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
574 ; This option is not documented as it does not perform any useful optimization.
576 Common Report Var(flag_graphite_identity) Optimization
577 Enable Graphite Identity transformation
579 ; This option is not documented as it will be removed
580 floop-parallelize-all
581 Common Report Var(flag_loop_parallelize_all) Optimization
582 Mark all loops as parallel
585 Common Report Var(flag_loop_strip_mine) Optimization
586 Enable Loop Strip Mining transformation
589 Common Report Var(flag_loop_interchange) Optimization
590 Enable Loop Interchange transformation
593 Common Report Var(flag_loop_block) Optimization
594 Enable Loop Blocking transformation
596 fguess-branch-probability
597 Common Report Var(flag_guess_branch_prob) Optimization
598 Enable guessing of branch probabilities
600 ; Nonzero means ignore `#ident' directives. 0 means handle them.
601 ; Generate position-independent code for executables if possible
602 ; On SVR4 targets, it also controls whether or not to emit a
603 ; string identifying the compiler.
605 Common Report Var(flag_no_ident,0)
606 Process #ident directives
609 Common Report Var(flag_if_conversion) Optimization
610 Perform conversion of conditional jumps to branchless equivalents
613 Common Report Var(flag_if_conversion2) Optimization
614 Perform conversion of conditional jumps to conditional execution
616 ; -finhibit-size-directive inhibits output of .size for ELF.
617 ; This is used only for compiling crtstuff.c,
618 ; and it may be extended to other effects
619 ; needed for crtstuff.c on other systems.
620 finhibit-size-directive
621 Common Report Var(flag_inhibit_size_directive)
622 Do not generate .size directives
625 Common Report Var(flag_indirect_inlining)
626 Perform indirect inlining
628 ; Nonzero means that functions declared `inline' will be treated
629 ; as `static'. Prevents generation of zillions of copies of unused
630 ; static inline functions; instead, `inlines' are written out
631 ; only when actually used. Used in conjunction with -g. Also
632 ; does the right thing with #pragma interface.
634 Common Report Var(flag_no_inline,0) Init(0)
635 Pay attention to the \"inline\" keyword
637 finline-small-functions
638 Common Report Var(flag_inline_small_functions) Optimization
639 Integrate simple functions into their callers when code size is known to not growth
642 Common Report Var(flag_inline_functions) Optimization
643 Integrate simple functions into their callers
645 finline-functions-called-once
646 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
647 Integrate functions called once into their callers
650 Common RejectNegative Joined UInteger
653 Common RejectNegative Joined UInteger
654 -finline-limit=<number> Limit the size of inlined functions to <number>
656 finstrument-functions
657 Common Report Var(flag_instrument_function_entry_exit)
658 Instrument function entry and exit with profiling calls
660 finstrument-functions-exclude-function-list=
661 Common RejectNegative Joined
662 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
664 finstrument-functions-exclude-file-list=
665 Common RejectNegative Joined
666 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
669 Common Report Var(flag_ipa_cp) Optimization
670 Perform Interprocedural constant propagation
673 Common Report Var(flag_ipa_cp_clone) Optimization
674 Perform cloning to make Interprocedural constant propagation stronger
677 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
678 Discover pure and const functions
681 Common Report Var(flag_ipa_pta) Init(0) Optimization
682 Perform interprocedural points-to analysis
685 Common Report Var(flag_ipa_reference) Init(0) Optimization
686 Discover readonly and non addressable static variables
689 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
690 Type based escape and alias analysis
693 Common Report Var(flag_ipa_matrix_reorg) Optimization
694 Perform matrix layout flattening and transposing based
695 on profiling information.
698 Common Report Var(flag_ipa_struct_reorg)
699 Perform structure layout optimizations based
700 on profiling information.
703 Common Joined RejectNegative
704 -fira-algorithm=[CB|priority] Set the used IRA algorithm
707 Common Joined RejectNegative
708 -fira-region=[one|all|mixed] Set regions for IRA
711 Common Report Var(flag_ira_coalesce) Init(0)
712 Do optimistic coalescing.
714 fira-share-save-slots
715 Common Report Var(flag_ira_share_save_slots) Init(1)
716 Share slots for saving different hard registers.
718 fira-share-spill-slots
719 Common Report Var(flag_ira_share_spill_slots) Init(1)
720 Share stack slots for spilled pseudo-registers.
723 Common RejectNegative Joined UInteger
724 -fira-verbose=<number> Control IRA's level of diagnostic messages.
