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_enable_icf_debug)
507 Generate debug information to support Identical Code Folding (ICF)
510 Common Report Var(flag_exceptions) Optimization
511 Enable exception handling
513 fexpensive-optimizations
514 Common Report Var(flag_expensive_optimizations) Optimization
515 Perform a number of minor, expensive optimizations
518 Common Joined RejectNegative
519 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision
525 Common Report Var(flag_finite_math_only) Optimization
526 Assume no NaNs or infinities are generated
529 Common Joined RejectNegative
530 -ffixed-<register> Mark <register> as being unavailable to the compiler
533 Common Report Var(flag_float_store) Optimization
534 Don't allocate floats and doubles in extended-precision registers
538 Does nothing. Preserved for backward compatibility.
541 Common Report Var(flag_forward_propagate) Optimization
542 Perform a forward propagation pass on RTL
544 ; Nonzero means don't put addresses of constant functions in registers.
545 ; Used for compiling the Unix kernel, where strange substitutions are
546 ; done on the assembly output.
548 Common Report Var(flag_no_function_cse,0)
549 Allow function addresses to be held in registers
552 Common Report Var(flag_function_sections)
553 Place each function into its own section
556 Common Report Var(flag_gcse) Optimization
557 Perform global common subexpression elimination
560 Common Report Var(flag_gcse_lm) Init(1) Optimization
561 Perform enhanced load motion during global common subexpression elimination
564 Common Report Var(flag_gcse_sm) Init(0) Optimization
565 Perform store motion after global common subexpression elimination
568 Common Report Var(flag_gcse_las) Init(0) Optimization
569 Perform redundant load after store elimination in global common subexpression
573 Common Report Var(flag_gcse_after_reload) Optimization
574 Perform global common subexpression elimination after register allocation
577 ; This option is not documented yet as its semantics will change.
579 Common Report Var(flag_graphite)
580 Enable in and out of Graphite representation
583 Common Report Var(flag_graphite_identity) Optimization
584 Enable Graphite Identity transformation
586 floop-parallelize-all
587 Common Report Var(flag_loop_parallelize_all) Optimization
588 Mark all loops as parallel
591 Common Report Var(flag_loop_strip_mine) Optimization
592 Enable Loop Strip Mining transformation
595 Common Report Var(flag_loop_interchange) Optimization
596 Enable Loop Interchange transformation
599 Common Report Var(flag_loop_block) Optimization
600 Enable Loop Blocking transformation
602 fguess-branch-probability
603 Common Report Var(flag_guess_branch_prob) Optimization
604 Enable guessing of branch probabilities
606 ; Nonzero means ignore `#ident' directives. 0 means handle them.
607 ; Generate position-independent code for executables if possible
608 ; On SVR4 targets, it also controls whether or not to emit a
609 ; string identifying the compiler.
611 Common Report Var(flag_no_ident,0)
612 Process #ident directives
615 Common Report Var(flag_if_conversion) Optimization
616 Perform conversion of conditional jumps to branchless equivalents
619 Common Report Var(flag_if_conversion2) Optimization
620 Perform conversion of conditional jumps to conditional execution
622 ; -finhibit-size-directive inhibits output of .size for ELF.
623 ; This is used only for compiling crtstuff.c,
624 ; and it may be extended to other effects
625 ; needed for crtstuff.c on other systems.
626 finhibit-size-directive
627 Common Report Var(flag_inhibit_size_directive)
628 Do not generate .size directives
631 Common Report Var(flag_indirect_inlining)
632 Perform indirect inlining
634 ; Nonzero means that functions declared `inline' will be treated
635 ; as `static'. Prevents generation of zillions of copies of unused
636 ; static inline functions; instead, `inlines' are written out
637 ; only when actually used. Used in conjunction with -g. Also
638 ; does the right thing with #pragma interface.
