1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
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 four 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).
55 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
61 Common Joined Separate UInteger
62 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
65 Common JoinedOrMissing Optimization
66 -O<number> Set optimization level to <number>
70 Optimize for space rather than speed
74 This switch is deprecated; use -Wextra instead
77 Common Var(warn_aggregate_return) Warning
78 Warn about returning structures, unions or arrays
81 Common Var(warn_array_bounds) Warning
82 Warn if an array is accessed out of bounds
85 Common Var(warn_attributes) Init(1) Warning
86 Warn about inappropriate attribute usage
89 Common Var(warn_cast_align) Warning
90 Warn about pointer casts which increase alignment
92 Wdeprecated-declarations
93 Common Var(warn_deprecated_decl) Init(1) Warning
94 Warn about uses of __attribute__((deprecated)) declarations
96 Wdisabled-optimization
97 Common Var(warn_disabled_optimization) Warning
98 Warn when an optimization pass is disabled
101 Common Var(warnings_are_errors)
102 Treat all warnings as errors
106 Treat specified warning as error
110 Print extra (possibly unwanted) warnings
113 Common Var(flag_fatal_errors)
114 Exit on the first error occurred
117 Common RejectNegative Joined UInteger
118 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes
121 Common Var(warn_inline) Warning
122 Warn when an inlined function cannot be inlined
125 Common RejectNegative Joined UInteger Warning
128 Common RejectNegative Joined UInteger Warning
129 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
132 Common Warning Var(warn_logical_op)
133 Warn when a logical operator is suspicously always evaluating to true or false
135 Wunsafe-loop-optimizations
136 Common Var(warn_unsafe_loop_optimizations) Warning
137 Warn if the loop cannot be optimized due to nontrivial assumptions.
140 Common Var(warn_missing_noreturn) Warning
141 Warn about functions which might be candidates for __attribute__((noreturn))
144 Common Var(warn_mudflap) Init(1) Warning
145 Warn about constructs not instrumented by -fmudflap
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
212 Common Var(warn_unused) Init(0) Warning
213 Enable all -Wunused- warnings
216 Common Var(warn_unused_function) Init(-1) Warning
217 Warn when a function is unused
220 Common Var(warn_unused_label) Init(-1) Warning
221 Warn when a label is unused
224 Common Var(warn_unused_parameter) Init(-1) Warning
225 Warn when a function parameter is unused
228 Common Var(warn_unused_value) Init(-1) Warning
229 Warn when an expression value is unused
232 Common Var(warn_unused_variable) Init(-1) 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) Optimization UInteger
278 Align the start of functions
281 Common RejectNegative Joined UInteger
284 Common Report Var(align_jumps,0) Optimization UInteger
285 Align labels which are only reached by jumping
288 Common RejectNegative Joined UInteger
291 Common Report Var(align_labels,0) Optimization UInteger
295 Common RejectNegative Joined UInteger
298 Common Report Var(align_loops) Optimization UInteger
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 Var(flag_conserve_stack) Optimization
389 Do not perform optimizations increasing noticeably stack usage
392 Common Report Var(flag_cprop_registers) Optimization
393 Perform a register copy-propagation optimization pass
396 Common Report Var(flag_crossjumping) Optimization
397 Perform cross-jumping optimization
400 Common Report Var(flag_cse_follow_jumps) Optimization
401 When running CSE, follow jumps to their targets
404 Common Report Var(flag_cse_skip_blocks) Optimization
405 When running CSE, follow conditional jumps
408 Common Report Var(flag_cx_limited_range) Optimization
409 Omit range reduction step when performing complex division
412 Common Report Var(flag_cx_fortran_rules) Optimization
413 Complex multiplication and division follow Fortran rules
416 Common Report Var(flag_data_sections) Optimization
417 Place data items into their own section
421 List all available debugging counters with their limits and counts.
424 Common RejectNegative Joined
425 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
428 Common Joined RejectNegative
429 Map one directory name to another in debug information
431 ; Nonzero for -fdefer-pop: don't pop args after each function call
432 ; instead save them up to pop many calls' args with one insns.
