1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
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
92 Wdeprecated-declarations
93 Common Var(warn_deprecated_decl) Init(1) Warning
94 Warn about uses of __attribute__((deprecated)) declarations
96 Wdisabled-optimization
97 Common Var(warn_disabled_optimization) Warning
98 Warn when an optimization pass is disabled
101 Common Var(warnings_are_errors)
102 Treat all warnings as errors
106 Treat specified warning as error
109 Common Var(extra_warnings) Warning
110 Print extra (possibly unwanted) warnings
113 Common Var(flag_fatal_errors)
114 Exit on the first error occurred
117 Common RejectNegative Joined UInteger
118 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes
121 Common Var(warn_inline) Warning
122 Warn when an inlined function cannot be inlined
125 Common RejectNegative Joined UInteger Warning
128 Common RejectNegative Joined UInteger Warning
129 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
131 Wunsafe-loop-optimizations
132 Common Var(warn_unsafe_loop_optimizations) Warning
133 Warn if the loop cannot be optimized due to nontrivial assumptions.
136 Common Var(warn_missing_noreturn) Warning
137 Warn about functions which might be candidates for __attribute__((noreturn))
140 Common Var(warn_mudflap) Init(1) Warning
141 Warn about constructs not instrumented by -fmudflap
144 Common Var(warn_overflow) Init(1) Warning
145 Warn about overflow in arithmetic expressions
148 Common Var(warn_packed) Warning
149 Warn when the packed attribute has no effect on struct layout
152 Common Var(warn_padded) Warning
153 Warn when padding is required to align structure members
156 Common Var(warn_shadow) Warning
157 Warn when one local variable shadows another
160 Common Var(warn_stack_protect) Warning
161 Warn when not issuing stack smashing protection for some reason
165 Warn about code which might break strict aliasing rules
168 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
169 Warn about code which might break strict aliasing rules
173 Warn about optimizations that assume that signed overflow is undefined
176 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
177 Warn about optimizations that assume that signed overflow is undefined
180 Common Var(warn_switch) Warning
181 Warn about enumerated switches, with no default, missing a case
184 Common Var(warn_switch_default) Warning
185 Warn about enumerated switches missing a \"default:\" statement
188 Common Var(warn_switch_enum) Warning
189 Warn about all enumerated switches missing a specific case
192 Common Var(warn_system_headers) Warning
193 Do not suppress warnings from system headers
196 Common Var(warn_type_limits) Init(-1) Warning
197 Warn if a comparison is always true or always false due to the limited range of the data type
200 Common Var(warn_uninitialized) Init(-1) Warning
201 Warn about uninitialized automatic variables
204 Common Var(warn_notreached) Warning
205 Warn about code that will never be executed
208 Common Var(warn_unused) Init(0) Warning
209 Enable all -Wunused- warnings
212 Common Var(warn_unused_function) Init(-1) Warning
213 Warn when a function is unused
216 Common Var(warn_unused_label) Init(-1) Warning
217 Warn when a label is unused
220 Common Var(warn_unused_parameter) Init(-1) Warning
221 Warn when a function parameter is unused
224 Common Var(warn_unused_value) Init(-1) Warning
225 Warn when an expression value is unused
228 Common Var(warn_unused_variable) Init(-1) Warning
229 Warn when a variable is unused
232 Common RejectNegative Var(warn_coverage_mismatch) Warning
233 Warn instead of error in case profiles in -fprofile-use do not match
237 -aux-info <file> Emit declaration information into <file>
250 -d<letters> Enable dumps from specific passes of the compiler
254 -dumpbase <file> Set the file basename to be used for dumps
256 ; The version of the C++ ABI in use. The following values are allowed:
258 ; 0: The version of the ABI believed most conformant with the C++ ABI
259 ; specification. This ABI may change as bugs are discovered and fixed.
260 ; Therefore, 0 will not necessarily indicate the same ABI in different
263 ; 1: The version of the ABI first used in G++ 3.2.
265 ; 2: The version of the ABI first used in G++ 3.4.
267 ; Additional positive integers will be assigned as new versions of
268 ; the ABI become the default version of the ABI.
270 Common Joined UInteger Var(flag_abi_version) Init(2)
273 Common Report Var(align_functions,0) Optimization UInteger
274 Align the start of functions
277 Common RejectNegative Joined UInteger
280 Common Report Var(align_jumps,0) Optimization UInteger
281 Align labels which are only reached by jumping
284 Common RejectNegative Joined UInteger
287 Common Report Var(align_labels,0) Optimization UInteger
291 Common RejectNegative Joined UInteger
294 Common Report Var(align_loops) Optimization UInteger
295 Align the start of loops
298 Common RejectNegative Joined UInteger
300 ; This flag is only tested if alias checking is enabled.
301 ; 0 if pointer arguments may alias each other. True in C.
