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 RejectNegative Joined UInteger
115 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes
118 Common Var(warn_inline) Warning
119 Warn when an inlined function cannot be inlined
122 Common RejectNegative Joined UInteger Warning
125 Common RejectNegative Joined UInteger Warning
126 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
129 Common Warning Var(warn_logical_op)
130 Warn when a logical operator is suspicously always evaluating to true or false
132 Wunsafe-loop-optimizations
133 Common Var(warn_unsafe_loop_optimizations) Warning
134 Warn if the loop cannot be optimized due to nontrivial assumptions.
137 Common Var(warn_missing_noreturn) Warning
138 Warn about functions which might be candidates for __attribute__((noreturn))
141 Common Var(warn_mudflap) Init(1) Warning
142 Warn about constructs not instrumented by -fmudflap
145 Common Var(warn_overflow) Init(1) Warning
146 Warn about overflow in arithmetic expressions
149 Common Var(warn_packed) Warning
150 Warn when the packed attribute has no effect on struct layout
153 Common Var(warn_padded) Warning
154 Warn when padding is required to align structure members
157 Common Var(warn_shadow) Warning
158 Warn when one local variable shadows another
161 Common Var(warn_stack_protect) Warning
162 Warn when not issuing stack smashing protection for some reason
166 Warn about code which might break strict aliasing rules
169 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
170 Warn about code which might break strict aliasing rules
174 Warn about optimizations that assume that signed overflow is undefined
177 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
178 Warn about optimizations that assume that signed overflow is undefined
181 Common Var(warn_switch) Warning
182 Warn about enumerated switches, with no default, missing a case
185 Common Var(warn_switch_default) Warning
186 Warn about enumerated switches missing a \"default:\" statement
189 Common Var(warn_switch_enum) Warning
190 Warn about all enumerated switches missing a specific case
193 Common Var(warn_system_headers) Warning
194 Do not suppress warnings from system headers
197 Common Var(warn_type_limits) Init(-1) Warning
198 Warn if a comparison is always true or always false due to the limited range of the data type
201 Common Var(warn_uninitialized) Warning
202 Warn about uninitialized automatic variables
205 Common Var(warn_notreached) Warning
206 Warn about code that will never be executed
210 Enable all -Wunused- warnings
213 Common Var(warn_unused_function) Warning
214 Warn when a function is unused
217 Common Var(warn_unused_label) Warning
218 Warn when a label is unused
221 Common Var(warn_unused_parameter) Warning
222 Warn when a function parameter is unused
225 Common Var(warn_unused_value) Warning
226 Warn when an expression value is unused
229 Common Var(warn_unused_variable) Warning
230 Warn when a variable is unused
233 Common RejectNegative Var(warn_coverage_mismatch) Warning
234 Warn instead of error in case profiles in -fprofile-use do not match
238 -aux-info <file> Emit declaration information into <file>
251 -d<letters> Enable dumps from specific passes of the compiler
255 -dumpbase <file> Set the file basename to be used for dumps
257 ; The version of the C++ ABI in use. The following values are allowed:
259 ; 0: The version of the ABI believed most conformant with the C++ ABI
260 ; specification. This ABI may change as bugs are discovered and fixed.
261 ; Therefore, 0 will not necessarily indicate the same ABI in different
264 ; 1: The version of the ABI first used in G++ 3.2.
266 ; 2: The version of the ABI first used in G++ 3.4.
268 ; Additional positive integers will be assigned as new versions of
269 ; the ABI become the default version of the ABI.
271 Common Joined UInteger Var(flag_abi_version) Init(2)
274 Common Report Var(align_functions,0)
275 Align the start of functions
278 Common RejectNegative Joined UInteger
281 Common Report Var(align_jumps,0) Optimization
282 Align labels which are only reached by jumping
285 Common RejectNegative Joined UInteger
288 Common Report Var(align_labels,0) Optimization
292 Common RejectNegative Joined UInteger
295 Common Report Var(align_loops) Optimization
296 Align the start of loops
299 Common RejectNegative Joined UInteger
301 ; This flag is only tested if alias checking is enabled.
302 ; 0 if pointer arguments may alias each other. True in C.
