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=@var{len} Warn whenever a function's stack frame requires
116 more than @var{len} bytes. The computation done to determine
117 the stack frame size is approximate and not conservative.
118 The actual requirements may be somewhat greater than @var{len}
119 even if you do not get a warning. In addition, any space allocated
120 via @code{alloca}, variable-length arrays, or related constructs
121 is not included by the compiler when determining
122 whether or not to issue a warning.
125 Common Var(warn_inline) Warning
126 Warn when an inlined function cannot be inlined
129 Common RejectNegative Joined UInteger Warning
132 Common RejectNegative Joined UInteger Warning
133 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
136 Common Warning Var(warn_logical_op)
137 Warn when a logical operator is suspicously always evaluating to true or false
139 Wunsafe-loop-optimizations
140 Common Var(warn_unsafe_loop_optimizations) Warning
141 Warn if the loop cannot be optimized due to nontrivial assumptions.
144 Common Var(warn_missing_noreturn) Warning
145 Warn about functions which might be candidates for __attribute__((noreturn))
148 Common Var(warn_overflow) Init(1) Warning
149 Warn about overflow in arithmetic expressions
152 Common Var(warn_packed) Warning
153 Warn when the packed attribute has no effect on struct layout
156 Common Var(warn_padded) Warning
157 Warn when padding is required to align structure members
160 Common Var(warn_shadow) Warning
161 Warn when one local variable shadows another
164 Common Var(warn_stack_protect) Warning
165 Warn when not issuing stack smashing protection for some reason
169 Warn about code which might break strict aliasing rules
172 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
173 Warn about code which might break strict aliasing rules
177 Warn about optimizations that assume that signed overflow is undefined
180 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
181 Warn about optimizations that assume that signed overflow is undefined
184 Common Var(warn_switch) Warning
185 Warn about enumerated switches, with no default, missing a case
188 Common Var(warn_switch_default) Warning
189 Warn about enumerated switches missing a \"default:\" statement
192 Common Var(warn_switch_enum) Warning
193 Warn about all enumerated switches missing a specific case
196 Common Var(warn_system_headers) Warning
197 Do not suppress warnings from system headers
200 Common Var(warn_type_limits) Init(-1) Warning
201 Warn if a comparison is always true or always false due to the limited range of the data type
204 Common Var(warn_uninitialized) Warning
205 Warn about uninitialized automatic variables
208 Common Var(warn_notreached) Warning
209 Warn about code that will never be executed
213 Enable all -Wunused- warnings
216 Common Var(warn_unused_function) Warning
217 Warn when a function is unused
220 Common Var(warn_unused_label) Warning
221 Warn when a label is unused
224 Common Var(warn_unused_parameter) Warning
225 Warn when a function parameter is unused
228 Common Var(warn_unused_value) Warning
229 Warn when an expression value is unused
232 Common Var(warn_unused_variable) Warning
233 Warn when a variable is unused
236 Common RejectNegative Var(warn_coverage_mismatch) Warning
237 Warn instead of error in case profiles in -fprofile-use do not match
241 -aux-info <file> Emit declaration information into <file>
254 -d<letters> Enable dumps from specific passes of the compiler
258 -dumpbase <file> Set the file basename to be used for dumps
260 ; The version of the C++ ABI in use. The following values are allowed:
262 ; 0: The version of the ABI believed most conformant with the C++ ABI
263 ; specification. This ABI may change as bugs are discovered and fixed.
264 ; Therefore, 0 will not necessarily indicate the same ABI in different
267 ; 1: The version of the ABI first used in G++ 3.2.
269 ; 2: The version of the ABI first used in G++ 3.4.
271 ; Additional positive integers will be assigned as new versions of
272 ; the ABI become the default version of the ABI.
274 Common Joined UInteger Var(flag_abi_version) Init(2)
277 Common Report Var(align_functions,0)
278 Align the start of functions
281 Common RejectNegative Joined UInteger
284 Common Report Var(align_jumps,0) Optimization
285 Align labels which are only reached by jumping
288 Common RejectNegative Joined UInteger
291 Common Report Var(align_labels,0) Optimization
295 Common RejectNegative Joined UInteger
298 Common Report Var(align_loops) Optimization
299 Align the start of loops
302 Common RejectNegative Joined UInteger
304 ; This flag is only tested if alias checking is enabled.
