1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
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 four 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).
55 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
61 Common Joined Separate UInteger
62 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
65 Common JoinedOrMissing Optimization
66 -O<number> Set optimization level to <number>
70 Optimize for space rather than speed
73 Common RejectNegative Var(extra_warnings) Warning
74 This switch is deprecated; use -Wextra instead
77 Common Var(warn_aggregate_return) Warning
78 Warn about returning structures, unions or arrays
81 Common Var(warn_array_bounds) Warning
82 Warn if an array is accessed out of bounds
85 Common Var(warn_attributes) Init(1) Warning
86 Warn about inappropriate attribute usage
89 Common Var(warn_cast_align) Warning
90 Warn about pointer casts which increase alignment
93 Common Var(warn_cpp) Init(1) Warning
94 Warn when a #warning directive is encountered
96 Wdeprecated-declarations
97 Common Var(warn_deprecated_decl) Init(1) Warning
98 Warn about uses of __attribute__((deprecated)) declarations
100 Wdisabled-optimization
101 Common Var(warn_disabled_optimization) Warning
102 Warn when an optimization pass is disabled
105 Common Var(warnings_are_errors)
106 Treat all warnings as errors
110 Treat specified warning as error
113 Common Var(extra_warnings) Warning
114 Print extra (possibly unwanted) warnings
117 Common Var(flag_fatal_errors)
118 Exit on the first error occurred
121 Common RejectNegative Joined UInteger
122 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes
125 Common Var(warn_inline) Warning
126 Warn when an inlined function cannot be inlined
129 Common RejectNegative Joined UInteger Warning Undocumented
132 Common RejectNegative Joined UInteger Warning
133 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
135 Wunsafe-loop-optimizations
136 Common Var(warn_unsafe_loop_optimizations) Warning
137 Warn if the loop cannot be optimized due to nontrivial assumptions.
140 Common Var(warn_missing_noreturn) Warning
141 Warn about functions which might be candidates for __attribute__((noreturn))
144 Common Var(warn_mudflap) Init(1) Warning
145 Warn about constructs not instrumented by -fmudflap
148 Common Var(warn_overflow) Init(1) Warning
149 Warn about overflow in arithmetic expressions
152 Common Var(warn_packed) Warning
153 Warn when the packed attribute has no effect on struct layout
156 Common Var(warn_padded) Warning
157 Warn when padding is required to align structure members
160 Common Var(warn_shadow) Warning
161 Warn when one local variable shadows another
164 Common Var(warn_stack_protect) Warning
165 Warn when not issuing stack smashing protection for some reason
169 Warn about code which might break strict aliasing rules
172 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
173 Warn about code which might break strict aliasing rules
177 Warn about optimizations that assume that signed overflow is undefined
180 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
181 Warn about optimizations that assume that signed overflow is undefined
183 Wsuggest-attribute=const
184 Common Var(warn_suggest_attribute_const) Warning
185 Warn about functions which might be candidates for __attribute__((const))
187 Wsuggest-attribute=pure
188 Common Var(warn_suggest_attribute_pure) Warning
189 Warn about functions which might be candidates for __attribute__((pure))
192 Common Var(warn_switch) Warning
193 Warn about enumerated switches, with no default, missing a case
196 Common Var(warn_switch_default) Warning
197 Warn about enumerated switches missing a \"default:\" statement
200 Common Var(warn_switch_enum) Warning
201 Warn about all enumerated switches missing a specific case
204 Common Var(warn_system_headers) Warning
205 Do not suppress warnings from system headers
208 Common Var(warn_type_limits) Init(-1) Warning
209 Warn if a comparison is always true or always false due to the limited range of the data type
212 Common Var(warn_uninitialized) Init(-1) Warning
213 Warn about uninitialized automatic variables
217 Does nothing. Preserved for backward compatibility.
220 Common Var(warn_unused) Init(0) Warning
221 Enable all -Wunused- warnings
223 Wunused-but-set-parameter
224 Common Var(warn_unused_but_set_parameter) Init(-1) Warning
225 Warn when a function parameter is only set, otherwise unused
227 Wunused-but-set-variable
228 Common Var(warn_unused_but_set_variable) Init(-1) Warning
229 Warn when a variable is only set, otherwise unused
232 Common Var(warn_unused_function) Init(-1) Warning
233 Warn when a function is unused
236 Common Var(warn_unused_label) Init(-1) Warning
237 Warn when a label is unused
240 Common Var(warn_unused_parameter) Init(-1) Warning
241 Warn when a function parameter is unused
244 Common Var(warn_unused_value) Init(-1) Warning
245 Warn when an expression value is unused
248 Common Var(warn_unused_variable) Init(-1) Warning
249 Warn when a variable is unused
252 Common Var(warn_coverage_mismatch) Init(1) Warning
253 Warn in case profiles in -fprofile-use do not match
257 -aux-info <file> Emit declaration information into <file>
270 -d<letters> Enable dumps from specific passes of the compiler
274 -dumpbase <file> Set the file basename to be used for dumps
278 -dumpdir <dir> Set the directory name to be used for dumps
280 ; The version of the C++ ABI in use. The following values are allowed:
282 ; 0: The version of the ABI believed most conformant with the C++ ABI
283 ; specification. This ABI may change as bugs are discovered and fixed.
