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 Var(flag_conserve_stack) Optimization
385 Do not perform optimizations increasing noticeably stack usage
388 Common JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
389 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump
391 fcompare-debug-second
392 Common RejectNegative Var(flag_compare_debug)
393 Run only the second compilation of -fcompare-debug
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
474 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
475 Enable CFI tables via GAS assembler directives.
477 fdump-unnumbered-links
478 Common Report Var(flag_dump_unnumbered_links) VarExists
479 Suppress output of previous and next insn numbers in debugging dumps
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
489 feliminate-unused-debug-symbols
490 Common Report Var(flag_debug_only_used_symbols)
491 Perform unused type elimination in debug info
493 feliminate-unused-debug-types
494 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
495 Perform unused type elimination in debug info
497 femit-class-debug-always
498 Common Report Var(flag_emit_class_debug_always) Init(0)
499 Do not suppress C++ class debug information.
502 Common Report Var(flag_exceptions) Optimization
503 Enable exception handling
505 fexpensive-optimizations
506 Common Report Var(flag_expensive_optimizations) Optimization
507 Perform a number of minor, expensive optimizations
510 Common Joined RejectNegative
511 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision
517 Common Report Var(flag_finite_math_only) Optimization
518 Assume no NaNs or infinities are generated
521 Common Joined RejectNegative
522 -ffixed-<register> Mark <register> as being unavailable to the compiler
525 Common Report Var(flag_float_store) Optimization
526 Don't allocate floats and doubles in extended-precision registers
530 Does nothing. Preserved for backward compatibility.
533 Common Report Var(flag_forward_propagate) Optimization
534 Perform a forward propagation pass on RTL
536 ; Nonzero means don't put addresses of constant functions in registers.
537 ; Used for compiling the Unix kernel, where strange substitutions are
538 ; done on the assembly output.
540 Common Report Var(flag_no_function_cse,0)
541 Allow function addresses to be held in registers
544 Common Report Var(flag_function_sections)
545 Place each function into its own section
548 Common Report Var(flag_gcse) Optimization
549 Perform global common subexpression elimination
552 Common Report Var(flag_gcse_lm) Init(1) Optimization
553 Perform enhanced load motion during global common subexpression elimination
556 Common Report Var(flag_gcse_sm) Init(0) Optimization
557 Perform store motion after global common subexpression elimination
560 Common Report Var(flag_gcse_las) Init(0) Optimization
561 Perform redundant load after store elimination in global common subexpression
565 Common Report Var(flag_gcse_after_reload) Optimization
566 Perform global common subexpression elimination after register allocation
569 ; This option is not documented yet as its semantics will change.
571 Common Report Var(flag_graphite)
572 Enable in and out of Graphite representation
575 Common Report Var(flag_graphite_identity) Optimization
576 Enable Graphite Identity transformation
578 floop-parallelize-all
579 Common Report Var(flag_loop_parallelize_all) Optimization
580 Mark all loops as parallel
583 Common Report Var(flag_loop_strip_mine) Optimization
584 Enable Loop Strip Mining transformation
587 Common Report Var(flag_loop_interchange) Optimization
588 Enable Loop Interchange transformation
591 Common Report Var(flag_loop_block) Optimization
592 Enable Loop Blocking transformation
594 fguess-branch-probability
595 Common Report Var(flag_guess_branch_prob) Optimization
596 Enable guessing of branch probabilities
598 ; Nonzero means ignore `#ident' directives. 0 means handle them.
599 ; Generate position-independent code for executables if possible
600 ; On SVR4 targets, it also controls whether or not to emit a
601 ; string identifying the compiler.
603 Common Report Var(flag_no_ident,0)
604 Process #ident directives
607 Common Report Var(flag_if_conversion) Optimization
608 Perform conversion of conditional jumps to branchless equivalents
611 Common Report Var(flag_if_conversion2) Optimization
612 Perform conversion of conditional jumps to conditional execution
614 ; -finhibit-size-directive inhibits output of .size for ELF.