303 ; 1 if pointer arguments may not alias each other but may alias
305 ; 2 if pointer arguments may not alias each other and may not
306 ; alias global variables.
307 ; 3 if pointer arguments may not alias anything. True in Fortran.
308 ; Set by the front end.
310 Common Report Var(flag_argument_noalias,0) Optimization
311 Specify that arguments may alias each other and globals
314 Common Report Var(flag_argument_noalias,1) VarExists Optimization
315 Assume arguments may alias globals but not each other
317 fargument-noalias-global
318 Common Report Var(flag_argument_noalias,2) VarExists Optimization
319 Assume arguments alias neither each other nor globals
321 fargument-noalias-anything
322 Common Report Var(flag_argument_noalias,3) VarExists Optimization
323 Assume arguments alias no other storage
325 fasynchronous-unwind-tables
326 Common Report Var(flag_asynchronous_unwind_tables) Optimization
327 Generate unwind tables that are exact at each instruction boundary
330 Common Report Var(flag_auto_inc_dec) Init(1)
331 Generate auto-inc/dec instructions
333 ; -fcheck-bounds causes gcc to generate array bounds checks.
334 ; For C, C++ and ObjC: defaults off.
335 ; For Java: defaults to on.
336 ; For Fortran: defaults to off.
338 Common Report Var(flag_bounds_check)
339 Generate code to check bounds before indexing arrays
342 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
343 Replace add, compare, branch with branch on count register
345 fbranch-probabilities
346 Common Report Var(flag_branch_probabilities) Optimization
347 Use profiling information for branch probabilities
349 fbranch-target-load-optimize
350 Common Report Var(flag_branch_target_load_optimize) Optimization
351 Perform branch target load optimization before prologue / epilogue threading
353 fbranch-target-load-optimize2
354 Common Report Var(flag_branch_target_load_optimize2) Optimization
355 Perform branch target load optimization after prologue / epilogue threading
358 Common Report Var(flag_btr_bb_exclusive) Optimization
359 Restrict target load migration not to re-use registers in any basic block
362 Common Joined RejectNegative
363 -fcall-saved-<register> Mark <register> as being preserved across functions
366 Common Joined RejectNegative
367 -fcall-used-<register> Mark <register> as being corrupted by function calls
369 ; Nonzero for -fcaller-saves: allocate values in regs that need to
370 ; be saved across function calls, if that produces overall better code.
371 ; Optional now, so people can test it.
373 Common Report Var(flag_caller_saves) Optimization
374 Save registers around function calls
377 Common Report Var(flag_check_data_deps)
378 Compare the results of several data dependence analyzers.
381 Common Report Var(flag_no_common,0) Optimization
382 Do not put uninitialized globals in the common section
385 Common Report Var(flag_cprop_registers) Optimization
386 Perform a register copy-propagation optimization pass
389 Common Report Var(flag_crossjumping) Optimization
390 Perform cross-jumping optimization
393 Common Report Var(flag_cse_follow_jumps) Optimization
394 When running CSE, follow jumps to their targets
397 Common Report Var(flag_cse_skip_blocks) Optimization
398 When running CSE, follow conditional jumps
401 Common Report Var(flag_cx_limited_range) Optimization
402 Omit range reduction step when performing complex division
405 Common Report Var(flag_cx_fortran_rules) Optimization
406 Complex multiplication and division follow Fortran rules
409 Common Report Var(flag_data_sections) Optimization
410 Place data items into their own section
414 List all available debugging counters with their limits and counts.
417 Common RejectNegative Joined
418 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
421 Common Joined RejectNegative
422 Map one directory name to another in debug information
424 ; Nonzero for -fdefer-pop: don't pop args after each function call
425 ; instead save them up to pop many calls' args with one insns.
