1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
4 ; Free Software Foundation, Inc.
6 ; This file is part of GCC.
8 ; GCC is free software; you can redistribute it and/or modify it under
9 ; the terms of the GNU General Public License as published by the Free
10 ; Software Foundation; either version 3, or (at your option) any later
13 ; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 ; WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 ; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 ; You should have received a copy of the GNU General Public License
19 ; along with GCC; see the file COPYING3. If not see
20 ; <http://www.gnu.org/licenses/>.
22 ; See the GCC internals manual (options.texi) for a description of this file's format.
24 ; Please try to keep this file in ASCII collating order.
28 Display this information
32 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params
36 Alias for --help=target
38 ;; The following four entries are to work around the gcc driver
39 ;; program's insatiable desire to turn options starting with a
40 ;; double dash (--) into options starting with a dash f (-f).
55 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
61 Common Joined Separate UInteger
62 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
65 Common JoinedOrMissing Optimization
66 -O<number> Set optimization level to <number>
70 Optimize for space rather than speed
73 Common RejectNegative Var(extra_warnings) Warning
74 This switch is deprecated; use -Wextra instead
77 Common Var(warn_aggregate_return) Warning
78 Warn about returning structures, unions or arrays
81 Common Var(warn_array_bounds) Warning
82 Warn if an array is accessed out of bounds
85 Common Var(warn_attributes) Init(1) Warning
86 Warn about inappropriate attribute usage
89 Common Var(warn_cast_align) Warning
90 Warn about pointer casts which increase alignment
92 Wdeprecated-declarations
93 Common Var(warn_deprecated_decl) Init(1) Warning
94 Warn about uses of __attribute__((deprecated)) declarations
96 Wdisabled-optimization
97 Common Var(warn_disabled_optimization) Warning
98 Warn when an optimization pass is disabled
101 Common Var(warnings_are_errors)
102 Treat all warnings as errors
106 Treat specified warning as error
109 Common Var(extra_warnings) Warning
110 Print extra (possibly unwanted) warnings
113 Common Var(flag_fatal_errors)
114 Exit on the first error occurred
117 Common RejectNegative Joined UInteger
118 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes
121 Common Var(warn_inline) Warning
122 Warn when an inlined function cannot be inlined
125 Common RejectNegative Joined UInteger Warning
128 Common RejectNegative Joined UInteger Warning
129 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
131 Wunsafe-loop-optimizations
132 Common Var(warn_unsafe_loop_optimizations) Warning
133 Warn if the loop cannot be optimized due to nontrivial assumptions.
136 Common Var(warn_missing_noreturn) Warning
137 Warn about functions which might be candidates for __attribute__((noreturn))
140 Common Var(warn_mudflap) Init(1) Warning
141 Warn about constructs not instrumented by -fmudflap
144 Common Var(warn_overflow) Init(1) Warning
145 Warn about overflow in arithmetic expressions
148 Common Var(warn_packed) Warning
149 Warn when the packed attribute has no effect on struct layout
152 Common Var(warn_padded) Warning
153 Warn when padding is required to align structure members
156 Common Var(warn_shadow) Warning
157 Warn when one local variable shadows another
160 Common Var(warn_stack_protect) Warning
161 Warn when not issuing stack smashing protection for some reason
165 Warn about code which might break strict aliasing rules
168 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
169 Warn about code which might break strict aliasing rules
173 Warn about optimizations that assume that signed overflow is undefined
176 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
177 Warn about optimizations that assume that signed overflow is undefined
180 Common Var(warn_switch) Warning
181 Warn about enumerated switches, with no default, missing a case
184 Common Var(warn_switch_default) Warning
185 Warn about enumerated switches missing a \"default:\" statement
188 Common Var(warn_switch_enum) Warning
189 Warn about all enumerated switches missing a specific case
192 Common Var(warn_system_headers) Warning
193 Do not suppress warnings from system headers
196 Common Var(warn_type_limits) Init(-1) Warning
197 Warn if a comparison is always true or always false due to the limited range of the data type
200 Common Var(warn_uninitialized) Init(-1) Warning
201 Warn about uninitialized automatic variables
204 Common Var(warn_notreached) Warning
205 Warn about code that will never be executed
208 Common Var(warn_unused) Init(0) Warning
209 Enable all -Wunused- warnings
212 Common Var(warn_unused_function) Init(-1) Warning
213 Warn when a function is unused
216 Common Var(warn_unused_label) Init(-1) Warning
217 Warn when a label is unused
220 Common Var(warn_unused_parameter) Init(-1) Warning
221 Warn when a function parameter is unused
224 Common Var(warn_unused_value) Init(-1) Warning
225 Warn when an expression value is unused
228 Common Var(warn_unused_variable) Init(-1) Warning
229 Warn when a variable is unused
232 Common RejectNegative Var(warn_coverage_mismatch) Warning
233 Warn instead of error in case profiles in -fprofile-use do not match
237 -aux-info <file> Emit declaration information into <file>
250 -d<letters> Enable dumps from specific passes of the compiler
254 -dumpbase <file> Set the file basename to be used for dumps
256 ; The version of the C++ ABI in use. The following values are allowed:
258 ; 0: The version of the ABI believed most conformant with the C++ ABI
259 ; specification. This ABI may change as bugs are discovered and fixed.