302 ; 1 if pointer arguments may not alias each other but may alias
304 ; 2 if pointer arguments may not alias each other and may not
305 ; alias global variables.
306 ; 3 if pointer arguments may not alias anything. True in Fortran.
307 ; Set by the front end.
309 Common Report Var(flag_argument_noalias,0) Optimization
310 Specify that arguments may alias each other and globals
313 Common Report Var(flag_argument_noalias,1) VarExists Optimization
314 Assume arguments may alias globals but not each other
316 fargument-noalias-global
317 Common Report Var(flag_argument_noalias,2) VarExists Optimization
318 Assume arguments alias neither each other nor globals
320 fargument-noalias-anything
321 Common Report Var(flag_argument_noalias,3) VarExists Optimization
322 Assume arguments alias no other storage
324 fasynchronous-unwind-tables
325 Common Report Var(flag_asynchronous_unwind_tables) Optimization
326 Generate unwind tables that are exact at each instruction boundary
329 Common Report Var(flag_auto_inc_dec) Init(1)
330 Generate auto-inc/dec instructions
332 ; -fcheck-bounds causes gcc to generate array bounds checks.
333 ; For C, C++ and ObjC: defaults off.
334 ; For Java: defaults to on.
335 ; For Fortran: defaults to off.
337 Common Report Var(flag_bounds_check)
338 Generate code to check bounds before indexing arrays
341 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
342 Replace add, compare, branch with branch on count register
344 fbranch-probabilities
345 Common Report Var(flag_branch_probabilities) Optimization
346 Use profiling information for branch probabilities
348 fbranch-target-load-optimize
349 Common Report Var(flag_branch_target_load_optimize) Optimization
350 Perform branch target load optimization before prologue / epilogue threading
352 fbranch-target-load-optimize2
353 Common Report Var(flag_branch_target_load_optimize2) Optimization
354 Perform branch target load optimization after prologue / epilogue threading
357 Common Report Var(flag_btr_bb_exclusive) Optimization
358 Restrict target load migration not to re-use registers in any basic block
361 Common Joined RejectNegative
362 -fcall-saved-<register> Mark <register> as being preserved across functions
365 Common Joined RejectNegative
366 -fcall-used-<register> Mark <register> as being corrupted by function calls
368 ; Nonzero for -fcaller-saves: allocate values in regs that need to
369 ; be saved across function calls, if that produces overall better code.
370 ; Optional now, so people can test it.
372 Common Report Var(flag_caller_saves) Optimization
373 Save registers around function calls
376 Common Report Var(flag_check_data_deps)
377 Compare the results of several data dependence analyzers.
380 Common Report Var(flag_no_common,0) Optimization
381 Do not put uninitialized globals in the common section
384 Common JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
385 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump
387 fcompare-debug-second
388 Common RejectNegative Var(flag_compare_debug)
389 Run only the second compilation of -fcompare-debug
392 Common Var(flag_conserve_stack) Optimization
393 Do not perform optimizations increasing noticeably stack usage
396 Common Report Var(flag_cprop_registers) Optimization
397 Perform a register copy-propagation optimization pass
400 Common Report Var(flag_crossjumping) Optimization
401 Perform cross-jumping optimization
404 Common Report Var(flag_cse_follow_jumps) Optimization
405 When running CSE, follow jumps to their targets
409 Does nothing. Preserved for backward compatibility.
412 Common Report Var(flag_cx_limited_range) Optimization
413 Omit range reduction step when performing complex division
416 Common Report Var(flag_cx_fortran_rules) Optimization
417 Complex multiplication and division follow Fortran rules
420 Common Report Var(flag_data_sections) Optimization
421 Place data items into their own section
425 List all available debugging counters with their limits and counts.
428 Common RejectNegative Joined
429 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
432 Common Joined RejectNegative
433 Map one directory name to another in debug information
435 ; Nonzero for -fdefer-pop: don't pop args after each function call
436 ; instead save them up to pop many calls' args with one insns.
438 Common Report Var(flag_defer_pop) Optimization
439 Defer popping functions args from stack until later
442 Common Report Var(flag_delayed_branch) Optimization
443 Attempt to fill delay slots of branch instructions
445 fdelete-null-pointer-checks
446 Common Report Var(flag_delete_null_pointer_checks) Init(1) Optimization
447 Delete useless null pointer checks
449 fdiagnostics-show-location=
450 Common Joined RejectNegative
451 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
453 fdiagnostics-show-option
455 Amend appropriate diagnostic messages with the command line option that controls them
458 Common Joined RejectNegative
459 -fdump-<type> Dump various compiler internals to a file
462 Common RejectNegative Joined Var(flag_dump_final_insns)
463 -fdump-final-insns=filename Dump to filename the insns at the end of translation