305 ; 0 if pointer arguments may alias each other. True in C.
306 ; 1 if pointer arguments may not alias each other but may alias
308 ; 2 if pointer arguments may not alias each other and may not
309 ; alias global variables.
310 ; 3 if pointer arguments may not alias anything. True in Fortran.
311 ; Set by the front end.
313 Common Report Var(flag_argument_noalias,0) Optimization
314 Specify that arguments may alias each other and globals
317 Common Report Var(flag_argument_noalias,1) VarExists Optimization
318 Assume arguments may alias globals but not each other
320 fargument-noalias-global
321 Common Report Var(flag_argument_noalias,2) VarExists Optimization
322 Assume arguments alias neither each other nor globals
324 fargument-noalias-anything
325 Common Report Var(flag_argument_noalias,3) VarExists Optimization
326 Assume arguments alias no other storage
328 fasynchronous-unwind-tables
329 Common Report Var(flag_asynchronous_unwind_tables) Optimization
330 Generate unwind tables that are exact at each instruction boundary
333 Common Report Var(flag_auto_inc_dec) Init(1)
334 Generate auto-inc/dec instructions
336 ; -fcheck-bounds causes gcc to generate array bounds checks.
337 ; For C, C++ and ObjC: defaults off.
338 ; For Java: defaults to on.
339 ; For Fortran: defaults to off.
341 Common Report Var(flag_bounds_check)
342 Generate code to check bounds before indexing arrays
345 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
346 Replace add, compare, branch with branch on count register
348 fbranch-probabilities
349 Common Report Var(flag_branch_probabilities) Optimization
350 Use profiling information for branch probabilities
352 fbranch-target-load-optimize
353 Common Report Var(flag_branch_target_load_optimize) Optimization
354 Perform branch target load optimization before prologue / epilogue threading
356 fbranch-target-load-optimize2
357 Common Report Var(flag_branch_target_load_optimize2) Optimization
358 Perform branch target load optimization after prologue / epilogue threading
361 Common Report Var(flag_btr_bb_exclusive) Optimization
362 Restrict target load migration not to re-use registers in any basic block
365 Common Joined RejectNegative
366 -fcall-saved-<register> Mark <register> as being preserved across functions
369 Common Joined RejectNegative
370 -fcall-used-<register> Mark <register> as being corrupted by function calls
372 ; Nonzero for -fcaller-saves: allocate values in regs that need to
373 ; be saved across function calls, if that produces overall better code.
374 ; Optional now, so people can test it.
376 Common Report Var(flag_caller_saves) Optimization
377 Save registers around function calls
380 Common Report Var(flag_check_data_deps)
381 Compare the results of several data dependence analyzers.
384 Common Report Var(flag_no_common,0) Optimization
385 Do not put uninitialized globals in the common section
388 Common Report Var(flag_cprop_registers) Optimization
389 Perform a register copy-propagation optimization pass
392 Common Report Var(flag_crossjumping) Optimization
393 Perform cross-jumping optimization
396 Common Report Var(flag_cse_follow_jumps) Optimization
397 When running CSE, follow jumps to their targets
400 Common Report Var(flag_cse_skip_blocks) Optimization
401 When running CSE, follow conditional jumps
404 Common Report Var(flag_cx_limited_range) Optimization
405 Omit range reduction step when performing complex division
408 Common Report Var(flag_cx_fortran_rules) Optimization
409 Complex multiplication and division follow Fortran rules
412 Common Report Var(flag_data_sections) Optimization
413 Place data items into their own section
417 List all available debugging counters with their limits and counts.
420 Common RejectNegative Joined
421 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
424 Common Joined RejectNegative
425 Map one directory name to another in debug information
427 ; Nonzero for -fdefer-pop: don't pop args after each function call
428 ; instead save them up to pop many calls' args with one insns.