434 Common Report Var(flag_defer_pop) Optimization
435 Defer popping functions args from stack until later
438 Common Report Var(flag_delayed_branch) Optimization
439 Attempt to fill delay slots of branch instructions
441 fdelete-null-pointer-checks
442 Common Report Var(flag_delete_null_pointer_checks) Init(1) Optimization
443 Delete useless null pointer checks
445 fdiagnostics-show-location=
446 Common Joined RejectNegative
447 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
449 fdiagnostics-show-option
451 Amend appropriate diagnostic messages with the command line option that controls them
454 Common Joined RejectNegative
455 -fdump-<type> Dump various compiler internals to a file
458 Common Report Var(flag_dump_noaddr)
459 Suppress output of addresses in debugging dumps
462 Common Report Var(flag_dump_unnumbered) VarExists
463 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
466 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
467 Enable CFI tables via GAS assembler directives.
470 Common Report Var(flag_early_inlining) Init(1) Optimization
471 Perform early inlining
473 feliminate-dwarf2-dups
474 Common Report Var(flag_eliminate_dwarf2_dups)
475 Perform DWARF2 duplicate elimination
477 feliminate-unused-debug-symbols
478 Common Report Var(flag_debug_only_used_symbols)
479 Perform unused type elimination in debug info
481 feliminate-unused-debug-types
482 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
483 Perform unused type elimination in debug info
485 femit-class-debug-always
486 Common Report Var(flag_emit_class_debug_always) Init(0)
487 Do not suppress C++ class debug information.
490 Common Report Var(flag_exceptions) Optimization
491 Enable exception handling
493 fexpensive-optimizations
494 Common Report Var(flag_expensive_optimizations) Optimization
495 Perform a number of minor, expensive optimizations
498 Common Joined RejectNegative
499 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision
505 Common Report Var(flag_finite_math_only) Optimization
506 Assume no NaNs or infinities are generated
509 Common Joined RejectNegative
510 -ffixed-<register> Mark <register> as being unavailable to the compiler
513 Common Report Var(flag_float_store) Optimization
514 Don't allocate floats and doubles in extended-precision registers
518 Does nothing. Preserved for backward compatibility.
521 Common Report Var(flag_forward_propagate) Optimization
522 Perform a forward propagation pass on RTL
524 ; Nonzero means don't put addresses of constant functions in registers.
525 ; Used for compiling the Unix kernel, where strange substitutions are
526 ; done on the assembly output.
528 Common Report Var(flag_no_function_cse,0)
529 Allow function addresses to be held in registers
532 Common Report Var(flag_function_sections)
533 Place each function into its own section
536 Common Report Var(flag_gcse) Optimization
537 Perform global common subexpression elimination
540 Common Report Var(flag_gcse_lm) Init(1) Optimization
541 Perform enhanced load motion during global common subexpression elimination
544 Common Report Var(flag_gcse_sm) Init(0) Optimization
545 Perform store motion after global common subexpression elimination
548 Common Report Var(flag_gcse_las) Init(0) Optimization
549 Perform redundant load after store elimination in global common subexpression
553 Common Report Var(flag_gcse_after_reload) Optimization
554 Perform global common subexpression elimination after register allocation
557 ; This option is not documented yet as its semantics will change.
559 Common Report Var(flag_graphite)
560 Enable in and out of Graphite representation
563 Common Report Var(flag_loop_strip_mine) Optimization
564 Enable Loop Strip Mining transformation
567 Common Report Var(flag_loop_interchange) Optimization
568 Enable Loop Interchange transformation
571 Common Report Var(flag_loop_block) Optimization
572 Enable Loop Blocking transformation
574 ; This option is not documented as it does not perform any useful optimization.