284 ; Therefore, 0 will not necessarily indicate the same ABI in different
287 ; 1: The version of the ABI first used in G++ 3.2.
289 ; 2: The version of the ABI first used in G++ 3.4 (and current default).
291 ; 3: The version of the ABI that fixes the missing underscore
292 ; in template non-type arguments of pointer type.
294 ; 4: The version of the ABI that introduces unambiguous mangling of
297 ; Additional positive integers will be assigned as new versions of
298 ; the ABI become the default version of the ABI.
300 Common Joined UInteger Var(flag_abi_version) Init(2)
303 Common Report Var(align_functions,0) Optimization UInteger
304 Align the start of functions
307 Common RejectNegative Joined UInteger
310 Common Report Var(align_jumps,0) Optimization UInteger
311 Align labels which are only reached by jumping
314 Common RejectNegative Joined UInteger
317 Common Report Var(align_labels,0) Optimization UInteger
321 Common RejectNegative Joined UInteger
324 Common Report Var(align_loops) Optimization UInteger
325 Align the start of loops
328 Common RejectNegative Joined UInteger
332 Does nothing. Preserved for backward compatibility.
336 Does nothing. Preserved for backward compatibility.
338 fargument-noalias-global
340 Does nothing. Preserved for backward compatibility.
342 fargument-noalias-anything
344 Does nothing. Preserved for backward compatibility.
346 fasynchronous-unwind-tables
347 Common Report Var(flag_asynchronous_unwind_tables) Optimization
348 Generate unwind tables that are exact at each instruction boundary
351 Common Report Var(flag_auto_inc_dec) Init(1)
352 Generate auto-inc/dec instructions
354 ; -fcheck-bounds causes gcc to generate array bounds checks.
355 ; For C, C++ and ObjC: defaults off.
356 ; For Java: defaults to on.
357 ; For Fortran: defaults to off.
359 Common Report Var(flag_bounds_check)
360 Generate code to check bounds before indexing arrays
363 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
364 Replace add, compare, branch with branch on count register
366 fbranch-probabilities
367 Common Report Var(flag_branch_probabilities) Optimization
368 Use profiling information for branch probabilities
370 fbranch-target-load-optimize
371 Common Report Var(flag_branch_target_load_optimize) Optimization
372 Perform branch target load optimization before prologue / epilogue threading
374 fbranch-target-load-optimize2
375 Common Report Var(flag_branch_target_load_optimize2) Optimization
376 Perform branch target load optimization after prologue / epilogue threading
379 Common Report Var(flag_btr_bb_exclusive) Optimization
380 Restrict target load migration not to re-use registers in any basic block
383 Common Joined RejectNegative
384 -fcall-saved-<register> Mark <register> as being preserved across functions
387 Common Joined RejectNegative
388 -fcall-used-<register> Mark <register> as being corrupted by function calls
390 ; Nonzero for -fcaller-saves: allocate values in regs that need to
391 ; be saved across function calls, if that produces overall better code.
392 ; Optional now, so people can test it.
394 Common Report Var(flag_caller_saves) Optimization
395 Save registers around function calls
398 Common Report Var(flag_check_data_deps)
399 Compare the results of several data dependence analyzers.
402 Common Report Var(flag_no_common,0) Optimization
403 Do not put uninitialized globals in the common section
406 Common JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
407 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump
409 fcompare-debug-second
410 Common RejectNegative Var(flag_compare_debug)
411 Run only the second compilation of -fcompare-debug
414 Common Var(flag_conserve_stack) Optimization
415 Do not perform optimizations increasing noticeably stack usage
418 Common Report Var(flag_cprop_registers) Optimization
419 Perform a register copy-propagation optimization pass
422 Common Report Var(flag_crossjumping) Optimization
423 Perform cross-jumping optimization
426 Common Report Var(flag_cse_follow_jumps) Optimization
427 When running CSE, follow jumps to their targets
431 Does nothing. Preserved for backward compatibility.
434 Common Report Var(flag_cx_limited_range) Optimization
435 Omit range reduction step when performing complex division
438 Common Report Var(flag_cx_fortran_rules) Optimization
439 Complex multiplication and division follow Fortran rules
442 Common Report Var(flag_data_sections) Optimization
443 Place data items into their own section
447 List all available debugging counters with their limits and counts.
450 Common RejectNegative Joined
451 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
454 Common Joined RejectNegative
455 Map one directory name to another in debug information
457 ; Nonzero for -fdefer-pop: don't pop args after each function call
458 ; instead save them up to pop many calls' args with one insns.