615 ; This is used only for compiling crtstuff.c,
616 ; and it may be extended to other effects
617 ; needed for crtstuff.c on other systems.
618 finhibit-size-directive
619 Common Report Var(flag_inhibit_size_directive)
620 Do not generate .size directives
623 Common Report Var(flag_indirect_inlining)
624 Perform indirect inlining
626 ; Nonzero means that functions declared `inline' will be treated
627 ; as `static'. Prevents generation of zillions of copies of unused
628 ; static inline functions; instead, `inlines' are written out
629 ; only when actually used. Used in conjunction with -g. Also
630 ; does the right thing with #pragma interface.
632 Common Report Var(flag_no_inline,0) Init(0)
633 Pay attention to the \"inline\" keyword
635 finline-small-functions
636 Common Report Var(flag_inline_small_functions) Optimization
637 Integrate simple functions into their callers when code size is known to not growth
640 Common Report Var(flag_inline_functions) Optimization
641 Integrate simple functions into their callers
643 finline-functions-called-once
644 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
645 Integrate functions called once into their callers
648 Common RejectNegative Joined UInteger
651 Common RejectNegative Joined UInteger
652 -finline-limit=<number> Limit the size of inlined functions to <number>
654 finstrument-functions
655 Common Report Var(flag_instrument_function_entry_exit)
656 Instrument function entry and exit with profiling calls
658 finstrument-functions-exclude-function-list=
659 Common RejectNegative Joined
660 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
662 finstrument-functions-exclude-file-list=
663 Common RejectNegative Joined
664 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
667 Common Report Var(flag_ipa_cp) Optimization
668 Perform Interprocedural constant propagation
671 Common Report Var(flag_ipa_cp_clone) Optimization
672 Perform cloning to make Interprocedural constant propagation stronger
675 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
676 Discover pure and const functions
679 Common Report Var(flag_ipa_pta) Init(0) Optimization
680 Perform interprocedural points-to analysis
683 Common Report Var(flag_ipa_reference) Init(0) Optimization
684 Discover readonly and non addressable static variables
687 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
688 Type based escape and alias analysis
691 Common Report Var(flag_ipa_matrix_reorg) Optimization
692 Perform matrix layout flattening and transposing based
693 on profiling information.
696 Common Report Var(flag_ipa_struct_reorg)
697 Perform structure layout optimizations based
698 on profiling information.
701 Common Joined RejectNegative
702 -fira-algorithm=[CB|priority] Set the used IRA algorithm
705 Common Joined RejectNegative
706 -fira-region=[one|all|mixed] Set regions for IRA
709 Common Report Var(flag_ira_coalesce) Init(0)
710 Do optimistic coalescing.
712 fira-share-save-slots
713 Common Report Var(flag_ira_share_save_slots) Init(1)
714 Share slots for saving different hard registers.
716 fira-share-spill-slots
717 Common Report Var(flag_ira_share_spill_slots) Init(1)
718 Share stack slots for spilled pseudo-registers.
721 Common RejectNegative Joined UInteger
722 -fira-verbose=<number> Control IRA's level of diagnostic messages.