466 Common Report Var(flag_dump_noaddr)
467 Suppress output of addresses in debugging dumps
470 Common Report Var(flag_dump_unnumbered) VarExists
471 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
473 fdump-unnumbered-links
474 Common Report Var(flag_dump_unnumbered_links) VarExists
475 Suppress output of previous and next insn numbers in debugging dumps
478 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
479 Enable CFI tables via GAS assembler directives.
482 Common Report Var(flag_early_inlining) Init(1) Optimization
483 Perform early inlining
485 feliminate-dwarf2-dups
486 Common Report Var(flag_eliminate_dwarf2_dups)
487 Perform DWARF2 duplicate elimination
490 Common Report Var(flag_ipa_sra) Init(0) Optimization
491 Perform interprocedural reduction of aggregates
493 feliminate-unused-debug-symbols
494 Common Report Var(flag_debug_only_used_symbols)
495 Perform unused type elimination in debug info
497 feliminate-unused-debug-types
498 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
499 Perform unused type elimination in debug info
501 femit-class-debug-always
502 Common Report Var(flag_emit_class_debug_always) Init(0)
503 Do not suppress C++ class debug information.
506 Common Report Var(flag_exceptions) Optimization
507 Enable exception handling
509 fexpensive-optimizations
510 Common Report Var(flag_expensive_optimizations) Optimization
511 Perform a number of minor, expensive optimizations
514 Common Joined RejectNegative
515 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision
521 Common Report Var(flag_finite_math_only) Optimization
522 Assume no NaNs or infinities are generated
525 Common Joined RejectNegative
526 -ffixed-<register> Mark <register> as being unavailable to the compiler
529 Common Report Var(flag_float_store) Optimization
530 Don't allocate floats and doubles in extended-precision registers
534 Does nothing. Preserved for backward compatibility.
537 Common Report Var(flag_forward_propagate) Optimization
538 Perform a forward propagation pass on RTL
540 ; Nonzero means don't put addresses of constant functions in registers.
541 ; Used for compiling the Unix kernel, where strange substitutions are
542 ; done on the assembly output.
544 Common Report Var(flag_no_function_cse,0)
545 Allow function addresses to be held in registers
548 Common Report Var(flag_function_sections)
549 Place each function into its own section
552 Common Report Var(flag_gcse) Optimization
553 Perform global common subexpression elimination
556 Common Report Var(flag_gcse_lm) Init(1) Optimization
557 Perform enhanced load motion during global common subexpression elimination
560 Common Report Var(flag_gcse_sm) Init(0) Optimization
561 Perform store motion after global common subexpression elimination
564 Common Report Var(flag_gcse_las) Init(0) Optimization
565 Perform redundant load after store elimination in global common subexpression
569 Common Report Var(flag_gcse_after_reload) Optimization
570 Perform global common subexpression elimination after register allocation
573 ; This option is not documented yet as its semantics will change.
575 Common Report Var(flag_graphite)
576 Enable in and out of Graphite representation
579 Common Report Var(flag_graphite_identity) Optimization
580 Enable Graphite Identity transformation
582 floop-parallelize-all
583 Common Report Var(flag_loop_parallelize_all) Optimization
584 Mark all loops as parallel
587 Common Report Var(flag_loop_strip_mine) Optimization
588 Enable Loop Strip Mining transformation
591 Common Report Var(flag_loop_interchange) Optimization
592 Enable Loop Interchange transformation
595 Common Report Var(flag_loop_block) Optimization
596 Enable Loop Blocking transformation
598 fguess-branch-probability
599 Common Report Var(flag_guess_branch_prob) Optimization
600 Enable guessing of branch probabilities
602 ; Nonzero means ignore `#ident' directives. 0 means handle them.
603 ; Generate position-independent code for executables if possible
604 ; On SVR4 targets, it also controls whether or not to emit a
605 ; string identifying the compiler.
607 Common Report Var(flag_no_ident,0)
608 Process #ident directives
611 Common Report Var(flag_if_conversion) Optimization
612 Perform conversion of conditional jumps to branchless equivalents
615 Common Report Var(flag_if_conversion2) Optimization
616 Perform conversion of conditional jumps to conditional execution
618 ; -finhibit-size-directive inhibits output of .size for ELF.
619 ; This is used only for compiling crtstuff.c,
620 ; and it may be extended to other effects
621 ; needed for crtstuff.c on other systems.
622 finhibit-size-directive
623 Common Report Var(flag_inhibit_size_directive)
624 Do not generate .size directives
627 Common Report Var(flag_indirect_inlining)
628 Perform indirect inlining
630 ; Nonzero means that functions declared `inline' will be treated
631 ; as `static'. Prevents generation of zillions of copies of unused
632 ; static inline functions; instead, `inlines' are written out
633 ; only when actually used. Used in conjunction with -g. Also
634 ; does the right thing with #pragma interface.