460 Common Report Var(flag_defer_pop) Optimization
461 Defer popping functions args from stack until later
464 Common Report Var(flag_delayed_branch) Optimization
465 Attempt to fill delay slots of branch instructions
467 fdelete-null-pointer-checks
468 Common Report Var(flag_delete_null_pointer_checks) Init(1) Optimization
469 Delete useless null pointer checks
471 fdiagnostics-show-location=
472 Common Joined RejectNegative
473 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
475 fdiagnostics-show-option
476 Common Var(flag_diagnostics_show_option) Init(1)
477 Amend appropriate diagnostic messages with the command line option that controls them
480 Common Joined RejectNegative
481 -fdump-<type> Dump various compiler internals to a file
484 Common RejectNegative Joined Var(flag_dump_final_insns)
485 -fdump-final-insns=filename Dump to filename the insns at the end of translation
488 Common Report Var(flag_dump_noaddr)
489 Suppress output of addresses in debugging dumps
492 Common Report Var(flag_dump_unnumbered) VarExists
493 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
495 fdump-unnumbered-links
496 Common Report Var(flag_dump_unnumbered_links) VarExists
497 Suppress output of previous and next insn numbers in debugging dumps
500 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
501 Enable CFI tables via GAS assembler directives.
504 Common Report Var(flag_early_inlining) Init(1) Optimization
505 Perform early inlining
507 feliminate-dwarf2-dups
508 Common Report Var(flag_eliminate_dwarf2_dups)
509 Perform DWARF2 duplicate elimination
512 Common Report Var(flag_ipa_sra) Init(0) Optimization
513 Perform interprocedural reduction of aggregates
515 feliminate-unused-debug-symbols
516 Common Report Var(flag_debug_only_used_symbols)
517 Perform unused type elimination in debug info
519 feliminate-unused-debug-types
520 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
521 Perform unused type elimination in debug info
523 femit-class-debug-always
524 Common Report Var(flag_emit_class_debug_always) Init(0)
525 Do not suppress C++ class debug information.
528 Common Report Var(flag_enable_icf_debug)
529 Generate debug information to support Identical Code Folding (ICF)
532 Common Report Var(flag_exceptions) Optimization
533 Enable exception handling
535 fexpensive-optimizations
536 Common Report Var(flag_expensive_optimizations) Optimization
537 Perform a number of minor, expensive optimizations
540 Common Joined RejectNegative
541 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision
547 Common Report Var(flag_finite_math_only) Optimization
548 Assume no NaNs or infinities are generated
551 Common Joined RejectNegative
552 -ffixed-<register> Mark <register> as being unavailable to the compiler
555 Common Report Var(flag_float_store) Optimization
556 Don't allocate floats and doubles in extended-precision registers
560 Does nothing. Preserved for backward compatibility.
563 Common Report Var(flag_forward_propagate) Optimization
564 Perform a forward propagation pass on RTL
566 ; Nonzero means don't put addresses of constant functions in registers.
567 ; Used for compiling the Unix kernel, where strange substitutions are
568 ; done on the assembly output.
570 Common Report Var(flag_no_function_cse,0)
571 Allow function addresses to be held in registers
574 Common Report Var(flag_function_sections)
575 Place each function into its own section
578 Common Report Var(flag_gcse) Optimization
579 Perform global common subexpression elimination
582 Common Report Var(flag_gcse_lm) Init(1) Optimization
583 Perform enhanced load motion during global common subexpression elimination
586 Common Report Var(flag_gcse_sm) Init(0) Optimization
587 Perform store motion after global common subexpression elimination
590 Common Report Var(flag_gcse_las) Init(0) Optimization
591 Perform redundant load after store elimination in global common subexpression
595 Common Report Var(flag_gcse_after_reload) Optimization
596 Perform global common subexpression elimination after register allocation
599 ; This option is not documented yet as its semantics will change.
601 Common Report Var(flag_graphite)
602 Enable in and out of Graphite representation
605 Common Report Var(flag_graphite_identity) Optimization
606 Enable Graphite Identity transformation
608 floop-parallelize-all
609 Common Report Var(flag_loop_parallelize_all) Optimization
610 Mark all loops as parallel
613 Common Report Var(flag_loop_strip_mine) Optimization
614 Enable Loop Strip Mining transformation
617 Common Report Var(flag_loop_interchange) Optimization
618 Enable Loop Interchange transformation
621 Common Report Var(flag_loop_block) Optimization
622 Enable Loop Blocking transformation
624 fguess-branch-probability
625 Common Report Var(flag_guess_branch_prob) Optimization
626 Enable guessing of branch probabilities
628 ; Nonzero means ignore `#ident' directives. 0 means handle them.
629 ; Generate position-independent code for executables if possible
630 ; On SVR4 targets, it also controls whether or not to emit a
631 ; string identifying the compiler.
633 Common Report Var(flag_no_ident,0)
634 Process #ident directives
637 Common Report Var(flag_if_conversion) Optimization
638 Perform conversion of conditional jumps to branchless equivalents
641 Common Report Var(flag_if_conversion2) Optimization
642 Perform conversion of conditional jumps to conditional execution
644 ; -finhibit-size-directive inhibits output of .size for ELF.
645 ; This is used only for compiling crtstuff.c,
646 ; and it may be extended to other effects
647 ; needed for crtstuff.c on other systems.