430 Common Report Var(flag_defer_pop) Optimization
431 Defer popping functions args from stack until later
434 Common Report Var(flag_delayed_branch) Optimization
435 Attempt to fill delay slots of branch instructions
437 fdelete-null-pointer-checks
438 Common Report Var(flag_delete_null_pointer_checks) Optimization
439 Delete useless null pointer checks
441 fdiagnostics-show-location=
442 Common Joined RejectNegative
443 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
445 fdiagnostics-show-option
447 Amend appropriate diagnostic messages with the command line option that controls them
450 Common Joined RejectNegative
451 -fdump-<type> Dump various compiler internals to a file
454 Common Report Var(flag_dump_noaddr)
455 Suppress output of addresses in debugging dumps
458 Common Report Var(flag_dump_unnumbered) VarExists
459 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
462 Common Report Var(flag_early_inlining) Init(1) Optimization
463 Perform early inlining
465 feliminate-dwarf2-dups
466 Common Report Var(flag_eliminate_dwarf2_dups)
467 Perform DWARF2 duplicate elimination
469 feliminate-unused-debug-symbols
470 Common Report Var(flag_debug_only_used_symbols)
471 Perform unused type elimination in debug info
473 feliminate-unused-debug-types
474 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
475 Perform unused type elimination in debug info
477 femit-class-debug-always
478 Common Report Var(flag_emit_class_debug_always) Init(0)
479 Do not suppress C++ class debug information.
482 Common Report Var(flag_exceptions) Optimization
483 Enable exception handling
485 fexpensive-optimizations
486 Common Report Var(flag_expensive_optimizations) Optimization
487 Perform a number of minor, expensive optimizations
493 Common Report Var(flag_finite_math_only) Optimization
494 Assume no NaNs or infinities are generated
497 Common Joined RejectNegative
498 -ffixed-<register> Mark <register> as being unavailable to the compiler
501 Common Report Var(flag_float_store) Optimization
502 Don't allocate floats and doubles in extended-precision registers
506 Does nothing. Preserved for backward compatibility.
509 Common Report Var(flag_forward_propagate) Optimization
510 Perform a forward propagation pass on RTL
512 ; Nonzero means don't put addresses of constant functions in registers.
513 ; Used for compiling the Unix kernel, where strange substitutions are
514 ; done on the assembly output.
516 Common Report Var(flag_no_function_cse,0)
517 Allow function addresses to be held in registers
520 Common Report Var(flag_function_sections)
521 Place each function into its own section
524 Common Report Var(flag_gcse) Optimization
525 Perform global common subexpression elimination
528 Common Report Var(flag_gcse_lm) Init(1) Optimization
529 Perform enhanced load motion during global common subexpression elimination
532 Common Report Var(flag_gcse_sm) Init(0) Optimization
533 Perform store motion after global common subexpression elimination
536 Common Report Var(flag_gcse_las) Init(0) Optimization
537 Perform redundant load after store elimination in global common subexpression
541 Common Report Var(flag_gcse_after_reload) Optimization
542 Perform global common subexpression elimination after register allocation
545 fguess-branch-probability
546 Common Report Var(flag_guess_branch_prob) Optimization
547 Enable guessing of branch probabilities
549 ; Nonzero means ignore `#ident' directives. 0 means handle them.
550 ; Generate position-independent code for executables if possible
551 ; On SVR4 targets, it also controls whether or not to emit a
552 ; string identifying the compiler.
554 Common Report Var(flag_no_ident,0)
555 Process #ident directives
558 Common Report Var(flag_if_conversion) Optimization
559 Perform conversion of conditional jumps to branchless equivalents
562 Common Report Var(flag_if_conversion2) Optimization
563 Perform conversion of conditional jumps to conditional execution
565 ; -finhibit-size-directive inhibits output of .size for ELF.
566 ; This is used only for compiling crtstuff.c,
567 ; and it may be extended to other effects
568 ; needed for crtstuff.c on other systems.
