flag_exceptions) Optimization
487 Enable exception handling
489 fexpensive-optimizations
490 Common Report Var(flag_expensive_optimizations) Optimization
491 Perform a number of minor, expensive optimizations
497 Common Report Var(flag_finite_math_only) Optimization
498 Assume no NaNs or infinities are generated
501 Common Joined RejectNegative
502 -ffixed-<register> Mark <register> as being unavailable to the compiler
505 Common Report Var(flag_float_store) Optimization
506 Don't allocate floats and doubles in extended-precision registers
510 Does nothing. Preserved for backward compatibility.
513 Common Report Var(flag_forward_propagate) Optimization
514 Perform a forward propagation pass on RTL
516 ; Nonzero means don't put addresses of constant functions in registers.
517 ; Used for compiling the Unix kernel, where strange substitutions are
518 ; done on the assembly output.
520 Common Report Var(flag_no_function_cse,0)
521 Allow function addresses to be held in registers
524 Common Report Var(flag_function_sections)
525 Place each function into its own section
528 Common Report Var(flag_gcse) Optimization
529 Perform global common subexpression elimination
532 Common Report Var(flag_gcse_lm) Init(1) Optimization
533 Perform enhanced load motion during global common subexpression elimination
536 Common Report Var(flag_gcse_sm) Init(0) Optimization
537 Perform store motion after global common subexpression elimination
540 Common Report Var(flag_gcse_las) Init(0) Optimization
541 Perform redundant load after store elimination in global common subexpression
545 Common Report Var(flag_gcse_after_reload) Optimization
546 Perform global common subexpression elimination after register allocation
549 fguess-branch-probability
550 Common Report Var(flag_guess_branch_prob) Optimization
551 Enable guessing of branch probabilities
553 ; Nonzero means ignore `#ident' directives. 0 means handle them.
554 ; Generate position-independent code for executables if possible
555 ; On SVR4 targets, it also controls whether or not to emit a
556 ; string identifying the compiler.
558 Common Report Var(flag_no_ident,0)
559 Process #ident directives
562 Common Report Var(flag_if_conversion) Optimization
563 Perform conversion of conditional jumps to branchless equivalents
566 Common Report Var(flag_if_conversion2) Optimization
567 Perform conversion of conditional jumps to conditional execution
569 ; -finhibit-size-directive inhibits output of .size for ELF.
570 ; This is used only for compiling crtstuff.c,
571 ; and it may be extended to other effects
572 ; needed for crtstuff.c on other systems.
573 finhibit-size-directive
574 Common Report Var(flag_inhibit_size_directive)
575 Do not generate .size directives
577 ; Nonzero means that functions declared `inline' will be treated
578 ; as `static'. Prevents generation of zillions of copies of unused
579 ; static inline functions; instead, `inlines' are written out
580 ; only when actually used. Used in conjunction with -g. Also
581 ; does the right thing with #pragma interface.
583 Common Report Var(flag_no_inline,0) Init(2)
584 Pay attention to the \"inline\" keyword
586 finline-small-functions
587 Common Report Var(flag_inline_small_functions) Optimization
588 Integrate simple functions into their callers when code size is known to not growth
591 Common Report Var(flag_inline_functions) Optimization
592 Integrate simple functions into their callers
594 finline-functions-called-once
595 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
596 Integrate functions called once into their callers
599 Common RejectNegative Joined UInteger
602 Common RejectNegative Joined UInteger
603 -finline-limit=<number> Limit the size of inlined functions to <number>
605 finstrument-functions
606 Common Report Var(flag_instrument_function_entry_exit)
607 Instrument function entry and exit with profiling calls
609 finstrument-functions-exclude-function-list=
610 Common RejectNegative Joined
611 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
613 finstrument-functions-exclude-file-list=
614 Common RejectNegative Joined
615 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
618 Common Report Var(flag_ipa_cp) Optimization
619 Perform Interprocedural constant propagation
622 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
623 Discover pure and const functions
626 Common Report Var(flag_ipa_pta) Init(0) Optimization
627 Perform interprocedural points-to analysis
630 Common Report Var(flag_ipa_reference) Init(0) Optimization
631 Discover readonly and non addressable static variables
634 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
635 Type based escape and alias analysis
638 Common Report Var(flag_ipa_matrix_reorg) Optimization
639 Perform matrix layout flattening and transposing based
640 on profiling information.