640 Common Report Var(flag_no_inline,0) Init(0)
641 Pay attention to the \"inline\" keyword
643 finline-small-functions
644 Common Report Var(flag_inline_small_functions) Optimization
645 Integrate simple functions into their callers when code size is known to not growth
648 Common Report Var(flag_inline_functions) Optimization
649 Integrate simple functions into their callers
651 finline-functions-called-once
652 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
653 Integrate functions called once into their callers
656 Common RejectNegative Joined UInteger
659 Common RejectNegative Joined UInteger
660 -finline-limit=<number> Limit the size of inlined functions to <number>
662 finstrument-functions
663 Common Report Var(flag_instrument_function_entry_exit)
664 Instrument function entry and exit with profiling calls
666 finstrument-functions-exclude-function-list=
667 Common RejectNegative Joined
668 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
670 finstrument-functions-exclude-file-list=
671 Common RejectNegative Joined
672 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
675 Common Report Var(flag_ipa_cp) Optimization
676 Perform Interprocedural constant propagation
679 Common Report Var(flag_ipa_cp_clone) Optimization
680 Perform cloning to make Interprocedural constant propagation stronger
683 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
684 Discover pure and const functions
687 Common Report Var(flag_ipa_pta) Init(0) Optimization
688 Perform interprocedural points-to analysis
691 Common Report Var(flag_ipa_reference) Init(0) Optimization
692 Discover readonly and non addressable static variables
695 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
696 Type based escape and alias analysis
699 Common Report Var(flag_ipa_matrix_reorg) Optimization
700 Perform matrix layout flattening and transposing based
701 on profiling information.
704 Common Report Var(flag_ipa_struct_reorg)
705 Perform structure layout optimizations based
706 on profiling information.
709 Common Joined RejectNegative
710 -fira-algorithm=[CB|priority] Set the used IRA algorithm
713 Common Joined RejectNegative
714 -fira-region=[one|all|mixed] Set regions for IRA
717 Common Report Var(flag_ira_coalesce) Init(0)
718 Do optimistic coalescing.
720 fira-share-save-slots
721 Common Report Var(flag_ira_share_save_slots) Init(1)
722 Share slots for saving different hard registers.
724 fira-share-spill-slots
725 Common Report Var(flag_ira_share_spill_slots) Init(1)
726 Share stack slots for spilled pseudo-registers.
729 Common RejectNegative Joined UInteger
730 -fira-verbose=<number> Control IRA's level of diagnostic messages.