427 Common Report Var(flag_defer_pop) Optimization
428 Defer popping functions args from stack until later
431 Common Report Var(flag_delayed_branch) Optimization
432 Attempt to fill delay slots of branch instructions
434 fdelete-null-pointer-checks
435 Common Report Var(flag_delete_null_pointer_checks) Optimization
436 Delete useless null pointer checks
438 fdiagnostics-show-location=
439 Common Joined RejectNegative
440 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
442 fdiagnostics-show-option
444 Amend appropriate diagnostic messages with the command line option that controls them
447 Common Joined RejectNegative
448 -fdump-<type> Dump various compiler internals to a file
451 Common Report Var(flag_dump_noaddr)
452 Suppress output of addresses in debugging dumps
455 Common Report Var(flag_dump_simple_rtl) Init(0)
456 Switch on dumping simple RTL code
459 Common Report Var(flag_dump_unnumbered) VarExists
460 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
463 Common Report Var(flag_early_inlining) Init(1) Optimization
464 Perform early inlining
466 feliminate-dwarf2-dups
467 Common Report Var(flag_eliminate_dwarf2_dups)
468 Perform DWARF2 duplicate elimination
470 feliminate-unused-debug-symbols
471 Common Report Var(flag_debug_only_used_symbols)
472 Perform unused type elimination in debug info
474 feliminate-unused-debug-types
475 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
476 Perform unused type elimination in debug info
478 femit-class-debug-always
479 Common Report Var(flag_emit_class_debug_always) Init(0)
480 Do not suppress C++ class debug information.
483 Common Report Var(flag_exceptions) Optimization
484 Enable exception handling
486 fexpensive-optimizations
487 Common Report Var(flag_expensive_optimizations) Optimization
488 Perform a number of minor, expensive optimizations
494 Common Report Var(flag_finite_math_only) Optimization
495 Assume no NaNs or infinities are generated
498 Common Joined RejectNegative
499 -ffixed-<register> Mark <register> as being unavailable to the compiler
502 Common Report Var(flag_float_store) Optimization
503 Don't allocate floats and doubles in extended-precision registers
507 Does nothing. Preserved for backward compatibility.
510 Common Report Var(flag_forward_propagate) Optimization
511 Perform a forward propagation pass on RTL
513 ; Nonzero means don't put addresses of constant functions in registers.
514 ; Used for compiling the Unix kernel, where strange substitutions are
515 ; done on the assembly output.
517 Common Report Var(flag_no_function_cse,0)
518 Allow function addresses to be held in registers
521 Common Report Var(flag_function_sections)
522 Place each function into its own section
525 Common Report Var(flag_gcse) Optimization
526 Perform global common subexpression elimination
529 Common Report Var(flag_gcse_lm) Init(1) Optimization
530 Perform enhanced load motion during global common subexpression elimination
533 Common Report Var(flag_gcse_sm) Init(0) Optimization
534 Perform store motion after global common subexpression elimination
537 Common Report Var(flag_gcse_las) Init(0) Optimization
538 Perform redundant load after store elimination in global common subexpression
542 Common Report Var(flag_gcse_after_reload) Optimization
543 Perform global common subexpression elimination after register allocation
546 fguess-branch-probability
547 Common Report Var(flag_guess_branch_prob) Optimization
548 Enable guessing of branch probabilities
550 ; Nonzero means ignore `#ident' directives. 0 means handle them.
551 ; Generate position-independent code for executables if possible
552 ; On SVR4 targets, it also controls whether or not to emit a
553 ; string identifying the compiler.
555 Common Report Var(flag_no_ident,0)
556 Process #ident directives
559 Common Report Var(flag_if_conversion) Optimization
560 Perform conversion of conditional jumps to branchless equivalents
563 Common Report Var(flag_if_conversion2) Optimization
564 Perform conversion of conditional jumps to conditional execution
566 ; -finhibit-size-directive inhibits output of .size for ELF.
567 ; This is used only for compiling crtstuff.c,
568 ; and it may be extended to other effects
569 ; needed for crtstuff.c on other systems.
570 finhibit-size-directive
571 Common Report Var(flag_inhibit_size_directive)
572 Do not generate .size directives
574 ; Nonzero means that functions declared `inline' will be treated
575 ; as `static'. Prevents generation of zillions of copies of unused
576 ; static inline functions; instead, `inlines' are written out
577 ; only when actually used. Used in conjunction with -g. Also
578 ; does the right thing with #pragma interface.