648 finhibit-size-directive
649 Common Report Var(flag_inhibit_size_directive)
650 Do not generate .size directives
653 Common Report Var(flag_indirect_inlining)
654 Perform indirect inlining
656 ; Nonzero means that functions declared `inline' will be treated
657 ; as `static'. Prevents generation of zillions of copies of unused
658 ; static inline functions; instead, `inlines' are written out
659 ; only when actually used. Used in conjunction with -g. Also
660 ; does the right thing with #pragma interface.
662 Common Report Var(flag_no_inline,0) Init(0)
663 Pay attention to the \"inline\" keyword
665 finline-small-functions
666 Common Report Var(flag_inline_small_functions) Optimization
667 Integrate simple functions into their callers when code size is known to not growth
670 Common Report Var(flag_inline_functions) Optimization
671 Integrate simple functions into their callers
673 finline-functions-called-once
674 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
675 Integrate functions called once into their callers
678 Common RejectNegative Joined UInteger
681 Common RejectNegative Joined UInteger
682 -finline-limit=<number> Limit the size of inlined functions to <number>
684 finstrument-functions
685 Common Report Var(flag_instrument_function_entry_exit)
686 Instrument function entry and exit with profiling calls
688 finstrument-functions-exclude-function-list=
689 Common RejectNegative Joined
690 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
692 finstrument-functions-exclude-file-list=
693 Common RejectNegative Joined
694 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
697 Common Report Var(flag_ipa_cp) Optimization
698 Perform Interprocedural constant propagation
701 Common Report Var(flag_ipa_cp_clone) Optimization
702 Perform cloning to make Interprocedural constant propagation stronger
705 Common Report Var(flag_ipa_profile) Init(0) Optimization
706 Perform interprocedural profile propagation
709 Common Report Var(flag_ipa_pta) Init(0) Optimization
710 Perform interprocedural points-to analysis
713 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
714 Discover pure and const functions
717 Common Report Var(flag_ipa_reference) Init(0) Optimization
718 Discover readonly and non addressable static variables
721 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
722 Type based escape and alias analysis
725 Common Report Var(flag_ipa_matrix_reorg) Optimization
726 Perform matrix layout flattening and transposing based
727 on profiling information.
730 Common Report Var(flag_ipa_struct_reorg)
731 Perform structure layout optimizations based
732 on profiling information.
735 Common Joined RejectNegative
736 -fira-algorithm=[CB|priority] Set the used IRA algorithm
739 Common Joined RejectNegative
740 -fira-region=[one|all|mixed] Set regions for IRA
743 Common Report Var(flag_ira_coalesce) Init(0)
744 Do optimistic coalescing.
747 Common Report Var(flag_ira_loop_pressure)
748 Use IRA based register pressure calculation
749 in RTL loop optimizations.
751 fira-share-save-slots
752 Common Report Var(flag_ira_share_save_slots) Init(1)
753 Share slots for saving different hard registers.
755 fira-share-spill-slots
756 Common Report Var(flag_ira_share_spill_slots) Init(1)
757 Share stack slots for spilled pseudo-registers.
760 Common RejectNegative Joined UInteger
761 -fira-verbose=<number> Control IRA's level of diagnostic messages.