569 finhibit-size-directive
570 Common Report Var(flag_inhibit_size_directive)
571 Do not generate .size directives
573 ; Nonzero means that functions declared `inline' will be treated
574 ; as `static'. Prevents generation of zillions of copies of unused
575 ; static inline functions; instead, `inlines' are written out
576 ; only when actually used. Used in conjunction with -g. Also
577 ; does the right thing with #pragma interface.
579 Common Report Var(flag_no_inline,0) Init(2)
580 Pay attention to the \"inline\" keyword
582 finline-small-functions
583 Common Report Var(flag_inline_small_functions) Optimization
584 Integrate simple functions into their callers when code size is known to not growth
587 Common Report Var(flag_inline_functions) Optimization
588 Integrate simple functions into their callers
590 finline-functions-called-once
591 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
592 Integrate functions called once into their callers
595 Common RejectNegative Joined UInteger
598 Common RejectNegative Joined UInteger
599 -finline-limit=<number> Limit the size of inlined functions to <number>
601 finstrument-functions
602 Common Report Var(flag_instrument_function_entry_exit)
603 Instrument function entry and exit with profiling calls
605 finstrument-functions-exclude-function-list=
606 Common RejectNegative Joined
607 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
609 finstrument-functions-exclude-file-list=
610 Common RejectNegative Joined
611 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
614 Common Report Var(flag_ipa_cp) Optimization
615 Perform Interprocedural constant propagation
618 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
619 Discover pure and const functions
622 Common Report Var(flag_ipa_pta) Init(0) Optimization
623 Perform interprocedural points-to analysis
626 Common Report Var(flag_ipa_reference) Init(0) Optimization
627 Discover readonly and non addressable static variables
630 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
631 Type based escape and alias analysis
634 Common Report Var(flag_ipa_matrix_reorg) Optimization
635 Perform matrix layout flattening and transposing based
636 on profiling information.
639 Common Report Var(flag_ipa_struct_reorg)
640 Perform structure layout optimizations based
641 on profiling information.
644 Common Report Var(flag_ivopts) Init(1) Optimization
645 Optimize induction variables on trees
648 Common Var(flag_jump_tables) Init(1) Optimization
649 Use jump tables for sufficiently large switch statements
651 fkeep-inline-functions
652 Common Report Var(flag_keep_inline_functions)
653 Generate code for functions even if they are fully inlined
656 Common Report Var(flag_keep_static_consts) Init(1)
657 Emit static const variables even if they are not used
660 Common Report Var(flag_leading_underscore) Init(-1)
661 Give external symbols a leading underscore
665 Does nothing. Preserved for backward compatibility.
668 Common Report Var(flag_errno_math) Init(1)
669 Set errno after built-in math functions
672 Common Report Var(mem_report)
673 Report on permanent memory allocation
675 ; This will attempt to merge constant section constants, if 1 only
676 ; string constants and constants from constant pool, if 2 also constant
679 Common Report Var(flag_merge_constants,2) Init(1) Optimization
680 Attempt to merge identical constants and constant variables
683 Common Report Var(flag_merge_constants,1) VarExists Optimization
684 Attempt to merge identical constants across compilation units
687 Common Report Var(flag_merge_debug_strings) Init(1)
688 Attempt to merge identical debug strings across compilation units
691 Common RejectNegative Joined UInteger
692 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
695 Common Report Var(flag_modulo_sched) Optimization
696 Perform SMS based modulo scheduling before the first scheduling pass
698 fmodulo-sched-allow-regmoves
699 Common Report Var(flag_modulo_sched_allow_regmoves)