636 Common Report Var(flag_no_inline,0) Init(0)
637 Pay attention to the \"inline\" keyword
639 finline-small-functions
640 Common Report Var(flag_inline_small_functions) Optimization
641 Integrate simple functions into their callers when code size is known to not growth
644 Common Report Var(flag_inline_functions) Optimization
645 Integrate simple functions into their callers
647 finline-functions-called-once
648 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
649 Integrate functions called once into their callers
652 Common RejectNegative Joined UInteger
655 Common RejectNegative Joined UInteger
656 -finline-limit=<number> Limit the size of inlined functions to <number>
658 finstrument-functions
659 Common Report Var(flag_instrument_function_entry_exit)
660 Instrument function entry and exit with profiling calls
662 finstrument-functions-exclude-function-list=
663 Common RejectNegative Joined
664 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
666 finstrument-functions-exclude-file-list=
667 Common RejectNegative Joined
668 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
671 Common Report Var(flag_ipa_cp) Optimization
672 Perform Interprocedural constant propagation
675 Common Report Var(flag_ipa_cp_clone) Optimization
676 Perform cloning to make Interprocedural constant propagation stronger
679 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
680 Discover pure and const functions
683 Common Report Var(flag_ipa_pta) Init(0) Optimization
684 Perform interprocedural points-to analysis
687 Common Report Var(flag_ipa_reference) Init(0) Optimization
688 Discover readonly and non addressable static variables
691 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
692 Type based escape and alias analysis
695 Common Report Var(flag_ipa_matrix_reorg) Optimization
696 Perform matrix layout flattening and transposing based
697 on profiling information.
700 Common Report Var(flag_ipa_struct_reorg)
701 Perform structure layout optimizations based
702 on profiling information.
705 Common Joined RejectNegative
706 -fira-algorithm=[CB|priority] Set the used IRA algorithm
709 Common Joined RejectNegative
710 -fira-region=[one|all|mixed] Set regions for IRA
713 Common Report Var(flag_ira_coalesce) Init(0)
714 Do optimistic coalescing.
716 fira-share-save-slots
717 Common Report Var(flag_ira_share_save_slots) Init(1)
718 Share slots for saving different hard registers.
720 fira-share-spill-slots
721 Common Report Var(flag_ira_share_spill_slots) Init(1)
722 Share stack slots for spilled pseudo-registers.
725 Common RejectNegative Joined UInteger
726 -fira-verbose=<number> Control IRA's level of diagnostic messages.
729 Common Report Var(flag_ivopts) Init(1) Optimization
730 Optimize induction variables on trees
733 Common Var(flag_jump_tables) Init(1) Optimization
734 Use jump tables for sufficiently large switch statements
736 fkeep-inline-functions
737 Common Report Var(flag_keep_inline_functions)
738 Generate code for functions even if they are fully inlined
741 Common Report Var(flag_keep_static_consts) Init(1)
742 Emit static const variables even if they are not used
745 Common Report Var(flag_leading_underscore) Init(-1)
746 Give external symbols a leading underscore
750 Does nothing. Preserved for backward compatibility.
753 Common Report Var(flag_errno_math) Init(1) Optimization
754 Set errno after built-in math functions
757 Common Report Var(mem_report)
758 Report on permanent memory allocation
760 ; This will attempt to merge constant section constants, if 1 only
761 ; string constants and constants from constant pool, if 2 also constant
764 Common Report Var(flag_merge_constants,2) Init(1) Optimization
765 Attempt to merge identical constants and constant variables
768 Common Report Var(flag_merge_constants,1) VarExists Optimization
769 Attempt to merge identical constants across compilation units
772 Common Report Var(flag_merge_debug_strings) Init(1)
773 Attempt to merge identical debug strings across compilation units
776 Common RejectNegative Joined UInteger
777 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
780 Common Report Var(flag_modulo_sched) Optimization
781 Perform SMS based modulo scheduling before the first scheduling pass
783 fmodulo-sched-allow-regmoves
784 Common Report Var(flag_modulo_sched_allow_regmoves)
785 Perform SMS based modulo scheduling with register moves allowed