643 Common Report Var(flag_ipa_struct_reorg)
644 Perform structure layout optimizations based
645 on profiling information.
648 Common Report Var(flag_ivopts) Init(1) Optimization
649 Optimize induction variables on trees
652 Common Var(flag_jump_tables) Init(1) Optimization
653 Use jump tables for sufficiently large switch statements
655 fkeep-inline-functions
656 Common Report Var(flag_keep_inline_functions)
657 Generate code for functions even if they are fully inlined
660 Common Report Var(flag_keep_static_consts) Init(1)
661 Emit static const variables even if they are not used
664 Common Report Var(flag_leading_underscore) Init(-1)
665 Give external symbols a leading underscore
669 Does nothing. Preserved for backward compatibility.
672 Common Report Var(flag_errno_math) Init(1)
673 Set errno after built-in math functions
676 Common Report Var(mem_report)
677 Report on permanent memory allocation
679 ; This will attempt to merge constant section constants, if 1 only
680 ; string constants and constants from constant pool, if 2 also constant
683 Common Report Var(flag_merge_constants,2) Init(1) Optimization
684 Attempt to merge identical constants and constant variables
687 Common Report Var(flag_merge_constants,1) VarExists Optimization
688 Attempt to merge identical constants across compilation units
691 Common Report Var(flag_merge_debug_strings) Init(1)
692 Attempt to merge identical debug strings across compilation units
695 Common RejectNegative Joined UInteger
696 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
699 Common Report Var(flag_modulo_sched) Optimization
700 Perform SMS based modulo scheduling before the first scheduling pass
702 fmodulo-sched-allow-regmoves
703 Common Report Var(flag_modulo_sched_allow_regmoves)
704 Perform SMS based modulo scheduling with register moves allowed
706 fmove-loop-invariants
707 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
708 Move loop invariant computations out of loops
711 Common RejectNegative Report Var(flag_mudflap)
712 Add mudflap bounds-checking instrumentation for single-threaded program
715 Common RejectNegative Report VarExists Var(flag_mudflap,2)
716 Add mudflap bounds-checking instrumentation for multi-threaded program
719 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
720 Ignore read operations when inserting mudflap instrumentation
723 Common Var(flag_dce) Init(1) Optimization
724 Use the RTL dead code elimination pass
727 Common Var(flag_dse) Init(1) Optimization
728 Use the RTL dead store elimination pass
730 freschedule-modulo-scheduled-loops
731 Common Report Var(flag_resched_modulo_sched) Optimization
732 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
735 Common Report Var(flag_non_call_exceptions) Optimization
736 Support synchronous non-call exceptions
739 Common Report Var(flag_omit_frame_pointer) Optimization
740 When possible do not generate stack frames
743 Common Report Var(flag_openmp_ssa)
744 Expand OpenMP operations on SSA form
746 foptimize-register-move
747 Common Report Var(flag_regmove) Optimization
748 Do the full register move optimization pass
750 foptimize-sibling-calls
751 Common Report Var(flag_optimize_sibling_calls) Optimization
752 Optimize sibling and tail recursive calls
755 Common Report Var(pre_ipa_mem_report)
756 Report on memory allocation before interprocedural optimization
759 Common Report Var(post_ipa_mem_report)
760 Report on memory allocation before interprocedural optimization
763 Common Report Var(flag_pack_struct) Optimization
764 Pack structure members together without holes
767 Common RejectNegative Joined UInteger Optimization
768 -fpack-struct=<number> Set initial maximum structure member alignment
771 Common Report Var(flag_pcc_struct_return,1) VarExists
772 Return small aggregates in memory, not registers
775 Common Report Var(flag_peel_loops) Optimization
779 Common Report Var(flag_no_peephole,0) Optimization
780 Enable machine specific peephole optimizations
783 Common Report Var(flag_peephole2) Optimization
784 Enable an RTL peephole pass before sched2
787 Common Report Var(flag_pic,2)
788 Generate position-independent code if possible (large mode)
791 Common Report Var(flag_pie,2)
