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_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
575 Common Report Var(flag_indirect_inlining)
576 Perform indirect inlining
578 ; Nonzero means that functions declared `inline' will be treated
579 ; as `static'. Prevents generation of zillions of copies of unused
580 ; static inline functions; instead, `inlines' are written out
581 ; only when actually used. Used in conjunction with -g. Also
582 ; does the right thing with #pragma interface.
584 Common Report Var(flag_no_inline,0) Init(2)
585 Pay attention to the \"inline\" keyword
587 finline-small-functions
588 Common Report Var(flag_inline_small_functions) Optimization
589 Integrate simple functions into their callers when code size is known to not growth
592 Common Report Var(flag_inline_functions) Optimization
593 Integrate simple functions into their callers
595 finline-functions-called-once
596 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
597 Integrate functions called once into their callers
600 Common RejectNegative Joined UInteger
603 Common RejectNegative Joined UInteger
604 -finline-limit=<number> Limit the size of inlined functions to <number>
606 finstrument-functions
607 Common Report Var(flag_instrument_function_entry_exit)
608 Instrument function entry and exit with profiling calls
610 finstrument-functions-exclude-function-list=
611 Common RejectNegative Joined
612 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
614 finstrument-functions-exclude-file-list=
615 Common RejectNegative Joined
616 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
619 Common Report Var(flag_ipa_cp) Optimization
620 Perform Interprocedural constant propagation
623 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
624 Discover pure and const functions
627 Common Report Var(flag_ipa_pta) Init(0) Optimization
628 Perform interprocedural points-to analysis
631 Common Report Var(flag_ipa_reference) Init(0) Optimization
632 Discover readonly and non addressable static variables
635 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
636 Type based escape and alias analysis
639 Common Report Var(flag_ipa_matrix_reorg) Optimization
640 Perform matrix layout flattening and transposing based
641 on profiling information.
644 Common Report Var(flag_ipa_struct_reorg)
645 Perform structure layout optimizations based
646 on profiling information.
649 Common Report Var(flag_ivopts) Init(1) Optimization
650 Optimize induction variables on trees
653 Common Var(flag_jump_tables) Init(1) Optimization
654 Use jump tables for sufficiently large switch statements
656 fkeep-inline-functions
657 Common Report Var(flag_keep_inline_functions)
658 Generate code for functions even if they are fully inlined
661 Common Report Var(flag_keep_static_consts) Init(1)
662 Emit static const variables even if they are not used
665 Common Report Var(flag_leading_underscore) Init(-1)
666 Give external symbols a leading underscore
670 Does nothing. Preserved for backward compatibility.
673 Common Report Var(flag_errno_math) Init(1) Optimization
674 Set errno after built-in math functions
677 Common Report Var(mem_report)
678 Report on permanent memory allocation
680 ; This will attempt to merge constant section constants, if 1 only
681 ; string constants and constants from constant pool, if 2 also constant
684 Common Report Var(flag_merge_constants,2) Init(1) Optimization
685 Attempt to merge identical constants and constant variables
688 Common Report Var(flag_merge_constants,1) VarExists Optimization
689 Attempt to merge identical constants across compilation units
692 Common Report Var(flag_merge_debug_strings) Init(1)
693 Attempt to merge identical debug strings across compilation units
696 Common RejectNegative Joined UInteger
697 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
700 Common Report Var(flag_modulo_sched) Optimization
701 Perform SMS based modulo scheduling before the first scheduling pass
703 fmodulo-sched-allow-regmoves
704 Common Report Var(flag_modulo_sched_allow_regmoves)
705 Perform SMS based modulo scheduling with register moves allowed