727 Common Report Var(flag_ivopts) Init(1) Optimization
728 Optimize induction variables on trees
731 Common Var(flag_jump_tables) Init(1) Optimization
732 Use jump tables for sufficiently large switch statements
734 fkeep-inline-functions
735 Common Report Var(flag_keep_inline_functions)
736 Generate code for functions even if they are fully inlined
739 Common Report Var(flag_keep_static_consts) Init(1)
740 Emit static const variables even if they are not used
743 Common Report Var(flag_leading_underscore) Init(-1)
744 Give external symbols a leading underscore
748 Does nothing. Preserved for backward compatibility.
751 Common Report Var(flag_errno_math) Init(1) Optimization
752 Set errno after built-in math functions
755 Common Report Var(mem_report)
756 Report on permanent memory allocation
758 ; This will attempt to merge constant section constants, if 1 only
759 ; string constants and constants from constant pool, if 2 also constant
762 Common Report Var(flag_merge_constants,2) Init(1) Optimization
763 Attempt to merge identical constants and constant variables
766 Common Report Var(flag_merge_constants,1) VarExists Optimization
767 Attempt to merge identical constants across compilation units
770 Common Report Var(flag_merge_debug_strings) Init(1)
771 Attempt to merge identical debug strings across compilation units
774 Common RejectNegative Joined UInteger
775 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
778 Common Report Var(flag_modulo_sched) Optimization
779 Perform SMS based modulo scheduling before the first scheduling pass
781 fmodulo-sched-allow-regmoves
782 Common Report Var(flag_modulo_sched_allow_regmoves)
783 Perform SMS based modulo scheduling with register moves allowed
785 fmove-loop-invariants
786 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
787 Move loop invariant computations out of loops
790 Common RejectNegative Report Var(flag_mudflap)
791 Add mudflap bounds-checking instrumentation for single-threaded program
794 Common RejectNegative Report VarExists Var(flag_mudflap,2)
795 Add mudflap bounds-checking instrumentation for multi-threaded program
798 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
799 Ignore read operations when inserting mudflap instrumentation
802 Common Var(flag_dce) Init(1) Optimization
803 Use the RTL dead code elimination pass
806 Common Var(flag_dse) Init(1) Optimization
807 Use the RTL dead store elimination pass
809 freschedule-modulo-scheduled-loops
810 Common Report Var(flag_resched_modulo_sched) Optimization
811 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
814 Common Report Var(flag_non_call_exceptions) Optimization
815 Support synchronous non-call exceptions
818 Common Report Var(flag_omit_frame_pointer) Optimization
819 When possible do not generate stack frames
821 foptimize-register-move
822 Common Report Var(flag_regmove) Optimization
823 Do the full register move optimization pass
825 foptimize-sibling-calls
826 Common Report Var(flag_optimize_sibling_calls) Optimization
827 Optimize sibling and tail recursive calls
830 Common Report Var(pre_ipa_mem_report)
831 Report on memory allocation before interprocedural optimization
834 Common Report Var(post_ipa_mem_report)
835 Report on memory allocation before interprocedural optimization
838 Common Report Var(flag_pack_struct) Optimization
839 Pack structure members together without holes
842 Common RejectNegative Joined UInteger Optimization
843 -fpack-struct=<number> Set initial maximum structure member alignment
846 Common Report Var(flag_pcc_struct_return,1) VarExists
847 Return small aggregates in memory, not registers
850 Common Report Var(flag_peel_loops) Optimization
854 Common Report Var(flag_no_peephole,0) Optimization
855 Enable machine specific peephole optimizations
858 Common Report Var(flag_peephole2) Optimization
859 Enable an RTL peephole pass before sched2
862 Common Report Var(flag_pic,2)
863 Generate position-independent code if possible (large mode)
866 Common Report Var(flag_pie,2)
867 Generate position-independent code for executables if possible (large mode)
870 Common Report Var(flag_pic,1) VarExists
871 Generate position-independent code if possible (small mode)
874 Common Report Var(flag_pie,1) VarExists
875 Generate position-independent code for executables if possible (small mode)
878 Common Joined RejectNegative
879 Specify a plugin to load
882 Common Joined RejectNegative
883 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
885 fpredictive-commoning
886 Common Report Var(flag_predictive_commoning) Optimization
887 Run predictive commoning optimization.
889 fprefetch-loop-arrays
890 Common Report Var(flag_prefetch_loop_arrays) Optimization