260 ; Therefore, 0 will not necessarily indicate the same ABI in different
263 ; 1: The version of the ABI first used in G++ 3.2.
265 ; 2: The version of the ABI first used in G++ 3.4.
267 ; Additional positive integers will be assigned as new versions of
268 ; the ABI become the default version of the ABI.
270 Common Joined UInteger Var(flag_abi_version) Init(2)
273 Common Report Var(align_functions,0) Optimization UInteger
274 Align the start of functions
277 Common RejectNegative Joined UInteger
280 Common Report Var(align_jumps,0) Optimization UInteger
281 Align labels which are only reached by jumping
284 Common RejectNegative Joined UInteger
287 Common Report Var(align_labels,0) Optimization UInteger
291 Common RejectNegative Joined UInteger
294 Common Report Var(align_loops) Optimization UInteger
295 Align the start of loops
298 Common RejectNegative Joined UInteger
300 ; This flag is only tested if alias checking is enabled.
301 ; 0 if pointer arguments may alias each other. True in C.
302 ; 1 if pointer arguments may not alias each other but may alias
304 ; 2 if pointer arguments may not alias each other and may not
305 ; alias global variables.
306 ; 3 if pointer arguments may not alias anything. True in Fortran.
307 ; Set by the front end.
309 Common Report Var(flag_argument_noalias,0) Optimization
310 Specify that arguments may alias each other and globals
313 Common Report Var(flag_argument_noalias,1) VarExists Optimization
314 Assume arguments may alias globals but not each other
316 fargument-noalias-global
317 Common Report Var(flag_argument_noalias,2) VarExists Optimization
318 Assume arguments alias neither each other nor globals
320 fargument-noalias-anything
321 Common Report Var(flag_argument_noalias,3) VarExists Optimization
322 Assume arguments alias no other storage
324 fasynchronous-unwind-tables
325 Common Report Var(flag_asynchronous_unwind_tables) Optimization
326 Generate unwind tables that are exact at each instruction boundary
329 Common Report Var(flag_auto_inc_dec) Init(1)
330 Generate auto-inc/dec instructions
332 ; -fcheck-bounds causes gcc to generate array bounds checks.
333 ; For C, C++ and ObjC: defaults off.
334 ; For Java: defaults to on.
335 ; For Fortran: defaults to off.
337 Common Report Var(flag_bounds_check)
338 Generate code to check bounds before indexing arrays
341 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
342 Replace add, compare, branch with branch on count register
344 fbranch-probabilities
345 Common Report Var(flag_branch_probabilities) Optimization
346 Use profiling information for branch probabilities
348 fbranch-target-load-optimize
349 Common Report Var(flag_branch_target_load_optimize) Optimization
350 Perform branch target load optimization before prologue / epilogue threading
352 fbranch-target-load-optimize2
353 Common Report Var(flag_branch_target_load_optimize2) Optimization
354 Perform branch target load optimization after prologue / epilogue threading
357 Common Report Var(flag_btr_bb_exclusive) Optimization
358 Restrict target load migration not to re-use registers in any basic block
361 Common Joined RejectNegative
362 -fcall-saved-<register> Mark <register> as being preserved across functions
365 Common Joined RejectNegative
366 -fcall-used-<register> Mark <register> as being corrupted by function calls
368 ; Nonzero for -fcaller-saves: allocate values in regs that need to
369 ; be saved across function calls, if that produces overall better code.
370 ; Optional now, so people can test it.
372 Common Report Var(flag_caller_saves) Optimization
373 Save registers around function calls
376 Common Report Var(flag_check_data_deps)
377 Compare the results of several data dependence analyzers.
380 Common Report Var(flag_no_common,0) Optimization
381 Do not put uninitialized globals in the common section
384 Common JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
385 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump
387 fcompare-debug-second
388 Common RejectNegative Var(flag_compare_debug)
389 Run only the second compilation of -fcompare-debug
392 Common Var(flag_conserve_stack) Optimization
393 Do not perform optimizations increasing noticeably stack usage
396 Common Report Var(flag_cprop_registers) Optimization
397 Perform a register copy-propagation optimization pass
400 Common Report Var(flag_crossjumping) Optimization
401 Perform cross-jumping optimization
404 Common Report Var(flag_cse_follow_jumps) Optimization
405 When running CSE, follow jumps to their targets
409 Does nothing. Preserved for backward compatibility.
412 Common Report Var(flag_cx_limited_range) Optimization
413 Omit range reduction step when performing complex division
416 Common Report Var(flag_cx_fortran_rules) Optimization
417 Complex multiplication and division follow Fortran rules
420 Common Report Var(flag_data_sections) Optimization
421 Place data items into their own section
425 List all available debugging counters with their limits and counts.
428 Common RejectNegative Joined
429 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
432 Common Joined RejectNegative
433 Map one directory name to another in debug information
435 ; Nonzero for -fdefer-pop: don't pop args after each function call
436 ; instead save them up to pop many calls' args with one insns.
