1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008
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 three 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).
52 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
58 Common Joined Separate UInteger
59 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
62 Common JoinedOrMissing
63 -O<number> Set optimization level to <number>
67 Optimize for space rather than speed
71 This switch is deprecated; use -Wextra instead
74 Common Var(warn_aggregate_return) Warning
75 Warn about returning structures, unions or arrays
78 Common Var(warn_array_bounds) Warning
79 Warn if an array is accessed out of bounds
82 Common Var(warn_attributes) Init(1) Warning
83 Warn about inappropriate attribute usage
86 Common Var(warn_cast_align) Warning
87 Warn about pointer casts which increase alignment
89 Wdeprecated-declarations
90 Common Var(warn_deprecated_decl) Init(1) Warning
91 Warn about uses of __attribute__((deprecated)) declarations
93 Wdisabled-optimization
94 Common Var(warn_disabled_optimization) Warning
95 Warn when an optimization pass is disabled
98 Common Var(warnings_are_errors)
99 Treat all warnings as errors
103 Treat specified warning as error
107 Print extra (possibly unwanted) warnings
110 Common Var(flag_fatal_errors)
111 Exit on the first error occurred
114 Common Var(warn_inline) Warning
115 Warn when an inlined function cannot be inlined
118 Common RejectNegative Joined UInteger Warning
119 -Wlarger-than-<number> Warn if an object is larger than <number> bytes
122 Common Warning Var(warn_logical_op)
123 Warn when a logical operator is suspicously always evaluating to true or false
125 Wunsafe-loop-optimizations
126 Common Var(warn_unsafe_loop_optimizations) Warning
127 Warn if the loop cannot be optimized due to nontrivial assumptions.
130 Common Var(warn_missing_noreturn) Warning
131 Warn about functions which might be candidates for __attribute__((noreturn))
134 Common Var(warn_overflow) Init(1) Warning
135 Warn about overflow in arithmetic expressions
138 Common Var(warn_packed) Warning
139 Warn when the packed attribute has no effect on struct layout
142 Common Var(warn_padded) Warning
143 Warn when padding is required to align structure members
146 Common Var(warn_shadow) Warning
147 Warn when one local variable shadows another
150 Common Var(warn_stack_protect) Warning
151 Warn when not issuing stack smashing protection for some reason
155 Warn about code which might break strict aliasing rules
158 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
159 Warn about code which might break strict aliasing rules
163 Warn about optimizations that assume that signed overflow is undefined
166 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
167 Warn about optimizations that assume that signed overflow is undefined
170 Common Var(warn_switch) Warning
171 Warn about enumerated switches, with no default, missing a case
174 Common Var(warn_switch_default) Warning
175 Warn about enumerated switches missing a \"default:\" statement
178 Common Var(warn_switch_enum) Warning
179 Warn about all enumerated switches missing a specific case
182 Common Var(warn_system_headers) Warning
183 Do not suppress warnings from system headers
186 Common Var(warn_uninitialized) Warning
187 Warn about uninitialized automatic variables
190 Common Var(warn_notreached) Warning
191 Warn about code that will never be executed
195 Enable all -Wunused- warnings
198 Common Var(warn_unused_function) Warning
199 Warn when a function is unused
202 Common Var(warn_unused_label) Warning
203 Warn when a label is unused
206 Common Var(warn_unused_parameter) Warning
207 Warn when a function parameter is unused
210 Common Var(warn_unused_value) Warning
211 Warn when an expression value is unused
214 Common Var(warn_unused_variable) Warning
215 Warn when a variable is unused
217 Wvolatile-register-var
218 Common Var(warn_register_var) Warning
219 Warn when a register variable is declared volatile
222 Common RejectNegative Var(warn_coverage_mismatch) Warning
223 Warn instead of error in case profiles in -fprofile-use do not match
227 -aux-info <file> Emit declaration information into <file>
240 -d<letters> Enable dumps from specific passes of the compiler
244 -dumpbase <file> Set the file basename to be used for dumps
246 ; The version of the C++ ABI in use. The following values are allowed:
248 ; 0: The version of the ABI believed most conformant with the C++ ABI
249 ; specification. This ABI may change as bugs are discovered and fixed.
250 ; Therefore, 0 will not necessarily indicate the same ABI in different
253 ; 1: The version of the ABI first used in G++ 3.2.