580 Common Report Var(flag_no_inline,0) Init(2)
581 Pay attention to the \"inline\" keyword
583 finline-small-functions
584 Common Report Var(flag_inline_small_functions) Optimization
585 Integrate simple functions into their callers when code size is known to not growth
588 Common Report Var(flag_inline_functions) Optimization
589 Integrate simple functions into their callers
591 finline-functions-called-once
592 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
593 Integrate functions called once into their callers
596 Common RejectNegative Joined UInteger
599 Common RejectNegative Joined UInteger
600 -finline-limit=<number> Limit the size of inlined functions to <number>
602 finstrument-functions
603 Common Report Var(flag_instrument_function_entry_exit)
604 Instrument function entry and exit with profiling calls
606 finstrument-functions-exclude-function-list=
607 Common RejectNegative Joined
608 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
610 finstrument-functions-exclude-file-list=
611 Common RejectNegative Joined
612 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
615 Common Report Var(flag_ipa_cp) Optimization
616 Perform Interprocedural constant propagation
619 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
620 Discover pure and const functions
623 Common Report Var(flag_ipa_pta) Init(0) Optimization
624 Perform interprocedural points-to analysis
627 Common Report Var(flag_ipa_reference) Init(0) Optimization
628 Discover readonly and non addressable static variables
631 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
632 Type based escape and alias analysis
635 Common Report Var(flag_ipa_matrix_reorg) Optimization
636 Perform matrix layout flattening and transposing based
637 on profiling information.
640 Common Report Var(flag_ipa_struct_reorg)
641 Perform structure layout optimizations based
642 on profiling information.
645 Common Report Var(flag_ira) Init(0)
646 Use integrated register allocator.
649 Common Joined RejectNegative
650 -fira-algorithm=[regional|CB|mixed] Set the used IRA algorithm
653 Common Report Var(flag_ira_coalesce) Init(0)
654 Do optimistic coalescing.
657 Common Report Var(flag_ira_propagate_cost) Init(0)
658 Propagate hard reg costs down for regional or mixed ira allocation algorithm.
660 fira-share-save-slots
661 Common Report Var(flag_ira_share_save_slots) Init(1)
662 Share slots for saving different hard registers.
664 fira-share-spill-slots
665 Common Report Var(flag_ira_share_spill_slots) Init(1)
666 Share stack slots for spilled pseudo-registers.
669 Common RejectNegative Joined UInteger
670 -fira-verbose=<number> Control IRA's level of diagnostic messages.
673 Common Report Var(flag_ivopts) Init(1) Optimization
674 Optimize induction variables on trees
677 Common Var(flag_jump_tables) Init(1) Optimization
678 Use jump tables for sufficiently large switch statements
680 fkeep-inline-functions
681 Common Report Var(flag_keep_inline_functions)
682 Generate code for functions even if they are fully inlined
685 Common Report Var(flag_keep_static_consts) Init(1)
686 Emit static const variables even if they are not used
689 Common Report Var(flag_leading_underscore) Init(-1)
690 Give external symbols a leading underscore
694 Does nothing. Preserved for backward compatibility.
697 Common Report Var(flag_errno_math) Init(1)
698 Set errno after built-in math functions
701 Common Report Var(mem_report)
702 Report on permanent memory allocation
704 ; This will attempt to merge constant section constants, if 1 only
705 ; string constants and constants from constant pool, if 2 also constant
708 Common Report Var(flag_merge_constants,2) Init(1) Optimization
709 Attempt to merge identical constants and constant variables
712 Common Report Var(flag_merge_constants,1) VarExists Optimization
713 Attempt to merge identical constants across compilation units
716 Common Report Var(flag_merge_debug_strings) Init(1)
717 Attempt to merge identical debug strings across compilation units
720 Common RejectNegative Joined UInteger
721 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
724 Common Report Var(flag_modulo_sched) Optimization
725 Perform SMS based modulo scheduling before the first scheduling pass
727 fmodulo-sched-allow-regmoves