438 Common Report Var(flag_defer_pop) Optimization
439 Defer popping functions args from stack until later
442 Common Report Var(flag_delayed_branch) Optimization
443 Attempt to fill delay slots of branch instructions
445 fdelete-null-pointer-checks
446 Common Report Var(flag_delete_null_pointer_checks) Init(1) Optimization
447 Delete useless null pointer checks
449 fdiagnostics-show-location=
450 Common Joined RejectNegative
451 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
453 fdiagnostics-show-option
455 Amend appropriate diagnostic messages with the command line option that controls them
458 Common Joined RejectNegative
459 -fdump-<type> Dump various compiler internals to a file
462 Common RejectNegative Joined Var(flag_dump_final_insns)
463 -fdump-final-insns=filename Dump to filename the insns at the end of translation
466 Common Report Var(flag_dump_noaddr)
467 Suppress output of addresses in debugging dumps
470 Common Report Var(flag_dump_unnumbered) VarExists
471 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
473 fdump-unnumbered-links
474 Common Report Var(flag_dump_unnumbered_links) VarExists
475 Suppress output of previous and next insn numbers in debugging dumps
478 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
479 Enable CFI tables via GAS assembler directives.
482 Common Report Var(flag_early_inlining) Init(1) Optimization
483 Perform early inlining
485 feliminate-dwarf2-dups
486 Common Report Var(flag_eliminate_dwarf2_dups)
487 Perform DWARF2 duplicate elimination
490 Common Report Var(flag_ipa_sra) Init(0) Optimization
491 Perform interprocedural reduction of aggregates
493 feliminate-unused-debug-symbols
494 Common Report Var(flag_debug_only_used_symbols)
495 Perform unused type elimination in debug info
497 feliminate-unused-debug-types
498 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
499 Perform unused type elimination in debug info
501 femit-class-debug-always
502 Common Report Var(flag_emit_class_debug_always) Init(0)
503 Do not suppress C++ class debug information.
506 Common Report Var(flag_exceptions) Optimization
507 Enable exception handling
509 fexpensive-optimizations
510 Common Report Var(flag_expensive_optimizations) Optimization
511 Perform a number of minor, expensive optimizations
514 Common Joined RejectNegative
515 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision
521 Common Report Var(flag_finite_math_only) Optimization
522 Assume no NaNs or infinities are generated
525 Common Joined RejectNegative
526 -ffixed-<register> Mark <register> as being unavailable to the compiler
529 Common Report Var(flag_float_store) Optimization
530 Don't allocate floats and doubles in extended-precision registers
534 Does nothing. Preserved for backward compatibility.
537 Common Report Var(flag_forward_propagate) Optimization
538 Perform a forward propagation pass on RTL
540 ; Nonzero means don't put addresses of constant functions in registers.
541 ; Used for compiling the Unix kernel, where strange substitutions are
542 ; done on the assembly output.
544 Common Report Var(flag_no_function_cse,0)
545 Allow function addresses to be held in registers
548 Common Report Var(flag_function_sections)
549 Place each function into its own section
552 Common Report Var(flag_gcse) Optimization
553 Perform global common subexpression elimination
556 Common Report Var(flag_gcse_lm) Init(1) Optimization
557 Perform enhanced load motion during global common subexpression elimination
560 Common Report Var(flag_gcse_sm) Init(0) Optimization
561 Perform store motion after global common subexpression elimination
564 Common Report Var(flag_gcse_las) Init(0) Optimization
565 Perform redundant load after store elimination in global common subexpression
569 Common Report Var(flag_gcse_after_reload) Optimization
570 Perform global common subexpression elimination after register allocation
573 ; This option is not documented yet as its semantics will change.
575 Common Report Var(flag_graphite)
576 Enable in and out of Graphite representation
579 Common Report Var(flag_graphite_identity) Optimization
580 Enable Graphite Identity transformation
582 floop-parallelize-all
583 Common Report Var(flag_loop_parallelize_all) Optimization
584 Mark all loops as parallel
587 Common Report Var(flag_loop_strip_mine) Optimization
588 Enable Loop Strip Mining transformation
591 Common Report Var(flag_loop_interchange) Optimization
592 Enable Loop Interchange transformation
595 Common Report Var(flag_loop_block) Optimization
596 Enable Loop Blocking transformation
598 fguess-branch-probability
599 Common Report Var(flag_guess_branch_prob) Optimization
600 Enable guessing of branch probabilities
602 ; Nonzero means ignore `#ident' directives. 0 means handle them.
603 ; Generate position-independent code for executables if possible
604 ; On SVR4 targets, it also controls whether or not to emit a
605 ; string identifying the compiler.
607 Common Report Var(flag_no_ident,0)
608 Process #ident directives
611 Common Report Var(flag_if_conversion) Optimization
612 Perform conversion of conditional jumps to branchless equivalents
615 Common Report Var(flag_if_conversion2) Optimization
616 Perform conversion of conditional jumps to conditional execution
618 ; -finhibit-size-directive inhibits output of .size for ELF.