733 Common Report Var(flag_ivopts) Init(1) Optimization
734 Optimize induction variables on trees
737 Common Var(flag_jump_tables) Init(1) Optimization
738 Use jump tables for sufficiently large switch statements
740 fkeep-inline-functions
741 Common Report Var(flag_keep_inline_functions)
742 Generate code for functions even if they are fully inlined
745 Common Report Var(flag_keep_static_consts) Init(1)
746 Emit static const variables even if they are not used
749 Common Report Var(flag_leading_underscore) Init(-1)
750 Give external symbols a leading underscore
754 Does nothing. Preserved for backward compatibility.
758 Enable link-time optimization.
760 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
761 flto-compression-level=
762 Common Joined UInteger Var(flag_lto_compression_level) Init(-1)
763 -flto-compression-level=<number> Use zlib compression level <number> for IL
766 Common Report Var(flag_lto_report) Init(0) Optimization
767 Report various link-time optimization statistics
770 Common Report Var(flag_errno_math) Init(1) Optimization
771 Set errno after built-in math functions
774 Common Report Var(mem_report)
775 Report on permanent memory allocation
777 ; This will attempt to merge constant section constants, if 1 only
778 ; string constants and constants from constant pool, if 2 also constant
781 Common Report Var(flag_merge_constants,2) Init(1) Optimization
782 Attempt to merge identical constants and constant variables
785 Common Report Var(flag_merge_constants,1) VarExists Optimization
786 Attempt to merge identical constants across compilation units
789 Common Report Var(flag_merge_debug_strings) Init(1)
790 Attempt to merge identical debug strings across compilation units
793 Common RejectNegative Joined UInteger
794 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
797 Common Report Var(flag_modulo_sched) Optimization
798 Perform SMS based modulo scheduling before the first scheduling pass
800 fmodulo-sched-allow-regmoves
801 Common Report Var(flag_modulo_sched_allow_regmoves)
802 Perform SMS based modulo scheduling with register moves allowed
804 fmove-loop-invariants
805 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
806 Move loop invariant computations out of loops
809 Common RejectNegative Report Var(flag_mudflap)
810 Add mudflap bounds-checking instrumentation for single-threaded program
813 Common RejectNegative Report VarExists Var(flag_mudflap,2)
814 Add mudflap bounds-checking instrumentation for multi-threaded program
817 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
818 Ignore read operations when inserting mudflap instrumentation
821 Common Var(flag_dce) Init(1) Optimization
822 Use the RTL dead code elimination pass
825 Common Var(flag_dse) Init(1) Optimization
826 Use the RTL dead store elimination pass
828 freschedule-modulo-scheduled-loops
829 Common Report Var(flag_resched_modulo_sched) Optimization
830 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
833 Common Report Var(flag_non_call_exceptions) Optimization
834 Support synchronous non-call exceptions
837 Common Report Var(flag_omit_frame_pointer) Optimization
838 When possible do not generate stack frames
840 foptimize-register-move
841 Common Report Var(flag_regmove) Optimization
842 Do the full register move optimization pass
844 foptimize-sibling-calls
845 Common Report Var(flag_optimize_sibling_calls) Optimization
846 Optimize sibling and tail recursive calls
849 Common Report Var(pre_ipa_mem_report)
850 Report on memory allocation before interprocedural optimization
853 Common Report Var(post_ipa_mem_report)
854 Report on memory allocation before interprocedural optimization
857 Common Report Var(flag_pack_struct) Optimization
858 Pack structure members together without holes
861 Common RejectNegative Joined UInteger Optimization
862 -fpack-struct=<number> Set initial maximum structure member alignment
865 Common Report Var(flag_pcc_struct_return,1) VarExists
866 Return small aggregates in memory, not registers
869 Common Report Var(flag_peel_loops) Optimization
873 Common Report Var(flag_no_peephole,0) Optimization
874 Enable machine specific peephole optimizations
877 Common Report Var(flag_peephole2) Optimization
878 Enable an RTL peephole pass before sched2
881 Common Report Var(flag_pic,2)
882 Generate position-independent code if possible (large mode)
885 Common Report Var(flag_pie,2)
886 Generate position-independent code for executables if possible (large mode)
889 Common Report Var(flag_pic,1) VarExists
890 Generate position-independent code if possible (small mode)
893 Common Report Var(flag_pie,1) VarExists
894 Generate position-independent code for executables if possible (small mode)
897 Common Joined RejectNegative
898 Specify a plugin to load
901 Common Joined RejectNegative
902 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
904 fpredictive-commoning
905 Common Report Var(flag_predictive_commoning) Optimization
906 Run predictive commoning optimization.
908 fprefetch-loop-arrays
909 Common Report Var(flag_prefetch_loop_arrays) Optimization
910 Generate prefetch instructions, if available, for arrays in loops
913 Common Report Var(profile_flag)
914 Enable basic program profiling code
917 Common Report Var(profile_arc_flag)
918 Insert arc-based program profiling code
921 Common Joined RejectNegative
922 Set the top-level directory for storing the profile data.
923 The default is 'pwd'.
926 Common Report Var(flag_profile_correction)
927 Enable correction of flow inconsistent profile data input
931 Enable common options for generating profile info for profile feedback directed optimizations
934 Common Joined RejectNegative
935 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
938 Common Var(flag_profile_use)
939 Enable common options for performing profile feedback directed optimizations
942 Common Joined RejectNegative
943 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
946 Common Report Var(flag_profile_values)
947 Insert code to profile values of expressions
953 Common Joined RejectNegative
954 -frandom-seed=<string> Make compile reproducible using <string>
956 ; This switch causes the command line that was used to create an
957 ; object file to be recorded into the object file. The exact format
958 ; of this recording is target and binary file format dependent.