725 Common Report Var(flag_ivopts) Init(1) Optimization
726 Optimize induction variables on trees
729 Common Var(flag_jump_tables) Init(1) Optimization
730 Use jump tables for sufficiently large switch statements
732 fkeep-inline-functions
733 Common Report Var(flag_keep_inline_functions)
734 Generate code for functions even if they are fully inlined
737 Common Report Var(flag_keep_static_consts) Init(1)
738 Emit static const variables even if they are not used
741 Common Report Var(flag_leading_underscore) Init(-1)
742 Give external symbols a leading underscore
746 Does nothing. Preserved for backward compatibility.
749 Common Report Var(flag_errno_math) Init(1) Optimization
750 Set errno after built-in math functions
753 Common Report Var(mem_report)
754 Report on permanent memory allocation
756 ; This will attempt to merge constant section constants, if 1 only
757 ; string constants and constants from constant pool, if 2 also constant
760 Common Report Var(flag_merge_constants,2) Init(1) Optimization
761 Attempt to merge identical constants and constant variables
764 Common Report Var(flag_merge_constants,1) VarExists Optimization
765 Attempt to merge identical constants across compilation units
768 Common Report Var(flag_merge_debug_strings) Init(1)
769 Attempt to merge identical debug strings across compilation units
772 Common RejectNegative Joined UInteger
773 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
776 Common Report Var(flag_modulo_sched) Optimization
777 Perform SMS based modulo scheduling before the first scheduling pass
779 fmodulo-sched-allow-regmoves
780 Common Report Var(flag_modulo_sched_allow_regmoves)
781 Perform SMS based modulo scheduling with register moves allowed
783 fmove-loop-invariants
784 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
785 Move loop invariant computations out of loops
788 Common RejectNegative Report Var(flag_mudflap)
789 Add mudflap bounds-checking instrumentation for single-threaded program
792 Common RejectNegative Report VarExists Var(flag_mudflap,2)
793 Add mudflap bounds-checking instrumentation for multi-threaded program
796 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
797 Ignore read operations when inserting mudflap instrumentation
800 Common Var(flag_dce) Init(1) Optimization
801 Use the RTL dead code elimination pass
804 Common Var(flag_dse) Init(1) Optimization
805 Use the RTL dead store elimination pass
807 freschedule-modulo-scheduled-loops
808 Common Report Var(flag_resched_modulo_sched) Optimization
809 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
812 Common Report Var(flag_non_call_exceptions) Optimization
813 Support synchronous non-call exceptions
816 Common Report Var(flag_omit_frame_pointer) Optimization
817 When possible do not generate stack frames
819 foptimize-register-move
820 Common Report Var(flag_regmove) Optimization
821 Do the full register move optimization pass
823 foptimize-sibling-calls
824 Common Report Var(flag_optimize_sibling_calls) Optimization
825 Optimize sibling and tail recursive calls
828 Common Report Var(pre_ipa_mem_report)
829 Report on memory allocation before interprocedural optimization
832 Common Report Var(post_ipa_mem_report)
833 Report on memory allocation before interprocedural optimization
836 Common Report Var(flag_pack_struct) Optimization
837 Pack structure members together without holes
840 Common RejectNegative Joined UInteger Optimization
841 -fpack-struct=<number> Set initial maximum structure member alignment
844 Common Report Var(flag_pcc_struct_return,1) VarExists
845 Return small aggregates in memory, not registers
848 Common Report Var(flag_peel_loops) Optimization
852 Common Report Var(flag_no_peephole,0) Optimization
853 Enable machine specific peephole optimizations
856 Common Report Var(flag_peephole2) Optimization
857 Enable an RTL peephole pass before sched2
860 Common Report Var(flag_pic,2)
861 Generate position-independent code if possible (large mode)
864 Common Report Var(flag_pie,2)
865 Generate position-independent code for executables if possible (large mode)
868 Common Report Var(flag_pic,1) VarExists
869 Generate position-independent code if possible (small mode)
872 Common Report Var(flag_pie,1) VarExists
873 Generate position-independent code for executables if possible (small mode)
876 Common Joined RejectNegative
877 Specify a plugin to load
880 Common Joined RejectNegative
881 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
883 fpredictive-commoning
884 Common Report Var(flag_predictive_commoning) Optimization
885 Run predictive commoning optimization.
887 fprefetch-loop-arrays
888 Common Report Var(flag_prefetch_loop_arrays) Optimization
889 Generate prefetch instructions, if available, for arrays in loops
892 Common Report Var(profile_flag)
893 Enable basic program profiling code
896 Common Report Var(profile_arc_flag)
897 Insert arc-based program profiling code
900 Common Joined RejectNegative
901 Set the top-level directory for storing the profile data.
902 The default is 'pwd'.
905 Common Report Var(flag_profile_correction)
906 Enable correction of flow inconsistent profile data input
910 Enable common options for generating profile info for profile feedback directed optimizations
913 Common Joined RejectNegative
914 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
917 Common Var(flag_profile_use)
918 Enable common options for performing profile feedback directed optimizations
921 Common Joined RejectNegative
922 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
925 Common Report Var(flag_profile_values)
926 Insert code to profile values of expressions
932 Common Joined RejectNegative
933 -frandom-seed=<string> Make compile reproducible using <string>
935 ; This switch causes the command line that was used to create an
936 ; object file to be recorded into the object file. The exact format
937 ; of this recording is target and binary file format dependent.