700 Perform SMS based modulo scheduling with register moves allowed
702 fmove-loop-invariants
703 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
704 Move loop invariant computations out of loops
707 Common RejectNegative Report Var(flag_mudflap)
708 Add mudflap bounds-checking instrumentation for single-threaded program
711 Common RejectNegative Report VarExists Var(flag_mudflap,2)
712 Add mudflap bounds-checking instrumentation for multi-threaded program
715 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
716 Ignore read operations when inserting mudflap instrumentation
719 Common Var(flag_dce) Init(1) Optimization
720 Use the RTL dead code elimination pass
723 Common Var(flag_dse) Init(1) Optimization
724 Use the RTL dead store elimination pass
726 freschedule-modulo-scheduled-loops
727 Common Report Var(flag_resched_modulo_sched) Optimization
728 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
731 Common Report Var(flag_non_call_exceptions) Optimization
732 Support synchronous non-call exceptions
735 Common Report Var(flag_omit_frame_pointer) Optimization
736 When possible do not generate stack frames
739 Common Report Var(flag_openmp_ssa)
740 Expand OpenMP operations on SSA form
742 foptimize-register-move
743 Common Report Var(flag_regmove) Optimization
744 Do the full register move optimization pass
746 foptimize-sibling-calls
747 Common Report Var(flag_optimize_sibling_calls) Optimization
748 Optimize sibling and tail recursive calls
751 Common Report Var(pre_ipa_mem_report)
752 Report on memory allocation before interprocedural optimization
755 Common Report Var(post_ipa_mem_report)
756 Report on memory allocation before interprocedural optimization
759 Common Report Var(flag_pack_struct) Optimization
760 Pack structure members together without holes
763 Common RejectNegative Joined UInteger Optimization
764 -fpack-struct=<number> Set initial maximum structure member alignment
767 Common Report Var(flag_pcc_struct_return,1) VarExists
768 Return small aggregates in memory, not registers
771 Common Report Var(flag_peel_loops) Optimization
775 Common Report Var(flag_no_peephole,0) Optimization
776 Enable machine specific peephole optimizations
779 Common Report Var(flag_peephole2) Optimization
780 Enable an RTL peephole pass before sched2
783 Common Report Var(flag_pic,2)
784 Generate position-independent code if possible (large mode)
787 Common Report Var(flag_pie,2)
788 Generate position-independent code for executables if possible (large mode)
791 Common Report Var(flag_pic,1) VarExists
792 Generate position-independent code if possible (small mode)
795 Common Report Var(flag_pie,1) VarExists
796 Generate position-independent code for executables if possible (small mode)
798 fpredictive-commoning
799 Common Report Var(flag_predictive_commoning) Optimization
800 Run predictive commoning optimization.
802 fprefetch-loop-arrays
803 Common Report Var(flag_prefetch_loop_arrays) Optimization
804 Generate prefetch instructions, if available, for arrays in loops
807 Common Report Var(profile_flag)
808 Enable basic program profiling code
811 Common Report Var(profile_arc_flag)
812 Insert arc-based program profiling code
816 Enable common options for generating profile info for profile feedback directed optimizations
820 Enable common options for performing profile feedback directed optimizations
823 Common Report Var(flag_profile_values)
824 Insert code to profile values of expressions
830 Common Joined RejectNegative
831 -frandom-seed=<string> Make compile reproducible using <string>
833 ; This switch causes the command line that was used to create an
834 ; object file to be recorded into the object file. The exact format
835 ; of this recording is target and binary file format dependent.
836 ; It is related to the -fverbose-asm switch, but that switch only
837 ; records information in the assembler output file as comments, so
838 ; they never reach the object file.