764 Common Report Var(flag_ivopts) Init(1) Optimization
765 Optimize induction variables on trees
768 Common Var(flag_jump_tables) Init(1) Optimization
769 Use jump tables for sufficiently large switch statements
771 fkeep-inline-functions
772 Common Report Var(flag_keep_inline_functions)
773 Generate code for functions even if they are fully inlined
776 Common Report Var(flag_keep_static_consts) Init(1)
777 Emit static const variables even if they are not used
780 Common Report Var(flag_leading_underscore) Init(-1)
781 Give external symbols a leading underscore
785 Does nothing. Preserved for backward compatibility.
789 Enable link-time optimization.
791 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
792 flto-compression-level=
793 Common Joined UInteger Var(flag_lto_compression_level) Init(-1)
794 -flto-compression-level=<number> Use zlib compression level <number> for IL
797 Common Report Var(flag_lto_report) Init(0) Optimization
798 Report various link-time optimization statistics
801 Common Report Var(flag_errno_math) Init(1) Optimization
802 Set errno after built-in math functions
805 Common Report Var(mem_report)
806 Report on permanent memory allocation
808 ; This will attempt to merge constant section constants, if 1 only
809 ; string constants and constants from constant pool, if 2 also constant
812 Common Report Var(flag_merge_constants,2) Init(1) Optimization
813 Attempt to merge identical constants and constant variables
816 Common Report Var(flag_merge_constants,1) VarExists Optimization
817 Attempt to merge identical constants across compilation units
820 Common Report Var(flag_merge_debug_strings) Init(1)
821 Attempt to merge identical debug strings across compilation units
824 Common RejectNegative Joined UInteger
825 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
828 Common Report Var(flag_modulo_sched) Optimization
829 Perform SMS based modulo scheduling before the first scheduling pass
831 fmodulo-sched-allow-regmoves
832 Common Report Var(flag_modulo_sched_allow_regmoves)
833 Perform SMS based modulo scheduling with register moves allowed
835 fmove-loop-invariants
836 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
837 Move loop invariant computations out of loops
840 Common RejectNegative Report Var(flag_mudflap)
841 Add mudflap bounds-checking instrumentation for single-threaded program
844 Common RejectNegative Report VarExists Var(flag_mudflap,2)
845 Add mudflap bounds-checking instrumentation for multi-threaded program
848 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
849 Ignore read operations when inserting mudflap instrumentation
852 Common Var(flag_dce) Init(1) Optimization
853 Use the RTL dead code elimination pass
856 Common Var(flag_dse) Init(1) Optimization
857 Use the RTL dead store elimination pass
859 freschedule-modulo-scheduled-loops
860 Common Report Var(flag_resched_modulo_sched) Optimization
861 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
864 Common Report Var(flag_non_call_exceptions) Optimization
865 Support synchronous non-call exceptions
868 Common Report Var(flag_omit_frame_pointer) Optimization
869 When possible do not generate stack frames
871 foptimize-register-move
872 Common Report Var(flag_regmove) Optimization
873 Do the full register move optimization pass
875 foptimize-sibling-calls
876 Common Report Var(flag_optimize_sibling_calls) Optimization
877 Optimize sibling and tail recursive calls
880 Common Report Var(pre_ipa_mem_report)
881 Report on memory allocation before interprocedural optimization
884 Common Report Var(post_ipa_mem_report)
885 Report on memory allocation before interprocedural optimization
888 Common Report Var(flag_pack_struct) Optimization
889 Pack structure members together without holes
892 Common RejectNegative Joined UInteger Optimization
893 -fpack-struct=<number> Set initial maximum structure member alignment
896 Common Report Var(flag_pcc_struct_return,1) VarExists
897 Return small aggregates in memory, not registers
900 Common Report Var(flag_peel_loops) Optimization
904 Common Report Var(flag_no_peephole,0) Optimization
905 Enable machine specific peephole optimizations
908 Common Report Var(flag_peephole2) Optimization
909 Enable an RTL peephole pass before sched2
912 Common Report Var(flag_pic,2)
913 Generate position-independent code if possible (large mode)
916 Common Report Var(flag_pie,2)
917 Generate position-independent code for executables if possible (large mode)
920 Common Report Var(flag_pic,1) VarExists
921 Generate position-independent code if possible (small mode)
924 Common Report Var(flag_pie,1) VarExists
925 Generate position-independent code for executables if possible (small mode)
928 Common Joined RejectNegative
929 Specify a plugin to load
932 Common Joined RejectNegative
933 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
935 fpredictive-commoning
936 Common Report Var(flag_predictive_commoning) Optimization
937 Run predictive commoning optimization.
939 fprefetch-loop-arrays
940 Common Report Var(flag_prefetch_loop_arrays) Optimization
941 Generate prefetch instructions, if available, for arrays in loops
944 Common Report Var(profile_flag)
945 Enable basic program profiling code
948 Common Report Var(profile_arc_flag)
949 Insert arc-based program profiling code
952 Common Joined RejectNegative
953 Set the top-level directory for storing the profile data.
954 The default is 'pwd'.
957 Common Report Var(flag_profile_correction)
958 Enable correction of flow inconsistent profile data input
962 Enable common options for generating profile info for profile feedback directed optimizations
965 Common Joined RejectNegative
966 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
969 Common Var(flag_profile_use)
970 Enable common options for performing profile feedback directed optimizations
973 Common Joined RejectNegative
974 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
977 Common Report Var(flag_profile_values)
978 Insert code to profile values of expressions
984 Common Joined RejectNegative
985 -frandom-seed=<string> Make compile reproducible using <string>
987 ; This switch causes the command line that was used to create an
988 ; object file to be recorded into the object file. The exact format
989 ; of this recording is target and binary file format dependent.
990 ; It is related to the -fverbose-asm switch, but that switch only
991 ; records information in the assembler output file as comments, so
992 ; they never reach the object file.