787 fmove-loop-invariants
788 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
789 Move loop invariant computations out of loops
792 Common RejectNegative Report Var(flag_mudflap)
793 Add mudflap bounds-checking instrumentation for single-threaded program
796 Common RejectNegative Report VarExists Var(flag_mudflap,2)
797 Add mudflap bounds-checking instrumentation for multi-threaded program
800 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
801 Ignore read operations when inserting mudflap instrumentation
804 Common Var(flag_dce) Init(1) Optimization
805 Use the RTL dead code elimination pass
808 Common Var(flag_dse) Init(1) Optimization
809 Use the RTL dead store elimination pass
811 freschedule-modulo-scheduled-loops
812 Common Report Var(flag_resched_modulo_sched) Optimization
813 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
816 Common Report Var(flag_non_call_exceptions) Optimization
817 Support synchronous non-call exceptions
820 Common Report Var(flag_omit_frame_pointer) Optimization
821 When possible do not generate stack frames
823 foptimize-register-move
824 Common Report Var(flag_regmove) Optimization
825 Do the full register move optimization pass
827 foptimize-sibling-calls
828 Common Report Var(flag_optimize_sibling_calls) Optimization
829 Optimize sibling and tail recursive calls
832 Common Report Var(pre_ipa_mem_report)
833 Report on memory allocation before interprocedural optimization
836 Common Report Var(post_ipa_mem_report)
837 Report on memory allocation before interprocedural optimization
840 Common Report Var(flag_pack_struct) Optimization
841 Pack structure members together without holes
844 Common RejectNegative Joined UInteger Optimization
845 -fpack-struct=<number> Set initial maximum structure member alignment
848 Common Report Var(flag_pcc_struct_return,1) VarExists
849 Return small aggregates in memory, not registers
852 Common Report Var(flag_peel_loops) Optimization
856 Common Report Var(flag_no_peephole,0) Optimization
857 Enable machine specific peephole optimizations
860 Common Report Var(flag_peephole2) Optimization
861 Enable an RTL peephole pass before sched2
864 Common Report Var(flag_pic,2)
865 Generate position-independent code if possible (large mode)
868 Common Report Var(flag_pie,2)
869 Generate position-independent code for executables if possible (large mode)
872 Common Report Var(flag_pic,1) VarExists
873 Generate position-independent code if possible (small mode)
876 Common Report Var(flag_pie,1) VarExists
877 Generate position-independent code for executables if possible (small mode)
880 Common Joined RejectNegative
881 Specify a plugin to load
884 Common Joined RejectNegative
885 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
887 fpredictive-commoning
888 Common Report Var(flag_predictive_commoning) Optimization
889 Run predictive commoning optimization.
891 fprefetch-loop-arrays
892 Common Report Var(flag_prefetch_loop_arrays) Optimization
893 Generate prefetch instructions, if available, for arrays in loops
896 Common Report Var(profile_flag)
897 Enable basic program profiling code
900 Common Report Var(profile_arc_flag)
901 Insert arc-based program profiling code
904 Common Joined RejectNegative
905 Set the top-level directory for storing the profile data.
906 The default is 'pwd'.
909 Common Report Var(flag_profile_correction)
910 Enable correction of flow inconsistent profile data input
914 Enable common options for generating profile info for profile feedback directed optimizations
917 Common Joined RejectNegative
918 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
921 Common Var(flag_profile_use)
922 Enable common options for performing profile feedback directed optimizations
925 Common Joined RejectNegative
926 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
929 Common Report Var(flag_profile_values)
930 Insert code to profile values of expressions
936 Common Joined RejectNegative
937 -frandom-seed=<string> Make compile reproducible using <string>
939 ; This switch causes the command line that was used to create an
940 ; object file to be recorded into the object file. The exact format
941 ; of this recording is target and binary file format dependent.
942 ; It is related to the -fverbose-asm switch, but that switch only
943 ; records information in the assembler output file as comments, so
944 ; they never reach the object file.