576 Common Report Var(flag_graphite_identity) Optimization
577 Enable Graphite Identity transformation
579 fguess-branch-probability
580 Common Report Var(flag_guess_branch_prob) Optimization
581 Enable guessing of branch probabilities
583 ; Nonzero means ignore `#ident' directives. 0 means handle them.
584 ; Generate position-independent code for executables if possible
585 ; On SVR4 targets, it also controls whether or not to emit a
586 ; string identifying the compiler.
588 Common Report Var(flag_no_ident,0)
589 Process #ident directives
592 Common Report Var(flag_if_conversion) Optimization
593 Perform conversion of conditional jumps to branchless equivalents
596 Common Report Var(flag_if_conversion2) Optimization
597 Perform conversion of conditional jumps to conditional execution
599 ; -finhibit-size-directive inhibits output of .size for ELF.
600 ; This is used only for compiling crtstuff.c,
601 ; and it may be extended to other effects
602 ; needed for crtstuff.c on other systems.
603 finhibit-size-directive
604 Common Report Var(flag_inhibit_size_directive)
605 Do not generate .size directives
608 Common Report Var(flag_indirect_inlining)
609 Perform indirect inlining
611 ; Nonzero means that functions declared `inline' will be treated
612 ; as `static'. Prevents generation of zillions of copies of unused
613 ; static inline functions; instead, `inlines' are written out
614 ; only when actually used. Used in conjunction with -g. Also
615 ; does the right thing with #pragma interface.
617 Common Report Var(flag_no_inline,0) Init(0)
618 Pay attention to the \"inline\" keyword
620 finline-small-functions
621 Common Report Var(flag_inline_small_functions) Optimization
622 Integrate simple functions into their callers when code size is known to not growth
625 Common Report Var(flag_inline_functions) Optimization
626 Integrate simple functions into their callers
628 finline-functions-called-once
629 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
630 Integrate functions called once into their callers
633 Common RejectNegative Joined UInteger
636 Common RejectNegative Joined UInteger
637 -finline-limit=<number> Limit the size of inlined functions to <number>
639 finstrument-functions
640 Common Report Var(flag_instrument_function_entry_exit)
641 Instrument function entry and exit with profiling calls
643 finstrument-functions-exclude-function-list=
644 Common RejectNegative Joined
645 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
647 finstrument-functions-exclude-file-list=
648 Common RejectNegative Joined
649 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
652 Common Report Var(flag_ipa_cp) Optimization
653 Perform Interprocedural constant propagation
656 Common Report Var(flag_ipa_cp_clone) Optimization
657 Perform cloning to make Interprocedural constant propagation stronger
660 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
661 Discover pure and const functions
664 Common Report Var(flag_ipa_pta) Init(0) Optimization
665 Perform interprocedural points-to analysis
668 Common Report Var(flag_ipa_reference) Init(0) Optimization
669 Discover readonly and non addressable static variables
672 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
673 Type based escape and alias analysis
676 Common Report Var(flag_ipa_matrix_reorg) Optimization
677 Perform matrix layout flattening and transposing based
678 on profiling information.
681 Common Report Var(flag_ipa_struct_reorg)
682 Perform structure layout optimizations based
683 on profiling information.
686 Common Joined RejectNegative
687 -fira-algorithm=[CB|priority] Set the used IRA algorithm
690 Common Joined RejectNegative
691 -fira-region=[one|all|mixed] Set regions for IRA
694 Common Report Var(flag_ira_coalesce) Init(0)
695 Do optimistic coalescing.
697 fira-share-save-slots
698 Common Report Var(flag_ira_share_save_slots) Init(1)
699 Share slots for saving different hard registers.
701 fira-share-spill-slots
702 Common Report Var(flag_ira_share_spill_slots) Init(1)
703 Share stack slots for spilled pseudo-registers.
706 Common RejectNegative Joined UInteger
707 -fira-verbose=<number> Control IRA's level of diagnostic messages.
