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 Optimization
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
97 Wdisallowed-function-list=
98 Common RejectNegative Joined Warning
99 Warn on calls to these functions
102 Common Var(warnings_are_errors)
103 Treat all warnings as errors
107 Treat specified warning as error
111 Print extra (possibly unwanted) warnings
114 Common Var(flag_fatal_errors)
115 Exit on the first error occurred
118 Common RejectNegative Joined UInteger
119 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes
122 Common Var(warn_inline) Warning
123 Warn when an inlined function cannot be inlined
126 Common RejectNegative Joined UInteger Warning
129 Common RejectNegative Joined UInteger Warning
130 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
133 Common Warning Var(warn_logical_op)
134 Warn when a logical operator is suspicously always evaluating to true or false
136 Wunsafe-loop-optimizations
137 Common Var(warn_unsafe_loop_optimizations) Warning
138 Warn if the loop cannot be optimized due to nontrivial assumptions.
141 Common Var(warn_missing_noreturn) Warning
142 Warn about functions which might be candidates for __attribute__((noreturn))
145 Common Var(warn_mudflap) Init(1) Warning
146 Warn about constructs not instrumented by -fmudflap
149 Common Var(warn_overflow) Init(1) Warning
150 Warn about overflow in arithmetic expressions
153 Common Var(warn_packed) Warning
154 Warn when the packed attribute has no effect on struct layout
157 Common Var(warn_padded) Warning
158 Warn when padding is required to align structure members
161 Common Var(warn_shadow) Warning
162 Warn when one local variable shadows another
165 Common Var(warn_stack_protect) Warning
166 Warn when not issuing stack smashing protection for some reason
170 Warn about code which might break strict aliasing rules
173 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
174 Warn about code which might break strict aliasing rules
178 Warn about optimizations that assume that signed overflow is undefined
181 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
182 Warn about optimizations that assume that signed overflow is undefined
185 Common Var(warn_switch) Warning
186 Warn about enumerated switches, with no default, missing a case
189 Common Var(warn_switch_default) Warning
190 Warn about enumerated switches missing a \"default:\" statement
193 Common Var(warn_switch_enum) Warning
194 Warn about all enumerated switches missing a specific case
197 Common Var(warn_system_headers) Warning
198 Do not suppress warnings from system headers
201 Common Var(warn_type_limits) Init(-1) Warning
202 Warn if a comparison is always true or always false due to the limited range of the data type
205 Common Var(warn_uninitialized) Warning
206 Warn about uninitialized automatic variables
209 Common Var(warn_notreached) Warning
210 Warn about code that will never be executed
214 Enable all -Wunused- warnings
217 Common Var(warn_unused_function) Warning
218 Warn when a function is unused
221 Common Var(warn_unused_label) Warning
222 Warn when a label is unused
225 Common Var(warn_unused_parameter) Warning
226 Warn when a function parameter is unused
229 Common Var(warn_unused_value) Warning
230 Warn when an expression value is unused
233 Common Var(warn_unused_variable) Warning
234 Warn when a variable is unused
237 Common RejectNegative Var(warn_coverage_mismatch) Warning
238 Warn instead of error in case profiles in -fprofile-use do not match
242 -aux-info <file> Emit declaration information into <file>
255 -d<letters> Enable dumps from specific passes of the compiler
259 -dumpbase <file> Set the file basename to be used for dumps
261 ; The version of the C++ ABI in use. The following values are allowed:
263 ; 0: The version of the ABI believed most conformant with the C++ ABI
264 ; specification. This ABI may change as bugs are discovered and fixed.
265 ; Therefore, 0 will not necessarily indicate the same ABI in different
268 ; 1: The version of the ABI first used in G++ 3.2.
270 ; 2: The version of the ABI first used in G++ 3.4.
272 ; Additional positive integers will be assigned as new versions of
273 ; the ABI become the default version of the ABI.
275 Common Joined UInteger Var(flag_abi_version) Init(2)
278 Common Report Var(align_functions,0) Optimization UInteger
279 Align the start of functions
282 Common RejectNegative Joined UInteger
285 Common Report Var(align_jumps,0) Optimization UInteger
286 Align labels which are only reached by jumping
289 Common RejectNegative Joined UInteger
292 Common Report Var(align_labels,0) Optimization UInteger
296 Common RejectNegative Joined UInteger
299 Common Report Var(align_loops) Optimization UInteger
300 Align the start of loops
303 Common RejectNegative Joined UInteger
305 ; This flag is only tested if alias checking is enabled.