792 Generate position-independent code for executables if possible (large mode)
795 Common Report Var(flag_pic,1) VarExists
796 Generate position-independent code if possible (small mode)
799 Common Report Var(flag_pie,1) VarExists
800 Generate position-independent code for executables if possible (small mode)
802 fpredictive-commoning
803 Common Report Var(flag_predictive_commoning) Optimization
804 Run predictive commoning optimization.
806 fprefetch-loop-arrays
807 Common Report Var(flag_prefetch_loop_arrays) Optimization
808 Generate prefetch instructions, if available, for arrays in loops
811 Common Report Var(profile_flag)
812 Enable basic program profiling code
815 Common Report Var(profile_arc_flag)
816 Insert arc-based program profiling code
819 Common Joined RejectNegative
820 Set the top-level directory for storing the profile data.
821 The default is 'pwd'.
825 Enable common options for generating profile info for profile feedback directed optimizations
828 Common Joined RejectNegative
829 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
832 Common Var(flag_profile_use)
833 Enable common options for performing profile feedback directed optimizations
836 Common Joined RejectNegative
837 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
840 Common Report Var(flag_profile_values)
841 Insert code to profile values of expressions
847 Common Joined RejectNegative
848 -frandom-seed=<string> Make compile reproducible using <string>
850 ; This switch causes the command line that was used to create an
851 ; object file to be recorded into the object file. The exact format
852 ; of this recording is target and binary file format dependent.
853 ; It is related to the -fverbose-asm switch, but that switch only
854 ; records information in the assembler output file as comments, so
855 ; they never reach the object file.
857 Common Report Var(flag_record_gcc_switches)
858 Record gcc command line switches in the object file.
861 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
862 Return small aggregates in registers
865 Common Report Var(flag_regmove) Optimization
866 Enables a register move optimization
869 Common Report Var(flag_rename_registers) Init(2) Optimization
870 Perform a register renaming optimization pass
873 Common Report Var(flag_reorder_blocks) Optimization
874 Reorder basic blocks to improve code placement
876 freorder-blocks-and-partition
877 Common Report Var(flag_reorder_blocks_and_partition) Optimization
878 Reorder basic blocks and partition into hot and cold sections
881 Common Report Var(flag_reorder_functions) Optimization
882 Reorder functions to improve code placement
884 frerun-cse-after-loop
885 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
886 Add a common subexpression elimination pass after loop optimizations
890 Does nothing. Preserved for backward compatibility.
893 Common Report Var(flag_rounding_math) Optimization
894 Disable optimizations that assume default FP rounding behavior
897 Common Report Var(flag_schedule_interblock) Init(1) Optimization
898 Enable scheduling across basic blocks
901 Common Report Var(flag_schedule_speculative) Init(1) Optimization
902 Allow speculative motion of non-loads
905 Common Report Var(flag_schedule_speculative_load) Optimization
906 Allow speculative motion of some loads
908 fsched-spec-load-dangerous
909 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
910 Allow speculative motion of more loads
913 Common RejectNegative Joined
914 -fsched-verbose=<number> Set the verbosity level of the scheduler
916 fsched2-use-superblocks
917 Common Report Var(flag_sched2_use_superblocks) Optimization
918 If scheduling post reload, do superblock scheduling
921 Common Report Var(flag_sched2_use_traces) Optimization
922 If scheduling post reload, do trace scheduling
925 Common Report Var(flag_schedule_insns) Optimization
926 Reschedule instructions before register allocation
929 Common Report Var(flag_schedule_insns_after_reload) Optimization
930 Reschedule instructions after register allocation
932 ; sched_stalled_insns means that insns can be moved prematurely from the queue
933 ; of stalled insns into the ready list.