994 Common Report Var(flag_record_gcc_switches)
995 Record gcc command line switches in the object file.
998 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
999 Return small aggregates in registers
1002 Common Report Var(flag_regmove) Optimization
1003 Enables a register move optimization
1006 Common Report Var(flag_rename_registers) Init(2) Optimization
1007 Perform a register renaming optimization pass
1010 Common Report Var(flag_reorder_blocks) Optimization
1011 Reorder basic blocks to improve code placement
1013 freorder-blocks-and-partition
1014 Common Report Var(flag_reorder_blocks_and_partition) Optimization
1015 Reorder basic blocks and partition into hot and cold sections
1018 Common Report Var(flag_reorder_functions) Optimization
1019 Reorder functions to improve code placement
1021 frerun-cse-after-loop
1022 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
1023 Add a common subexpression elimination pass after loop optimizations
1027 Does nothing. Preserved for backward compatibility.
1030 Common Report Var(flag_rounding_math) Optimization
1031 Disable optimizations that assume default FP rounding behavior
1034 Common Report Var(flag_schedule_interblock) Init(1) Optimization
1035 Enable scheduling across basic blocks
1038 Common Report Var(flag_sched_pressure) Init(0) Optimization
1039 Enable register pressure sensitive insn scheduling
1042 Common Report Var(flag_schedule_speculative) Init(1) Optimization
1043 Allow speculative motion of non-loads
1046 Common Report Var(flag_schedule_speculative_load) Optimization
1047 Allow speculative motion of some loads
1049 fsched-spec-load-dangerous
1050 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
1051 Allow speculative motion of more loads
1054 Common RejectNegative Joined
1055 -fsched-verbose=<number> Set the verbosity level of the scheduler
1057 fsched2-use-superblocks
1058 Common Report Var(flag_sched2_use_superblocks) Optimization
1059 If scheduling post reload, do superblock scheduling
1063 Does nothing. Preserved for backward compatibility.
1066 Common Report Var(flag_schedule_insns) Optimization
1067 Reschedule instructions before register allocation
1070 Common Report Var(flag_schedule_insns_after_reload) Optimization
1071 Reschedule instructions after register allocation
1073 ; This flag should be on when a target implements non-trivial
1074 ; scheduling hooks, maybe saving some information for its own sake.
1075 ; On IA64, for example, this is used for correct bundling.
1076 fselective-scheduling
1077 Common Report Var(flag_selective_scheduling) Optimization
1078 Schedule instructions using selective scheduling algorithm
1080 fselective-scheduling2
1081 Common Report Var(flag_selective_scheduling2) Optimization
1082 Run selective scheduling after reload
1084 fsel-sched-pipelining
1085 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1086 Perform software pipelining of inner loops during selective scheduling
1088 fsel-sched-pipelining-outer-loops
1089 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1090 Perform software pipelining of outer loops during selective scheduling
1092 fsel-sched-reschedule-pipelined
1093 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1094 Reschedule pipelined regions without pipelining
1096 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1097 ; of stalled insns into the ready list.
1098 fsched-stalled-insns
1099 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1100 Allow premature scheduling of queued insns
1102 fsched-stalled-insns=
1103 Common RejectNegative Joined UInteger
1104 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1106 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1107 ; be examined for a dependency on a stalled insn that is candidate for
1108 ; premature removal from the queue of stalled insns into the ready list (has
1109 ; an effect only if the flag 'sched_stalled_insns' is set).
1110 fsched-stalled-insns-dep
1111 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1112 Set dependence distance checking in premature scheduling of queued insns
1114 fsched-stalled-insns-dep=
1115 Common RejectNegative Joined UInteger
1116 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1118 fsched-group-heuristic
1119 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
1120 Enable the group heuristic in the scheduler
1122 fsched-critical-path-heuristic
1123 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
1124 Enable the critical path heuristic in the scheduler
1126 fsched-spec-insn-heuristic
1127 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
1128 Enable the speculative instruction heuristic in the scheduler
1130 fsched-rank-heuristic
1131 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
1132 Enable the rank heuristic in the scheduler
1134 fsched-last-insn-heuristic
1135 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
1136 Enable the last instruction heuristic in the scheduler
1138 fsched-dep-count-heuristic
1139 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
1140 Enable the dependent count heuristic in the scheduler
1143 Common Report Var(flag_section_anchors) Optimization
1144 Access data in the same section from shared anchor points
1148 Does nothing. Preserved for backward compatibility.
1151 Common Report Var(flag_zee) Init(0)
1152 Eliminate redundant zero extensions on targets that support implicit extensions.
1155 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
1156 Show column numbers in diagnostics, when available. Default on
1159 Common Report Var(flag_signaling_nans) Optimization
1160 Disable optimizations observable by IEEE signaling NaNs
1163 Common Report Var(flag_signed_zeros) Init(1) Optimization
1164 Disable floating point optimizations that ignore the IEEE signedness of zero
1166 fsingle-precision-constant
1167 Common Report Var(flag_single_precision_constant) Optimization
1168 Convert floating point constants to single precision constants
1170 fsplit-ivs-in-unroller
1171 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1172 Split lifetimes of induction variables when loops are unrolled
1175 Common Report Var(flag_split_wide_types) Optimization
1176 Split wide types into independent registers
1178 fvariable-expansion-in-unroller
1179 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1180 Apply variable expansion when loops are unrolled
1183 Common Report RejectNegative Joined
1184 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1188 Insert stack checking code into the program. Same as -fstack-check=specific
1193 fstack-limit-register=
1194 Common RejectNegative Joined
1195 -fstack-limit-register=<register> Trap if the stack goes past <register>
1197 fstack-limit-symbol=
1198 Common RejectNegative Joined
1199 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1202 Common Report Var(flag_stack_protect, 1)
1203 Use propolice as a stack protection method
1205 fstack-protector-all
1206 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1207 Use a stack protection method for every function
1211 Does nothing. Preserved for backward compatibility.
1213 ; Nonzero if we should do (language-dependent) alias analysis.