891 Generate prefetch instructions, if available, for arrays in loops
894 Common Report Var(profile_flag)
895 Enable basic program profiling code
898 Common Report Var(profile_arc_flag)
899 Insert arc-based program profiling code
902 Common Joined RejectNegative
903 Set the top-level directory for storing the profile data.
904 The default is 'pwd'.
907 Common Report Var(flag_profile_correction)
908 Enable correction of flow inconsistent profile data input
912 Enable common options for generating profile info for profile feedback directed optimizations
915 Common Joined RejectNegative
916 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
919 Common Var(flag_profile_use)
920 Enable common options for performing profile feedback directed optimizations
923 Common Joined RejectNegative
924 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
927 Common Report Var(flag_profile_values)
928 Insert code to profile values of expressions
934 Common Joined RejectNegative
935 -frandom-seed=<string> Make compile reproducible using <string>
937 ; This switch causes the command line that was used to create an
938 ; object file to be recorded into the object file. The exact format
939 ; of this recording is target and binary file format dependent.
940 ; It is related to the -fverbose-asm switch, but that switch only
941 ; records information in the assembler output file as comments, so
942 ; they never reach the object file.
944 Common Report Var(flag_record_gcc_switches)
945 Record gcc command line switches in the object file.
948 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
949 Return small aggregates in registers
952 Common Report Var(flag_regmove) Optimization
953 Enables a register move optimization
956 Common Report Var(flag_rename_registers) Init(2) Optimization
957 Perform a register renaming optimization pass
960 Common Report Var(flag_reorder_blocks) Optimization
961 Reorder basic blocks to improve code placement
963 freorder-blocks-and-partition
964 Common Report Var(flag_reorder_blocks_and_partition) Optimization
965 Reorder basic blocks and partition into hot and cold sections
968 Common Report Var(flag_reorder_functions) Optimization
969 Reorder functions to improve code placement
971 frerun-cse-after-loop
972 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
973 Add a common subexpression elimination pass after loop optimizations
977 Does nothing. Preserved for backward compatibility.
980 Common Report Var(flag_rounding_math) Optimization
981 Disable optimizations that assume default FP rounding behavior
984 Common Report Var(flag_schedule_interblock) Init(1) Optimization
985 Enable scheduling across basic blocks
988 Common Report Var(flag_schedule_speculative) Init(1) Optimization
989 Allow speculative motion of non-loads
992 Common Report Var(flag_schedule_speculative_load) Optimization
993 Allow speculative motion of some loads
995 fsched-spec-load-dangerous
996 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
997 Allow speculative motion of more loads
1000 Common RejectNegative Joined
1001 -fsched-verbose=<number> Set the verbosity level of the scheduler
1003 fsched2-use-superblocks
1004 Common Report Var(flag_sched2_use_superblocks) Optimization
1005 If scheduling post reload, do superblock scheduling
1008 Common Report Var(flag_sched2_use_traces) Optimization
1009 If scheduling post reload, do trace scheduling
1012 Common Report Var(flag_schedule_insns) Optimization
1013 Reschedule instructions before register allocation
1016 Common Report Var(flag_schedule_insns_after_reload) Optimization
1017 Reschedule instructions after register allocation
1019 ; This flag should be on when a target implements non-trivial
1020 ; scheduling hooks, maybe saving some information for its own sake.
1021 ; On IA64, for example, this is used for correct bundling.
1022 fselective-scheduling
1023 Common Report Var(flag_selective_scheduling) Optimization
1024 Schedule instructions using selective scheduling algorithm
1026 fselective-scheduling2
1027 Common Report Var(flag_selective_scheduling2) Optimization
1028 Run selective scheduling after reload
1030 fsel-sched-pipelining
1031 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1032 Perform software pipelining of inner loops during selective scheduling
1034 fsel-sched-pipelining-outer-loops
1035 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1036 Perform software pipelining of outer loops during selective scheduling
1038 fsel-sched-reschedule-pipelined
1039 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1040 Reschedule pipelined regions without pipelining
1042 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1043 ; of stalled insns into the ready list.