935 Common Report Var(flag_sched_stalled_insns) Optimization
936 Allow premature scheduling of queued insns
938 fsched-stalled-insns=
939 Common RejectNegative Joined UInteger
940 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
942 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
943 ; be examined for a dependency on a stalled insn that is candidate for
944 ; premature removal from the queue of stalled insns into the ready list (has
945 ; an effect only if the flag 'sched_stalled_insns' is set).
946 fsched-stalled-insns-dep
947 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
948 Set dependence distance checking in premature scheduling of queued insns
950 fsched-stalled-insns-dep=
951 Common RejectNegative Joined UInteger
952 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
955 Common Report Var(flag_section_anchors) Optimization
956 Access data in the same section from shared anchor points
958 frtl-abstract-sequences
959 Common Report Var(flag_rtl_seqabstr) Optimization
960 Perform sequence abstraction optimization on RTL
963 Common Report Var(flag_see) Init(0)
964 Eliminate redundant sign extensions using LCM.
967 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
968 Show column numbers in diagnostics, when available. Default off
971 Common Report Var(flag_signaling_nans) Optimization
972 Disable optimizations observable by IEEE signaling NaNs
975 Common Report Var(flag_signed_zeros) Init(1) Optimization
976 Disable floating point optimizations that ignore the IEEE signedness of zero
978 fsingle-precision-constant
979 Common Report Var(flag_single_precision_constant) Optimization
980 Convert floating point constants to single precision constants
982 fsplit-ivs-in-unroller
983 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
984 Split lifetimes of induction variables when loops are unrolled
987 Common Report Var(flag_split_wide_types) Optimization
988 Split wide types into independent registers
990 fvariable-expansion-in-unroller
991 Common Report Var(flag_variable_expansion_in_unroller) Optimization
992 Apply variable expansion when loops are unrolled
994 ; Emit code to probe the stack, to help detect stack overflow; also
995 ; may cause large objects to be allocated dynamically.
997 Common Report Var(flag_stack_check)
998 Insert stack checking code into the program
1003 fstack-limit-register=
1004 Common RejectNegative Joined
1005 -fstack-limit-register=<register> Trap if the stack goes past <register>
1007 fstack-limit-symbol=
1008 Common RejectNegative Joined
1009 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1012 Common Report Var(flag_stack_protect, 1)
1013 Use propolice as a stack protection method
1015 fstack-protector-all
1016 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1017 Use a stack protection method for every function
1021 Does nothing. Preserved for backward compatibility.
1023 ; Nonzero if we should do (language-dependent) alias analysis.
1024 ; Typically, this analysis will assume that expressions of certain
1025 ; types do not alias expressions of certain other types. Only used
1026 ; if alias analysis (in general) is enabled.
1028 Common Report Var(flag_strict_aliasing) Optimization
1029 Assume strict aliasing rules apply
1032 Common Report Var(flag_strict_overflow)
1033 Treat signed overflow as undefined
1036 Common Report Var(flag_syntax_only)
1037 Check for syntax errors, then stop
1040 Common Report Var(flag_test_coverage)
1041 Create data files needed by \"gcov\"
1044 Common Report Var(flag_thread_jumps) Optimization
1045 Perform jump threading optimizations
1048 Common Report Var(time_report)
1049 Report the time taken by each compiler pass
1052 Common Joined RejectNegative
1053 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1056 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
1057 Reorder top level functions, variables, and asms
1060 Common Report Var(flag_tracer)
1061 Perform superblock formation via tail duplication
1063 ; Zero means that floating-point math operations cannot generate a
1064 ; (user-visible) trap. This is the case, for example, in nonstop
1065 ; IEEE 754 arithmetic.