306 ; 0 if pointer arguments may alias each other. True in C.
307 ; 1 if pointer arguments may not alias each other but may alias
309 ; 2 if pointer arguments may not alias each other and may not
310 ; alias global variables.
311 ; 3 if pointer arguments may not alias anything. True in Fortran.
312 ; Set by the front end.
314 Common Report Var(flag_argument_noalias,0) Optimization
315 Specify that arguments may alias each other and globals
318 Common Report Var(flag_argument_noalias,1) VarExists Optimization
319 Assume arguments may alias globals but not each other
321 fargument-noalias-global
322 Common Report Var(flag_argument_noalias,2) VarExists Optimization
323 Assume arguments alias neither each other nor globals
325 fargument-noalias-anything
326 Common Report Var(flag_argument_noalias,3) VarExists Optimization
327 Assume arguments alias no other storage
329 fasynchronous-unwind-tables
330 Common Report Var(flag_asynchronous_unwind_tables) Optimization
331 Generate unwind tables that are exact at each instruction boundary
334 Common Report Var(flag_auto_inc_dec) Init(1)
335 Generate auto-inc/dec instructions
337 ; -fcheck-bounds causes gcc to generate array bounds checks.
338 ; For C, C++ and ObjC: defaults off.
339 ; For Java: defaults to on.
340 ; For Fortran: defaults to off.
342 Common Report Var(flag_bounds_check)
343 Generate code to check bounds before indexing arrays
346 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
347 Replace add, compare, branch with branch on count register
349 fbranch-probabilities
350 Common Report Var(flag_branch_probabilities) Optimization
351 Use profiling information for branch probabilities
353 fbranch-target-load-optimize
354 Common Report Var(flag_branch_target_load_optimize) Optimization
355 Perform branch target load optimization before prologue / epilogue threading
357 fbranch-target-load-optimize2
358 Common Report Var(flag_branch_target_load_optimize2) Optimization
359 Perform branch target load optimization after prologue / epilogue threading
362 Common Report Var(flag_btr_bb_exclusive) Optimization
363 Restrict target load migration not to re-use registers in any basic block
366 Common Joined RejectNegative
367 -fcall-saved-<register> Mark <register> as being preserved across functions
370 Common Joined RejectNegative
371 -fcall-used-<register> Mark <register> as being corrupted by function calls
373 ; Nonzero for -fcaller-saves: allocate values in regs that need to
374 ; be saved across function calls, if that produces overall better code.
375 ; Optional now, so people can test it.
377 Common Report Var(flag_caller_saves) Optimization
378 Save registers around function calls
381 Common Report Var(flag_check_data_deps)
382 Compare the results of several data dependence analyzers.
385 Common Report Var(flag_no_common,0) Optimization
386 Do not put uninitialized globals in the common section
389 Common Report Var(flag_cprop_registers) Optimization
390 Perform a register copy-propagation optimization pass
393 Common Report Var(flag_crossjumping) Optimization
394 Perform cross-jumping optimization
397 Common Report Var(flag_cse_follow_jumps) Optimization
398 When running CSE, follow jumps to their targets
401 Common Report Var(flag_cse_skip_blocks) Optimization
402 When running CSE, follow conditional jumps
405 Common Report Var(flag_cx_limited_range) Optimization
406 Omit range reduction step when performing complex division
409 Common Report Var(flag_cx_fortran_rules) Optimization
410 Complex multiplication and division follow Fortran rules
413 Common Report Var(flag_data_sections) Optimization
414 Place data items into their own section
418 List all available debugging counters with their limits and counts.
421 Common RejectNegative Joined
422 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
425 Common Joined RejectNegative
426 Map one directory name to another in debug information
428 ; Nonzero for -fdefer-pop: don't pop args after each function call
429 ; instead save them up to pop many calls' args with one insns.