938 ; It is related to the -fverbose-asm switch, but that switch only
939 ; records information in the assembler output file as comments, so
940 ; they never reach the object file.
942 Common Report Var(flag_record_gcc_switches)
943 Record gcc command line switches in the object file.
946 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
947 Return small aggregates in registers
950 Common Report Var(flag_regmove) Optimization
951 Enables a register move optimization
954 Common Report Var(flag_rename_registers) Init(2) Optimization
955 Perform a register renaming optimization pass
958 Common Report Var(flag_reorder_blocks) Optimization
959 Reorder basic blocks to improve code placement
961 freorder-blocks-and-partition
962 Common Report Var(flag_reorder_blocks_and_partition) Optimization
963 Reorder basic blocks and partition into hot and cold sections
966 Common Report Var(flag_reorder_functions) Optimization
967 Reorder functions to improve code placement
969 frerun-cse-after-loop
970 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
971 Add a common subexpression elimination pass after loop optimizations
975 Does nothing. Preserved for backward compatibility.
978 Common Report Var(flag_rounding_math) Optimization
979 Disable optimizations that assume default FP rounding behavior
982 Common Report Var(flag_schedule_interblock) Init(1) Optimization
983 Enable scheduling across basic blocks
986 Common Report Var(flag_schedule_speculative) Init(1) Optimization
987 Allow speculative motion of non-loads
990 Common Report Var(flag_schedule_speculative_load) Optimization
991 Allow speculative motion of some loads
993 fsched-spec-load-dangerous
994 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
995 Allow speculative motion of more loads
998 Common RejectNegative Joined
999 -fsched-verbose=<number> Set the verbosity level of the scheduler
1001 fsched2-use-superblocks
1002 Common Report Var(flag_sched2_use_superblocks) Optimization
1003 If scheduling post reload, do superblock scheduling
1006 Common Report Var(flag_sched2_use_traces) Optimization
1007 If scheduling post reload, do trace scheduling
1010 Common Report Var(flag_schedule_insns) Optimization
1011 Reschedule instructions before register allocation
1014 Common Report Var(flag_schedule_insns_after_reload) Optimization
1015 Reschedule instructions after register allocation
1017 ; This flag should be on when a target implements non-trivial
1018 ; scheduling hooks, maybe saving some information for its own sake.
1019 ; On IA64, for example, this is used for correct bundling.
1020 fselective-scheduling
1021 Common Report Var(flag_selective_scheduling) Optimization
1022 Schedule instructions using selective scheduling algorithm
1024 fselective-scheduling2
1025 Common Report Var(flag_selective_scheduling2) Optimization
1026 Run selective scheduling after reload
1028 fsel-sched-pipelining
1029 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1030 Perform software pipelining of inner loops during selective scheduling
1032 fsel-sched-pipelining-outer-loops
1033 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1034 Perform software pipelining of outer loops during selective scheduling
1036 fsel-sched-reschedule-pipelined
1037 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1038 Reschedule pipelined regions without pipelining
1040 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1041 ; of stalled insns into the ready list.
1042 fsched-stalled-insns
1043 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1044 Allow premature scheduling of queued insns
1046 fsched-stalled-insns=
1047 Common RejectNegative Joined UInteger
1048 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1050 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1051 ; be examined for a dependency on a stalled insn that is candidate for
1052 ; premature removal from the queue of stalled insns into the ready list (has
1053 ; an effect only if the flag 'sched_stalled_insns' is set).