710 Common Report Var(flag_ivopts) Init(1) Optimization
711 Optimize induction variables on trees
714 Common Var(flag_jump_tables) Init(1) Optimization
715 Use jump tables for sufficiently large switch statements
717 fkeep-inline-functions
718 Common Report Var(flag_keep_inline_functions)
719 Generate code for functions even if they are fully inlined
722 Common Report Var(flag_keep_static_consts) Init(1)
723 Emit static const variables even if they are not used
726 Common Report Var(flag_leading_underscore) Init(-1)
727 Give external symbols a leading underscore
731 Does nothing. Preserved for backward compatibility.
734 Common Report Var(flag_errno_math) Init(1) Optimization
735 Set errno after built-in math functions
738 Common Report Var(mem_report)
739 Report on permanent memory allocation
741 ; This will attempt to merge constant section constants, if 1 only
742 ; string constants and constants from constant pool, if 2 also constant
745 Common Report Var(flag_merge_constants,2) Init(1) Optimization
746 Attempt to merge identical constants and constant variables
749 Common Report Var(flag_merge_constants,1) VarExists Optimization
750 Attempt to merge identical constants across compilation units
753 Common Report Var(flag_merge_debug_strings) Init(1)
754 Attempt to merge identical debug strings across compilation units
757 Common RejectNegative Joined UInteger
758 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
761 Common Report Var(flag_modulo_sched) Optimization
762 Perform SMS based modulo scheduling before the first scheduling pass
764 fmodulo-sched-allow-regmoves
765 Common Report Var(flag_modulo_sched_allow_regmoves)
766 Perform SMS based modulo scheduling with register moves allowed
768 fmove-loop-invariants
769 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
770 Move loop invariant computations out of loops
773 Common RejectNegative Report Var(flag_mudflap)
774 Add mudflap bounds-checking instrumentation for single-threaded program
777 Common RejectNegative Report VarExists Var(flag_mudflap,2)
778 Add mudflap bounds-checking instrumentation for multi-threaded program
781 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
782 Ignore read operations when inserting mudflap instrumentation
785 Common Var(flag_dce) Init(1) Optimization
786 Use the RTL dead code elimination pass
789 Common Var(flag_dse) Init(1) Optimization
790 Use the RTL dead store elimination pass
792 freschedule-modulo-scheduled-loops
793 Common Report Var(flag_resched_modulo_sched) Optimization
794 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
797 Common Report Var(flag_non_call_exceptions) Optimization
798 Support synchronous non-call exceptions
801 Common Report Var(flag_omit_frame_pointer) Optimization
802 When possible do not generate stack frames
804 foptimize-register-move
805 Common Report Var(flag_regmove) Optimization
806 Do the full register move optimization pass
808 foptimize-sibling-calls
809 Common Report Var(flag_optimize_sibling_calls) Optimization
810 Optimize sibling and tail recursive calls
813 Common Report Var(pre_ipa_mem_report)
814 Report on memory allocation before interprocedural optimization
817 Common Report Var(post_ipa_mem_report)
818 Report on memory allocation before interprocedural optimization
821 Common Report Var(flag_pack_struct) Optimization
822 Pack structure members together without holes
825 Common RejectNegative Joined UInteger Optimization
826 -fpack-struct=<number> Set initial maximum structure member alignment
829 Common Report Var(flag_pcc_struct_return,1) VarExists
830 Return small aggregates in memory, not registers
833 Common Report Var(flag_peel_loops) Optimization
837 Common Report Var(flag_no_peephole,0) Optimization
838 Enable machine specific peephole optimizations
841 Common Report Var(flag_peephole2) Optimization
842 Enable an RTL peephole pass before sched2
845 Common Report Var(flag_pic,2)
846 Generate position-independent code if possible (large mode)
849 Common Report Var(flag_pie,2)
850 Generate position-independent code for executables if possible (large mode)
853 Common Report Var(flag_pic,1) VarExists
854 Generate position-independent code if possible (small mode)
857 Common Report Var(flag_pie,1) VarExists