431 Common Report Var(flag_defer_pop) Optimization
432 Defer popping functions args from stack until later
435 Common Report Var(flag_delayed_branch) Optimization
436 Attempt to fill delay slots of branch instructions
438 fdelete-null-pointer-checks
439 Common Report Var(flag_delete_null_pointer_checks) Optimization
440 Delete useless null pointer checks
442 fdiagnostics-show-location=
443 Common Joined RejectNegative
444 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
446 fdiagnostics-show-option
448 Amend appropriate diagnostic messages with the command line option that controls them
451 Common Joined RejectNegative
452 -fdump-<type> Dump various compiler internals to a file
455 Common Report Var(flag_dump_noaddr)
456 Suppress output of addresses in debugging dumps
459 Common Report Var(flag_dump_simple_rtl) Init(0)
460 Switch on dumping simple RTL code
463 Common Report Var(flag_dump_unnumbered) VarExists
464 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
467 Common Report Var(flag_early_inlining) Init(1) Optimization
468 Perform early inlining
470 feliminate-dwarf2-dups
471 Common Report Var(flag_eliminate_dwarf2_dups)
472 Perform DWARF2 duplicate elimination
474 feliminate-unused-debug-symbols
475 Common Report Var(flag_debug_only_used_symbols)
476 Perform unused type elimination in debug info
478 feliminate-unused-debug-types
479 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
480 Perform unused type elimination in debug info
482 femit-class-debug-always
483 Common Report Var(flag_emit_class_debug_always) Init(0)
484 Do not suppress C++ class debug information.
487 Common Report Var(flag_exceptions) Optimization
488 Enable exception handling
490 fexpensive-optimizations
491 Common Report Var(flag_expensive_optimizations) Optimization
492 Perform a number of minor, expensive optimizations
498 Common Report Var(flag_finite_math_only) Optimization
499 Assume no NaNs or infinities are generated
502 Common Joined RejectNegative
503 -ffixed-<register> Mark <register> as being unavailable to the compiler
506 Common Report Var(flag_float_store) Optimization
507 Don't allocate floats and doubles in extended-precision registers
511 Does nothing. Preserved for backward compatibility.
514 Common Report Var(flag_forward_propagate) Optimization
515 Perform a forward propagation pass on RTL
517 ; Nonzero means don't put addresses of constant functions in registers.
518 ; Used for compiling the Unix kernel, where strange substitutions are
519 ; done on the assembly output.
521 Common Report Var(flag_no_function_cse,0)
522 Allow function addresses to be held in registers
525 Common Report Var(flag_function_sections)
526 Place each function into its own section
529 Common Report Var(flag_gcse) Optimization
530 Perform global common subexpression elimination
533 Common Report Var(flag_gcse_lm) Init(1) Optimization
534 Perform enhanced load motion during global common subexpression elimination
537 Common Report Var(flag_gcse_sm) Init(0) Optimization
538 Perform store motion after global common subexpression elimination
541 Common Report Var(flag_gcse_las) Init(0) Optimization
542 Perform redundant load after store elimination in global common subexpression
546 Common Report Var(flag_gcse_after_reload) Optimization
547 Perform global common subexpression elimination after register allocation
550 fguess-branch-probability
551 Common Report Var(flag_guess_branch_prob) Optimization
552 Enable guessing of branch probabilities
554 ; Nonzero means ignore `#ident' directives. 0 means handle them.
555 ; Generate position-independent code for executables if possible
556 ; On SVR4 targets, it also controls whether or not to emit a
557 ; string identifying the compiler.
559 Common Report Var(flag_no_ident,0)
560 Process #ident directives
563 Common Report Var(flag_if_conversion) Optimization
564 Perform conversion of conditional jumps to branchless equivalents
567 Common Report Var(flag_if_conversion2) Optimization
568 Perform conversion of conditional jumps to conditional execution
570 ; -finhibit-size-directive inhibits output of .size for ELF.
571 ; This is used only for compiling crtstuff.c,
572 ; and it may be extended to other effects
573 ; needed for crtstuff.c on other systems.
574 finhibit-size-directive
575 Common Report Var(flag_inhibit_size_directive)
576 Do not generate .size directives
579 Common Report Var(flag_indirect_inlining)
580 Perform indirect inlining
582 ; Nonzero means that functions declared `inline' will be treated
583 ; as `static'. Prevents generation of zillions of copies of unused
584 ; static inline functions; instead, `inlines' are written out
585 ; only when actually used. Used in conjunction with -g. Also
586 ; does the right thing with #pragma interface.