728 Common Report Var(flag_modulo_sched_allow_regmoves)
729 Perform SMS based modulo scheduling with register moves allowed
731 fmove-loop-invariants
732 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
733 Move loop invariant computations out of loops
736 Common RejectNegative Report Var(flag_mudflap)
737 Add mudflap bounds-checking instrumentation for single-threaded program
740 Common RejectNegative Report VarExists Var(flag_mudflap,2)
741 Add mudflap bounds-checking instrumentation for multi-threaded program
744 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
745 Ignore read operations when inserting mudflap instrumentation
748 Common Var(flag_dce) Init(1) Optimization
749 Use the RTL dead code elimination pass
752 Common Var(flag_dse) Init(1) Optimization
753 Use the RTL dead store elimination pass
755 freschedule-modulo-scheduled-loops
756 Common Report Var(flag_resched_modulo_sched) Optimization
757 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
760 Common Report Var(flag_non_call_exceptions) Optimization
761 Support synchronous non-call exceptions
764 Common Report Var(flag_omit_frame_pointer) Optimization
765 When possible do not generate stack frames
767 foptimize-register-move
768 Common Report Var(flag_regmove) Optimization
769 Do the full register move optimization pass
771 foptimize-sibling-calls
772 Common Report Var(flag_optimize_sibling_calls) Optimization
773 Optimize sibling and tail recursive calls
776 Common Report Var(pre_ipa_mem_report)
777 Report on memory allocation before interprocedural optimization
780 Common Report Var(post_ipa_mem_report)
781 Report on memory allocation before interprocedural optimization
784 Common Report Var(flag_pack_struct) Optimization
785 Pack structure members together without holes
788 Common RejectNegative Joined UInteger Optimization
789 -fpack-struct=<number> Set initial maximum structure member alignment
792 Common Report Var(flag_pcc_struct_return,1) VarExists
793 Return small aggregates in memory, not registers
796 Common Report Var(flag_peel_loops) Optimization
800 Common Report Var(flag_no_peephole,0) Optimization
801 Enable machine specific peephole optimizations
804 Common Report Var(flag_peephole2) Optimization
805 Enable an RTL peephole pass before sched2
808 Common Report Var(flag_pic,2)
809 Generate position-independent code if possible (large mode)
812 Common Report Var(flag_pie,2)
813 Generate position-independent code for executables if possible (large mode)
816 Common Report Var(flag_pic,1) VarExists
817 Generate position-independent code if possible (small mode)
820 Common Report Var(flag_pie,1) VarExists
821 Generate position-independent code for executables if possible (small mode)
823 fpredictive-commoning
824 Common Report Var(flag_predictive_commoning) Optimization
825 Run predictive commoning optimization.
827 fprefetch-loop-arrays
828 Common Report Var(flag_prefetch_loop_arrays) Optimization
829 Generate prefetch instructions, if available, for arrays in loops
832 Common Report Var(profile_flag)
833 Enable basic program profiling code
836 Common Report Var(profile_arc_flag)
837 Insert arc-based program profiling code
840 Common Joined RejectNegative
841 Set the top-level directory for storing the profile data.
842 The default is 'pwd'.
846 Enable common options for generating profile info for profile feedback directed optimizations
849 Common Joined RejectNegative
850 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
853 Common Var(flag_profile_use)
854 Enable common options for performing profile feedback directed optimizations
857 Common Joined RejectNegative
858 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
861 Common Report Var(flag_profile_values)
862 Insert code to profile values of expressions
868 Common Joined RejectNegative
869 -frandom-seed=<string> Make compile reproducible using <string>
871 ; This switch causes the command line that was used to create an
872 ; object file to be recorded into the object file. The exact format
873 ; of this recording is target and binary file format dependent.
874 ; It is related to the -fverbose-asm switch, but that switch only
875 ; records information in the assembler output file as comments, so
876 ; they never reach the object file.