858 Generate position-independent code for executables if possible (small mode)
861 Common Joined RejectNegative
862 Specify a plugin to load
865 Common Joined RejectNegative
866 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
868 fpredictive-commoning
869 Common Report Var(flag_predictive_commoning) Optimization
870 Run predictive commoning optimization.
872 fprefetch-loop-arrays
873 Common Report Var(flag_prefetch_loop_arrays) Optimization
874 Generate prefetch instructions, if available, for arrays in loops
877 Common Report Var(profile_flag)
878 Enable basic program profiling code
881 Common Report Var(profile_arc_flag)
882 Insert arc-based program profiling code
885 Common Joined RejectNegative
886 Set the top-level directory for storing the profile data.
887 The default is 'pwd'.
890 Common Report Var(flag_profile_correction)
891 Enable correction of flow inconsistent profile data input
895 Enable common options for generating profile info for profile feedback directed optimizations
898 Common Joined RejectNegative
899 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
902 Common Var(flag_profile_use)
903 Enable common options for performing profile feedback directed optimizations
906 Common Joined RejectNegative
907 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
910 Common Report Var(flag_profile_values)
911 Insert code to profile values of expressions
917 Common Joined RejectNegative
918 -frandom-seed=<string> Make compile reproducible using <string>
920 ; This switch causes the command line that was used to create an
921 ; object file to be recorded into the object file. The exact format
922 ; of this recording is target and binary file format dependent.
923 ; It is related to the -fverbose-asm switch, but that switch only
924 ; records information in the assembler output file as comments, so
925 ; they never reach the object file.
927 Common Report Var(flag_record_gcc_switches)
928 Record gcc command line switches in the object file.
931 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
932 Return small aggregates in registers
935 Common Report Var(flag_regmove) Optimization
936 Enables a register move optimization
939 Common Report Var(flag_rename_registers) Init(2) Optimization
940 Perform a register renaming optimization pass
943 Common Report Var(flag_reorder_blocks) Optimization
944 Reorder basic blocks to improve code placement
946 freorder-blocks-and-partition
947 Common Report Var(flag_reorder_blocks_and_partition) Optimization
948 Reorder basic blocks and partition into hot and cold sections
951 Common Report Var(flag_reorder_functions) Optimization
952 Reorder functions to improve code placement
954 frerun-cse-after-loop
955 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
956 Add a common subexpression elimination pass after loop optimizations
960 Does nothing. Preserved for backward compatibility.
963 Common Report Var(flag_rounding_math) Optimization
964 Disable optimizations that assume default FP rounding behavior
967 Common Report Var(flag_schedule_interblock) Init(1) Optimization
968 Enable scheduling across basic blocks
971 Common Report Var(flag_schedule_speculative) Init(1) Optimization
972 Allow speculative motion of non-loads
975 Common Report Var(flag_schedule_speculative_load) Optimization
976 Allow speculative motion of some loads
978 fsched-spec-load-dangerous
979 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
980 Allow speculative motion of more loads
983 Common RejectNegative Joined
984 -fsched-verbose=<number> Set the verbosity level of the scheduler
986 fsched2-use-superblocks
987 Common Report Var(flag_sched2_use_superblocks) Optimization
988 If scheduling post reload, do superblock scheduling
991 Common Report Var(flag_sched2_use_traces) Optimization
992 If scheduling post reload, do trace scheduling
995 Common Report Var(flag_schedule_insns) Optimization
996 Reschedule instructions before register allocation
999 Common Report Var(flag_schedule_insns_after_reload) Optimization
1000 Reschedule instructions after register allocation
1002 ; This flag should be on when a target implements non-trivial
1003 ; scheduling hooks, maybe saving some information for its own sake.
1004 ; On IA64, for example, this is used for correct bundling.