588 Common Report Var(flag_no_inline,0) Init(2)
589 Pay attention to the \"inline\" keyword
591 finline-small-functions
592 Common Report Var(flag_inline_small_functions) Optimization
593 Integrate simple functions into their callers when code size is known to not growth
596 Common Report Var(flag_inline_functions) Optimization
597 Integrate simple functions into their callers
599 finline-functions-called-once
600 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
601 Integrate functions called once into their callers
604 Common RejectNegative Joined UInteger
607 Common RejectNegative Joined UInteger
608 -finline-limit=<number> Limit the size of inlined functions to <number>
610 finstrument-functions
611 Common Report Var(flag_instrument_function_entry_exit)
612 Instrument function entry and exit with profiling calls
614 finstrument-functions-exclude-function-list=
615 Common RejectNegative Joined
616 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
618 finstrument-functions-exclude-file-list=
619 Common RejectNegative Joined
620 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
623 Common Report Var(flag_ipa_cp) Optimization
624 Perform Interprocedural constant propagation
627 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
628 Discover pure and const functions
631 Common Report Var(flag_ipa_pta) Init(0) Optimization
632 Perform interprocedural points-to analysis
635 Common Report Var(flag_ipa_reference) Init(0) Optimization
636 Discover readonly and non addressable static variables
639 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
640 Type based escape and alias analysis
643 Common Report Var(flag_ipa_matrix_reorg) Optimization
644 Perform matrix layout flattening and transposing based
645 on profiling information.
648 Common Report Var(flag_ipa_struct_reorg)
649 Perform structure layout optimizations based
650 on profiling information.
653 Common Report Var(flag_ira) Init(0)
654 Use integrated register allocator.
657 Common Joined RejectNegative
658 -fira-algorithm=[regional|CB|mixed] Set the used IRA algorithm
661 Common Report Var(flag_ira_coalesce) Init(0)
662 Do optimistic coalescing.
665 Common Report Var(flag_ira_propagate_cost) Init(0)
666 Propagate hard reg costs down for regional or mixed ira allocation algorithm.
668 fira-share-save-slots
669 Common Report Var(flag_ira_share_save_slots) Init(1)
670 Share slots for saving different hard registers.
672 fira-share-spill-slots
673 Common Report Var(flag_ira_share_spill_slots) Init(1)
674 Share stack slots for spilled pseudo-registers.
677 Common RejectNegative Joined UInteger
678 -fira-verbose=<number> Control IRA's level of diagnostic messages.