619 ; This is used only for compiling crtstuff.c,
620 ; and it may be extended to other effects
621 ; needed for crtstuff.c on other systems.
622 finhibit-size-directive
623 Common Report Var(flag_inhibit_size_directive)
624 Do not generate .size directives
627 Common Report Var(flag_indirect_inlining)
628 Perform indirect inlining
630 ; Nonzero means that functions declared `inline' will be treated
631 ; as `static'. Prevents generation of zillions of copies of unused
632 ; static inline functions; instead, `inlines' are written out
633 ; only when actually used. Used in conjunction with -g. Also
634 ; does the right thing with #pragma interface.
636 Common Report Var(flag_no_inline,0) Init(0)
637 Pay attention to the \"inline\" keyword
639 finline-small-functions
640 Common Report Var(flag_inline_small_functions) Optimization
641 Integrate simple functions into their callers when code size is known to not growth
644 Common Report Var(flag_inline_functions) Optimization
645 Integrate simple functions into their callers
647 finline-functions-called-once
648 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
649 Integrate functions called once into their callers
652 Common RejectNegative Joined UInteger
655 Common RejectNegative Joined UInteger
656 -finline-limit=<number> Limit the size of inlined functions to <number>
658 finstrument-functions
659 Common Report Var(flag_instrument_function_entry_exit)
660 Instrument function entry and exit with profiling calls
662 finstrument-functions-exclude-function-list=
663 Common RejectNegative Joined
664 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
666 finstrument-functions-exclude-file-list=
667 Common RejectNegative Joined
668 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
671 Common Report Var(flag_ipa_cp) Optimization
672 Perform Interprocedural constant propagation
675 Common Report Var(flag_ipa_cp_clone) Optimization
676 Perform cloning to make Interprocedural constant propagation stronger
679 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
680 Discover pure and const functions
683 Common Report Var(flag_ipa_pta) Init(0) Optimization
684 Perform interprocedural points-to analysis
687 Common Report Var(flag_ipa_reference) Init(0) Optimization
688 Discover readonly and non addressable static variables
691 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
692 Type based escape and alias analysis
695 Common Report Var(flag_ipa_matrix_reorg) Optimization
696 Perform matrix layout flattening and transposing based
697 on profiling information.
700 Common Report Var(flag_ipa_struct_reorg)
701 Perform structure layout optimizations based
702 on profiling information.
705 Common Joined RejectNegative
706 -fira-algorithm=[CB|priority] Set the used IRA algorithm
709 Common Joined RejectNegative
710 -fira-region=[one|all|mixed] Set regions for IRA
713 Common Report Var(flag_ira_coalesce) Init(0)
714 Do optimistic coalescing.
716 fira-share-save-slots
717 Common Report Var(flag_ira_share_save_slots) Init(1)
718 Share slots for saving different hard registers.
720 fira-share-spill-slots
721 Common Report Var(flag_ira_share_spill_slots) Init(1)
722 Share stack slots for spilled pseudo-registers.
725 Common RejectNegative Joined UInteger
726 -fira-verbose=<number> Control IRA's level of diagnostic messages.