707 fmove-loop-invariants
708 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
709 Move loop invariant computations out of loops
712 Common RejectNegative Report Var(flag_mudflap)
713 Add mudflap bounds-checking instrumentation for single-threaded program
716 Common RejectNegative Report VarExists Var(flag_mudflap,2)
717 Add mudflap bounds-checking instrumentation for multi-threaded program
720 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
721 Ignore read operations when inserting mudflap instrumentation
724 Common Var(flag_dce) Init(1) Optimization
725 Use the RTL dead code elimination pass
728 Common Var(flag_dse) Init(1) Optimization
729 Use the RTL dead store elimination pass
731 freschedule-modulo-scheduled-loops
732 Common Report Var(flag_resched_modulo_sched) Optimization
733 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
736 Common Report Var(flag_non_call_exceptions) Optimization
737 Support synchronous non-call exceptions
740 Common Report Var(flag_omit_frame_pointer) Optimization
741 When possible do not generate stack frames
743 foptimize-register-move
744 Common Report Var(flag_regmove) Optimization
745 Do the full register move optimization pass
747 foptimize-sibling-calls
748 Common Report Var(flag_optimize_sibling_calls) Optimization
749 Optimize sibling and tail recursive calls
752 Common Report Var(pre_ipa_mem_report)
753 Report on memory allocation before interprocedural optimization
756 Common Report Var(post_ipa_mem_report)
757 Report on memory allocation before interprocedural optimization
760 Common Report Var(flag_pack_struct) Optimization
761 Pack structure members together without holes
764 Common RejectNegative Joined UInteger Optimization
765 -fpack-struct=<number> Set initial maximum structure member alignment
768 Common Report Var(flag_pcc_struct_return,1) VarExists
769 Return small aggregates in memory, not registers
772 Common Report Var(flag_peel_loops) Optimization
776 Common Report Var(flag_no_peephole,0) Optimization
777 Enable machine specific peephole optimizations
780 Common Report Var(flag_peephole2) Optimization
781 Enable an RTL peephole pass before sched2
784 Common Report Var(flag_pic,2)
785 Generate position-independent code if possible (large mode)
788 Common Report Var(flag_pie,2)
789 Generate position-independent code for executables if possible (large mode)
792 Common Report Var(flag_pic,1) VarExists
793 Generate position-independent code if possible (small mode)
796 Common Report Var(flag_pie,1) VarExists
797 Generate position-independent code for executables if possible (small mode)
799 fpredictive-commoning
800 Common Report Var(flag_predictive_commoning) Optimization
801 Run predictive commoning optimization.
803 fprefetch-loop-arrays
804 Common Report Var(flag_prefetch_loop_arrays) Optimization
805 Generate prefetch instructions, if available, for arrays in loops
808 Common Report Var(profile_flag)
809 Enable basic program profiling code
812 Common Report Var(profile_arc_flag)
813 Insert arc-based program profiling code
816 Common Joined RejectNegative
817 Set the top-level directory for storing the profile data.
818 The default is 'pwd'.
822 Enable common options for generating profile info for profile feedback directed optimizations
825 Common Joined RejectNegative
826 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
829 Common Var(flag_profile_use)
830 Enable common options for performing profile feedback directed optimizations
833 Common Joined RejectNegative
834 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
837 Common Report Var(flag_profile_values)
838 Insert code to profile values of expressions
844 Common Joined RejectNegative
845 -frandom-seed=<string> Make compile reproducible using <string>
847 ; This switch causes the command line that was used to create an
848 ; object file to be recorded into the object file. The exact format
849 ; of this recording is target and binary file format dependent.
850 ; It is related to the -fverbose-asm switch, but that switch only
851 ; records information in the assembler output file as comments, so
852 ; they never reach the object file.