959 ; It is related to the -fverbose-asm switch, but that switch only
960 ; records information in the assembler output file as comments, so
961 ; they never reach the object file.
963 Common Report Var(flag_record_gcc_switches)
964 Record gcc command line switches in the object file.
967 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
968 Return small aggregates in registers
971 Common Report Var(flag_regmove) Optimization
972 Enables a register move optimization
975 Common Report Var(flag_rename_registers) Init(2) Optimization
976 Perform a register renaming optimization pass
979 Common Report Var(flag_reorder_blocks) Optimization
980 Reorder basic blocks to improve code placement
982 freorder-blocks-and-partition
983 Common Report Var(flag_reorder_blocks_and_partition) Optimization
984 Reorder basic blocks and partition into hot and cold sections
987 Common Report Var(flag_reorder_functions) Optimization
988 Reorder functions to improve code placement
990 frerun-cse-after-loop
991 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
992 Add a common subexpression elimination pass after loop optimizations
996 Does nothing. Preserved for backward compatibility.
999 Common Report Var(flag_rounding_math) Optimization
1000 Disable optimizations that assume default FP rounding behavior
1003 Common Report Var(flag_schedule_interblock) Init(1) Optimization
1004 Enable scheduling across basic blocks
1007 Common Report Var(flag_sched_pressure) Init(0) Optimization
1008 Enable register pressure sensitive insn scheduling
1011 Common Report Var(flag_schedule_speculative) Init(1) Optimization
1012 Allow speculative motion of non-loads
1015 Common Report Var(flag_schedule_speculative_load) Optimization
1016 Allow speculative motion of some loads
1018 fsched-spec-load-dangerous
1019 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
1020 Allow speculative motion of more loads
1023 Common RejectNegative Joined
1024 -fsched-verbose=<number> Set the verbosity level of the scheduler
1026 fsched2-use-superblocks
1027 Common Report Var(flag_sched2_use_superblocks) Optimization
1028 If scheduling post reload, do superblock scheduling
1031 Common Report Var(flag_sched2_use_traces) Optimization
1032 If scheduling post reload, do trace scheduling
1035 Common Report Var(flag_schedule_insns) Optimization
1036 Reschedule instructions before register allocation
1039 Common Report Var(flag_schedule_insns_after_reload) Optimization
1040 Reschedule instructions after register allocation
1042 ; This flag should be on when a target implements non-trivial
1043 ; scheduling hooks, maybe saving some information for its own sake.
1044 ; On IA64, for example, this is used for correct bundling.
1045 fselective-scheduling
1046 Common Report Var(flag_selective_scheduling) Optimization
1047 Schedule instructions using selective scheduling algorithm
1049 fselective-scheduling2
1050 Common Report Var(flag_selective_scheduling2) Optimization
1051 Run selective scheduling after reload
1053 fsel-sched-pipelining
1054 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1055 Perform software pipelining of inner loops during selective scheduling
1057 fsel-sched-pipelining-outer-loops
1058 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1059 Perform software pipelining of outer loops during selective scheduling
1061 fsel-sched-reschedule-pipelined
1062 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1063 Reschedule pipelined regions without pipelining
1065 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1066 ; of stalled insns into the ready list.
1067 fsched-stalled-insns
1068 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1069 Allow premature scheduling of queued insns
1071 fsched-stalled-insns=
1072 Common RejectNegative Joined UInteger
1073 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1075 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1076 ; be examined for a dependency on a stalled insn that is candidate for
1077 ; premature removal from the queue of stalled insns into the ready list (has
1078 ; an effect only if the flag 'sched_stalled_insns' is set).