946 Common Report Var(flag_record_gcc_switches)
947 Record gcc command line switches in the object file.
950 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
951 Return small aggregates in registers
954 Common Report Var(flag_regmove) Optimization
955 Enables a register move optimization
958 Common Report Var(flag_rename_registers) Init(2) Optimization
959 Perform a register renaming optimization pass
962 Common Report Var(flag_reorder_blocks) Optimization
963 Reorder basic blocks to improve code placement
965 freorder-blocks-and-partition
966 Common Report Var(flag_reorder_blocks_and_partition) Optimization
967 Reorder basic blocks and partition into hot and cold sections
970 Common Report Var(flag_reorder_functions) Optimization
971 Reorder functions to improve code placement
973 frerun-cse-after-loop
974 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
975 Add a common subexpression elimination pass after loop optimizations
979 Does nothing. Preserved for backward compatibility.
982 Common Report Var(flag_rounding_math) Optimization
983 Disable optimizations that assume default FP rounding behavior
986 Common Report Var(flag_schedule_interblock) Init(1) Optimization
987 Enable scheduling across basic blocks
990 Common Report Var(flag_sched_pressure) Init(0) Optimization
991 Enable register pressure sensitive insn scheduling
994 Common Report Var(flag_schedule_speculative) Init(1) Optimization
995 Allow speculative motion of non-loads
998 Common Report Var(flag_schedule_speculative_load) Optimization
999 Allow speculative motion of some loads
1001 fsched-spec-load-dangerous
1002 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
1003 Allow speculative motion of more loads
1006 Common RejectNegative Joined
1007 -fsched-verbose=<number> Set the verbosity level of the scheduler
1009 fsched2-use-superblocks
1010 Common Report Var(flag_sched2_use_superblocks) Optimization
1011 If scheduling post reload, do superblock scheduling
1014 Common Report Var(flag_sched2_use_traces) Optimization
1015 If scheduling post reload, do trace scheduling
1018 Common Report Var(flag_schedule_insns) Optimization
1019 Reschedule instructions before register allocation
1022 Common Report Var(flag_schedule_insns_after_reload) Optimization
1023 Reschedule instructions after register allocation
1025 ; This flag should be on when a target implements non-trivial
1026 ; scheduling hooks, maybe saving some information for its own sake.
1027 ; On IA64, for example, this is used for correct bundling.
1028 fselective-scheduling
1029 Common Report Var(flag_selective_scheduling) Optimization
1030 Schedule instructions using selective scheduling algorithm
1032 fselective-scheduling2
1033 Common Report Var(flag_selective_scheduling2) Optimization
1034 Run selective scheduling after reload
1036 fsel-sched-pipelining
1037 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1038 Perform software pipelining of inner loops during selective scheduling
1040 fsel-sched-pipelining-outer-loops
1041 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1042 Perform software pipelining of outer loops during selective scheduling
1044 fsel-sched-reschedule-pipelined
1045 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1046 Reschedule pipelined regions without pipelining
1048 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1049 ; of stalled insns into the ready list.
1050 fsched-stalled-insns
1051 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1052 Allow premature scheduling of queued insns
1054 fsched-stalled-insns=
1055 Common RejectNegative Joined UInteger
1056 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1058 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1059 ; be examined for a dependency on a stalled insn that is candidate for
1060 ; premature removal from the queue of stalled insns into the ready list (has
1061 ; an effect only if the flag 'sched_stalled_insns' is set).
1062 fsched-stalled-insns-dep
1063 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1064 Set dependence distance checking in premature scheduling of queued insns
1066 fsched-stalled-insns-dep=
1067 Common RejectNegative Joined UInteger
1068 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1070 fsched-group-heuristic
1071 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
1072 Enable the group heuristic in the scheduler
1074 fsched-critical-path-heuristic
1075 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
1076 Enable the critical path heuristic in the scheduler
1078 fsched-spec-insn-heuristic
1079 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
1080 Enable the speculative instruction heuristic in the scheduler
1082 fsched-rank-heuristic
1083 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
1084 Enable the rank heuristic in the scheduler
1086 fsched-last-insn-heuristic
1087 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
1088 Enable the last instruction heuristic in the scheduler
1090 fsched-dep-count-heuristic
1091 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
1092 Enable the dependent count heuristic in the scheduler
1095 Common Report Var(flag_section_anchors) Optimization
1096 Access data in the same section from shared anchor points
1100 Does nothing. Preserved for backward compatibility.
1103 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
1104 Show column numbers in diagnostics, when available. Default on
1107 Common Report Var(flag_signaling_nans) Optimization
1108 Disable optimizations observable by IEEE signaling NaNs
1111 Common Report Var(flag_signed_zeros) Init(1) Optimization
1112 Disable floating point optimizations that ignore the IEEE signedness of zero
1114 fsingle-precision-constant
1115 Common Report Var(flag_single_precision_constant) Optimization
1116 Convert floating point constants to single precision constants
1118 fsplit-ivs-in-unroller
1119 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1120 Split lifetimes of induction variables when loops are unrolled
1123 Common Report Var(flag_split_wide_types) Optimization
1124 Split wide types into independent registers
1126 fvariable-expansion-in-unroller
1127 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1128 Apply variable expansion when loops are unrolled
1131 Common Report RejectNegative Joined
1132 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1136 Insert stack checking code into the program. Same as -fstack-check=specific
1141 fstack-limit-register=
1142 Common RejectNegative Joined
1143 -fstack-limit-register=<register> Trap if the stack goes past <register>
1145 fstack-limit-symbol=
1146 Common RejectNegative Joined
1147 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1150 Common Report Var(flag_stack_protect, 1)
1151 Use propolice as a stack protection method
1153 fstack-protector-all
1154 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1155 Use a stack protection method for every function
1159 Does nothing. Preserved for backward compatibility.
1161 ; Nonzero if we should do (language-dependent) alias analysis.
1162 ; Typically, this analysis will assume that expressions of certain
1163 ; types do not alias expressions of certain other types. Only used
1164 ; if alias analysis (in general) is enabled.