255 ; 2: The version of the ABI first used in G++ 3.4.
257 ; Additional positive integers will be assigned as new versions of
258 ; the ABI become the default version of the ABI.
260 Common Joined UInteger Var(flag_abi_version) Init(2)
263 Common Report Var(align_functions,0)
264 Align the start of functions
267 Common RejectNegative Joined UInteger
270 Common Report Var(align_jumps,0) Optimization
271 Align labels which are only reached by jumping
274 Common RejectNegative Joined UInteger
277 Common Report Var(align_labels,0) Optimization
281 Common RejectNegative Joined UInteger
284 Common Report Var(align_loops) Optimization
285 Align the start of loops
288 Common RejectNegative Joined UInteger
290 ; This flag is only tested if alias checking is enabled.
291 ; 0 if pointer arguments may alias each other. True in C.
292 ; 1 if pointer arguments may not alias each other but may alias
294 ; 2 if pointer arguments may not alias each other and may not
295 ; alias global variables.
296 ; 3 if pointer arguments may not alias anything. True in Fortran.
297 ; Set by the front end.
299 Common Report Var(flag_argument_noalias,0) Optimization
300 Specify that arguments may alias each other and globals
303 Common Report Var(flag_argument_noalias,1) VarExists Optimization
304 Assume arguments may alias globals but not each other
306 fargument-noalias-global
307 Common Report Var(flag_argument_noalias,2) VarExists Optimization
308 Assume arguments alias neither each other nor globals
310 fargument-noalias-anything
311 Common Report Var(flag_argument_noalias,3) VarExists Optimization
312 Assume arguments alias no other storage
314 fasynchronous-unwind-tables
315 Common Report Var(flag_asynchronous_unwind_tables) Optimization
316 Generate unwind tables that are exact at each instruction boundary
319 Common Report Var(flag_auto_inc_dec) Init(1)
320 Generate auto-inc/dec instructions
322 ; -fcheck-bounds causes gcc to generate array bounds checks.
323 ; For C, C++ and ObjC: defaults off.
324 ; For Java: defaults to on.
325 ; For Fortran: defaults to off.
327 Common Report Var(flag_bounds_check)
328 Generate code to check bounds before indexing arrays
331 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
332 Replace add, compare, branch with branch on count register
334 fbranch-probabilities
335 Common Report Var(flag_branch_probabilities) Optimization
336 Use profiling information for branch probabilities
338 fbranch-target-load-optimize
339 Common Report Var(flag_branch_target_load_optimize) Optimization
340 Perform branch target load optimization before prologue / epilogue threading
342 fbranch-target-load-optimize2
343 Common Report Var(flag_branch_target_load_optimize2) Optimization
344 Perform branch target load optimization after prologue / epilogue threading
347 Common Report Var(flag_btr_bb_exclusive) Optimization
348 Restrict target load migration not to re-use registers in any basic block
351 Common Joined RejectNegative
352 -fcall-saved-<register> Mark <register> as being preserved across functions
355 Common Joined RejectNegative
356 -fcall-used-<register> Mark <register> as being corrupted by function calls
358 ; Nonzero for -fcaller-saves: allocate values in regs that need to
359 ; be saved across function calls, if that produces overall better code.
360 ; Optional now, so people can test it.
362 Common Report Var(flag_caller_saves) Optimization
363 Save registers around function calls
366 Common Report Var(flag_check_data_deps)
367 Compare the results of several data dependence analyzers.
370 Common Report Var(flag_no_common,0) Optimization
371 Do not put uninitialized globals in the common section
374 Common Report Var(flag_cprop_registers) Optimization
375 Perform a register copy-propagation optimization pass
378 Common Report Var(flag_crossjumping) Optimization
379 Perform cross-jumping optimization
382 Common Report Var(flag_cse_follow_jumps) Optimization
383 When running CSE, follow jumps to their targets
386 Common Report Var(flag_cse_skip_blocks) Optimization
387 When running CSE, follow conditional jumps
390 Common Report Var(flag_cx_limited_range) Optimization
391 Omit range reduction step when performing complex division
394 Common Report Var(flag_data_sections) Optimization
395 Place data items into their own section
399 List all available debugging counters with their limits and counts.
402 Common RejectNegative Joined
403 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
406 Common Joined RejectNegative
407 Map one directory name to another in debug information
409 ; Nonzero for -fdefer-pop: don't pop args after each function call
410 ; instead save them up to pop many calls' args with one insns.