840 Common Report Var(flag_record_gcc_switches)
841 Record gcc command line switches in the object file.
844 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
845 Return small aggregates in registers
848 Common Report Var(flag_regmove) Optimization
849 Enables a register move optimization
852 Common Report Var(flag_rename_registers) Init(2) Optimization
853 Perform a register renaming optimization pass
856 Common Report Var(flag_reorder_blocks) Optimization
857 Reorder basic blocks to improve code placement
859 freorder-blocks-and-partition
860 Common Report Var(flag_reorder_blocks_and_partition) Optimization
861 Reorder basic blocks and partition into hot and cold sections
864 Common Report Var(flag_reorder_functions) Optimization
865 Reorder functions to improve code placement
867 frerun-cse-after-loop
868 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
869 Add a common subexpression elimination pass after loop optimizations
873 Does nothing. Preserved for backward compatibility.
876 Common Report Var(flag_rounding_math) Optimization
877 Disable optimizations that assume default FP rounding behavior
880 Common Report Var(flag_schedule_interblock) Init(1) Optimization
881 Enable scheduling across basic blocks
884 Common Report Var(flag_schedule_speculative) Init(1) Optimization
885 Allow speculative motion of non-loads
888 Common Report Var(flag_schedule_speculative_load) Optimization
889 Allow speculative motion of some loads
891 fsched-spec-load-dangerous
892 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
893 Allow speculative motion of more loads
896 Common RejectNegative Joined
897 -fsched-verbose=<number> Set the verbosity level of the scheduler
899 fsched2-use-superblocks
900 Common Report Var(flag_sched2_use_superblocks) Optimization
901 If scheduling post reload, do superblock scheduling
904 Common Report Var(flag_sched2_use_traces) Optimization
905 If scheduling post reload, do trace scheduling
908 Common Report Var(flag_schedule_insns) Optimization
909 Reschedule instructions before register allocation
912 Common Report Var(flag_schedule_insns_after_reload) Optimization
913 Reschedule instructions after register allocation
915 ; sched_stalled_insns means that insns can be moved prematurely from the queue
916 ; of stalled insns into the ready list.
918 Common Report Var(flag_sched_stalled_insns) Optimization
919 Allow premature scheduling of queued insns
921 fsched-stalled-insns=
922 Common RejectNegative Joined UInteger
923 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
925 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
926 ; be examined for a dependency on a stalled insn that is candidate for
927 ; premature removal from the queue of stalled insns into the ready list (has
928 ; an effect only if the flag 'sched_stalled_insns' is set).
929 fsched-stalled-insns-dep
930 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
931 Set dependence distance checking in premature scheduling of queued insns
933 fsched-stalled-insns-dep=
934 Common RejectNegative Joined UInteger
935 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
938 Common Report Var(flag_section_anchors) Optimization
939 Access data in the same section from shared anchor points
941 frtl-abstract-sequences
942 Common Report Var(flag_rtl_seqabstr) Optimization
943 Perform sequence abstraction optimization on RTL
946 Common Report Var(flag_see) Init(0)
947 Eliminate redundant sign extensions using LCM.
950 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
951 Show column numbers in diagnostics, when available. Default off
954 Common Report Var(flag_signaling_nans) Optimization
955 Disable optimizations observable by IEEE signaling NaNs
958 Common Report Var(flag_signed_zeros) Init(1) Optimization
959 Disable floating point optimizations that ignore the IEEE signedness of zero
961 fsingle-precision-constant
962 Common Report Var(flag_single_precision_constant) Optimization
963 Convert floating point constants to single precision constants
965 fsplit-ivs-in-unroller
966 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
967 Split lifetimes of induction variables when loops are unrolled
970 Common Report Var(flag_split_wide_types) Optimization
971 Split wide types into independent registers
973 fvariable-expansion-in-unroller
974 Common Report Var(flag_variable_expansion_in_unroller) Optimization
975 Apply variable expansion when loops are unrolled
977 ; Emit code to probe the stack, to help detect stack overflow; also
978 ; may cause large objects to be allocated dynamically.
980 Common Report Var(flag_stack_check)
981 Insert stack checking code into the program
986 fstack-limit-register=
987 Common RejectNegative Joined
988 -fstack-limit-register=<register> Trap if the stack goes past <register>
991 Common RejectNegative Joined
992 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
995 Common Report Var(flag_stack_protect, 1)
996 Use propolice as a stack protection method
999 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1000 Use a stack protection method for every function
1004 Does nothing. Preserved for backward compatibility.
1006 ; Nonzero if we should do (language-dependent) alias analysis.
1007 ; Typically, this analysis will assume that expressions of certain
1008 ; types do not alias expressions of certain other types. Only used
1009 ; if alias analysis (in general) is enabled.