854 Common Report Var(flag_record_gcc_switches)
855 Record gcc command line switches in the object file.
858 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
859 Return small aggregates in registers
862 Common Report Var(flag_regmove) Optimization
863 Enables a register move optimization
866 Common Report Var(flag_rename_registers) Init(2) Optimization
867 Perform a register renaming optimization pass
870 Common Report Var(flag_reorder_blocks) Optimization
871 Reorder basic blocks to improve code placement
873 freorder-blocks-and-partition
874 Common Report Var(flag_reorder_blocks_and_partition) Optimization
875 Reorder basic blocks and partition into hot and cold sections
878 Common Report Var(flag_reorder_functions) Optimization
879 Reorder functions to improve code placement
881 frerun-cse-after-loop
882 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
883 Add a common subexpression elimination pass after loop optimizations
887 Does nothing. Preserved for backward compatibility.
890 Common Report Var(flag_rounding_math) Optimization
891 Disable optimizations that assume default FP rounding behavior
894 Common Report Var(flag_schedule_interblock) Init(1) Optimization
895 Enable scheduling across basic blocks
898 Common Report Var(flag_schedule_speculative) Init(1) Optimization
899 Allow speculative motion of non-loads
902 Common Report Var(flag_schedule_speculative_load) Optimization
903 Allow speculative motion of some loads
905 fsched-spec-load-dangerous
906 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
907 Allow speculative motion of more loads
910 Common RejectNegative Joined
911 -fsched-verbose=<number> Set the verbosity level of the scheduler
913 fsched2-use-superblocks
914 Common Report Var(flag_sched2_use_superblocks) Optimization
915 If scheduling post reload, do superblock scheduling
918 Common Report Var(flag_sched2_use_traces) Optimization
919 If scheduling post reload, do trace scheduling
922 Common Report Var(flag_schedule_insns) Optimization
923 Reschedule instructions before register allocation
926 Common Report Var(flag_schedule_insns_after_reload) Optimization
927 Reschedule instructions after register allocation
929 ; sched_stalled_insns means that insns can be moved prematurely from the queue
930 ; of stalled insns into the ready list.
932 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
933 Allow premature scheduling of queued insns
935 fsched-stalled-insns=
936 Common RejectNegative Joined UInteger
937 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
939 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
940 ; be examined for a dependency on a stalled insn that is candidate for
941 ; premature removal from the queue of stalled insns into the ready list (has
942 ; an effect only if the flag 'sched_stalled_insns' is set).
943 fsched-stalled-insns-dep
944 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
945 Set dependence distance checking in premature scheduling of queued insns
947 fsched-stalled-insns-dep=
948 Common RejectNegative Joined UInteger
949 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
952 Common Report Var(flag_section_anchors) Optimization
953 Access data in the same section from shared anchor points
955 frtl-abstract-sequences
956 Common Report Var(flag_rtl_seqabstr) Optimization
957 Perform sequence abstraction optimization on RTL
960 Common Report Var(flag_see) Init(0)
961 Eliminate redundant sign extensions using LCM.
964 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
965 Show column numbers in diagnostics, when available. Default off
968 Common Report Var(flag_signaling_nans) Optimization
969 Disable optimizations observable by IEEE signaling NaNs
972 Common Report Var(flag_signed_zeros) Init(1) Optimization
973 Disable floating point optimizations that ignore the IEEE signedness of zero
975 fsingle-precision-constant
976 Common Report Var(flag_single_precision_constant) Optimization
977 Convert floating point constants to single precision constants
979 fsplit-ivs-in-unroller
980 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
981 Split lifetimes of induction variables when loops are unrolled
984 Common Report Var(flag_split_wide_types) Optimization
985 Split wide types into independent registers
987 fvariable-expansion-in-unroller
988 Common Report Var(flag_variable_expansion_in_unroller) Optimization
989 Apply variable expansion when loops are unrolled
991 ; Emit code to probe the stack, to help detect stack overflow; also
992 ; may cause large objects to be allocated dynamically.
994 Common Report Var(flag_stack_check)
995 Insert stack checking code into the program
1000 fstack-limit-register=
1001 Common RejectNegative Joined
1002 -fstack-limit-register=<register> Trap if the stack goes past <register>
1004 fstack-limit-symbol=
1005 Common RejectNegative Joined
1006 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1009 Common Report Var(flag_stack_protect, 1)
1010 Use propolice as a stack protection method
1012 fstack-protector-all
1013 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1014 Use a stack protection method for every function
1018 Does nothing. Preserved for backward compatibility.
1020 ; Nonzero if we should do (language-dependent) alias analysis.
1021 ; Typically, this analysis will assume that expressions of certain
1022 ; types do not alias expressions of certain other types. Only used
1023 ; if alias analysis (in general) is enabled.