412 Common Report Var(flag_defer_pop) Optimization
413 Defer popping functions args from stack until later
416 Common Report Var(flag_delayed_branch) Optimization
417 Attempt to fill delay slots of branch instructions
419 fdelete-null-pointer-checks
420 Common Report Var(flag_delete_null_pointer_checks) Optimization
421 Delete useless null pointer checks
423 fdiagnostics-show-location=
424 Common Joined RejectNegative
425 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
427 fdiagnostics-show-option
429 Amend appropriate diagnostic messages with the command line option that controls them
432 Common Joined RejectNegative
433 -fdump-<type> Dump various compiler internals to a file
436 Common Report Var(flag_dump_noaddr)
437 Suppress output of addresses in debugging dumps
440 Common Report Var(flag_dump_simple_rtl) Init(0)
441 Switch on dumping simple RTL code
444 Common Report Var(flag_dump_unnumbered) VarExists
445 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
448 Common Report Var(flag_early_inlining) Init(1) Optimization
449 Perform early inlining
451 feliminate-dwarf2-dups
452 Common Report Var(flag_eliminate_dwarf2_dups)
453 Perform DWARF2 duplicate elimination
455 feliminate-unused-debug-symbols
456 Common Report Var(flag_debug_only_used_symbols)
457 Perform unused type elimination in debug info
459 feliminate-unused-debug-types
460 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
461 Perform unused type elimination in debug info
463 femit-class-debug-always
464 Common Report Var(flag_emit_class_debug_always) Init(0)
465 Do not suppress C++ class debug information.
468 Common Report Var(flag_exceptions) Optimization
469 Enable exception handling
471 fexpensive-optimizations
472 Common Report Var(flag_expensive_optimizations) Optimization
473 Perform a number of minor, expensive optimizations
479 Common Report Var(flag_finite_math_only) Optimization
480 Assume no NaNs or infinities are generated
483 Common Joined RejectNegative
484 -ffixed-<register> Mark <register> as being unavailable to the compiler
487 Common Report Var(flag_float_store) Optimization
488 Don't allocate floats and doubles in extended-precision registers
492 Does nothing. Preserved for backward compatibility.
495 Common Report Var(flag_forward_propagate) Optimization
496 Perform a forward propagation pass on RTL
498 ; Nonzero means don't put addresses of constant functions in registers.
499 ; Used for compiling the Unix kernel, where strange substitutions are
500 ; done on the assembly output.
502 Common Report Var(flag_no_function_cse,0)
503 Allow function addresses to be held in registers
506 Common Report Var(flag_function_sections)
507 Place each function into its own section
510 Common Report Var(flag_gcse) Optimization
511 Perform global common subexpression elimination
514 Common Report Var(flag_gcse_lm) Init(1) Optimization
515 Perform enhanced load motion during global common subexpression elimination
518 Common Report Var(flag_gcse_sm) Init(0) Optimization
519 Perform store motion after global common subexpression elimination
522 Common Report Var(flag_gcse_las) Init(0) Optimization
523 Perform redundant load after store elimination in global common subexpression
527 Common Report Var(flag_gcse_after_reload) Optimization
528 Perform global common subexpression elimination after register allocation
531 fguess-branch-probability
532 Common Report Var(flag_guess_branch_prob) Optimization
533 Enable guessing of branch probabilities
535 ; Nonzero means ignore `#ident' directives. 0 means handle them.
536 ; Generate position-independent code for executables if possible
537 ; On SVR4 targets, it also controls whether or not to emit a
538 ; string identifying the compiler.
540 Common Report Var(flag_no_ident,0)
541 Process #ident directives
544 Common Report Var(flag_if_conversion) Optimization
545 Perform conversion of conditional jumps to branchless equivalents
548 Common Report Var(flag_if_conversion2) Optimization
549 Perform conversion of conditional jumps to conditional execution
551 ; -finhibit-size-directive inhibits output of .size for ELF.
552 ; This is used only for compiling crtstuff.c,
553 ; and it may be extended to other effects
554 ; needed for crtstuff.c on other systems.