878 Common Report Var(flag_record_gcc_switches)
879 Record gcc command line switches in the object file.
882 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
883 Return small aggregates in registers
886 Common Report Var(flag_regmove) Optimization
887 Enables a register move optimization
890 Common Report Var(flag_rename_registers) Init(2) Optimization
891 Perform a register renaming optimization pass
894 Common Report Var(flag_reorder_blocks) Optimization
895 Reorder basic blocks to improve code placement
897 freorder-blocks-and-partition
898 Common Report Var(flag_reorder_blocks_and_partition) Optimization
899 Reorder basic blocks and partition into hot and cold sections
902 Common Report Var(flag_reorder_functions) Optimization
903 Reorder functions to improve code placement
905 frerun-cse-after-loop
906 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
907 Add a common subexpression elimination pass after loop optimizations
911 Does nothing. Preserved for backward compatibility.
914 Common Report Var(flag_rounding_math) Optimization
915 Disable optimizations that assume default FP rounding behavior
918 Common Report Var(flag_schedule_interblock) Init(1) Optimization
919 Enable scheduling across basic blocks
922 Common Report Var(flag_schedule_speculative) Init(1) Optimization
923 Allow speculative motion of non-loads
926 Common Report Var(flag_schedule_speculative_load) Optimization
927 Allow speculative motion of some loads
929 fsched-spec-load-dangerous
930 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
931 Allow speculative motion of more loads
934 Common RejectNegative Joined
935 -fsched-verbose=<number> Set the verbosity level of the scheduler
937 fsched2-use-superblocks
938 Common Report Var(flag_sched2_use_superblocks) Optimization
939 If scheduling post reload, do superblock scheduling
942 Common Report Var(flag_sched2_use_traces) Optimization
943 If scheduling post reload, do trace scheduling
946 Common Report Var(flag_schedule_insns) Optimization
947 Reschedule instructions before register allocation
950 Common Report Var(flag_schedule_insns_after_reload) Optimization
951 Reschedule instructions after register allocation
953 ; sched_stalled_insns means that insns can be moved prematurely from the queue
954 ; of stalled insns into the ready list.
956 Common Report Var(flag_sched_stalled_insns) Optimization
957 Allow premature scheduling of queued insns
959 fsched-stalled-insns=
960 Common RejectNegative Joined UInteger
961 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
963 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
964 ; be examined for a dependency on a stalled insn that is candidate for
965 ; premature removal from the queue of stalled insns into the ready list (has
966 ; an effect only if the flag 'sched_stalled_insns' is set).
967 fsched-stalled-insns-dep
968 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
969 Set dependence distance checking in premature scheduling of queued insns
971 fsched-stalled-insns-dep=
972 Common RejectNegative Joined UInteger
973 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
976 Common Report Var(flag_section_anchors) Optimization
977 Access data in the same section from shared anchor points
979 frtl-abstract-sequences
980 Common Report Var(flag_rtl_seqabstr) Optimization
981 Perform sequence abstraction optimization on RTL
984 Common Report Var(flag_see) Init(0)
985 Eliminate redundant sign extensions using LCM.
988 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
989 Show column numbers in diagnostics, when available. Default off
992 Common Report Var(flag_signaling_nans) Optimization
993 Disable optimizations observable by IEEE signaling NaNs
996 Common Report Var(flag_signed_zeros) Init(1) Optimization
997 Disable floating point optimizations that ignore the IEEE signedness of zero
999 fsingle-precision-constant
1000 Common Report Var(flag_single_precision_constant) Optimization
1001 Convert floating point constants to single precision constants
1003 fsplit-ivs-in-unroller
1004 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1005 Split lifetimes of induction variables when loops are unrolled
1008 Common Report Var(flag_split_wide_types) Optimization
1009 Split wide types into independent registers
1011 fvariable-expansion-in-unroller
1012 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1013 Apply variable expansion when loops are unrolled
1015 ; Emit code to probe the stack, to help detect stack overflow; also
1016 ; may cause large objects to be allocated dynamically.
1018 Common Report Var(flag_stack_check)
1019 Insert stack checking code into the program
1024 fstack-limit-register=
1025 Common RejectNegative Joined
1026 -fstack-limit-register=<register> Trap if the stack goes past <register>
1028 fstack-limit-symbol=
1029 Common RejectNegative Joined
1030 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1033 Common Report Var(flag_stack_protect, 1)
1034 Use propolice as a stack protection method
1036 fstack-protector-all
1037 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1038 Use a stack protection method for every function
1042 Does nothing. Preserved for backward compatibility.
1044 ; Nonzero if we should do (language-dependent) alias analysis.
1045 ; Typically, this analysis will assume that expressions of certain
1046 ; types do not alias expressions of certain other types. Only used
1047 ; if alias analysis (in general) is enabled.