729 Common Report Var(flag_ivopts) Init(1) Optimization
730 Optimize induction variables on trees
733 Common Var(flag_jump_tables) Init(1) Optimization
734 Use jump tables for sufficiently large switch statements
736 fkeep-inline-functions
737 Common Report Var(flag_keep_inline_functions)
738 Generate code for functions even if they are fully inlined
741 Common Report Var(flag_keep_static_consts) Init(1)
742 Emit static const variables even if they are not used
745 Common Report Var(flag_leading_underscore) Init(-1)
746 Give external symbols a leading underscore
750 Does nothing. Preserved for backward compatibility.
754 Enable link-time optimization.
756 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
757 flto-compression-level=
758 Common Joined UInteger Var(flag_lto_compression_level) Init(-1)
759 -flto-compression-level=<number> Use zlib compression level <number> for IL
762 Common Report Var(flag_lto_report) Init(0) Optimization
763 Report various link-time optimization statistics
766 Common Report Var(flag_errno_math) Init(1) Optimization
767 Set errno after built-in math functions
770 Common Report Var(mem_report)
771 Report on permanent memory allocation
773 ; This will attempt to merge constant section constants, if 1 only
774 ; string constants and constants from constant pool, if 2 also constant
777 Common Report Var(flag_merge_constants,2) Init(1) Optimization
778 Attempt to merge identical constants and constant variables
781 Common Report Var(flag_merge_constants,1) VarExists Optimization
782 Attempt to merge identical constants across compilation units
785 Common Report Var(flag_merge_debug_strings) Init(1)
786 Attempt to merge identical debug strings across compilation units
789 Common RejectNegative Joined UInteger
790 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
793 Common Report Var(flag_modulo_sched) Optimization
794 Perform SMS based modulo scheduling before the first scheduling pass
796 fmodulo-sched-allow-regmoves
797 Common Report Var(flag_modulo_sched_allow_regmoves)
798 Perform SMS based modulo scheduling with register moves allowed
800 fmove-loop-invariants
801 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
802 Move loop invariant computations out of loops
805 Common RejectNegative Report Var(flag_mudflap)
806 Add mudflap bounds-checking instrumentation for single-threaded program
809 Common RejectNegative Report VarExists Var(flag_mudflap,2)
810 Add mudflap bounds-checking instrumentation for multi-threaded program
813 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
814 Ignore read operations when inserting mudflap instrumentation
817 Common Var(flag_dce) Init(1) Optimization
818 Use the RTL dead code elimination pass
821 Common Var(flag_dse) Init(1) Optimization
822 Use the RTL dead store elimination pass
824 freschedule-modulo-scheduled-loops
825 Common Report Var(flag_resched_modulo_sched) Optimization
826 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
829 Common Report Var(flag_non_call_exceptions) Optimization
830 Support synchronous non-call exceptions
833 Common Report Var(flag_omit_frame_pointer) Optimization
834 When possible do not generate stack frames
836 foptimize-register-move
837 Common Report Var(flag_regmove) Optimization
838 Do the full register move optimization pass
840 foptimize-sibling-calls
841 Common Report Var(flag_optimize_sibling_calls) Optimization
842 Optimize sibling and tail recursive calls
845 Common Report Var(pre_ipa_mem_report)
846 Report on memory allocation before interprocedural optimization
849 Common Report Var(post_ipa_mem_report)
850 Report on memory allocation before interprocedural optimization
853 Common Report Var(flag_pack_struct) Optimization
854 Pack structure members together without holes
857 Common RejectNegative Joined UInteger Optimization
858 -fpack-struct=<number> Set initial maximum structure member alignment
861 Common Report Var(flag_pcc_struct_return,1) VarExists
862 Return small aggregates in memory, not registers
865 Common Report Var(flag_peel_loops) Optimization
869 Common Report Var(flag_no_peephole,0) Optimization
870 Enable machine specific peephole optimizations
873 Common Report Var(flag_peephole2) Optimization
874 Enable an RTL peephole pass before sched2
877 Common Report Var(flag_pic,2)
878 Generate position-independent code if possible (large mode)
881 Common Report Var(flag_pie,2)
882 Generate position-independent code for executables if possible (large mode)
885 Common Report Var(flag_pic,1) VarExists
886 Generate position-independent code if possible (small mode)
889 Common Report Var(flag_pie,1) VarExists
890 Generate position-independent code for executables if possible (small mode)
893 Common Joined RejectNegative
894 Specify a plugin to load
897 Common Joined RejectNegative
898 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
900 fpredictive-commoning
901 Common Report Var(flag_predictive_commoning) Optimization
902 Run predictive commoning optimization.
904 fprefetch-loop-arrays
905 Common Report Var(flag_prefetch_loop_arrays) Optimization
906 Generate prefetch instructions, if available, for arrays in loops
909 Common Report Var(profile_flag)
910 Enable basic program profiling code
913 Common Report Var(profile_arc_flag)
914 Insert arc-based program profiling code
917 Common Joined RejectNegative
918 Set the top-level directory for storing the profile data.
919 The default is 'pwd'.
922 Common Report Var(flag_profile_correction)
923 Enable correction of flow inconsistent profile data input
927 Enable common options for generating profile info for profile feedback directed optimizations
930 Common Joined RejectNegative
931 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
934 Common Var(flag_profile_use)
935 Enable common options for performing profile feedback directed optimizations
938 Common Joined RejectNegative
939 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
942 Common Report Var(flag_profile_values)
943 Insert code to profile values of expressions
949 Common Joined RejectNegative
950 -frandom-seed=<string> Make compile reproducible using <string>
952 ; This switch causes the command line that was used to create an
953 ; object file to be recorded into the object file. The exact format
954 ; of this recording is target and binary file format dependent.
955 ; It is related to the -fverbose-asm switch, but that switch only
956 ; records information in the assembler output file as comments, so
957 ; they never reach the object file.