555 finhibit-size-directive
556 Common Report Var(flag_inhibit_size_directive)
557 Do not generate .size directives
559 ; Nonzero means that functions declared `inline' will be treated
560 ; as `static'. Prevents generation of zillions of copies of unused
561 ; static inline functions; instead, `inlines' are written out
562 ; only when actually used. Used in conjunction with -g. Also
563 ; does the right thing with #pragma interface.
565 Common Report Var(flag_no_inline,0) Init(2)
566 Pay attention to the \"inline\" keyword
568 finline-small-functions
569 Common Report Var(flag_inline_small_functions) Optimization
570 Integrate simple functions into their callers when code size is known to not growth
573 Common Report Var(flag_inline_functions) Optimization
574 Integrate simple functions into their callers
576 finline-functions-called-once
577 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
578 Integrate functions called once into their callers
581 Common RejectNegative Joined UInteger
584 Common RejectNegative Joined UInteger
585 -finline-limit=<number> Limit the size of inlined functions to <number>
587 finstrument-functions
588 Common Report Var(flag_instrument_function_entry_exit)
589 Instrument function entry and exit with profiling calls
591 finstrument-functions-exclude-function-list=
592 Common RejectNegative Joined
593 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
595 finstrument-functions-exclude-file-list=
596 Common RejectNegative Joined
597 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
600 Common Report Var(flag_ipa_cp) Optimization
601 Perform Interprocedural constant propagation
604 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
605 Discover pure and const functions
608 Common Report Var(flag_ipa_pta) Init(0) Optimization
609 Perform interprocedural points-to analysis
612 Common Report Var(flag_ipa_reference) Init(0) Optimization
613 Discover readonly and non addressable static variables
616 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
617 Type based escape and alias analysis
620 Common Report Var(flag_ipa_matrix_reorg) Optimization
621 Perform matrix layout flattening and transposing based
622 on profiling information.
625 Common Report Var(flag_ipa_struct_reorg)
626 Perform structure layout optimizations based
627 on profiling information.
630 Common Report Var(flag_ira) Init(0)
631 Use integrated register allocator.
634 Common Joined RejectNegative
635 -fira-algorithm=[regional|CB|mixed|priority] Set the used IRA algorithm
638 Common Report Var(flag_ira_coalesce) Init(0)
639 Do optimistic coalescing.
642 Common Report Var(flag_ira_ipra) Init(0)
643 Inter-procedural register allocation for IRA.
646 Common Report Var(flag_ira_move_spills) Init(1)
647 Increase gap between the corresponding save and restore insns.
650 Common Report Var(flag_ira_propagate_cost) Init(0)
651 Propagate hard reg costs down for regional or mixed ira allocation algorithm.
653 fira-share-save-slots
654 Common Report Var(flag_ira_share_save_slots) Init(1)
655 Share slots for saving different hard registers.
657 fira-share-spill-slots
658 Common Report Var(flag_ira_share_spill_slots) Init(1)
659 Share stack slots for spilled pseudo-registers.
662 Common RejectNegative Joined UInteger
663 -fira-verbose=<number> Control IRA's level of diagnostic messages.