1067 Common Report Var(flag_trapping_math) Init(1) Optimization
1068 Assume floating-point operations can trap
1071 Common Report Var(flag_trapv) Optimization
1072 Trap for signed overflow in addition, subtraction and multiplication
1075 Common Report Var(flag_tree_ccp) Optimization
1076 Enable SSA-CCP optimization on trees
1079 Common Report Var(flag_tree_store_ccp) Optimization
1080 Enable SSA-CCP optimization for stores and loads
1083 Common Report Var(flag_tree_ch) Optimization
1084 Enable loop header copying on trees
1087 Common Report Var(flag_tree_copyrename) Optimization
1088 Replace SSA temporaries with better names in copies
1091 Common Report Var(flag_tree_copy_prop) Optimization
1092 Enable copy propagation on trees
1094 ftree-store-copy-prop
1096 Does nothing. Preserved for backward compatibility.
1099 Common Report Var(flag_tree_cselim) Init(2) Optimization
1100 Transform condition stores into unconditional ones
1103 Common Report Var(flag_tree_dce) Optimization
1104 Enable SSA dead code elimination optimization on trees
1106 ftree-dominator-opts
1107 Common Report Var(flag_tree_dom) Optimization
1108 Enable dominator optimizations
1111 Common Report Var(flag_tree_dse) Optimization
1112 Enable dead store elimination
1115 Common Report Var(flag_tree_fre) Optimization
1116 Enable Full Redundancy Elimination (FRE) on trees
1118 ftree-loop-distribution
1119 Common Report Var(flag_tree_loop_distribution)
1120 Enable loop distribution on trees
1123 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1124 Enable loop invariant motion on trees
1127 Common Report Var(flag_tree_loop_linear) Optimization
1128 Enable linear loop transforms on trees
1131 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1132 Create canonical induction variables in loops
1135 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1136 Enable loop optimizations on tree level
1138 ftree-parallelize-loops=
1139 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1140 Enable automatic parallelization of loops
1143 Common Report Var(flag_tree_pre) Optimization
1144 Enable SSA-PRE optimization on trees
1147 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1148 Enable reassociation on tree level
1151 Common Report Var(flag_tree_salias) Optimization
1152 Perform structural alias analysis
1155 Common Report Var(flag_tree_sink) Optimization
1156 Enable SSA code sinking on trees
1159 Common Report Var(flag_tree_sra) Optimization
1160 Perform scalar replacement of aggregates
1163 Common Report Var(flag_tree_ter) Optimization
1164 Replace temporary expressions in the SSA->normal pass
1167 Common Report Var(flag_tree_live_range_split) Optimization
1168 Perform live range splitting during the SSA->normal pass
1171 Common Report Var(flag_tree_vrp) Init(0) Optimization
1172 Perform Value Range Propagation on trees
1175 Common Report Var(flag_unit_at_a_time) Optimization
1176 Compile whole compilation unit at a time
1179 Common Report Var(flag_unroll_loops) Optimization
1180 Perform loop unrolling when iteration count is known
1183 Common Report Var(flag_unroll_all_loops) Optimization
1184 Perform loop unrolling for all loops
1186 ; Nonzero means that loop optimizer may assume that the induction variables
1187 ; that control loops do not overflow and that the loops with nontrivial
1188 ; exit condition are not infinite
1189 funsafe-loop-optimizations
1190 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1191 Allow loop optimizations to assume that the loops behave in normal way
1194 Common Report Var(flag_associative_math)
1195 Allow optimization for floating-point arithmetic which may change the
1196 result of the operation due to rounding.
1199 Common Report Var(flag_reciprocal_math)
1200 Same as -fassociative-math for expressions which include division.
1202 ; Nonzero means that unsafe floating-point math optimizations are allowed
1203 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1204 ; are allowed to assume that their arguments and results are "normal"
1205 ; (e.g., nonnegative for SQRT).