1166 Common Report Var(flag_strict_aliasing) Optimization
1167 Assume strict aliasing rules apply
1170 Common Report Var(flag_strict_overflow)
1171 Treat signed overflow as undefined
1174 Common Report Var(flag_syntax_only)
1175 Check for syntax errors, then stop
1178 Common Report Var(flag_test_coverage)
1179 Create data files needed by \"gcov\"
1182 Common Report Var(flag_thread_jumps) Optimization
1183 Perform jump threading optimizations
1186 Common Report Var(time_report)
1187 Report the time taken by each compiler pass
1190 Common Joined RejectNegative
1191 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1194 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1195 Reorder top level functions, variables, and asms
1198 Common Report Var(flag_tracer)
1199 Perform superblock formation via tail duplication
1201 ; Zero means that floating-point math operations cannot generate a
1202 ; (user-visible) trap. This is the case, for example, in nonstop
1203 ; IEEE 754 arithmetic.
1205 Common Report Var(flag_trapping_math) Init(1) Optimization
1206 Assume floating-point operations can trap
1209 Common Report Var(flag_trapv) Optimization
1210 Trap for signed overflow in addition, subtraction and multiplication
1213 Common Report Var(flag_tree_ccp) Optimization
1214 Enable SSA-CCP optimization on trees
1218 Does nothing. Preserved for backward compatibility.
1221 Common Report Var(flag_tree_ch) Optimization
1222 Enable loop header copying on trees
1225 Common Report Var(flag_tree_copyrename) Optimization
1226 Replace SSA temporaries with better names in copies
1229 Common Report Var(flag_tree_copy_prop) Optimization
1230 Enable copy propagation on trees
1232 ftree-store-copy-prop
1234 Does nothing. Preserved for backward compatibility.
1237 Common Report Var(flag_tree_cselim) Init(2) Optimization
1238 Transform condition stores into unconditional ones
1240 ftree-switch-conversion
1241 Common Report Var(flag_tree_switch_conversion) Optimization
1242 Perform conversions of switch initializations.
1245 Common Report Var(flag_tree_dce) Optimization
1246 Enable SSA dead code elimination optimization on trees
1248 ftree-dominator-opts
1249 Common Report Var(flag_tree_dom) Optimization
1250 Enable dominator optimizations
1253 Common Report Var(flag_tree_dse) Optimization
1254 Enable dead store elimination
1257 Common Report Var(flag_tree_forwprop) Init(1) Optimization
1258 Enable forward propagation on trees
1261 Common Report Var(flag_tree_fre) Optimization
1262 Enable Full Redundancy Elimination (FRE) on trees
1264 ftree-loop-distribution
1265 Common Report Var(flag_tree_loop_distribution) Optimization
1266 Enable loop distribution on trees
1269 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1270 Enable loop invariant motion on trees
1273 Common Report Var(flag_tree_loop_linear) Optimization
1274 Enable linear loop transforms on trees
1277 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1278 Create canonical induction variables in loops
1281 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1282 Enable loop optimizations on tree level
1284 ftree-parallelize-loops=
1285 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1286 Enable automatic parallelization of loops
1289 Common Report Var(flag_tree_phiprop) Init(1) Optimization
1290 Enable hoisting loads from conditional pointers.
1293 Common Report Var(flag_tree_pre) Optimization
1294 Enable SSA-PRE optimization on trees
1297 Common Report Var(flag_tree_pta) Init(1) Optimization
1298 Perform function-local points-to analysis on trees.
1301 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1302 Enable reassociation on tree level
1306 Does nothing. Preserved for backward compatibility.
1309 Common Report Var(flag_tree_sink) Optimization
1310 Enable SSA code sinking on trees
1313 Common Report Var(flag_tree_sra) Optimization
1314 Perform scalar replacement of aggregates
1317 Common Report Var(flag_tree_ter) Init(1) Optimization
1318 Replace temporary expressions in the SSA->normal pass
1321 Common Report Var(flag_tree_live_range_split) Optimization
1322 Perform live range splitting during the SSA->normal pass
1325 Common Report Var(flag_tree_vrp) Init(0) Optimization
1326 Perform Value Range Propagation on trees
1329 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1330 Compile whole compilation unit at a time
1333 Common Report Var(flag_unroll_loops) Optimization
1334 Perform loop unrolling when iteration count is known
1337 Common Report Var(flag_unroll_all_loops) Optimization
1338 Perform loop unrolling for all loops
1340 ; Nonzero means that loop optimizer may assume that the induction variables
1341 ; that control loops do not overflow and that the loops with nontrivial
1342 ; exit condition are not infinite
1343 funsafe-loop-optimizations
1344 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1345 Allow loop optimizations to assume that the loops behave in normal way
1348 Common Report Var(flag_associative_math)
1349 Allow optimization for floating-point arithmetic which may change the
1350 result of the operation due to rounding.
1353 Common Report Var(flag_reciprocal_math)
1354 Same as -fassociative-math for expressions which include division.
1356 ; Nonzero means that unsafe floating-point math optimizations are allowed
1357 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1358 ; are allowed to assume that their arguments and results are "normal"
1359 ; (e.g., nonnegative for SQRT).