666 Common Report Var(flag_ivopts) Init(1) Optimization
667 Optimize induction variables on trees
670 Common Var(flag_jump_tables) Init(1) Optimization
671 Use jump tables for sufficiently large switch statements
673 fkeep-inline-functions
674 Common Report Var(flag_keep_inline_functions)
675 Generate code for functions even if they are fully inlined
678 Common Report Var(flag_keep_static_consts) Init(1)
679 Emit static const variables even if they are not used
682 Common Report Var(flag_leading_underscore) Init(-1)
683 Give external symbols a leading underscore
687 Does nothing. Preserved for backward compatibility.
690 Common Report Var(flag_lower_subreg)
694 Common Report Var(flag_errno_math) Init(1)
695 Set errno after built-in math functions
698 Common Report Var(mem_report)
699 Report on permanent memory allocation
701 ; This will attempt to merge constant section constants, if 1 only
702 ; string constants and constants from constant pool, if 2 also constant
705 Common Report Var(flag_merge_constants,2) Init(1) Optimization
706 Attempt to merge identical constants and constant variables
709 Common Report Var(flag_merge_constants,1) VarExists Optimization
710 Attempt to merge identical constants across compilation units
713 Common Report Var(flag_merge_debug_strings) Init(1)
714 Attempt to merge identical debug strings across compilation units
717 Common RejectNegative Joined UInteger
718 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
721 Common Report Var(flag_modulo_sched) Optimization
722 Perform SMS based modulo scheduling before the first scheduling pass
724 fmodulo-sched-allow-regmoves
725 Common Report Var(flag_modulo_sched_allow_regmoves)
726 Perform SMS based modulo scheduling with register moves allowed
728 fmove-loop-invariants
729 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
730 Move loop invariant computations out of loops
733 Common RejectNegative Report Var(flag_mudflap)
734 Add mudflap bounds-checking instrumentation for single-threaded program
737 Common RejectNegative Report VarExists Var(flag_mudflap,2)
738 Add mudflap bounds-checking instrumentation for multi-threaded program
741 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
742 Ignore read operations when inserting mudflap instrumentation
745 Common Var(flag_dce) Init(1) Optimization
746 Use the RTL dead code elimination pass
749 Common Var(flag_dse) Init(1) Optimization
750 Use the RTL dead store elimination pass
752 freschedule-modulo-scheduled-loops
753 Common Report Var(flag_resched_modulo_sched) Optimization
754 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
757 Common Report Var(flag_non_call_exceptions) Optimization
758 Support synchronous non-call exceptions
761 Common Report Var(flag_omit_frame_pointer) Optimization
762 When possible do not generate stack frames
765 Common Report Var(flag_openmp_ssa)
766 Expand OpenMP operations on SSA form
768 foptimize-register-move
769 Common Report Var(flag_regmove) Optimization
770 Do the full register move optimization pass
772 foptimize-sibling-calls
773 Common Report Var(flag_optimize_sibling_calls) Optimization
774 Optimize sibling and tail recursive calls
777 Common Report Var(pre_ipa_mem_report)
778 Report on memory allocation before interprocedural optimization
781 Common Report Var(post_ipa_mem_report)
782 Report on memory allocation before interprocedural optimization
785 Common Report Var(flag_pack_struct) Optimization
786 Pack structure members together without holes
789 Common RejectNegative Joined UInteger Optimization
790 -fpack-struct=<number> Set initial maximum structure member alignment
793 Common Report Var(flag_pcc_struct_return,1) VarExists
794 Return small aggregates in memory, not registers
797 Common Report Var(flag_peel_loops) Optimization
801 Common Report Var(flag_no_peephole,0) Optimization
802 Enable machine specific peephole optimizations
805 Common Report Var(flag_peephole2) Optimization
806 Enable an RTL peephole pass before sched2
809 Common Report Var(flag_pic,2)
810 Generate position-independent code if possible (large mode)
813 Common Report Var(flag_pie,2)
814 Generate position-independent code for executables if possible (large mode)
817 Common Report Var(flag_pic,1) VarExists
818 Generate position-independent code if possible (small mode)
821 Common Report Var(flag_pie,1) VarExists
822 Generate position-independent code for executables if possible (small mode)
824 fpredictive-commoning
825 Common Report Var(flag_predictive_commoning) Optimization
826 Run predictive commoning optimization.
828 fprefetch-loop-arrays
829 Common Report Var(flag_prefetch_loop_arrays) Optimization
830 Generate prefetch instructions, if available, for arrays in loops
833 Common Report Var(profile_flag)
834 Enable basic program profiling code
837 Common Report Var(profile_arc_flag)
838 Insert arc-based program profiling code
842 Enable common options for generating profile info for profile feedback directed optimizations
846 Enable common options for performing profile feedback directed optimizations
849 Common Report Var(flag_profile_values)
850 Insert code to profile values of expressions
856 Common Joined RejectNegative
857 -frandom-seed=<string> Make compile reproducible using <string>
859 ; This switch causes the command line that was used to create an
860 ; object file to be recorded into the object file. The exact format
861 ; of this recording is target and binary file format dependent.
862 ; It is related to the -fverbose-asm switch, but that switch only
863 ; records information in the assembler output file as comments, so
864 ; they never reach the object file.