1049 Common Report Var(flag_strict_aliasing) Optimization
1050 Assume strict aliasing rules apply
1053 Common Report Var(flag_strict_overflow)
1054 Treat signed overflow as undefined
1057 Common Report Var(flag_syntax_only)
1058 Check for syntax errors, then stop
1061 Common Report Var(flag_test_coverage)
1062 Create data files needed by \"gcov\"
1065 Common Report Var(flag_thread_jumps) Optimization
1066 Perform jump threading optimizations
1069 Common Report Var(time_report)
1070 Report the time taken by each compiler pass
1073 Common Joined RejectNegative
1074 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1077 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
1078 Reorder top level functions, variables, and asms
1081 Common Report Var(flag_tracer)
1082 Perform superblock formation via tail duplication
1084 ; Zero means that floating-point math operations cannot generate a
1085 ; (user-visible) trap. This is the case, for example, in nonstop
1086 ; IEEE 754 arithmetic.
1088 Common Report Var(flag_trapping_math) Init(1) Optimization
1089 Assume floating-point operations can trap
1092 Common Report Var(flag_trapv) Optimization
1093 Trap for signed overflow in addition, subtraction and multiplication
1096 Common Report Var(flag_tree_ccp) Optimization
1097 Enable SSA-CCP optimization on trees
1100 Common Report Var(flag_tree_store_ccp) Optimization
1101 Enable SSA-CCP optimization for stores and loads
1104 Common Report Var(flag_tree_ch) Optimization
1105 Enable loop header copying on trees
1108 Common Report Var(flag_tree_copyrename) Optimization
1109 Replace SSA temporaries with better names in copies
1112 Common Report Var(flag_tree_copy_prop) Optimization
1113 Enable copy propagation on trees
1115 ftree-store-copy-prop
1117 Does nothing. Preserved for backward compatibility.
1120 Common Report Var(flag_tree_cselim) Init(2) Optimization
1121 Transform condition stores into unconditional ones
1124 Common Report Var(flag_tree_dce) Optimization
1125 Enable SSA dead code elimination optimization on trees
1127 ftree-dominator-opts
1128 Common Report Var(flag_tree_dom) Optimization
1129 Enable dominator optimizations
1132 Common Report Var(flag_tree_dse) Optimization
1133 Enable dead store elimination
1136 Common Report Var(flag_tree_fre) Optimization
1137 Enable Full Redundancy Elimination (FRE) on trees
1139 ftree-loop-distribution
1140 Common Report Var(flag_tree_loop_distribution) Optimization
1141 Enable loop distribution on trees
1144 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1145 Enable loop invariant motion on trees
1148 Common Report Var(flag_tree_loop_linear) Optimization
1149 Enable linear loop transforms on trees
1152 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1153 Create canonical induction variables in loops
1156 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1157 Enable loop optimizations on tree level
1159 ftree-parallelize-loops=
1160 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1161 Enable automatic parallelization of loops
1164 Common Report Var(flag_tree_pre) Optimization
1165 Enable SSA-PRE optimization on trees
1168 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1169 Enable reassociation on tree level
1173 Does nothing. Preserved for backward compatibility.
1176 Common Report Var(flag_tree_sink) Optimization
1177 Enable SSA code sinking on trees
1180 Common Report Var(flag_tree_sra) Optimization
1181 Perform scalar replacement of aggregates
1184 Common Report Var(flag_tree_ter) Optimization
1185 Replace temporary expressions in the SSA->normal pass
1188 Common Report Var(flag_tree_live_range_split) Optimization
1189 Perform live range splitting during the SSA->normal pass
1192 Common Report Var(flag_tree_vrp) Init(0) Optimization
1193 Perform Value Range Propagation on trees
1196 Common Report Var(flag_unit_at_a_time) Optimization
1197 Compile whole compilation unit at a time
1200 Common Report Var(flag_unroll_loops) Optimization
1201 Perform loop unrolling when iteration count is known
1204 Common Report Var(flag_unroll_all_loops) Optimization
1205 Perform loop unrolling for all loops
1207 ; Nonzero means that loop optimizer may assume that the induction variables
1208 ; that control loops do not overflow and that the loops with nontrivial
1209 ; exit condition are not infinite
1210 funsafe-loop-optimizations
1211 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1212 Allow loop optimizations to assume that the loops behave in normal way
1215 Common Report Var(flag_associative_math)
1216 Allow optimization for floating-point arithmetic which may change the
1217 result of the operation due to rounding.