681 Common Report Var(flag_ivopts) Init(1) Optimization
682 Optimize induction variables on trees
685 Common Var(flag_jump_tables) Init(1) Optimization
686 Use jump tables for sufficiently large switch statements
688 fkeep-inline-functions
689 Common Report Var(flag_keep_inline_functions)
690 Generate code for functions even if they are fully inlined
693 Common Report Var(flag_keep_static_consts) Init(1)
694 Emit static const variables even if they are not used
697 Common Report Var(flag_leading_underscore) Init(-1)
698 Give external symbols a leading underscore
702 Does nothing. Preserved for backward compatibility.
705 Common Report Var(flag_errno_math) Init(1) Optimization
706 Set errno after built-in math functions
709 Common Report Var(mem_report)
710 Report on permanent memory allocation
712 ; This will attempt to merge constant section constants, if 1 only
713 ; string constants and constants from constant pool, if 2 also constant
716 Common Report Var(flag_merge_constants,2) Init(1) Optimization
717 Attempt to merge identical constants and constant variables
720 Common Report Var(flag_merge_constants,1) VarExists Optimization
721 Attempt to merge identical constants across compilation units
724 Common Report Var(flag_merge_debug_strings) Init(1)
725 Attempt to merge identical debug strings across compilation units
728 Common RejectNegative Joined UInteger
729 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
732 Common Report Var(flag_modulo_sched) Optimization
733 Perform SMS based modulo scheduling before the first scheduling pass
735 fmodulo-sched-allow-regmoves
736 Common Report Var(flag_modulo_sched_allow_regmoves)
737 Perform SMS based modulo scheduling with register moves allowed
739 fmove-loop-invariants
740 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
741 Move loop invariant computations out of loops
744 Common RejectNegative Report Var(flag_mudflap)
745 Add mudflap bounds-checking instrumentation for single-threaded program
748 Common RejectNegative Report VarExists Var(flag_mudflap,2)
749 Add mudflap bounds-checking instrumentation for multi-threaded program
752 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
753 Ignore read operations when inserting mudflap instrumentation
756 Common Var(flag_dce) Init(1) Optimization
757 Use the RTL dead code elimination pass
760 Common Var(flag_dse) Init(1) Optimization
761 Use the RTL dead store elimination pass
763 freschedule-modulo-scheduled-loops
764 Common Report Var(flag_resched_modulo_sched) Optimization
765 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
768 Common Report Var(flag_non_call_exceptions) Optimization
769 Support synchronous non-call exceptions
772 Common Report Var(flag_omit_frame_pointer) Optimization
773 When possible do not generate stack frames
775 foptimize-register-move
776 Common Report Var(flag_regmove) Optimization
777 Do the full register move optimization pass
779 foptimize-sibling-calls
780 Common Report Var(flag_optimize_sibling_calls) Optimization
781 Optimize sibling and tail recursive calls
784 Common Report Var(pre_ipa_mem_report)
785 Report on memory allocation before interprocedural optimization
788 Common Report Var(post_ipa_mem_report)
789 Report on memory allocation before interprocedural optimization
792 Common Report Var(flag_pack_struct) Optimization
793 Pack structure members together without holes
796 Common RejectNegative Joined UInteger Optimization
797 -fpack-struct=<number> Set initial maximum structure member alignment
800 Common Report Var(flag_pcc_struct_return,1) VarExists
801 Return small aggregates in memory, not registers
804 Common Report Var(flag_peel_loops) Optimization
808 Common Report Var(flag_no_peephole,0) Optimization
809 Enable machine specific peephole optimizations
812 Common Report Var(flag_peephole2) Optimization
813 Enable an RTL peephole pass before sched2
816 Common Report Var(flag_pic,2)
817 Generate position-independent code if possible (large mode)
820 Common Report Var(flag_pie,2)
821 Generate position-independent code for executables if possible (large mode)
824 Common Report Var(flag_pic,1) VarExists
825 Generate position-independent code if possible (small mode)
828 Common Report Var(flag_pie,1) VarExists
829 Generate position-independent code for executables if possible (small mode)
831 fpredictive-commoning
832 Common Report Var(flag_predictive_commoning) Optimization
833 Run predictive commoning optimization.
835 fprefetch-loop-arrays
836 Common Report Var(flag_prefetch_loop_arrays) Optimization
837 Generate prefetch instructions, if available, for arrays in loops
840 Common Report Var(profile_flag)
841 Enable basic program profiling code
844 Common Report Var(profile_arc_flag)
845 Insert arc-based program profiling code
848 Common Joined RejectNegative
849 Set the top-level directory for storing the profile data.
850 The default is 'pwd'.
854 Enable common options for generating profile info for profile feedback directed optimizations
857 Common Joined RejectNegative
858 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
861 Common Var(flag_profile_use)
862 Enable common options for performing profile feedback directed optimizations
865 Common Joined RejectNegative
866 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
869 Common Report Var(flag_profile_values)
870 Insert code to profile values of expressions
876 Common Joined RejectNegative
877 -frandom-seed=<string> Make compile reproducible using <string>
879 ; This switch causes the command line that was used to create an
880 ; object file to be recorded into the object file. The exact format
881 ; of this recording is target and binary file format dependent.
882 ; It is related to the -fverbose-asm switch, but that switch only
883 ; records information in the assembler output file as comments, so
884 ; they never reach the object file.