866 Common Report Var(flag_record_gcc_switches)
867 Record gcc command line switches in the object file.
870 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
871 Return small aggregates in registers
874 Common Report Var(flag_regmove) Optimization
875 Enables a register move optimization
878 Common Report Var(flag_rename_registers) Init(2) Optimization
879 Perform a register renaming optimization pass
882 Common Report Var(flag_reorder_blocks) Optimization
883 Reorder basic blocks to improve code placement
885 freorder-blocks-and-partition
886 Common Report Var(flag_reorder_blocks_and_partition) Optimization
887 Reorder basic blocks and partition into hot and cold sections
890 Common Report Var(flag_reorder_functions) Optimization
891 Reorder functions to improve code placement
893 frerun-cse-after-loop
894 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
895 Add a common subexpression elimination pass after loop optimizations
899 Does nothing. Preserved for backward compatibility.
902 Common Report Var(flag_rounding_math) Optimization
903 Disable optimizations that assume default FP rounding behavior
906 Common Report Var(flag_schedule_interblock) Init(1) Optimization
907 Enable scheduling across basic blocks
910 Common Report Var(flag_schedule_speculative) Init(1) Optimization
911 Allow speculative motion of non-loads
914 Common Report Var(flag_schedule_speculative_load) Optimization
915 Allow speculative motion of some loads
917 fsched-spec-load-dangerous
918 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
919 Allow speculative motion of more loads
922 Common RejectNegative Joined
923 -fsched-verbose=<number> Set the verbosity level of the scheduler
925 fsched2-use-superblocks
926 Common Report Var(flag_sched2_use_superblocks) Optimization
927 If scheduling post reload, do superblock scheduling
930 Common Report Var(flag_sched2_use_traces) Optimization
931 If scheduling post reload, do trace scheduling
934 Common Report Var(flag_schedule_insns) Optimization
935 Reschedule instructions before register allocation
938 Common Report Var(flag_schedule_insns_after_reload) Optimization
939 Reschedule instructions after register allocation
941 ; sched_stalled_insns means that insns can be moved prematurely from the queue
942 ; of stalled insns into the ready list.
944 Common Report Var(flag_sched_stalled_insns) Optimization
945 Allow premature scheduling of queued insns
947 fsched-stalled-insns=
948 Common RejectNegative Joined UInteger
949 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
951 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
952 ; be examined for a dependency on a stalled insn that is candidate for
953 ; premature removal from the queue of stalled insns into the ready list (has
954 ; an effect only if the flag 'sched_stalled_insns' is set).
955 fsched-stalled-insns-dep
956 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
957 Set dependence distance checking in premature scheduling of queued insns
959 fsched-stalled-insns-dep=
960 Common RejectNegative Joined UInteger
961 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
964 Common Report Var(flag_section_anchors) Optimization
965 Access data in the same section from shared anchor points
967 frtl-abstract-sequences
968 Common Report Var(flag_rtl_seqabstr) Optimization
969 Perform sequence abstraction optimization on RTL
972 Common Report Var(flag_see) Init(0)
973 Eliminate redundant sign extensions using LCM.
976 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
977 Show column numbers in diagnostics, when available. Default off
980 Common Report Var(flag_signaling_nans) Optimization
981 Disable optimizations observable by IEEE signaling NaNs
984 Common Report Var(flag_signed_zeros) Init(1) Optimization
985 Disable floating point optimizations that ignore the IEEE signedness of zero
987 fsingle-precision-constant
988 Common Report Var(flag_single_precision_constant) Optimization
989 Convert floating point constants to single precision constants
991 fsplit-ivs-in-unroller
992 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
993 Split lifetimes of induction variables when loops are unrolled
996 Common Report Var(flag_split_wide_types) Optimization
997 Split wide types into independent registers
999 fvariable-expansion-in-unroller
1000 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1001 Apply variable expansion when loops are unrolled
1003 ; Emit code to probe the stack, to help detect stack overflow; also
1004 ; may cause large objects to be allocated dynamically.
1006 Common Report Var(flag_stack_check)
1007 Insert stack checking code into the program
1012 fstack-limit-register=
1013 Common RejectNegative Joined
1014 -fstack-limit-register=<register> Trap if the stack goes past <register>
1016 fstack-limit-symbol=
1017 Common RejectNegative Joined
1018 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1021 Common Report Var(flag_stack_protect, 1)
1022 Use propolice as a stack protection method
1024 fstack-protector-all
1025 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1026 Use a stack protection method for every function
1030 Does nothing. Preserved for backward compatibility.
1032 ; Nonzero if we should do (language-dependent) alias analysis.