1005 fselective-scheduling
1006 Common Report Var(flag_selective_scheduling) Optimization
1007 Schedule instructions using selective scheduling algorithm
1009 fselective-scheduling2
1010 Common Report Var(flag_selective_scheduling2) Optimization
1011 Run selective scheduling after reload
1013 fsel-sched-pipelining
1014 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1015 Perform software pipelining of inner loops during selective scheduling
1017 fsel-sched-pipelining-outer-loops
1018 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1019 Perform software pipelining of outer loops during selective scheduling
1021 fsel-sched-reschedule-pipelined
1022 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1023 Reschedule pipelined regions without pipelining
1025 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1026 ; of stalled insns into the ready list.
1027 fsched-stalled-insns
1028 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1029 Allow premature scheduling of queued insns
1031 fsched-stalled-insns=
1032 Common RejectNegative Joined UInteger
1033 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1035 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1036 ; be examined for a dependency on a stalled insn that is candidate for
1037 ; premature removal from the queue of stalled insns into the ready list (has
1038 ; an effect only if the flag 'sched_stalled_insns' is set).
1039 fsched-stalled-insns-dep
1040 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1041 Set dependence distance checking in premature scheduling of queued insns
1043 fsched-stalled-insns-dep=
1044 Common RejectNegative Joined UInteger
1045 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1048 Common Report Var(flag_section_anchors) Optimization
1049 Access data in the same section from shared anchor points
1052 Common Report Var(flag_see) Init(0)
1053 Eliminate redundant sign extensions using LCM.
1056 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
1057 Show column numbers in diagnostics, when available. Default off
1060 Common Report Var(flag_signaling_nans) Optimization
1061 Disable optimizations observable by IEEE signaling NaNs
1064 Common Report Var(flag_signed_zeros) Init(1) Optimization
1065 Disable floating point optimizations that ignore the IEEE signedness of zero
1067 fsingle-precision-constant
1068 Common Report Var(flag_single_precision_constant) Optimization
1069 Convert floating point constants to single precision constants
1071 fsplit-ivs-in-unroller
1072 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1073 Split lifetimes of induction variables when loops are unrolled
1076 Common Report Var(flag_split_wide_types) Optimization
1077 Split wide types into independent registers
1079 fvariable-expansion-in-unroller
1080 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1081 Apply variable expansion when loops are unrolled
1084 Common Report RejectNegative Joined
1085 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1089 Insert stack checking code into the program. Same as -fstack-check=specific
1094 fstack-limit-register=
1095 Common RejectNegative Joined
1096 -fstack-limit-register=<register> Trap if the stack goes past <register>
1098 fstack-limit-symbol=
1099 Common RejectNegative Joined
1100 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1103 Common Report Var(flag_stack_protect, 1)
1104 Use propolice as a stack protection method
1106 fstack-protector-all
1107 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1108 Use a stack protection method for every function
1112 Does nothing. Preserved for backward compatibility.
1114 ; Nonzero if we should do (language-dependent) alias analysis.
1115 ; Typically, this analysis will assume that expressions of certain
1116 ; types do not alias expressions of certain other types. Only used
1117 ; if alias analysis (in general) is enabled.
1119 Common Report Var(flag_strict_aliasing) Optimization
1120 Assume strict aliasing rules apply
1123 Common Report Var(flag_strict_overflow)
1124 Treat signed overflow as undefined
1127 Common Report Var(flag_syntax_only)
1128 Check for syntax errors, then stop
1131 Common Report Var(flag_test_coverage)
1132 Create data files needed by \"gcov\"
1135 Common Report Var(flag_thread_jumps) Optimization
1136 Perform jump threading optimizations
1139 Common Report Var(time_report)
1140 Report the time taken by each compiler pass
1143 Common Joined RejectNegative
1144 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1147 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1148 Reorder top level functions, variables, and asms
1151 Common Report Var(flag_tracer)
1152 Perform superblock formation via tail duplication
1154 ; Zero means that floating-point math operations cannot generate a
1155 ; (user-visible) trap. This is the case, for example, in nonstop
1156 ; IEEE 754 arithmetic.