1079 fsched-stalled-insns-dep
1080 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1081 Set dependence distance checking in premature scheduling of queued insns
1083 fsched-stalled-insns-dep=
1084 Common RejectNegative Joined UInteger
1085 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1087 fsched-group-heuristic
1088 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
1089 Enable the group heuristic in the scheduler
1091 fsched-critical-path-heuristic
1092 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
1093 Enable the critical path heuristic in the scheduler
1095 fsched-spec-insn-heuristic
1096 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
1097 Enable the speculative instruction heuristic in the scheduler
1099 fsched-rank-heuristic
1100 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
1101 Enable the rank heuristic in the scheduler
1103 fsched-last-insn-heuristic
1104 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
1105 Enable the last instruction heuristic in the scheduler
1107 fsched-dep-count-heuristic
1108 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
1109 Enable the dependent count heuristic in the scheduler
1112 Common Report Var(flag_section_anchors) Optimization
1113 Access data in the same section from shared anchor points
1117 Does nothing. Preserved for backward compatibility.
1120 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
1121 Show column numbers in diagnostics, when available. Default on
1124 Common Report Var(flag_signaling_nans) Optimization
1125 Disable optimizations observable by IEEE signaling NaNs
1128 Common Report Var(flag_signed_zeros) Init(1) Optimization
1129 Disable floating point optimizations that ignore the IEEE signedness of zero
1131 fsingle-precision-constant
1132 Common Report Var(flag_single_precision_constant) Optimization
1133 Convert floating point constants to single precision constants
1135 fsplit-ivs-in-unroller
1136 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1137 Split lifetimes of induction variables when loops are unrolled
1140 Common Report Var(flag_split_wide_types) Optimization
1141 Split wide types into independent registers
1143 fvariable-expansion-in-unroller
1144 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1145 Apply variable expansion when loops are unrolled
1148 Common Report RejectNegative Joined
1149 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1153 Insert stack checking code into the program. Same as -fstack-check=specific
1158 fstack-limit-register=
1159 Common RejectNegative Joined
1160 -fstack-limit-register=<register> Trap if the stack goes past <register>
1162 fstack-limit-symbol=
1163 Common RejectNegative Joined
1164 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1167 Common Report Var(flag_stack_protect, 1)
1168 Use propolice as a stack protection method
1170 fstack-protector-all
1171 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1172 Use a stack protection method for every function
1176 Does nothing. Preserved for backward compatibility.
1178 ; Nonzero if we should do (language-dependent) alias analysis.
1179 ; Typically, this analysis will assume that expressions of certain
1180 ; types do not alias expressions of certain other types. Only used
1181 ; if alias analysis (in general) is enabled.
1183 Common Report Var(flag_strict_aliasing) Optimization
1184 Assume strict aliasing rules apply
1187 Common Report Var(flag_strict_overflow)
1188 Treat signed overflow as undefined
1191 Common Report Var(flag_syntax_only)
1192 Check for syntax errors, then stop
1195 Common Report Var(flag_test_coverage)
1196 Create data files needed by \"gcov\"
1199 Common Report Var(flag_thread_jumps) Optimization
1200 Perform jump threading optimizations
1203 Common Report Var(time_report)
1204 Report the time taken by each compiler pass
1207 Common Joined RejectNegative
1208 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1211 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1212 Reorder top level functions, variables, and asms
1215 Common Report Var(flag_tracer)
1216 Perform superblock formation via tail duplication
1218 ; Zero means that floating-point math operations cannot generate a
1219 ; (user-visible) trap. This is the case, for example, in nonstop
1220 ; IEEE 754 arithmetic.