1214 ; Typically, this analysis will assume that expressions of certain
1215 ; types do not alias expressions of certain other types. Only used
1216 ; if alias analysis (in general) is enabled.
1218 Common Report Var(flag_strict_aliasing) Optimization
1219 Assume strict aliasing rules apply
1222 Common Report Var(flag_strict_overflow)
1223 Treat signed overflow as undefined
1226 Common Report Var(flag_syntax_only)
1227 Check for syntax errors, then stop
1230 Common Report Var(flag_test_coverage)
1231 Create data files needed by \"gcov\"
1234 Common Report Var(flag_thread_jumps) Optimization
1235 Perform jump threading optimizations
1238 Common Report Var(time_report)
1239 Report the time taken by each compiler pass
1242 Common Joined RejectNegative
1243 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1246 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1247 Reorder top level functions, variables, and asms
1250 Common Report Var(flag_tracer)
1251 Perform superblock formation via tail duplication
1253 ; Zero means that floating-point math operations cannot generate a
1254 ; (user-visible) trap. This is the case, for example, in nonstop
1255 ; IEEE 754 arithmetic.
1257 Common Report Var(flag_trapping_math) Init(1) Optimization
1258 Assume floating-point operations can trap
1261 Common Report Var(flag_trapv) Optimization
1262 Trap for signed overflow in addition, subtraction and multiplication
1265 Common Report Var(flag_tree_ccp) Optimization
1266 Enable SSA-CCP optimization on trees
1270 Does nothing. Preserved for backward compatibility.
1273 Common Report Var(flag_tree_ch) Optimization
1274 Enable loop header copying on trees
1277 Common Report Var(flag_tree_copyrename) Optimization
1278 Replace SSA temporaries with better names in copies
1281 Common Report Var(flag_tree_copy_prop) Optimization
1282 Enable copy propagation on trees
1284 ftree-store-copy-prop
1286 Does nothing. Preserved for backward compatibility.
1289 Common Report Var(flag_tree_cselim) Init(2) Optimization
1290 Transform condition stores into unconditional ones
1292 ftree-switch-conversion
1293 Common Report Var(flag_tree_switch_conversion) Optimization
1294 Perform conversions of switch initializations.
1297 Common Report Var(flag_tree_dce) Optimization
1298 Enable SSA dead code elimination optimization on trees
1300 ftree-dominator-opts
1301 Common Report Var(flag_tree_dom) Optimization
1302 Enable dominator optimizations
1305 Common Report Var(flag_tree_dse) Optimization
1306 Enable dead store elimination
1309 Common Report Var(flag_tree_forwprop) Init(1) Optimization
1310 Enable forward propagation on trees
1313 Common Report Var(flag_tree_fre) Optimization
1314 Enable Full Redundancy Elimination (FRE) on trees
1316 ftree-loop-distribution
1317 Common Report Var(flag_tree_loop_distribution) Optimization
1318 Enable loop distribution on trees
1321 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1322 Enable loop invariant motion on trees
1325 Common Report Var(flag_tree_loop_linear) Optimization
1326 Enable linear loop transforms on trees
1329 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1330 Create canonical induction variables in loops
1333 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1334 Enable loop optimizations on tree level
1336 ftree-parallelize-loops=
1337 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1338 Enable automatic parallelization of loops
1341 Common Report Var(flag_tree_phiprop) Init(1) Optimization
1342 Enable hoisting loads from conditional pointers.
1345 Common Report Var(flag_tree_pre) Optimization
1346 Enable SSA-PRE optimization on trees
1349 Common Report Var(flag_tree_pta) Init(1) Optimization
1350 Perform function-local points-to analysis on trees.
1353 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1354 Enable reassociation on tree level
1358 Does nothing. Preserved for backward compatibility.
1361 Common Report Var(flag_tree_sink) Optimization
1362 Enable SSA code sinking on trees
1365 Common Report Var(flag_tree_sra) Optimization
1366 Perform scalar replacement of aggregates
1369 Common Report Var(flag_tree_ter) Init(1) Optimization
1370 Replace temporary expressions in the SSA->normal pass
1373 Common Report Var(flag_tree_live_range_split) Optimization
1374 Perform live range splitting during the SSA->normal pass
1377 Common Report Var(flag_tree_vrp) Init(0) Optimization
1378 Perform Value Range Propagation on trees
1381 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1382 Compile whole compilation unit at a time
1385 Common Report Var(flag_unroll_loops) Optimization
1386 Perform loop unrolling when iteration count is known
1389 Common Report Var(flag_unroll_all_loops) Optimization
1390 Perform loop unrolling for all loops
1392 ; Nonzero means that loop optimizer may assume that the induction variables
1393 ; that control loops do not overflow and that the loops with nontrivial
1394 ; exit condition are not infinite
1395 funsafe-loop-optimizations
1396 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1397 Allow loop optimizations to assume that the loops behave in normal way
1400 Common Report Var(flag_associative_math)
1401 Allow optimization for floating-point arithmetic which may change the
1402 result of the operation due to rounding.