1011 Common Report Var(flag_strict_aliasing) Optimization
1012 Assume strict aliasing rules apply
1015 Common Report Var(flag_strict_overflow)
1016 Treat signed overflow as undefined
1019 Common Report Var(flag_syntax_only)
1020 Check for syntax errors, then stop
1023 Common Report Var(flag_test_coverage)
1024 Create data files needed by \"gcov\"
1027 Common Report Var(flag_thread_jumps) Optimization
1028 Perform jump threading optimizations
1031 Common Report Var(time_report)
1032 Report the time taken by each compiler pass
1035 Common Joined RejectNegative
1036 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1039 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
1040 Reorder top level functions, variables, and asms
1043 Common Report Var(flag_tracer)
1044 Perform superblock formation via tail duplication
1046 ; Zero means that floating-point math operations cannot generate a
1047 ; (user-visible) trap. This is the case, for example, in nonstop
1048 ; IEEE 754 arithmetic.
1050 Common Report Var(flag_trapping_math) Init(1) Optimization
1051 Assume floating-point operations can trap
1054 Common Report Var(flag_trapv) Optimization
1055 Trap for signed overflow in addition, subtraction and multiplication
1058 Common Report Var(flag_tree_ccp) Optimization
1059 Enable SSA-CCP optimization on trees
1062 Common Report Var(flag_tree_store_ccp) Optimization
1063 Enable SSA-CCP optimization for stores and loads
1066 Common Report Var(flag_tree_ch) Optimization
1067 Enable loop header copying on trees
1070 Common Report Var(flag_tree_copyrename) Optimization
1071 Replace SSA temporaries with better names in copies
1074 Common Report Var(flag_tree_copy_prop) Optimization
1075 Enable copy propagation on trees
1077 ftree-store-copy-prop
1079 Does nothing. Preserved for backward compatibility.
1082 Common Report Var(flag_tree_cselim) Init(2) Optimization
1083 Transform condition stores into unconditional ones
1086 Common Report Var(flag_tree_dce) Optimization
1087 Enable SSA dead code elimination optimization on trees
1089 ftree-dominator-opts
1090 Common Report Var(flag_tree_dom) Optimization
1091 Enable dominator optimizations
1094 Common Report Var(flag_tree_dse) Optimization
1095 Enable dead store elimination
1098 Common Report Var(flag_tree_fre) Optimization
1099 Enable Full Redundancy Elimination (FRE) on trees
1101 ftree-loop-distribution
1102 Common Report Var(flag_tree_loop_distribution)
1103 Enable loop distribution on trees
1106 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1107 Enable loop invariant motion on trees
1110 Common Report Var(flag_tree_loop_linear) Optimization
1111 Enable linear loop transforms on trees
1114 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1115 Create canonical induction variables in loops
1118 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1119 Enable loop optimizations on tree level
1121 ftree-parallelize-loops=
1122 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1123 Enable automatic parallelization of loops
1126 Common Report Var(flag_tree_pre) Optimization
1127 Enable SSA-PRE optimization on trees
1130 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1131 Enable reassociation on tree level
1134 Common Report Var(flag_tree_salias) Optimization
1135 Perform structural alias analysis
1138 Common Report Var(flag_tree_sink) Optimization
1139 Enable SSA code sinking on trees
1142 Common Report Var(flag_tree_sra) Optimization
1143 Perform scalar replacement of aggregates
1146 Common Report Var(flag_tree_ter) Optimization
1147 Replace temporary expressions in the SSA->normal pass
1150 Common Report Var(flag_tree_live_range_split) Optimization
1151 Perform live range splitting during the SSA->normal pass
1154 Common Report Var(flag_tree_vrp) Init(0) Optimization
1155 Perform Value Range Propagation on trees
1158 Common Report Var(flag_unit_at_a_time) Optimization
1159 Compile whole compilation unit at a time
1162 Common Report Var(flag_unroll_loops) Optimization
1163 Perform loop unrolling when iteration count is known
1166 Common Report Var(flag_unroll_all_loops) Optimization
1167 Perform loop unrolling for all loops
1169 ; Nonzero means that loop optimizer may assume that the induction variables
1170 ; that control loops do not overflow and that the loops with nontrivial
1171 ; exit condition are not infinite
1172 funsafe-loop-optimizations
1173 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1174 Allow loop optimizations to assume that the loops behave in normal way
1177 Common Report Var(flag_associative_math)
1178 Allow optimization for floating-point arithmetic which may change the
1179 result of the operation due to rounding.