1360 funsafe-math-optimizations
1361 Common Report Var(flag_unsafe_math_optimizations) Optimization
1362 Allow math optimizations that may violate IEEE or ISO standards
1365 Common Report Var(flag_unswitch_loops) Optimization
1366 Perform loop unswitching
1369 Common Report Var(flag_unwind_tables) Optimization
1370 Just generate unwind tables for exception handling
1373 Common Report Var(flag_var_tracking) VarExists Optimization
1374 Perform variable tracking
1376 fvar-tracking-assignments
1377 Common Report Var(flag_var_tracking_assignments) VarExists Optimization
1378 Perform variable tracking by annotating assignments
1380 fvar-tracking-assignments-toggle
1381 Common Report Var(flag_var_tracking_assignments_toggle) VarExists Optimization
1382 Toggle -fvar-tracking-assignments
1384 fvar-tracking-uninit
1385 Common Report Var(flag_var_tracking_uninit) Optimization
1386 Perform variable tracking and also tag variables that are uninitialized
1389 Common Report Var(flag_tree_vectorize) Optimization
1390 Enable loop vectorization on trees
1393 Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
1394 Enable basic block vectorization (SLP) on trees
1397 Common Report Var(flag_vect_cost_model) Optimization
1398 Enable use of cost model in vectorization
1400 ftree-vect-loop-version
1401 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1402 Enable loop versioning when doing loop vectorization on trees
1404 ftree-vectorizer-verbose=
1405 Common RejectNegative Joined
1406 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1409 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1410 Enable copy propagation of scalar-evolution information.
1412 ; -fverbose-asm causes extra commentary information to be produced in
1413 ; the generated assembly code (to make it more readable). This option
1414 ; is generally only of use to those who actually need to read the
1415 ; generated assembly code (perhaps while debugging the compiler itself).
1416 ; -fno-verbose-asm, the default, causes the extra information
1417 ; to not be added and is useful when comparing two assembler files.
1419 Common Report Var(flag_verbose_asm)
1420 Add extra commentary to assembler output
1423 Common Joined RejectNegative
1424 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1428 Common Report Var(flag_value_profile_transformations) Optimization
1429 Use expression value profiles in optimizations
1432 Common Report Var(flag_web) Init(2) Optimization
1433 Construct webs and split unrelated uses of single variable
1435 ftree-builtin-call-dce
1436 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1437 Enable conditional dead code elimination for builtin calls
1440 Common Report Var(flag_whole_program) Init(0) Optimization
1441 Perform whole program optimizations
1444 Common Report Var(flag_wrapv) Optimization
1445 Assume signed arithmetic overflow wraps around
1447 fzero-initialized-in-bss
1448 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1449 Put zero initialized data in the bss section
1452 Common JoinedOrMissing
1453 Generate debug information in default format
1456 Common JoinedOrMissing Negative(gdwarf-)
1457 Generate debug information in COFF format
1460 Common Joined UInteger Var(dwarf_version) Init(2) Negative(gstabs)
1461 Generate debug information in DWARF v2 (or later) format
1464 Common JoinedOrMissing
1465 Generate debug information in default extended format
1468 Common JoinedOrMissing Negative(gstabs+)
1469 Generate debug information in STABS format
1472 Common JoinedOrMissing Negative(gvms)
1473 Generate debug information in extended STABS format
1476 Common RejectNegative Var(dwarf_strict,0) Init(-1)
1477 Emit DWARF additions beyond selected version
1480 Common Report RejectNegative Var(dwarf_strict,1) VarExists
1481 Don't emit DWARF additions beyond selected version
1484 Common Report Var(flag_gtoggle)
1485 Toggle debug information generation
1488 Common JoinedOrMissing Negative(gxcoff)
1489 Generate debug information in VMS format
1492 Common JoinedOrMissing Negative(gxcoff+)
1493 Generate debug information in XCOFF format
1496 Common JoinedOrMissing Negative(gcoff)
1497 Generate debug information in extended XCOFF format
1500 Common Joined Separate
1501 -o <file> Place output into <file>
1504 Common Var(profile_flag)
1505 Enable function profiling
1508 Common Var(pedantic)
1509 Issue warnings needed for strict compliance to the standard
1513 Like -pedantic but issue them as errors
1516 Common Var(quiet_flag)
1517 Do not display functions compiled or elapsed time
1520 Common Var(version_flag)
1521 Display the compiler's version
1524 Common Var(inhibit_warnings)
1528 Common RejectNegative Negative(pie)
1529 Create a shared library
1532 Common RejectNegative Negative(shared)
1533 Create a position independent executable
1535 ; This comment is to ensure we retain the blank line above.