1054 fsched-stalled-insns-dep
1055 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1056 Set dependence distance checking in premature scheduling of queued insns
1058 fsched-stalled-insns-dep=
1059 Common RejectNegative Joined UInteger
1060 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1062 fsched-group-heuristic
1063 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
1064 Enable the group heuristic in the scheduler
1066 fsched-critical-path-heuristic
1067 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
1068 Enable the critical path heuristic in the scheduler
1070 fsched-spec-insn-heuristic
1071 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
1072 Enable the speculative instruction heuristic in the scheduler
1074 fsched-reg-pressure-heuristic
1075 Common Report Var(flag_sched_reg_pressure_heuristic) Init(1) Optimization
1076 Enable the register pressure heuristic in the scheduler
1078 fsched-rank-heuristic
1079 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
1080 Enable the rank heuristic in the scheduler
1082 fsched-last-insn-heuristic
1083 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
1084 Enable the last instruction heuristic in the scheduler
1086 fsched-dep-count-heuristic
1087 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
1088 Enable the dependent count heuristic in the scheduler
1091 Common Report Var(flag_section_anchors) Optimization
1092 Access data in the same section from shared anchor points
1096 Does nothing. Preserved for backward compatibility.
1099 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
1100 Show column numbers in diagnostics, when available. Default on
1103 Common Report Var(flag_signaling_nans) Optimization
1104 Disable optimizations observable by IEEE signaling NaNs
1107 Common Report Var(flag_signed_zeros) Init(1) Optimization
1108 Disable floating point optimizations that ignore the IEEE signedness of zero
1110 fsingle-precision-constant
1111 Common Report Var(flag_single_precision_constant) Optimization
1112 Convert floating point constants to single precision constants
1114 fsplit-ivs-in-unroller
1115 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1116 Split lifetimes of induction variables when loops are unrolled
1119 Common Report Var(flag_split_wide_types) Optimization
1120 Split wide types into independent registers
1122 fvariable-expansion-in-unroller
1123 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1124 Apply variable expansion when loops are unrolled
1127 Common Report RejectNegative Joined
1128 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1132 Insert stack checking code into the program. Same as -fstack-check=specific
1137 fstack-limit-register=
1138 Common RejectNegative Joined
1139 -fstack-limit-register=<register> Trap if the stack goes past <register>
1141 fstack-limit-symbol=
1142 Common RejectNegative Joined
1143 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1146 Common Report Var(flag_stack_protect, 1)
1147 Use propolice as a stack protection method
1149 fstack-protector-all
1150 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1151 Use a stack protection method for every function
1155 Does nothing. Preserved for backward compatibility.
1157 ; Nonzero if we should do (language-dependent) alias analysis.
1158 ; Typically, this analysis will assume that expressions of certain
1159 ; types do not alias expressions of certain other types. Only used
1160 ; if alias analysis (in general) is enabled.
1162 Common Report Var(flag_strict_aliasing) Optimization
1163 Assume strict aliasing rules apply
1166 Common Report Var(flag_strict_overflow)
1167 Treat signed overflow as undefined
1170 Common Report Var(flag_syntax_only)
1171 Check for syntax errors, then stop
1174 Common Report Var(flag_test_coverage)
1175 Create data files needed by \"gcov\"
1178 Common Report Var(flag_thread_jumps) Optimization
1179 Perform jump threading optimizations
1182 Common Report Var(time_report)
1183 Report the time taken by each compiler pass
1186 Common Joined RejectNegative
1187 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1190 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1191 Reorder top level functions, variables, and asms
1194 Common Report Var(flag_tracer)
1195 Perform superblock formation via tail duplication
1197 ; Zero means that floating-point math operations cannot generate a
1198 ; (user-visible) trap. This is the case, for example, in nonstop
1199 ; IEEE 754 arithmetic.