959 Common Report Var(flag_record_gcc_switches)
960 Record gcc command line switches in the object file.
963 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
964 Return small aggregates in registers
967 Common Report Var(flag_regmove) Optimization
968 Enables a register move optimization
971 Common Report Var(flag_rename_registers) Init(2) Optimization
972 Perform a register renaming optimization pass
975 Common Report Var(flag_reorder_blocks) Optimization
976 Reorder basic blocks to improve code placement
978 freorder-blocks-and-partition
979 Common Report Var(flag_reorder_blocks_and_partition) Optimization
980 Reorder basic blocks and partition into hot and cold sections
983 Common Report Var(flag_reorder_functions) Optimization
984 Reorder functions to improve code placement
986 frerun-cse-after-loop
987 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
988 Add a common subexpression elimination pass after loop optimizations
992 Does nothing. Preserved for backward compatibility.
995 Common Report Var(flag_rounding_math) Optimization
996 Disable optimizations that assume default FP rounding behavior
999 Common Report Var(flag_schedule_interblock) Init(1) Optimization
1000 Enable scheduling across basic blocks
1003 Common Report Var(flag_sched_pressure) Init(0) Optimization
1004 Enable register pressure sensitive insn scheduling
1007 Common Report Var(flag_schedule_speculative) Init(1) Optimization
1008 Allow speculative motion of non-loads
1011 Common Report Var(flag_schedule_speculative_load) Optimization
1012 Allow speculative motion of some loads
1014 fsched-spec-load-dangerous
1015 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
1016 Allow speculative motion of more loads
1019 Common RejectNegative Joined
1020 -fsched-verbose=<number> Set the verbosity level of the scheduler
1022 fsched2-use-superblocks
1023 Common Report Var(flag_sched2_use_superblocks) Optimization
1024 If scheduling post reload, do superblock scheduling
1027 Common Report Var(flag_sched2_use_traces) Optimization
1028 If scheduling post reload, do trace scheduling
1031 Common Report Var(flag_schedule_insns) Optimization
1032 Reschedule instructions before register allocation
1035 Common Report Var(flag_schedule_insns_after_reload) Optimization
1036 Reschedule instructions after register allocation
1038 ; This flag should be on when a target implements non-trivial
1039 ; scheduling hooks, maybe saving some information for its own sake.
1040 ; On IA64, for example, this is used for correct bundling.
1041 fselective-scheduling
1042 Common Report Var(flag_selective_scheduling) Optimization
1043 Schedule instructions using selective scheduling algorithm
1045 fselective-scheduling2
1046 Common Report Var(flag_selective_scheduling2) Optimization
1047 Run selective scheduling after reload
1049 fsel-sched-pipelining
1050 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1051 Perform software pipelining of inner loops during selective scheduling
1053 fsel-sched-pipelining-outer-loops
1054 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1055 Perform software pipelining of outer loops during selective scheduling
1057 fsel-sched-reschedule-pipelined
1058 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1059 Reschedule pipelined regions without pipelining
1061 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1062 ; of stalled insns into the ready list.
1063 fsched-stalled-insns
1064 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1065 Allow premature scheduling of queued insns
1067 fsched-stalled-insns=
1068 Common RejectNegative Joined UInteger
1069 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1071 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1072 ; be examined for a dependency on a stalled insn that is candidate for
1073 ; premature removal from the queue of stalled insns into the ready list (has
1074 ; an effect only if the flag 'sched_stalled_insns' is set).
1075 fsched-stalled-insns-dep
1076 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1077 Set dependence distance checking in premature scheduling of queued insns
1079 fsched-stalled-insns-dep=
1080 Common RejectNegative Joined UInteger
1081 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1083 fsched-group-heuristic
1084 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
1085 Enable the group heuristic in the scheduler
1087 fsched-critical-path-heuristic
1088 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
1089 Enable the critical path heuristic in the scheduler
1091 fsched-spec-insn-heuristic
1092 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
1093 Enable the speculative instruction heuristic in the scheduler
1095 fsched-rank-heuristic
1096 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
1097 Enable the rank heuristic in the scheduler
1099 fsched-last-insn-heuristic
1100 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
1101 Enable the last instruction heuristic in the scheduler
1103 fsched-dep-count-heuristic
1104 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
1105 Enable the dependent count heuristic in the scheduler
1108 Common Report Var(flag_section_anchors) Optimization
1109 Access data in the same section from shared anchor points
1113 Does nothing. Preserved for backward compatibility.
1116 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
1117 Show column numbers in diagnostics, when available. Default on
1120 Common Report Var(flag_signaling_nans) Optimization
1121 Disable optimizations observable by IEEE signaling NaNs
1124 Common Report Var(flag_signed_zeros) Init(1) Optimization
1125 Disable floating point optimizations that ignore the IEEE signedness of zero
1127 fsingle-precision-constant
1128 Common Report Var(flag_single_precision_constant) Optimization
1129 Convert floating point constants to single precision constants
1131 fsplit-ivs-in-unroller
1132 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1133 Split lifetimes of induction variables when loops are unrolled
1136 Common Report Var(flag_split_wide_types) Optimization
1137 Split wide types into independent registers
1139 fvariable-expansion-in-unroller
1140 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1141 Apply variable expansion when loops are unrolled
1144 Common Report RejectNegative Joined
1145 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1149 Insert stack checking code into the program. Same as -fstack-check=specific
1154 fstack-limit-register=
1155 Common RejectNegative Joined
1156 -fstack-limit-register=<register> Trap if the stack goes past <register>
1158 fstack-limit-symbol=
1159 Common RejectNegative Joined
1160 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1163 Common Report Var(flag_stack_protect, 1)
1164 Use propolice as a stack protection method
1166 fstack-protector-all
1167 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1168 Use a stack protection method for every function
1172 Does nothing. Preserved for backward compatibility.
1174 ; Nonzero if we should do (language-dependent) alias analysis.