886 Common Report Var(flag_record_gcc_switches)
887 Record gcc command line switches in the object file.
890 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
891 Return small aggregates in registers
894 Common Report Var(flag_regmove) Optimization
895 Enables a register move optimization
898 Common Report Var(flag_rename_registers) Init(2) Optimization
899 Perform a register renaming optimization pass
902 Common Report Var(flag_reorder_blocks) Optimization
903 Reorder basic blocks to improve code placement
905 freorder-blocks-and-partition
906 Common Report Var(flag_reorder_blocks_and_partition) Optimization
907 Reorder basic blocks and partition into hot and cold sections
910 Common Report Var(flag_reorder_functions) Optimization
911 Reorder functions to improve code placement
913 frerun-cse-after-loop
914 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
915 Add a common subexpression elimination pass after loop optimizations
919 Does nothing. Preserved for backward compatibility.
922 Common Report Var(flag_rounding_math) Optimization
923 Disable optimizations that assume default FP rounding behavior
926 Common Report Var(flag_schedule_interblock) Init(1) Optimization
927 Enable scheduling across basic blocks
930 Common Report Var(flag_schedule_speculative) Init(1) Optimization
931 Allow speculative motion of non-loads
934 Common Report Var(flag_schedule_speculative_load) Optimization
935 Allow speculative motion of some loads
937 fsched-spec-load-dangerous
938 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
939 Allow speculative motion of more loads
942 Common RejectNegative Joined
943 -fsched-verbose=<number> Set the verbosity level of the scheduler
945 fsched2-use-superblocks
946 Common Report Var(flag_sched2_use_superblocks) Optimization
947 If scheduling post reload, do superblock scheduling
950 Common Report Var(flag_sched2_use_traces) Optimization
951 If scheduling post reload, do trace scheduling
954 Common Report Var(flag_schedule_insns) Optimization
955 Reschedule instructions before register allocation
958 Common Report Var(flag_schedule_insns_after_reload) Optimization
959 Reschedule instructions after register allocation
961 ; sched_stalled_insns means that insns can be moved prematurely from the queue
962 ; of stalled insns into the ready list.
964 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
965 Allow premature scheduling of queued insns
967 fsched-stalled-insns=
968 Common RejectNegative Joined UInteger
969 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
971 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
972 ; be examined for a dependency on a stalled insn that is candidate for
973 ; premature removal from the queue of stalled insns into the ready list (has
974 ; an effect only if the flag 'sched_stalled_insns' is set).
975 fsched-stalled-insns-dep
976 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
977 Set dependence distance checking in premature scheduling of queued insns
979 fsched-stalled-insns-dep=
980 Common RejectNegative Joined UInteger
981 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
984 Common Report Var(flag_section_anchors) Optimization
985 Access data in the same section from shared anchor points
987 frtl-abstract-sequences
988 Common Report Var(flag_rtl_seqabstr) Optimization
989 Perform sequence abstraction optimization on RTL
992 Common Report Var(flag_see) Init(0)
993 Eliminate redundant sign extensions using LCM.
996 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
997 Show column numbers in diagnostics, when available. Default off
1000 Common Report Var(flag_signaling_nans) Optimization
1001 Disable optimizations observable by IEEE signaling NaNs
1004 Common Report Var(flag_signed_zeros) Init(1) Optimization
1005 Disable floating point optimizations that ignore the IEEE signedness of zero
1007 fsingle-precision-constant
1008 Common Report Var(flag_single_precision_constant) Optimization
1009 Convert floating point constants to single precision constants
1011 fsplit-ivs-in-unroller
1012 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1013 Split lifetimes of induction variables when loops are unrolled
1016 Common Report Var(flag_split_wide_types) Optimization
1017 Split wide types into independent registers
1019 fvariable-expansion-in-unroller
1020 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1021 Apply variable expansion when loops are unrolled
1023 ; Emit code to probe the stack, to help detect stack overflow; also
1024 ; may cause large objects to be allocated dynamically.
1026 Common Report Var(flag_stack_check)
1027 Insert stack checking code into the program
1032 fstack-limit-register=
1033 Common RejectNegative Joined
1034 -fstack-limit-register=<register> Trap if the stack goes past <register>
1036 fstack-limit-symbol=
1037 Common RejectNegative Joined
1038 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1041 Common Report Var(flag_stack_protect, 1)
1042 Use propolice as a stack protection method
1044 fstack-protector-all
1045 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1046 Use a stack protection method for every function
1050 Does nothing. Preserved for backward compatibility.
1052 ; Nonzero if we should do (language-dependent) alias analysis.
1053 ; Typically, this analysis will assume that expressions of certain
1054 ; types do not alias expressions of certain other types. Only used
1055 ; if alias analysis (in general) is enabled.