1044 fsched-stalled-insns
1045 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1046 Allow premature scheduling of queued insns
1048 fsched-stalled-insns=
1049 Common RejectNegative Joined UInteger
1050 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1052 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1053 ; be examined for a dependency on a stalled insn that is candidate for
1054 ; premature removal from the queue of stalled insns into the ready list (has
1055 ; an effect only if the flag 'sched_stalled_insns' is set).
1056 fsched-stalled-insns-dep
1057 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1058 Set dependence distance checking in premature scheduling of queued insns
1060 fsched-stalled-insns-dep=
1061 Common RejectNegative Joined UInteger
1062 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1064 fsched-group-heuristic
1065 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
1066 Enable the group heuristic in the scheduler
1068 fsched-critical-path-heuristic
1069 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
1070 Enable the critical path heuristic in the scheduler
1072 fsched-spec-insn-heuristic
1073 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
1074 Enable the speculative instruction heuristic in the scheduler
1076 fsched-reg-pressure-heuristic
1077 Common Report Var(flag_sched_reg_pressure_heuristic) Init(1) Optimization
1078 Enable the register pressure heuristic in the scheduler
1080 fsched-rank-heuristic
1081 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
1082 Enable the rank heuristic in the scheduler
1084 fsched-last-insn-heuristic
1085 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
1086 Enable the last instruction heuristic in the scheduler
1088 fsched-dep-count-heuristic
1089 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
1090 Enable the dependent count heuristic in the scheduler
1093 Common Report Var(flag_section_anchors) Optimization
1094 Access data in the same section from shared anchor points
1098 Does nothing. Preserved for backward compatibility.
1101 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
1102 Show column numbers in diagnostics, when available. Default on
1105 Common Report Var(flag_signaling_nans) Optimization
1106 Disable optimizations observable by IEEE signaling NaNs
1109 Common Report Var(flag_signed_zeros) Init(1) Optimization
1110 Disable floating point optimizations that ignore the IEEE signedness of zero
1112 fsingle-precision-constant
1113 Common Report Var(flag_single_precision_constant) Optimization
1114 Convert floating point constants to single precision constants
1116 fsplit-ivs-in-unroller
1117 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1118 Split lifetimes of induction variables when loops are unrolled
1121 Common Report Var(flag_split_wide_types) Optimization
1122 Split wide types into independent registers
1124 fvariable-expansion-in-unroller
1125 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1126 Apply variable expansion when loops are unrolled
1129 Common Report RejectNegative Joined
1130 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1134 Insert stack checking code into the program. Same as -fstack-check=specific
1139 fstack-limit-register=
1140 Common RejectNegative Joined
1141 -fstack-limit-register=<register> Trap if the stack goes past <register>
1143 fstack-limit-symbol=
1144 Common RejectNegative Joined
1145 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1148 Common Report Var(flag_stack_protect, 1)
1149 Use propolice as a stack protection method
1151 fstack-protector-all
1152 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1153 Use a stack protection method for every function
1157 Does nothing. Preserved for backward compatibility.
1159 ; Nonzero if we should do (language-dependent) alias analysis.
1160 ; Typically, this analysis will assume that expressions of certain
1161 ; types do not alias expressions of certain other types. Only used
1162 ; if alias analysis (in general) is enabled.
1164 Common Report Var(flag_strict_aliasing) Optimization
1165 Assume strict aliasing rules apply
1168 Common Report Var(flag_strict_overflow)
1169 Treat signed overflow as undefined
1172 Common Report Var(flag_syntax_only)
1173 Check for syntax errors, then stop
1176 Common Report Var(flag_test_coverage)
1177 Create data files needed by \"gcov\"
1180 Common Report Var(flag_thread_jumps) Optimization
1181 Perform jump threading optimizations
1184 Common Report Var(time_report)
1185 Report the time taken by each compiler pass
1188 Common Joined RejectNegative
1189 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1192 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1193 Reorder top level functions, variables, and asms
1196 Common Report Var(flag_tracer)
1197 Perform superblock formation via tail duplication
1199 ; Zero means that floating-point math operations cannot generate a
1200 ; (user-visible) trap. This is the case, for example, in nonstop
1201 ; IEEE 754 arithmetic.