1405 Common Report Var(flag_reciprocal_math)
1406 Same as -fassociative-math for expressions which include division.
1408 ; Nonzero means that unsafe floating-point math optimizations are allowed
1409 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1410 ; are allowed to assume that their arguments and results are "normal"
1411 ; (e.g., nonnegative for SQRT).
1412 funsafe-math-optimizations
1413 Common Report Var(flag_unsafe_math_optimizations) Optimization
1414 Allow math optimizations that may violate IEEE or ISO standards
1417 Common Report Var(flag_unswitch_loops) Optimization
1418 Perform loop unswitching
1421 Common Report Var(flag_unwind_tables) Optimization
1422 Just generate unwind tables for exception handling
1428 Common Report Var(flag_var_tracking) VarExists Optimization
1429 Perform variable tracking
1431 fvar-tracking-assignments
1432 Common Report Var(flag_var_tracking_assignments) VarExists Optimization
1433 Perform variable tracking by annotating assignments
1435 fvar-tracking-assignments-toggle
1436 Common Report Var(flag_var_tracking_assignments_toggle) VarExists Optimization
1437 Toggle -fvar-tracking-assignments
1439 fvar-tracking-uninit
1440 Common Report Var(flag_var_tracking_uninit) Optimization
1441 Perform variable tracking and also tag variables that are uninitialized
1444 Common Report Var(flag_tree_vectorize) Optimization
1445 Enable loop vectorization on trees
1448 Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
1449 Enable basic block vectorization (SLP) on trees
1452 Common Report Var(flag_vect_cost_model) Optimization
1453 Enable use of cost model in vectorization
1455 ftree-vect-loop-version
1456 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1457 Enable loop versioning when doing loop vectorization on trees
1459 ftree-vectorizer-verbose=
1460 Common RejectNegative Joined
1461 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1464 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1465 Enable copy propagation of scalar-evolution information.
1467 ; -fverbose-asm causes extra commentary information to be produced in
1468 ; the generated assembly code (to make it more readable). This option
1469 ; is generally only of use to those who actually need to read the
1470 ; generated assembly code (perhaps while debugging the compiler itself).
1471 ; -fno-verbose-asm, the default, causes the extra information
1472 ; to not be added and is useful when comparing two assembler files.
1474 Common Report Var(flag_verbose_asm)
1475 Add extra commentary to assembler output
1478 Common Joined RejectNegative
1479 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1483 Common Report Var(flag_value_profile_transformations) Optimization
1484 Use expression value profiles in optimizations
1487 Common Report Var(flag_web) Init(2) Optimization
1488 Construct webs and split unrelated uses of single variable
1491 Common Var(flag_whopr)
1492 Enable partitioned link-time optimization.
1494 ftree-builtin-call-dce
1495 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1496 Enable conditional dead code elimination for builtin calls
1499 Common Report Var(flag_whole_program) Init(0) Optimization
1500 Perform whole program optimizations
1503 Common Report Var(flag_wrapv) Optimization
1504 Assume signed arithmetic overflow wraps around
1506 fzero-initialized-in-bss
1507 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1508 Put zero initialized data in the bss section
1511 Common JoinedOrMissing
1512 Generate debug information in default format
1515 Common JoinedOrMissing Negative(gdwarf-)
1516 Generate debug information in COFF format
1519 Common Joined UInteger Var(dwarf_version) Init(2) Negative(gstabs)
1520 Generate debug information in DWARF v2 (or later) format
1523 Common JoinedOrMissing
1524 Generate debug information in default extended format
1527 Common JoinedOrMissing Negative(gstabs+)
1528 Generate debug information in STABS format
1531 Common JoinedOrMissing Negative(gvms)
1532 Generate debug information in extended STABS format
1535 Common RejectNegative Var(dwarf_strict,0) Init(-1)
1536 Emit DWARF additions beyond selected version
1539 Common Report RejectNegative Var(dwarf_strict,1) VarExists
1540 Don't emit DWARF additions beyond selected version
1543 Common Report Var(flag_gtoggle)
1544 Toggle debug information generation
1547 Common JoinedOrMissing Negative(gxcoff)
1548 Generate debug information in VMS format
1551 Common JoinedOrMissing Negative(gxcoff+)
1552 Generate debug information in XCOFF format
1555 Common JoinedOrMissing Negative(gcoff)
1556 Generate debug information in extended XCOFF format
1559 Common Joined Var(plugindir_string) Init(0)
1560 -iplugindir=<dir> Set <dir> to be the default plugin directory
1563 Common Joined Separate
1564 -o <file> Place output into <file>
1567 Common Var(profile_flag)
1568 Enable function profiling
1571 Common Var(pedantic)
1572 Issue warnings needed for strict compliance to the standard
1576 Like -pedantic but issue them as errors
1579 Common Var(quiet_flag)
1580 Do not display functions compiled or elapsed time
1583 Common Var(version_flag)
1584 Display the compiler's version
1587 Common Var(inhibit_warnings)
1591 Common RejectNegative Negative(pie)
1592 Create a shared library
1595 Common RejectNegative Negative(shared)
1596 Create a position independent executable
1598 ; This comment is to ensure we retain the blank line above.