1033 ; Typically, this analysis will assume that expressions of certain
1034 ; types do not alias expressions of certain other types. Only used
1035 ; if alias analysis (in general) is enabled.
1037 Common Report Var(flag_strict_aliasing) Optimization
1038 Assume strict aliasing rules apply
1041 Common Report Var(flag_strict_overflow)
1042 Treat signed overflow as undefined
1045 Common Report Var(flag_syntax_only)
1046 Check for syntax errors, then stop
1049 Common Report Var(flag_test_coverage)
1050 Create data files needed by \"gcov\"
1053 Common Report Var(flag_thread_jumps) Optimization
1054 Perform jump threading optimizations
1057 Common Report Var(time_report)
1058 Report the time taken by each compiler pass
1061 Common Joined RejectNegative
1062 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1065 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
1066 Reorder top level functions, variables, and asms
1069 Common Report Var(flag_tracer)
1070 Perform superblock formation via tail duplication
1072 ; Zero means that floating-point math operations cannot generate a
1073 ; (user-visible) trap. This is the case, for example, in nonstop
1074 ; IEEE 754 arithmetic.
1076 Common Report Var(flag_trapping_math) Init(1) Optimization
1077 Assume floating-point operations can trap
1080 Common Report Var(flag_trapv) Optimization
1081 Trap for signed overflow in addition, subtraction and multiplication
1084 Common Report Var(flag_tree_ccp) Optimization
1085 Enable SSA-CCP optimization on trees
1088 Common Report Var(flag_tree_store_ccp) Optimization
1089 Enable SSA-CCP optimization for stores and loads
1092 Common Report Var(flag_tree_ch) Optimization
1093 Enable loop header copying on trees
1096 Common Report Var(flag_tree_copyrename) Optimization
1097 Replace SSA temporaries with better names in copies
1100 Common Report Var(flag_tree_copy_prop) Optimization
1101 Enable copy propagation on trees
1103 ftree-store-copy-prop
1105 Does nothing. Preserved for backward compatibility.
1108 Common Report Var(flag_tree_cselim) Init(2) Optimization
1109 Transform condition stores into unconditional ones
1112 Common Report Var(flag_tree_dce) Optimization
1113 Enable SSA dead code elimination optimization on trees
1115 ftree-dominator-opts
1116 Common Report Var(flag_tree_dom) Optimization
1117 Enable dominator optimizations
1120 Common Report Var(flag_tree_dse) Optimization
1121 Enable dead store elimination
1124 Common Report Var(flag_tree_fre) Optimization
1125 Enable Full Redundancy Elimination (FRE) on trees
1128 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1129 Enable loop invariant motion on trees
1132 Common Report Var(flag_tree_loop_linear) Optimization
1133 Enable linear loop transforms on trees
1136 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1137 Create canonical induction variables in loops
1140 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1141 Enable loop optimizations on tree level
1143 ftree-parallelize-loops=
1144 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1145 Enable automatic parallelization of loops
1148 Common Report Var(flag_tree_pre) Optimization
1149 Enable SSA-PRE optimization on trees
1152 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1153 Enable reassociation on tree level
1156 Common Report Var(flag_tree_salias) Optimization
1157 Perform structural alias analysis
1160 Common Report Var(flag_tree_sink) Optimization
1161 Enable SSA code sinking on trees
1164 Common Report Var(flag_tree_sra) Optimization
1165 Perform scalar replacement of aggregates
1168 Common Report Var(flag_tree_ter) Optimization
1169 Replace temporary expressions in the SSA->normal pass
1172 Common Report Var(flag_tree_live_range_split) Optimization
1173 Perform live range splitting during the SSA->normal pass
1176 Common Report Var(flag_tree_vrp) Init(0) Optimization
1177 Perform Value Range Propagation on trees
1180 Common Report Var(flag_unit_at_a_time) Optimization
1181 Compile whole compilation unit at a time
1184 Common Report Var(flag_unroll_loops) Optimization
1185 Perform loop unrolling when iteration count is known
1188 Common Report Var(flag_unroll_all_loops) Optimization
1189 Perform loop unrolling for all loops
1191 ; Nonzero means that loop optimizer may assume that the induction variables
1192 ; that control loops do not overflow and that the loops with nontrivial
1193 ; exit condition are not infinite
1194 funsafe-loop-optimizations
1195 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1196 Allow loop optimizations to assume that the loops behave in normal way
1199 Common Report Var(flag_associative_math)
1200 Allow optimization for floating-point arithmetic which may change the
1201 result of the operation due to rounding.