1057 Common Report Var(flag_strict_aliasing) Optimization
1058 Assume strict aliasing rules apply
1061 Common Report Var(flag_strict_overflow)
1062 Treat signed overflow as undefined
1065 Common Report Var(flag_syntax_only)
1066 Check for syntax errors, then stop
1069 Common Report Var(flag_test_coverage)
1070 Create data files needed by \"gcov\"
1073 Common Report Var(flag_thread_jumps) Optimization
1074 Perform jump threading optimizations
1077 Common Report Var(time_report)
1078 Report the time taken by each compiler pass
1081 Common Joined RejectNegative
1082 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1085 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1086 Reorder top level functions, variables, and asms
1089 Common Report Var(flag_tracer)
1090 Perform superblock formation via tail duplication
1092 ; Zero means that floating-point math operations cannot generate a
1093 ; (user-visible) trap. This is the case, for example, in nonstop
1094 ; IEEE 754 arithmetic.
1096 Common Report Var(flag_trapping_math) Init(1) Optimization
1097 Assume floating-point operations can trap
1100 Common Report Var(flag_trapv) Optimization
1101 Trap for signed overflow in addition, subtraction and multiplication
1104 Common Report Var(flag_tree_ccp) Optimization
1105 Enable SSA-CCP optimization on trees
1108 Common Report Var(flag_tree_store_ccp) Optimization
1109 Enable SSA-CCP optimization for stores and loads
1112 Common Report Var(flag_tree_ch) Optimization
1113 Enable loop header copying on trees
1116 Common Report Var(flag_tree_copyrename) Optimization
1117 Replace SSA temporaries with better names in copies
1120 Common Report Var(flag_tree_copy_prop) Optimization
1121 Enable copy propagation on trees
1123 ftree-store-copy-prop
1125 Does nothing. Preserved for backward compatibility.
1128 Common Report Var(flag_tree_cselim) Init(2) Optimization
1129 Transform condition stores into unconditional ones
1131 ftree-switch-conversion
1132 Common Report Var(flag_tree_switch_conversion) Optimization
1133 Perform conversions of switch initializations.
1136 Common Report Var(flag_tree_dce) Optimization
1137 Enable SSA dead code elimination optimization on trees
1139 ftree-dominator-opts
1140 Common Report Var(flag_tree_dom) Optimization
1141 Enable dominator optimizations
1144 Common Report Var(flag_tree_dse) Optimization
1145 Enable dead store elimination
1148 Common Report Var(flag_tree_fre) Optimization
1149 Enable Full Redundancy Elimination (FRE) on trees
1151 ftree-loop-distribution
1152 Common Report Var(flag_tree_loop_distribution) Optimization
1153 Enable loop distribution on trees
1156 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1157 Enable loop invariant motion on trees
1160 Common Report Var(flag_tree_loop_linear) Optimization
1161 Enable linear loop transforms on trees
1164 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1165 Create canonical induction variables in loops
1168 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1169 Enable loop optimizations on tree level
1171 ftree-parallelize-loops=
1172 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1173 Enable automatic parallelization of loops
1176 Common Report Var(flag_tree_pre) Optimization
1177 Enable SSA-PRE optimization on trees
1180 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1181 Enable reassociation on tree level
1185 Does nothing. Preserved for backward compatibility.
1188 Common Report Var(flag_tree_sink) Optimization
1189 Enable SSA code sinking on trees
1192 Common Report Var(flag_tree_sra) Optimization
1193 Perform scalar replacement of aggregates
1196 Common Report Var(flag_tree_ter) Init(1) Optimization
1197 Replace temporary expressions in the SSA->normal pass
1200 Common Report Var(flag_tree_live_range_split) Optimization
1201 Perform live range splitting during the SSA->normal pass
1204 Common Report Var(flag_tree_vrp) Init(0) Optimization
1205 Perform Value Range Propagation on trees
1208 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1209 Compile whole compilation unit at a time
1212 Common Report Var(flag_unroll_loops) Optimization
1213 Perform loop unrolling when iteration count is known
1216 Common Report Var(flag_unroll_all_loops) Optimization
1217 Perform loop unrolling for all loops
1219 ; Nonzero means that loop optimizer may assume that the induction variables
1220 ; that control loops do not overflow and that the loops with nontrivial
1221 ; exit condition are not infinite
1222 funsafe-loop-optimizations
1223 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1224 Allow loop optimizations to assume that the loops behave in normal way
1227 Common Report Var(flag_associative_math)
1228 Allow optimization for floating-point arithmetic which may change the
1229 result of the operation due to rounding.