1201 Common Report Var(flag_trapping_math) Init(1) Optimization
1202 Assume floating-point operations can trap
1205 Common Report Var(flag_trapv) Optimization
1206 Trap for signed overflow in addition, subtraction and multiplication
1209 Common Report Var(flag_tree_ccp) Optimization
1210 Enable SSA-CCP optimization on trees
1214 Does nothing. Preserved for backward compatibility.
1217 Common Report Var(flag_tree_ch) Optimization
1218 Enable loop header copying on trees
1221 Common Report Var(flag_tree_copyrename) Optimization
1222 Replace SSA temporaries with better names in copies
1225 Common Report Var(flag_tree_copy_prop) Optimization
1226 Enable copy propagation on trees
1228 ftree-store-copy-prop
1230 Does nothing. Preserved for backward compatibility.
1233 Common Report Var(flag_tree_cselim) Init(2) Optimization
1234 Transform condition stores into unconditional ones
1236 ftree-switch-conversion
1237 Common Report Var(flag_tree_switch_conversion) Optimization
1238 Perform conversions of switch initializations.
1241 Common Report Var(flag_tree_dce) Optimization
1242 Enable SSA dead code elimination optimization on trees
1244 ftree-dominator-opts
1245 Common Report Var(flag_tree_dom) Optimization
1246 Enable dominator optimizations
1249 Common Report Var(flag_tree_dse) Optimization
1250 Enable dead store elimination
1253 Common Report Var(flag_tree_forwprop) Init(1) Optimization
1254 Enable forward propagation on trees
1257 Common Report Var(flag_tree_fre) Optimization
1258 Enable Full Redundancy Elimination (FRE) on trees
1260 ftree-loop-distribution
1261 Common Report Var(flag_tree_loop_distribution) Optimization
1262 Enable loop distribution on trees
1265 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1266 Enable loop invariant motion on trees
1269 Common Report Var(flag_tree_loop_linear) Optimization
1270 Enable linear loop transforms on trees
1273 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1274 Create canonical induction variables in loops
1277 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1278 Enable loop optimizations on tree level
1280 ftree-parallelize-loops=
1281 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1282 Enable automatic parallelization of loops
1285 Common Report Var(flag_tree_phiprop) Init(1) Optimization
1286 Enable hoisting loads from conditional pointers.
1289 Common Report Var(flag_tree_pre) Optimization
1290 Enable SSA-PRE optimization on trees
1293 Common Report Var(flag_tree_pta) Init(1) Optimization
1294 Perform function-local points-to analysis on trees.
1297 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1298 Enable reassociation on tree level
1302 Does nothing. Preserved for backward compatibility.
1305 Common Report Var(flag_tree_sink) Optimization
1306 Enable SSA code sinking on trees
1309 Common Report Var(flag_tree_sra) Optimization
1310 Perform scalar replacement of aggregates
1313 Common Report Var(flag_tree_ter) Init(1) Optimization
1314 Replace temporary expressions in the SSA->normal pass
1317 Common Report Var(flag_tree_live_range_split) Optimization
1318 Perform live range splitting during the SSA->normal pass
1321 Common Report Var(flag_tree_vrp) Init(0) Optimization
1322 Perform Value Range Propagation on trees
1325 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1326 Compile whole compilation unit at a time
1329 Common Report Var(flag_unroll_loops) Optimization
1330 Perform loop unrolling when iteration count is known
1333 Common Report Var(flag_unroll_all_loops) Optimization
1334 Perform loop unrolling for all loops
1336 ; Nonzero means that loop optimizer may assume that the induction variables
1337 ; that control loops do not overflow and that the loops with nontrivial
1338 ; exit condition are not infinite
1339 funsafe-loop-optimizations
1340 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1341 Allow loop optimizations to assume that the loops behave in normal way
1344 Common Report Var(flag_associative_math)
1345 Allow optimization for floating-point arithmetic which may change the
1346 result of the operation due to rounding.
1349 Common Report Var(flag_reciprocal_math)
1350 Same as -fassociative-math for expressions which include division.
1352 ; Nonzero means that unsafe floating-point math optimizations are allowed
1353 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1354 ; are allowed to assume that their arguments and results are "normal"
1355 ; (e.g., nonnegative for SQRT).