1025 Common Report Var(flag_strict_aliasing) Optimization
1026 Assume strict aliasing rules apply
1029 Common Report Var(flag_strict_overflow)
1030 Treat signed overflow as undefined
1033 Common Report Var(flag_syntax_only)
1034 Check for syntax errors, then stop
1037 Common Report Var(flag_test_coverage)
1038 Create data files needed by \"gcov\"
1041 Common Report Var(flag_thread_jumps) Optimization
1042 Perform jump threading optimizations
1045 Common Report Var(time_report)
1046 Report the time taken by each compiler pass
1049 Common Joined RejectNegative
1050 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1053 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1054 Reorder top level functions, variables, and asms
1057 Common Report Var(flag_tracer)
1058 Perform superblock formation via tail duplication
1060 ; Zero means that floating-point math operations cannot generate a
1061 ; (user-visible) trap. This is the case, for example, in nonstop
1062 ; IEEE 754 arithmetic.
1064 Common Report Var(flag_trapping_math) Init(1) Optimization
1065 Assume floating-point operations can trap
1068 Common Report Var(flag_trapv) Optimization
1069 Trap for signed overflow in addition, subtraction and multiplication
1072 Common Report Var(flag_tree_ccp) Optimization
1073 Enable SSA-CCP optimization on trees
1076 Common Report Var(flag_tree_store_ccp) Optimization
1077 Enable SSA-CCP optimization for stores and loads
1080 Common Report Var(flag_tree_ch) Optimization
1081 Enable loop header copying on trees
1084 Common Report Var(flag_tree_copyrename) Optimization
1085 Replace SSA temporaries with better names in copies
1088 Common Report Var(flag_tree_copy_prop) Optimization
1089 Enable copy propagation on trees
1091 ftree-store-copy-prop
1093 Does nothing. Preserved for backward compatibility.
1096 Common Report Var(flag_tree_cselim) Init(2) Optimization
1097 Transform condition stores into unconditional ones
1099 ftree-switch-conversion
1100 Common Report Var(flag_tree_switch_conversion) Optimization
1101 Perform conversions of switch initializations.
1104 Common Report Var(flag_tree_dce) Optimization
1105 Enable SSA dead code elimination optimization on trees
1107 ftree-dominator-opts
1108 Common Report Var(flag_tree_dom) Optimization
1109 Enable dominator optimizations
1112 Common Report Var(flag_tree_dse) Optimization
1113 Enable dead store elimination
1116 Common Report Var(flag_tree_fre) Optimization
1117 Enable Full Redundancy Elimination (FRE) on trees
1119 ftree-loop-distribution
1120 Common Report Var(flag_tree_loop_distribution) Optimization
1121 Enable loop distribution on trees
1124 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1125 Enable loop invariant motion on trees
1128 Common Report Var(flag_tree_loop_linear) Optimization
1129 Enable linear loop transforms on trees
1132 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1133 Create canonical induction variables in loops
1136 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1137 Enable loop optimizations on tree level
1139 ftree-parallelize-loops=
1140 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1141 Enable automatic parallelization of loops
1144 Common Report Var(flag_tree_pre) Optimization
1145 Enable SSA-PRE optimization on trees
1148 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1149 Enable reassociation on tree level
1153 Does nothing. Preserved for backward compatibility.
1156 Common Report Var(flag_tree_sink) Optimization
1157 Enable SSA code sinking on trees
1160 Common Report Var(flag_tree_sra) Optimization
1161 Perform scalar replacement of aggregates
1164 Common Report Var(flag_tree_ter) Init(1) Optimization
1165 Replace temporary expressions in the SSA->normal pass
1168 Common Report Var(flag_tree_live_range_split) Optimization
1169 Perform live range splitting during the SSA->normal pass
1172 Common Report Var(flag_tree_vrp) Init(0) Optimization
1173 Perform Value Range Propagation on trees
1176 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1177 Compile whole compilation unit at a time
1180 Common Report Var(flag_unroll_loops) Optimization
1181 Perform loop unrolling when iteration count is known
1184 Common Report Var(flag_unroll_all_loops) Optimization
1185 Perform loop unrolling for all loops
1187 ; Nonzero means that loop optimizer may assume that the induction variables
1188 ; that control loops do not overflow and that the loops with nontrivial
1189 ; exit condition are not infinite
1190 funsafe-loop-optimizations
1191 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1192 Allow loop optimizations to assume that the loops behave in normal way
1195 Common Report Var(flag_associative_math)
1196 Allow optimization for floating-point arithmetic which may change the
1197 result of the operation due to rounding.