1232 Common Report Var(flag_reciprocal_math)
1233 Same as -fassociative-math for expressions which include division.
1235 ; Nonzero means that unsafe floating-point math optimizations are allowed
1236 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1237 ; are allowed to assume that their arguments and results are "normal"
1238 ; (e.g., nonnegative for SQRT).
1239 funsafe-math-optimizations
1240 Common Report Var(flag_unsafe_math_optimizations) Optimization
1241 Allow math optimizations that may violate IEEE or ISO standards
1244 Common Report Var(flag_unswitch_loops) Optimization
1245 Perform loop unswitching
1248 Common Report Var(flag_unwind_tables) Optimization
1249 Just generate unwind tables for exception handling
1252 Common Report Var(flag_var_tracking) VarExists Optimization
1253 Perform variable tracking
1255 fvar-tracking-uninit
1256 Common Report Var(flag_var_tracking_uninit) Optimization
1257 Perform variable tracking and also tag variables that are uninitialized
1260 Common Report Var(flag_tree_vectorize) Optimization
1261 Enable loop vectorization on trees
1264 Common Report Var(flag_vect_cost_model) Optimization
1265 Enable use of cost model in vectorization
1267 ftree-vect-loop-version
1268 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1269 Enable loop versioning when doing loop vectorization on trees
1271 ftree-vectorizer-verbose=
1272 Common RejectNegative Joined
1273 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1276 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1277 Enable copy propagation of scalar-evolution information.
1279 ; -fverbose-asm causes extra commentary information to be produced in
1280 ; the generated assembly code (to make it more readable). This option
1281 ; is generally only of use to those who actually need to read the
1282 ; generated assembly code (perhaps while debugging the compiler itself).
1283 ; -fno-verbose-asm, the default, causes the extra information
1284 ; to not be added and is useful when comparing two assembler files.
1286 Common Report Var(flag_verbose_asm)
1287 Add extra commentary to assembler output
1290 Common Joined RejectNegative
1291 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1295 Common Report Var(flag_value_profile_transformations) Optimization
1296 Use expression value profiles in optimizations
1299 Common Report Var(flag_web) Init(2) Optimization
1300 Construct webs and split unrelated uses of single variable
1302 ftree-builtin-call-dce
1303 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1304 Enable conditional dead code elimination for builtin calls
1307 Common Report Var(flag_whole_program) Init(0) Optimization
1308 Perform whole program optimizations
1311 Common Report Var(flag_wrapv) Optimization
1312 Assume signed arithmetic overflow wraps around
1314 fzero-initialized-in-bss
1315 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1316 Put zero initialized data in the bss section
1319 Common JoinedOrMissing
1320 Generate debug information in default format
1323 Common JoinedOrMissing Negative(gdwarf-2)
1324 Generate debug information in COFF format
1327 Common JoinedOrMissing Negative(gstabs)
1328 Generate debug information in DWARF v2 format
1331 Common JoinedOrMissing
1332 Generate debug information in default extended format
1335 Common JoinedOrMissing Negative(gstabs+)
1336 Generate debug information in STABS format
1339 Common JoinedOrMissing Negative(gvms)
1340 Generate debug information in extended STABS format
1343 Common JoinedOrMissing Negative(gxcoff)
1344 Generate debug information in VMS format
1347 Common JoinedOrMissing Negative(gxcoff+)
1348 Generate debug information in XCOFF format
1351 Common JoinedOrMissing Negative(gcoff)
1352 Generate debug information in extended XCOFF format
1355 Common Joined Separate
1356 -o <file> Place output into <file>
1359 Common Var(profile_flag)
1360 Enable function profiling
1363 Common Var(pedantic)
1364 Issue warnings needed for strict compliance to the standard
1368 Like -pedantic but issue them as errors
1371 Common Var(quiet_flag)
1372 Do not display functions compiled or elapsed time
1375 Common Var(version_flag)
1376 Display the compiler's version
1379 Common Var(inhibit_warnings)
1383 Common RejectNegative Negative(pie)
1384 Create a shared library
1387 Common RejectNegative Negative(shared)
1388 Create a position independent executable
1390 ; This comment is to ensure we retain the blank line above.