1222 Common Report Var(flag_trapping_math) Init(1) Optimization
1223 Assume floating-point operations can trap
1226 Common Report Var(flag_trapv) Optimization
1227 Trap for signed overflow in addition, subtraction and multiplication
1230 Common Report Var(flag_tree_ccp) Optimization
1231 Enable SSA-CCP optimization on trees
1235 Does nothing. Preserved for backward compatibility.
1238 Common Report Var(flag_tree_ch) Optimization
1239 Enable loop header copying on trees
1242 Common Report Var(flag_tree_copyrename) Optimization
1243 Replace SSA temporaries with better names in copies
1246 Common Report Var(flag_tree_copy_prop) Optimization
1247 Enable copy propagation on trees
1249 ftree-store-copy-prop
1251 Does nothing. Preserved for backward compatibility.
1254 Common Report Var(flag_tree_cselim) Init(2) Optimization
1255 Transform condition stores into unconditional ones
1257 ftree-switch-conversion
1258 Common Report Var(flag_tree_switch_conversion) Optimization
1259 Perform conversions of switch initializations.
1262 Common Report Var(flag_tree_dce) Optimization
1263 Enable SSA dead code elimination optimization on trees
1265 ftree-dominator-opts
1266 Common Report Var(flag_tree_dom) Optimization
1267 Enable dominator optimizations
1270 Common Report Var(flag_tree_dse) Optimization
1271 Enable dead store elimination
1274 Common Report Var(flag_tree_forwprop) Init(1) Optimization
1275 Enable forward propagation on trees
1278 Common Report Var(flag_tree_fre) Optimization
1279 Enable Full Redundancy Elimination (FRE) on trees
1281 ftree-loop-distribution
1282 Common Report Var(flag_tree_loop_distribution) Optimization
1283 Enable loop distribution on trees
1286 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1287 Enable loop invariant motion on trees
1290 Common Report Var(flag_tree_loop_linear) Optimization
1291 Enable linear loop transforms on trees
1294 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1295 Create canonical induction variables in loops
1298 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1299 Enable loop optimizations on tree level
1301 ftree-parallelize-loops=
1302 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1303 Enable automatic parallelization of loops
1306 Common Report Var(flag_tree_phiprop) Init(1) Optimization
1307 Enable hoisting loads from conditional pointers.
1310 Common Report Var(flag_tree_pre) Optimization
1311 Enable SSA-PRE optimization on trees
1314 Common Report Var(flag_tree_pta) Init(1) Optimization
1315 Perform function-local points-to analysis on trees.
1318 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1319 Enable reassociation on tree level
1323 Does nothing. Preserved for backward compatibility.
1326 Common Report Var(flag_tree_sink) Optimization
1327 Enable SSA code sinking on trees
1330 Common Report Var(flag_tree_sra) Optimization
1331 Perform scalar replacement of aggregates
1334 Common Report Var(flag_tree_ter) Init(1) Optimization
1335 Replace temporary expressions in the SSA->normal pass
1338 Common Report Var(flag_tree_live_range_split) Optimization
1339 Perform live range splitting during the SSA->normal pass
1342 Common Report Var(flag_tree_vrp) Init(0) Optimization
1343 Perform Value Range Propagation on trees
1346 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1347 Compile whole compilation unit at a time
1350 Common Report Var(flag_unroll_loops) Optimization
1351 Perform loop unrolling when iteration count is known
1354 Common Report Var(flag_unroll_all_loops) Optimization
1355 Perform loop unrolling for all loops
1357 ; Nonzero means that loop optimizer may assume that the induction variables
1358 ; that control loops do not overflow and that the loops with nontrivial
1359 ; exit condition are not infinite
1360 funsafe-loop-optimizations
1361 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1362 Allow loop optimizations to assume that the loops behave in normal way
1365 Common Report Var(flag_associative_math)
1366 Allow optimization for floating-point arithmetic which may change the
1367 result of the operation due to rounding.
1370 Common Report Var(flag_reciprocal_math)
1371 Same as -fassociative-math for expressions which include division.
1373 ; Nonzero means that unsafe floating-point math optimizations are allowed
1374 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1375 ; are allowed to assume that their arguments and results are "normal"
1376 ; (e.g., nonnegative for SQRT).