1158 Common Report Var(flag_trapping_math) Init(1) Optimization
1159 Assume floating-point operations can trap
1162 Common Report Var(flag_trapv) Optimization
1163 Trap for signed overflow in addition, subtraction and multiplication
1166 Common Report Var(flag_tree_ccp) Optimization
1167 Enable SSA-CCP optimization on trees
1171 Does nothing. Preserved for backward compatibility.
1174 Common Report Var(flag_tree_ch) Optimization
1175 Enable loop header copying on trees
1178 Common Report Var(flag_tree_copyrename) Optimization
1179 Replace SSA temporaries with better names in copies
1182 Common Report Var(flag_tree_copy_prop) Optimization
1183 Enable copy propagation on trees
1185 ftree-store-copy-prop
1187 Does nothing. Preserved for backward compatibility.
1190 Common Report Var(flag_tree_cselim) Init(2) Optimization
1191 Transform condition stores into unconditional ones
1193 ftree-switch-conversion
1194 Common Report Var(flag_tree_switch_conversion) Optimization
1195 Perform conversions of switch initializations.
1198 Common Report Var(flag_tree_dce) Optimization
1199 Enable SSA dead code elimination optimization on trees
1201 ftree-dominator-opts
1202 Common Report Var(flag_tree_dom) Optimization
1203 Enable dominator optimizations
1206 Common Report Var(flag_tree_dse) Optimization
1207 Enable dead store elimination
1210 Common Report Var(flag_tree_fre) Optimization
1211 Enable Full Redundancy Elimination (FRE) on trees
1213 ftree-loop-distribution
1214 Common Report Var(flag_tree_loop_distribution) Optimization
1215 Enable loop distribution on trees
1218 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1219 Enable loop invariant motion on trees
1222 Common Report Var(flag_tree_loop_linear) Optimization
1223 Enable linear loop transforms on trees
1226 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1227 Create canonical induction variables in loops
1230 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1231 Enable loop optimizations on tree level
1233 ftree-parallelize-loops=
1234 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1235 Enable automatic parallelization of loops
1238 Common Report Var(flag_tree_pre) Optimization
1239 Enable SSA-PRE optimization on trees
1242 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1243 Enable reassociation on tree level
1247 Does nothing. Preserved for backward compatibility.
1250 Common Report Var(flag_tree_sink) Optimization
1251 Enable SSA code sinking on trees
1254 Common Report Var(flag_tree_sra) Optimization
1255 Perform scalar replacement of aggregates
1258 Common Report Var(flag_tree_ter) Init(1) Optimization
1259 Replace temporary expressions in the SSA->normal pass
1262 Common Report Var(flag_tree_live_range_split) Optimization
1263 Perform live range splitting during the SSA->normal pass
1266 Common Report Var(flag_tree_vrp) Init(0) Optimization
1267 Perform Value Range Propagation on trees
1270 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1271 Compile whole compilation unit at a time
1274 Common Report Var(flag_unroll_loops) Optimization
1275 Perform loop unrolling when iteration count is known
1278 Common Report Var(flag_unroll_all_loops) Optimization
1279 Perform loop unrolling for all loops
1281 ; Nonzero means that loop optimizer may assume that the induction variables
1282 ; that control loops do not overflow and that the loops with nontrivial
1283 ; exit condition are not infinite
1284 funsafe-loop-optimizations
1285 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1286 Allow loop optimizations to assume that the loops behave in normal way
1289 Common Report Var(flag_associative_math)
1290 Allow optimization for floating-point arithmetic which may change the
1291 result of the operation due to rounding.
1294 Common Report Var(flag_reciprocal_math)
1295 Same as -fassociative-math for expressions which include division.
1297 ; Nonzero means that unsafe floating-point math optimizations are allowed
1298 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1299 ; are allowed to assume that their arguments and results are "normal"
1300 ; (e.g., nonnegative for SQRT).