1203 Common Report Var(flag_trapping_math) Init(1) Optimization
1204 Assume floating-point operations can trap
1207 Common Report Var(flag_trapv) Optimization
1208 Trap for signed overflow in addition, subtraction and multiplication
1211 Common Report Var(flag_tree_ccp) Optimization
1212 Enable SSA-CCP optimization on trees
1216 Does nothing. Preserved for backward compatibility.
1219 Common Report Var(flag_tree_ch) Optimization
1220 Enable loop header copying on trees
1223 Common Report Var(flag_tree_copyrename) Optimization
1224 Replace SSA temporaries with better names in copies
1227 Common Report Var(flag_tree_copy_prop) Optimization
1228 Enable copy propagation on trees
1230 ftree-store-copy-prop
1232 Does nothing. Preserved for backward compatibility.
1235 Common Report Var(flag_tree_cselim) Init(2) Optimization
1236 Transform condition stores into unconditional ones
1238 ftree-switch-conversion
1239 Common Report Var(flag_tree_switch_conversion) Optimization
1240 Perform conversions of switch initializations.
1243 Common Report Var(flag_tree_dce) Optimization
1244 Enable SSA dead code elimination optimization on trees
1246 ftree-dominator-opts
1247 Common Report Var(flag_tree_dom) Optimization
1248 Enable dominator optimizations
1251 Common Report Var(flag_tree_dse) Optimization
1252 Enable dead store elimination
1255 Common Report Var(flag_tree_forwprop) Init(1) Optimization
1256 Enable forward propagation on trees
1259 Common Report Var(flag_tree_fre) Optimization
1260 Enable Full Redundancy Elimination (FRE) on trees
1262 ftree-loop-distribution
1263 Common Report Var(flag_tree_loop_distribution) Optimization
1264 Enable loop distribution on trees
1267 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1268 Enable loop invariant motion on trees
1271 Common Report Var(flag_tree_loop_linear) Optimization
1272 Enable linear loop transforms on trees
1275 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1276 Create canonical induction variables in loops
1279 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1280 Enable loop optimizations on tree level
1282 ftree-parallelize-loops=
1283 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1284 Enable automatic parallelization of loops
1287 Common Report Var(flag_tree_phiprop) Init(1) Optimization
1288 Enable hoisting loads from conditional pointers.
1291 Common Report Var(flag_tree_pre) Optimization
1292 Enable SSA-PRE optimization on trees
1295 Common Report Var(flag_tree_pta) Init(1) Optimization
1296 Perform function-local points-to analysis on trees.
1299 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1300 Enable reassociation on tree level
1304 Does nothing. Preserved for backward compatibility.
1307 Common Report Var(flag_tree_sink) Optimization
1308 Enable SSA code sinking on trees
1311 Common Report Var(flag_tree_sra) Optimization
1312 Perform scalar replacement of aggregates
1315 Common Report Var(flag_tree_ter) Init(1) Optimization
1316 Replace temporary expressions in the SSA->normal pass
1319 Common Report Var(flag_tree_live_range_split) Optimization
1320 Perform live range splitting during the SSA->normal pass
1323 Common Report Var(flag_tree_vrp) Init(0) Optimization
1324 Perform Value Range Propagation on trees
1327 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1328 Compile whole compilation unit at a time
1331 Common Report Var(flag_unroll_loops) Optimization
1332 Perform loop unrolling when iteration count is known
1335 Common Report Var(flag_unroll_all_loops) Optimization
1336 Perform loop unrolling for all loops
1338 ; Nonzero means that loop optimizer may assume that the induction variables
1339 ; that control loops do not overflow and that the loops with nontrivial
1340 ; exit condition are not infinite
1341 funsafe-loop-optimizations
1342 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1343 Allow loop optimizations to assume that the loops behave in normal way
1346 Common Report Var(flag_associative_math)
1347 Allow optimization for floating-point arithmetic which may change the
1348 result of the operation due to rounding.