1377 funsafe-math-optimizations
1378 Common Report Var(flag_unsafe_math_optimizations) Optimization
1379 Allow math optimizations that may violate IEEE or ISO standards
1382 Common Report Var(flag_unswitch_loops) Optimization
1383 Perform loop unswitching
1386 Common Report Var(flag_unwind_tables) Optimization
1387 Just generate unwind tables for exception handling
1390 Common Report Var(flag_var_tracking) VarExists Optimization
1391 Perform variable tracking
1393 fvar-tracking-assignments
1394 Common Report Var(flag_var_tracking_assignments) VarExists Optimization
1395 Perform variable tracking by annotating assignments
1397 fvar-tracking-assignments-toggle
1398 Common Report Var(flag_var_tracking_assignments_toggle) VarExists Optimization
1399 Toggle -fvar-tracking-assignments
1401 fvar-tracking-uninit
1402 Common Report Var(flag_var_tracking_uninit) Optimization
1403 Perform variable tracking and also tag variables that are uninitialized
1406 Common Report Var(flag_tree_vectorize) Optimization
1407 Enable loop vectorization on trees
1410 Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
1411 Enable basic block vectorization (SLP) on trees
1414 Common Report Var(flag_vect_cost_model) Optimization
1415 Enable use of cost model in vectorization
1417 ftree-vect-loop-version
1418 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1419 Enable loop versioning when doing loop vectorization on trees
1421 ftree-vectorizer-verbose=
1422 Common RejectNegative Joined
1423 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1426 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1427 Enable copy propagation of scalar-evolution information.
1429 ; -fverbose-asm causes extra commentary information to be produced in
1430 ; the generated assembly code (to make it more readable). This option
1431 ; is generally only of use to those who actually need to read the
1432 ; generated assembly code (perhaps while debugging the compiler itself).
1433 ; -fno-verbose-asm, the default, causes the extra information
1434 ; to not be added and is useful when comparing two assembler files.
1436 Common Report Var(flag_verbose_asm)
1437 Add extra commentary to assembler output
1440 Common Joined RejectNegative
1441 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1445 Common Report Var(flag_value_profile_transformations) Optimization
1446 Use expression value profiles in optimizations
1449 Common Report Var(flag_web) Init(2) Optimization
1450 Construct webs and split unrelated uses of single variable
1453 Common Var(flag_whopr)
1454 Enable partitioned link-time optimization.
1456 ftree-builtin-call-dce
1457 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1458 Enable conditional dead code elimination for builtin calls
1461 Common Report Var(flag_whole_program) Init(0) Optimization
1462 Perform whole program optimizations
1465 Common Report Var(flag_wrapv) Optimization
1466 Assume signed arithmetic overflow wraps around
1468 fzero-initialized-in-bss
1469 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1470 Put zero initialized data in the bss section
1473 Common JoinedOrMissing
1474 Generate debug information in default format
1477 Common JoinedOrMissing Negative(gdwarf-)
1478 Generate debug information in COFF format
1481 Common Joined UInteger Var(dwarf_version) Init(2) Negative(gstabs)
1482 Generate debug information in DWARF v2 (or later) format
1485 Common JoinedOrMissing
1486 Generate debug information in default extended format
1489 Common JoinedOrMissing Negative(gstabs+)
1490 Generate debug information in STABS format
1493 Common JoinedOrMissing Negative(gvms)
1494 Generate debug information in extended STABS format
1497 Common RejectNegative Var(dwarf_strict,0) Init(-1)
1498 Emit DWARF additions beyond selected version
1501 Common Report RejectNegative Var(dwarf_strict,1) VarExists
1502 Don't emit DWARF additions beyond selected version
1505 Common Report Var(flag_gtoggle)
1506 Toggle debug information generation
1509 Common JoinedOrMissing Negative(gxcoff)
1510 Generate debug information in VMS format
1513 Common JoinedOrMissing Negative(gxcoff+)
1514 Generate debug information in XCOFF format
1517 Common JoinedOrMissing Negative(gcoff)
1518 Generate debug information in extended XCOFF format
1521 Common Joined Separate
1522 -o <file> Place output into <file>
1525 Common Var(profile_flag)
1526 Enable function profiling
1529 Common Var(pedantic)
1530 Issue warnings needed for strict compliance to the standard
1534 Like -pedantic but issue them as errors
1537 Common Var(quiet_flag)
1538 Do not display functions compiled or elapsed time
1541 Common Var(version_flag)
1542 Display the compiler's version
1545 Common Var(inhibit_warnings)
1549 Common RejectNegative Negative(pie)
1550 Create a shared library
1553 Common RejectNegative Negative(shared)
1554 Create a position independent executable
1556 ; This comment is to ensure we retain the blank line above.