1204 Common Report Var(flag_reciprocal_math)
1205 Same as -fassociative-math for expressions which include division.
1207 ; Nonzero means that unsafe floating-point math optimizations are allowed
1208 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1209 ; are allowed to assume that their arguments and results are "normal"
1210 ; (e.g., nonnegative for SQRT).
1211 funsafe-math-optimizations
1212 Common Report Var(flag_unsafe_math_optimizations) Optimization
1213 Allow math optimizations that may violate IEEE or ISO standards
1216 Common Report Var(flag_unswitch_loops) Optimization
1217 Perform loop unswitching
1220 Common Report Var(flag_unwind_tables) Optimization
1221 Just generate unwind tables for exception handling
1224 Common Report Var(flag_var_tracking) VarExists Optimization
1225 Perform variable tracking
1227 fvar-tracking-uninit
1228 Common Report Var(flag_var_tracking_uninit) Optimization
1229 Perform variable tracking and also tag variables that are uninitialized
1232 Common Report Var(flag_tree_vectorize) Optimization
1233 Enable loop vectorization on trees
1236 Common Report Var(flag_vect_cost_model) Optimization
1237 Enable use of cost model in vectorization
1239 ftree-vect-loop-version
1240 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1241 Enable loop versioning when doing loop vectorization on trees
1243 ftree-vectorizer-verbose=
1244 Common RejectNegative Joined
1245 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1248 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1249 Enable copy propagation of scalar-evolution information.
1251 ; -fverbose-asm causes extra commentary information to be produced in
1252 ; the generated assembly code (to make it more readable). This option
1253 ; is generally only of use to those who actually need to read the
1254 ; generated assembly code (perhaps while debugging the compiler itself).
1255 ; -fno-verbose-asm, the default, causes the extra information
1256 ; to not be added and is useful when comparing two assembler files.
1258 Common Report Var(flag_verbose_asm)
1259 Add extra commentary to assembler output
1262 Common Joined RejectNegative
1263 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1267 Common Report Var(flag_value_profile_transformations) Optimization
1268 Use expression value profiles in optimizations
1271 Common Report Var(flag_web) Init(2) Optimization
1272 Construct webs and split unrelated uses of single variable
1275 Common Report Var(flag_whole_program) Init(0) Optimization
1276 Perform whole program optimizations
1279 Common Report Var(flag_wrapv) Optimization
1280 Assume signed arithmetic overflow wraps around
1282 fzero-initialized-in-bss
1283 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1284 Put zero initialized data in the bss section
1287 Common JoinedOrMissing
1288 Generate debug information in default format
1291 Common JoinedOrMissing Negative(gdwarf-2)
1292 Generate debug information in COFF format
1295 Common JoinedOrMissing Negative(gstabs)
1296 Generate debug information in DWARF v2 format
1299 Common JoinedOrMissing
1300 Generate debug information in default extended format
1303 Common JoinedOrMissing Negative(gstabs+)
1304 Generate debug information in STABS format
1307 Common JoinedOrMissing Negative(gvms)
1308 Generate debug information in extended STABS format
1311 Common JoinedOrMissing Negative(gxcoff)
1312 Generate debug information in VMS format
1315 Common JoinedOrMissing Negative(gxcoff+)
1316 Generate debug information in XCOFF format
1319 Common JoinedOrMissing Negative(gcoff)
1320 Generate debug information in extended XCOFF format
1323 Common Joined Separate
1324 -o <file> Place output into <file>
1327 Common Var(profile_flag)
1328 Enable function profiling
1331 Common Var(pedantic)
1332 Issue warnings needed for strict compliance to the standard
1336 Like -pedantic but issue them as errors
1339 Common Var(quiet_flag)
1340 Do not display functions compiled or elapsed time
1343 Common Var(version_flag)
1344 Display the compiler's version
1347 Common Var(inhibit_warnings)
1351 Common RejectNegative Negative(pie)
1352 Create a shared library
1355 Common RejectNegative Negative(shared)
1356 Create a position independent executable
1358 ; This comment is to ensure we retain the blank line above.