1206 funsafe-math-optimizations
1207 Common Report Var(flag_unsafe_math_optimizations) Optimization
1208 Allow math optimizations that may violate IEEE or ISO standards
1211 Common Report Var(flag_unswitch_loops) Optimization
1212 Perform loop unswitching
1215 Common Report Var(flag_unwind_tables) Optimization
1216 Just generate unwind tables for exception handling
1219 Common Report Var(flag_var_tracking) VarExists Optimization
1220 Perform variable tracking
1222 fvar-tracking-uninit
1223 Common Report Var(flag_var_tracking_uninit) Optimization
1224 Perform variable tracking and also tag variables that are uninitialized
1227 Common Report Var(flag_tree_vectorize) Optimization
1228 Enable loop vectorization on trees
1231 Common Report Var(flag_vect_cost_model) Optimization
1232 Enable use of cost model in vectorization
1234 ftree-vect-loop-version
1235 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1236 Enable loop versioning when doing loop vectorization on trees
1238 ftree-vectorizer-verbose=
1239 Common RejectNegative Joined
1240 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1243 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1244 Enable copy propagation of scalar-evolution information.
1246 ; -fverbose-asm causes extra commentary information to be produced in
1247 ; the generated assembly code (to make it more readable). This option
1248 ; is generally only of use to those who actually need to read the
1249 ; generated assembly code (perhaps while debugging the compiler itself).
1250 ; -fno-verbose-asm, the default, causes the extra information
1251 ; to not be added and is useful when comparing two assembler files.
1253 Common Report Var(flag_verbose_asm)
1254 Add extra commentary to assembler output
1257 Common Joined RejectNegative
1258 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1262 Common Report Var(flag_value_profile_transformations) Optimization
1263 Use expression value profiles in optimizations
1266 Common Report Var(flag_web) Init(2) Optimization
1267 Construct webs and split unrelated uses of single variable
1270 Common Report Var(flag_whole_program) Init(0) Optimization
1271 Perform whole program optimizations
1274 Common Report Var(flag_wrapv) Optimization
1275 Assume signed arithmetic overflow wraps around
1277 fzero-initialized-in-bss
1278 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1279 Put zero initialized data in the bss section
1282 Common JoinedOrMissing
1283 Generate debug information in default format
1286 Common JoinedOrMissing Negative(gdwarf-2)
1287 Generate debug information in COFF format
1290 Common JoinedOrMissing Negative(gstabs)
1291 Generate debug information in DWARF v2 format
1294 Common JoinedOrMissing
1295 Generate debug information in default extended format
1298 Common JoinedOrMissing Negative(gstabs+)
1299 Generate debug information in STABS format
1302 Common JoinedOrMissing Negative(gvms)
1303 Generate debug information in extended STABS format
1306 Common JoinedOrMissing Negative(gxcoff)
1307 Generate debug information in VMS format
1310 Common JoinedOrMissing Negative(gxcoff+)
1311 Generate debug information in XCOFF format
1314 Common JoinedOrMissing Negative(gcoff)
1315 Generate debug information in extended XCOFF format
1318 Common Joined Separate
1319 -o <file> Place output into <file>
1322 Common Var(profile_flag)
1323 Enable function profiling
1326 Common Var(pedantic)
1327 Issue warnings needed for strict compliance to the standard
1331 Like -pedantic but issue them as errors
1334 Common Var(quiet_flag)
1335 Do not display functions compiled or elapsed time
1338 Common Var(version_flag)
1339 Display the compiler's version
1342 Common Var(inhibit_warnings)
1346 Common RejectNegative Negative(pie)
1347 Create a shared library
1350 Common RejectNegative Negative(shared)
1351 Create a position independent executable
1353 ; This comment is to ensure we retain the blank line above.