1356 funsafe-math-optimizations
1357 Common Report Var(flag_unsafe_math_optimizations) Optimization
1358 Allow math optimizations that may violate IEEE or ISO standards
1361 Common Report Var(flag_unswitch_loops) Optimization
1362 Perform loop unswitching
1365 Common Report Var(flag_unwind_tables) Optimization
1366 Just generate unwind tables for exception handling
1369 Common Report Var(flag_var_tracking) VarExists Optimization
1370 Perform variable tracking
1372 fvar-tracking-uninit
1373 Common Report Var(flag_var_tracking_uninit) Optimization
1374 Perform variable tracking and also tag variables that are uninitialized
1377 Common Report Var(flag_tree_vectorize) Optimization
1378 Enable loop vectorization on trees
1381 Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
1382 Enable basic block vectorization (SLP) on trees
1385 Common Report Var(flag_vect_cost_model) Optimization
1386 Enable use of cost model in vectorization
1388 ftree-vect-loop-version
1389 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1390 Enable loop versioning when doing loop vectorization on trees
1392 ftree-vectorizer-verbose=
1393 Common RejectNegative Joined
1394 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1397 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1398 Enable copy propagation of scalar-evolution information.
1400 ; -fverbose-asm causes extra commentary information to be produced in
1401 ; the generated assembly code (to make it more readable). This option
1402 ; is generally only of use to those who actually need to read the
1403 ; generated assembly code (perhaps while debugging the compiler itself).
1404 ; -fno-verbose-asm, the default, causes the extra information
1405 ; to not be added and is useful when comparing two assembler files.
1407 Common Report Var(flag_verbose_asm)
1408 Add extra commentary to assembler output
1411 Common Joined RejectNegative
1412 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1416 Common Report Var(flag_value_profile_transformations) Optimization
1417 Use expression value profiles in optimizations
1420 Common Report Var(flag_web) Init(2) Optimization
1421 Construct webs and split unrelated uses of single variable
1423 ftree-builtin-call-dce
1424 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1425 Enable conditional dead code elimination for builtin calls
1428 Common Report Var(flag_whole_program) Init(0) Optimization
1429 Perform whole program optimizations
1432 Common Report Var(flag_wrapv) Optimization
1433 Assume signed arithmetic overflow wraps around
1435 fzero-initialized-in-bss
1436 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1437 Put zero initialized data in the bss section
1440 Common JoinedOrMissing
1441 Generate debug information in default format
1444 Common JoinedOrMissing Negative(gdwarf-)
1445 Generate debug information in COFF format
1448 Common Joined UInteger Var(dwarf_version) Init(2) Negative(gstabs)
1449 Generate debug information in DWARF v2 (or later) format
1452 Common JoinedOrMissing
1453 Generate debug information in default extended format
1456 Common JoinedOrMissing Negative(gstabs+)
1457 Generate debug information in STABS format
1460 Common JoinedOrMissing Negative(gvms)
1461 Generate debug information in extended STABS format
1464 Common Report Var(flag_gtoggle)
1465 Toggle debug information generation
1468 Common JoinedOrMissing Negative(gxcoff)
1469 Generate debug information in VMS format
1472 Common JoinedOrMissing Negative(gxcoff+)
1473 Generate debug information in XCOFF format
1476 Common JoinedOrMissing Negative(gcoff)
1477 Generate debug information in extended XCOFF format
1480 Common Joined Separate
1481 -o <file> Place output into <file>
1484 Common Var(profile_flag)
1485 Enable function profiling
1488 Common Var(pedantic)
1489 Issue warnings needed for strict compliance to the standard
1493 Like -pedantic but issue them as errors
1496 Common Var(quiet_flag)
1497 Do not display functions compiled or elapsed time
1500 Common Var(version_flag)
1501 Display the compiler's version
1504 Common Var(inhibit_warnings)
1508 Common RejectNegative Negative(pie)
1509 Create a shared library
1512 Common RejectNegative Negative(shared)
1513 Create a position independent executable
1515 ; This comment is to ensure we retain the blank line above.