1301 funsafe-math-optimizations
1302 Common Report Var(flag_unsafe_math_optimizations) Optimization
1303 Allow math optimizations that may violate IEEE or ISO standards
1306 Common Report Var(flag_unswitch_loops) Optimization
1307 Perform loop unswitching
1310 Common Report Var(flag_unwind_tables) Optimization
1311 Just generate unwind tables for exception handling
1314 Common Report Var(flag_var_tracking) VarExists Optimization
1315 Perform variable tracking
1317 fvar-tracking-uninit
1318 Common Report Var(flag_var_tracking_uninit) Optimization
1319 Perform variable tracking and also tag variables that are uninitialized
1322 Common Report Var(flag_tree_vectorize) Optimization
1323 Enable loop vectorization on trees
1326 Common Report Var(flag_vect_cost_model) Optimization
1327 Enable use of cost model in vectorization
1329 ftree-vect-loop-version
1330 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1331 Enable loop versioning when doing loop vectorization on trees
1333 ftree-vectorizer-verbose=
1334 Common RejectNegative Joined
1335 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1338 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1339 Enable copy propagation of scalar-evolution information.
1341 ; -fverbose-asm causes extra commentary information to be produced in
1342 ; the generated assembly code (to make it more readable). This option
1343 ; is generally only of use to those who actually need to read the
1344 ; generated assembly code (perhaps while debugging the compiler itself).
1345 ; -fno-verbose-asm, the default, causes the extra information
1346 ; to not be added and is useful when comparing two assembler files.
1348 Common Report Var(flag_verbose_asm)
1349 Add extra commentary to assembler output
1352 Common Joined RejectNegative
1353 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1357 Common Report Var(flag_value_profile_transformations) Optimization
1358 Use expression value profiles in optimizations
1361 Common Report Var(flag_web) Init(2) Optimization
1362 Construct webs and split unrelated uses of single variable
1364 ftree-builtin-call-dce
1365 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1366 Enable conditional dead code elimination for builtin calls
1369 Common Report Var(flag_whole_program) Init(0) Optimization
1370 Perform whole program optimizations
1373 Common Report Var(flag_wrapv) Optimization
1374 Assume signed arithmetic overflow wraps around
1376 fzero-initialized-in-bss
1377 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1378 Put zero initialized data in the bss section
1381 Common JoinedOrMissing
1382 Generate debug information in default format
1385 Common JoinedOrMissing Negative(gdwarf-2)
1386 Generate debug information in COFF format
1389 Common JoinedOrMissing Negative(gstabs)
1390 Generate debug information in DWARF v2 format
1393 Common JoinedOrMissing
1394 Generate debug information in default extended format
1397 Common JoinedOrMissing Negative(gstabs+)
1398 Generate debug information in STABS format
1401 Common JoinedOrMissing Negative(gvms)
1402 Generate debug information in extended STABS format
1405 Common JoinedOrMissing Negative(gxcoff)
1406 Generate debug information in VMS format
1409 Common JoinedOrMissing Negative(gxcoff+)
1410 Generate debug information in XCOFF format
1413 Common JoinedOrMissing Negative(gcoff)
1414 Generate debug information in extended XCOFF format
1417 Common Joined Separate
1418 -o <file> Place output into <file>
1421 Common Var(profile_flag)
1422 Enable function profiling
1425 Common Var(pedantic)
1426 Issue warnings needed for strict compliance to the standard
1430 Like -pedantic but issue them as errors
1433 Common Var(quiet_flag)
1434 Do not display functions compiled or elapsed time
1437 Common Var(version_flag)
1438 Display the compiler's version
1441 Common Var(inhibit_warnings)
1445 Common RejectNegative Negative(pie)
1446 Create a shared library
1449 Common RejectNegative Negative(shared)
1450 Create a position independent executable
1452 ; This comment is to ensure we retain the blank line above.