1182 Common Report Var(flag_reciprocal_math)
1183 Same as -fassociative-math for expressions which include division.
1185 ; Nonzero means that unsafe floating-point math optimizations are allowed
1186 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1187 ; are allowed to assume that their arguments and results are "normal"
1188 ; (e.g., nonnegative for SQRT).
1189 funsafe-math-optimizations
1190 Common Report Var(flag_unsafe_math_optimizations) Optimization
1191 Allow math optimizations that may violate IEEE or ISO standards
1194 Common Report Var(flag_unswitch_loops) Optimization
1195 Perform loop unswitching
1198 Common Report Var(flag_unwind_tables) Optimization
1199 Just generate unwind tables for exception handling
1202 Common Report Var(flag_var_tracking) VarExists Optimization
1203 Perform variable tracking
1205 fvar-tracking-uninit
1206 Common Report Var(flag_var_tracking_uninit) Optimization
1207 Perform variable tracking and also tag variables that are uninitialized
1210 Common Report Var(flag_tree_vectorize) Optimization
1211 Enable loop vectorization on trees
1214 Common Report Var(flag_vect_cost_model) Optimization
1215 Enable use of cost model in vectorization
1217 ftree-vect-loop-version
1218 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1219 Enable loop versioning when doing loop vectorization on trees
1221 ftree-vectorizer-verbose=
1222 Common RejectNegative Joined
1223 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1226 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1227 Enable copy propagation of scalar-evolution information.
1229 ; -fverbose-asm causes extra commentary information to be produced in
1230 ; the generated assembly code (to make it more readable). This option
1231 ; is generally only of use to those who actually need to read the
1232 ; generated assembly code (perhaps while debugging the compiler itself).
1233 ; -fno-verbose-asm, the default, causes the extra information
1234 ; to not be added and is useful when comparing two assembler files.
1236 Common Report Var(flag_verbose_asm)
1237 Add extra commentary to assembler output
1240 Common Joined RejectNegative
1241 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1245 Common Report Var(flag_value_profile_transformations) Optimization
1246 Use expression value profiles in optimizations
1249 Common Report Var(flag_web) Init(2) Optimization
1250 Construct webs and split unrelated uses of single variable
1253 Common Report Var(flag_whole_program) Init(0) Optimization
1254 Perform whole program optimizations
1257 Common Report Var(flag_wrapv) Optimization
1258 Assume signed arithmetic overflow wraps around
1260 fzero-initialized-in-bss
1261 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1262 Put zero initialized data in the bss section
1265 Common JoinedOrMissing
1266 Generate debug information in default format
1269 Common JoinedOrMissing Negative(gdwarf-2)
1270 Generate debug information in COFF format
1273 Common JoinedOrMissing Negative(gstabs)
1274 Generate debug information in DWARF v2 format
1277 Common JoinedOrMissing
1278 Generate debug information in default extended format
1281 Common JoinedOrMissing Negative(gstabs+)
1282 Generate debug information in STABS format
1285 Common JoinedOrMissing Negative(gvms)
1286 Generate debug information in extended STABS format
1289 Common JoinedOrMissing Negative(gxcoff)
1290 Generate debug information in VMS format
1293 Common JoinedOrMissing Negative(gxcoff+)
1294 Generate debug information in XCOFF format
1297 Common JoinedOrMissing Negative(gcoff)
1298 Generate debug information in extended XCOFF format
1301 Common Joined Separate
1302 -o <file> Place output into <file>
1305 Common Var(profile_flag)
1306 Enable function profiling
1309 Common Var(pedantic)
1310 Issue warnings needed for strict compliance to the standard
1314 Like -pedantic but issue them as errors
1317 Common Var(quiet_flag)
1318 Do not display functions compiled or elapsed time
1321 Common Var(version_flag)
1322 Display the compiler's version
1325 Common Var(inhibit_warnings)
1329 Common RejectNegative Negative(pie)
1330 Create a shared library
1333 Common RejectNegative Negative(shared)
1334 Create a position independent executable
1336 ; This comment is to ensure we retain the blank line above.