1175 ; Typically, this analysis will assume that expressions of certain
1176 ; types do not alias expressions of certain other types. Only used
1177 ; if alias analysis (in general) is enabled.
1179 Common Report Var(flag_strict_aliasing) Optimization
1180 Assume strict aliasing rules apply
1183 Common Report Var(flag_strict_overflow)
1184 Treat signed overflow as undefined
1187 Common Report Var(flag_syntax_only)
1188 Check for syntax errors, then stop
1191 Common Report Var(flag_test_coverage)
1192 Create data files needed by \"gcov\"
1195 Common Report Var(flag_thread_jumps) Optimization
1196 Perform jump threading optimizations
1199 Common Report Var(time_report)
1200 Report the time taken by each compiler pass
1203 Common Joined RejectNegative
1204 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1207 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1208 Reorder top level functions, variables, and asms
1211 Common Report Var(flag_tracer)
1212 Perform superblock formation via tail duplication
1214 ; Zero means that floating-point math operations cannot generate a
1215 ; (user-visible) trap. This is the case, for example, in nonstop
1216 ; IEEE 754 arithmetic.
1218 Common Report Var(flag_trapping_math) Init(1) Optimization
1219 Assume floating-point operations can trap
1222 Common Report Var(flag_trapv) Optimization
1223 Trap for signed overflow in addition, subtraction and multiplication
1226 Common Report Var(flag_tree_ccp) Optimization
1227 Enable SSA-CCP optimization on trees
1231 Does nothing. Preserved for backward compatibility.
1234 Common Report Var(flag_tree_ch) Optimization
1235 Enable loop header copying on trees
1238 Common Report Var(flag_tree_copyrename) Optimization
1239 Replace SSA temporaries with better names in copies
1242 Common Report Var(flag_tree_copy_prop) Optimization
1243 Enable copy propagation on trees
1245 ftree-store-copy-prop
1247 Does nothing. Preserved for backward compatibility.
1250 Common Report Var(flag_tree_cselim) Init(2) Optimization
1251 Transform condition stores into unconditional ones
1253 ftree-switch-conversion
1254 Common Report Var(flag_tree_switch_conversion) Optimization
1255 Perform conversions of switch initializations.
1258 Common Report Var(flag_tree_dce) Optimization
1259 Enable SSA dead code elimination optimization on trees
1261 ftree-dominator-opts
1262 Common Report Var(flag_tree_dom) Optimization
1263 Enable dominator optimizations
1266 Common Report Var(flag_tree_dse) Optimization
1267 Enable dead store elimination
1270 Common Report Var(flag_tree_forwprop) Init(1) Optimization
1271 Enable forward propagation on trees
1274 Common Report Var(flag_tree_fre) Optimization
1275 Enable Full Redundancy Elimination (FRE) on trees
1277 ftree-loop-distribution
1278 Common Report Var(flag_tree_loop_distribution) Optimization
1279 Enable loop distribution on trees
1282 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1283 Enable loop invariant motion on trees
1286 Common Report Var(flag_tree_loop_linear) Optimization
1287 Enable linear loop transforms on trees
1290 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1291 Create canonical induction variables in loops
1294 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1295 Enable loop optimizations on tree level
1297 ftree-parallelize-loops=
1298 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1299 Enable automatic parallelization of loops
1302 Common Report Var(flag_tree_phiprop) Init(1) Optimization
1303 Enable hoisting loads from conditional pointers.
1306 Common Report Var(flag_tree_pre) Optimization
1307 Enable SSA-PRE optimization on trees
1310 Common Report Var(flag_tree_pta) Init(1) Optimization
1311 Perform function-local points-to analysis on trees.
1314 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1315 Enable reassociation on tree level
1319 Does nothing. Preserved for backward compatibility.
1322 Common Report Var(flag_tree_sink) Optimization
1323 Enable SSA code sinking on trees
1326 Common Report Var(flag_tree_sra) Optimization
1327 Perform scalar replacement of aggregates
1330 Common Report Var(flag_tree_ter) Init(1) Optimization
1331 Replace temporary expressions in the SSA->normal pass
1334 Common Report Var(flag_tree_live_range_split) Optimization
1335 Perform live range splitting during the SSA->normal pass
1338 Common Report Var(flag_tree_vrp) Init(0) Optimization
1339 Perform Value Range Propagation on trees
1342 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1343 Compile whole compilation unit at a time
1346 Common Report Var(flag_unroll_loops) Optimization
1347 Perform loop unrolling when iteration count is known
1350 Common Report Var(flag_unroll_all_loops) Optimization
1351 Perform loop unrolling for all loops
1353 ; Nonzero means that loop optimizer may assume that the induction variables
1354 ; that control loops do not overflow and that the loops with nontrivial
1355 ; exit condition are not infinite
1356 funsafe-loop-optimizations
1357 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1358 Allow loop optimizations to assume that the loops behave in normal way
1361 Common Report Var(flag_associative_math)
1362 Allow optimization for floating-point arithmetic which may change the
1363 result of the operation due to rounding.