1220 Common Report Var(flag_reciprocal_math)
1221 Same as -fassociative-math for expressions which include division.
1223 ; Nonzero means that unsafe floating-point math optimizations are allowed
1224 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1225 ; are allowed to assume that their arguments and results are "normal"
1226 ; (e.g., nonnegative for SQRT).
1227 funsafe-math-optimizations
1228 Common Report Var(flag_unsafe_math_optimizations) Optimization
1229 Allow math optimizations that may violate IEEE or ISO standards
1232 Common Report Var(flag_unswitch_loops) Optimization
1233 Perform loop unswitching
1236 Common Report Var(flag_unwind_tables) Optimization
1237 Just generate unwind tables for exception handling
1240 Common Report Var(flag_var_tracking) VarExists Optimization
1241 Perform variable tracking
1243 fvar-tracking-uninit
1244 Common Report Var(flag_var_tracking_uninit) Optimization
1245 Perform variable tracking and also tag variables that are uninitialized
1248 Common Report Var(flag_tree_vectorize) Optimization
1249 Enable loop vectorization on trees
1252 Common Report Var(flag_vect_cost_model) Optimization
1253 Enable use of cost model in vectorization
1255 ftree-vect-loop-version
1256 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1257 Enable loop versioning when doing loop vectorization on trees
1259 ftree-vectorizer-verbose=
1260 Common RejectNegative Joined
1261 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1264 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1265 Enable copy propagation of scalar-evolution information.
1267 ; -fverbose-asm causes extra commentary information to be produced in
1268 ; the generated assembly code (to make it more readable). This option
1269 ; is generally only of use to those who actually need to read the
1270 ; generated assembly code (perhaps while debugging the compiler itself).
1271 ; -fno-verbose-asm, the default, causes the extra information
1272 ; to not be added and is useful when comparing two assembler files.
1274 Common Report Var(flag_verbose_asm)
1275 Add extra commentary to assembler output
1278 Common Joined RejectNegative
1279 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1283 Common Report Var(flag_value_profile_transformations) Optimization
1284 Use expression value profiles in optimizations
1287 Common Report Var(flag_web) Init(2) Optimization
1288 Construct webs and split unrelated uses of single variable
1291 Common Report Var(flag_whole_program) Init(0) Optimization
1292 Perform whole program optimizations
1295 Common Report Var(flag_wrapv) Optimization
1296 Assume signed arithmetic overflow wraps around
1298 fzero-initialized-in-bss
1299 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1300 Put zero initialized data in the bss section
1303 Common JoinedOrMissing
1304 Generate debug information in default format
1307 Common JoinedOrMissing Negative(gdwarf-2)
1308 Generate debug information in COFF format
1311 Common JoinedOrMissing Negative(gstabs)
1312 Generate debug information in DWARF v2 format
1315 Common JoinedOrMissing
1316 Generate debug information in default extended format
1319 Common JoinedOrMissing Negative(gstabs+)
1320 Generate debug information in STABS format
1323 Common JoinedOrMissing Negative(gvms)
1324 Generate debug information in extended STABS format
1327 Common JoinedOrMissing Negative(gxcoff)
1328 Generate debug information in VMS format
1331 Common JoinedOrMissing Negative(gxcoff+)
1332 Generate debug information in XCOFF format
1335 Common JoinedOrMissing Negative(gcoff)
1336 Generate debug information in extended XCOFF format
1339 Common Joined Separate
1340 -o <file> Place output into <file>
1343 Common Var(profile_flag)
1344 Enable function profiling
1347 Common Var(pedantic)
1348 Issue warnings needed for strict compliance to the standard
1352 Like -pedantic but issue them as errors
1355 Common Var(quiet_flag)
1356 Do not display functions compiled or elapsed time
1359 Common Var(version_flag)
1360 Display the compiler's version
1363 Common Var(inhibit_warnings)
1367 Common RejectNegative Negative(pie)
1368 Create a shared library
1371 Common RejectNegative Negative(shared)
1372 Create a position independent executable
1374 ; This comment is to ensure we retain the blank line above.