1351 Common Report Var(flag_reciprocal_math)
1352 Same as -fassociative-math for expressions which include division.
1354 ; Nonzero means that unsafe floating-point math optimizations are allowed
1355 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1356 ; are allowed to assume that their arguments and results are "normal"
1357 ; (e.g., nonnegative for SQRT).
1358 funsafe-math-optimizations
1359 Common Report Var(flag_unsafe_math_optimizations) Optimization
1360 Allow math optimizations that may violate IEEE or ISO standards
1363 Common Report Var(flag_unswitch_loops) Optimization
1364 Perform loop unswitching
1367 Common Report Var(flag_unwind_tables) Optimization
1368 Just generate unwind tables for exception handling
1371 Common Report Var(flag_var_tracking) VarExists Optimization
1372 Perform variable tracking
1374 fvar-tracking-uninit
1375 Common Report Var(flag_var_tracking_uninit) Optimization
1376 Perform variable tracking and also tag variables that are uninitialized
1379 Common Report Var(flag_tree_vectorize) Optimization
1380 Enable loop vectorization on trees
1383 Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
1384 Enable basic block vectorization (SLP) on trees
1387 Common Report Var(flag_vect_cost_model) Optimization
1388 Enable use of cost model in vectorization
1390 ftree-vect-loop-version
1391 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1392 Enable loop versioning when doing loop vectorization on trees
1394 ftree-vectorizer-verbose=
1395 Common RejectNegative Joined
1396 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1399 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1400 Enable copy propagation of scalar-evolution information.
1402 ; -fverbose-asm causes extra commentary information to be produced in
1403 ; the generated assembly code (to make it more readable). This option
1404 ; is generally only of use to those who actually need to read the
1405 ; generated assembly code (perhaps while debugging the compiler itself).
1406 ; -fno-verbose-asm, the default, causes the extra information
1407 ; to not be added and is useful when comparing two assembler files.
1409 Common Report Var(flag_verbose_asm)
1410 Add extra commentary to assembler output
1413 Common Joined RejectNegative
1414 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1418 Common Report Var(flag_value_profile_transformations) Optimization
1419 Use expression value profiles in optimizations
1422 Common Report Var(flag_web) Init(2) Optimization
1423 Construct webs and split unrelated uses of single variable
1425 ftree-builtin-call-dce
1426 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1427 Enable conditional dead code elimination for builtin calls
1430 Common Report Var(flag_whole_program) Init(0) Optimization
1431 Perform whole program optimizations
1434 Common Report Var(flag_wrapv) Optimization
1435 Assume signed arithmetic overflow wraps around
1437 fzero-initialized-in-bss
1438 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1439 Put zero initialized data in the bss section
1442 Common JoinedOrMissing
1443 Generate debug information in default format
1446 Common JoinedOrMissing Negative(gdwarf-)
1447 Generate debug information in COFF format
1450 Common Joined UInteger Var(dwarf_version) Init(2) Negative(gstabs)
1451 Generate debug information in DWARF v2 (or later) format
1454 Common JoinedOrMissing
1455 Generate debug information in default extended format
1458 Common JoinedOrMissing Negative(gstabs+)
1459 Generate debug information in STABS format
1462 Common JoinedOrMissing Negative(gvms)
1463 Generate debug information in extended STABS format
1466 Common Report Var(flag_gtoggle)
1467 Toggle debug information generation
1470 Common JoinedOrMissing Negative(gxcoff)
1471 Generate debug information in VMS format
1474 Common JoinedOrMissing Negative(gxcoff+)
1475 Generate debug information in XCOFF format
1478 Common JoinedOrMissing Negative(gcoff)
1479 Generate debug information in extended XCOFF format
1482 Common Joined Separate
1483 -o <file> Place output into <file>
1486 Common Var(profile_flag)
1487 Enable function profiling
1490 Common Var(pedantic)
1491 Issue warnings needed for strict compliance to the standard
1495 Like -pedantic but issue them as errors
1498 Common Var(quiet_flag)
1499 Do not display functions compiled or elapsed time
1502 Common Var(version_flag)
1503 Display the compiler's version
1506 Common Var(inhibit_warnings)
1510 Common RejectNegative Negative(pie)
1511 Create a shared library
1514 Common RejectNegative Negative(shared)
1515 Create a position independent executable
1517 ; This comment is to ensure we retain the blank line above.