1366 Common Report Var(flag_reciprocal_math)
1367 Same as -fassociative-math for expressions which include division.
1369 ; Nonzero means that unsafe floating-point math optimizations are allowed
1370 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1371 ; are allowed to assume that their arguments and results are "normal"
1372 ; (e.g., nonnegative for SQRT).
1373 funsafe-math-optimizations
1374 Common Report Var(flag_unsafe_math_optimizations) Optimization
1375 Allow math optimizations that may violate IEEE or ISO standards
1378 Common Report Var(flag_unswitch_loops) Optimization
1379 Perform loop unswitching
1382 Common Report Var(flag_unwind_tables) Optimization
1383 Just generate unwind tables for exception handling
1386 Common Report Var(flag_var_tracking) VarExists Optimization
1387 Perform variable tracking
1389 fvar-tracking-assignments
1390 Common Report Var(flag_var_tracking_assignments) VarExists Optimization
1391 Perform variable tracking by annotating assignments
1393 fvar-tracking-assignments-toggle
1394 Common Report Var(flag_var_tracking_assignments_toggle) VarExists Optimization
1395 Toggle -fvar-tracking-assignments
1397 fvar-tracking-uninit
1398 Common Report Var(flag_var_tracking_uninit) Optimization
1399 Perform variable tracking and also tag variables that are uninitialized
1402 Common Report Var(flag_tree_vectorize) Optimization
1403 Enable loop vectorization on trees
1406 Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
1407 Enable basic block vectorization (SLP) on trees
1410 Common Report Var(flag_vect_cost_model) Optimization
1411 Enable use of cost model in vectorization
1413 ftree-vect-loop-version
1414 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1415 Enable loop versioning when doing loop vectorization on trees
1417 ftree-vectorizer-verbose=
1418 Common RejectNegative Joined
1419 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1422 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1423 Enable copy propagation of scalar-evolution information.
1425 ; -fverbose-asm causes extra commentary information to be produced in
1426 ; the generated assembly code (to make it more readable). This option
1427 ; is generally only of use to those who actually need to read the
1428 ; generated assembly code (perhaps while debugging the compiler itself).
1429 ; -fno-verbose-asm, the default, causes the extra information
1430 ; to not be added and is useful when comparing two assembler files.
1432 Common Report Var(flag_verbose_asm)
1433 Add extra commentary to assembler output
1436 Common Joined RejectNegative
1437 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1441 Common Report Var(flag_value_profile_transformations) Optimization
1442 Use expression value profiles in optimizations
1445 Common Report Var(flag_web) Init(2) Optimization
1446 Construct webs and split unrelated uses of single variable
1449 Common Var(flag_whopr)
1450 Enable partitioned link-time optimization.
1452 ftree-builtin-call-dce
1453 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1454 Enable conditional dead code elimination for builtin calls
1457 Common Report Var(flag_whole_program) Init(0) Optimization
1458 Perform whole program optimizations
1461 Common Report Var(flag_wrapv) Optimization
1462 Assume signed arithmetic overflow wraps around
1464 fzero-initialized-in-bss
1465 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1466 Put zero initialized data in the bss section
1469 Common JoinedOrMissing
1470 Generate debug information in default format
1473 Common JoinedOrMissing Negative(gdwarf-)
1474 Generate debug information in COFF format
1477 Common Joined UInteger Var(dwarf_version) Init(2) Negative(gstabs)
1478 Generate debug information in DWARF v2 (or later) format
1481 Common JoinedOrMissing
1482 Generate debug information in default extended format
1485 Common JoinedOrMissing Negative(gstabs+)
1486 Generate debug information in STABS format
1489 Common JoinedOrMissing Negative(gvms)
1490 Generate debug information in extended STABS format
1493 Common RejectNegative Var(dwarf_strict,0) Init(-1)
1494 Emit DWARF additions beyond selected version
1497 Common Report RejectNegative Var(dwarf_strict,1) VarExists
1498 Don't emit DWARF additions beyond selected version
1501 Common Report Var(flag_gtoggle)
1502 Toggle debug information generation
1505 Common JoinedOrMissing Negative(gxcoff)
1506 Generate debug information in VMS format
1509 Common JoinedOrMissing Negative(gxcoff+)
1510 Generate debug information in XCOFF format
1513 Common JoinedOrMissing Negative(gcoff)
1514 Generate debug information in extended XCOFF format
1517 Common Joined Separate
1518 -o <file> Place output into <file>
1521 Common Var(profile_flag)
1522 Enable function profiling
1525 Common Var(pedantic)
1526 Issue warnings needed for strict compliance to the standard
1530 Like -pedantic but issue them as errors
1533 Common Var(quiet_flag)
1534 Do not display functions compiled or elapsed time
1537 Common Var(version_flag)
1538 Display the compiler's version
1541 Common Var(inhibit_warnings)
1545 Common RejectNegative Negative(pie)
1546 Create a shared library
1549 Common RejectNegative Negative(shared)
1550 Create a position independent executable
1552 ; This comment is to ensure we retain the blank line above.