1200 Common Report Var(flag_reciprocal_math)
1201 Same as -fassociative-math for expressions which include division.
1203 ; Nonzero means that unsafe floating-point math optimizations are allowed
1204 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1205 ; are allowed to assume that their arguments and results are "normal"
1206 ; (e.g., nonnegative for SQRT).
1207 funsafe-math-optimizations
1208 Common Report Var(flag_unsafe_math_optimizations) Optimization
1209 Allow math optimizations that may violate IEEE or ISO standards
1212 Common Report Var(flag_unswitch_loops) Optimization
1213 Perform loop unswitching
1216 Common Report Var(flag_unwind_tables) Optimization
1217 Just generate unwind tables for exception handling
1220 Common Report Var(flag_var_tracking) VarExists Optimization
1221 Perform variable tracking
1223 fvar-tracking-uninit
1224 Common Report Var(flag_var_tracking_uninit) Optimization
1225 Perform variable tracking and also tag variables that are uninitialized
1228 Common Report Var(flag_tree_vectorize) Optimization
1229 Enable loop vectorization on trees
1232 Common Report Var(flag_vect_cost_model) Optimization
1233 Enable use of cost model in vectorization
1235 ftree-vect-loop-version
1236 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1237 Enable loop versioning when doing loop vectorization on trees
1239 ftree-vectorizer-verbose=
1240 Common RejectNegative Joined
1241 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1244 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1245 Enable copy propagation of scalar-evolution information.
1247 ; -fverbose-asm causes extra commentary information to be produced in
1248 ; the generated assembly code (to make it more readable). This option
1249 ; is generally only of use to those who actually need to read the
1250 ; generated assembly code (perhaps while debugging the compiler itself).
1251 ; -fno-verbose-asm, the default, causes the extra information
1252 ; to not be added and is useful when comparing two assembler files.
1254 Common Report Var(flag_verbose_asm)
1255 Add extra commentary to assembler output
1258 Common Joined RejectNegative
1259 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1263 Common Report Var(flag_value_profile_transformations) Optimization
1264 Use expression value profiles in optimizations
1267 Common Report Var(flag_web) Init(2) Optimization
1268 Construct webs and split unrelated uses of single variable
1270 ftree-builtin-call-dce
1271 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1272 Enable conditional dead code elimination for builtin calls
1275 Common Report Var(flag_whole_program) Init(0) Optimization
1276 Perform whole program optimizations
1279 Common Report Var(flag_wrapv) Optimization
1280 Assume signed arithmetic overflow wraps around
1282 fzero-initialized-in-bss
1283 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1284 Put zero initialized data in the bss section
1287 Common JoinedOrMissing
1288 Generate debug information in default format
1291 Common JoinedOrMissing Negative(gdwarf-2)
1292 Generate debug information in COFF format
1295 Common JoinedOrMissing Negative(gstabs)
1296 Generate debug information in DWARF v2 format
1299 Common JoinedOrMissing
1300 Generate debug information in default extended format
1303 Common JoinedOrMissing Negative(gstabs+)
1304 Generate debug information in STABS format
1307 Common JoinedOrMissing Negative(gvms)
1308 Generate debug information in extended STABS format
1311 Common JoinedOrMissing Negative(gxcoff)
1312 Generate debug information in VMS format
1315 Common JoinedOrMissing Negative(gxcoff+)
1316 Generate debug information in XCOFF format
1319 Common JoinedOrMissing Negative(gcoff)
1320 Generate debug information in extended XCOFF format
1323 Common Joined Separate
1324 -o <file> Place output into <file>
1327 Common Var(profile_flag)
1328 Enable function profiling
1331 Common Var(pedantic)
1332 Issue warnings needed for strict compliance to the standard
1336 Like -pedantic but issue them as errors
1339 Common Var(quiet_flag)
1340 Do not display functions compiled or elapsed time
1343 Common Var(version_flag)
1344 Display the compiler's version
1347 Common Var(inhibit_warnings)
1351 Common RejectNegative Negative(pie)
1352 Create a shared library
1355 Common RejectNegative Negative(shared)
1356 Create a position independent executable
1358 ; This comment is to ensure we retain the blank line above.