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
213 Common Var(warn_unused) Init(0) Warning
214 Enable all -Wunused- warnings
217 Common Var(warn_unused_function) Init(-1) Warning
218 Warn when a function is unused
221 Common Var(warn_unused_label) Init(-1) Warning
222 Warn when a label is unused
225 Common Var(warn_unused_parameter) Init(-1) Warning
226 Warn when a function parameter is unused
229 Common Var(warn_unused_value) Init(-1) Warning
230 Warn when an expression value is unused
233 Common Var(warn_unused_variable) Init(-1) 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_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
464 Enable CFI tables via GAS assembler directives.
467 Common Report Var(flag_early_inlining) Init(1) Optimization
468 Perform early inlining
470 feliminate-dwarf2-dups
471 Common Report Var(flag_eliminate_dwarf2_dups)
472 Perform DWARF2 duplicate elimination
474 feliminate-unused-debug-symbols
475 Common Report Var(flag_debug_only_used_symbols)
476 Perform unused type elimination in debug info
478 feliminate-unused-debug-types
479 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
480 Perform unused type elimination in debug info
482 femit-class-debug-always
483 Common Report Var(flag_emit_class_debug_always) Init(0)
484 Do not suppress C++ class debug information.
487 Common Report Var(flag_exceptions) Optimization
488 Enable exception handling
490 fexpensive-optimizations
491 Common Report Var(flag_expensive_optimizations) Optimization
492 Perform a number of minor, expensive optimizations
498 Common Report Var(flag_finite_math_only) Optimization
499 Assume no NaNs or infinities are generated
502 Common Joined RejectNegative
503 -ffixed-<register> Mark <register> as being unavailable to the compiler
506 Common Report Var(flag_float_store) Optimization
507 Don't allocate floats and doubles in extended-precision registers
511 Does nothing. Preserved for backward compatibility.
514 Common Report Var(flag_forward_propagate) Optimization
515 Perform a forward propagation pass on RTL
517 ; Nonzero means don't put addresses of constant functions in registers.
518 ; Used for compiling the Unix kernel, where strange substitutions are
519 ; done on the assembly output.
521 Common Report Var(flag_no_function_cse,0)
522 Allow function addresses to be held in registers
525 Common Report Var(flag_function_sections)
526 Place each function into its own section
529 Common Report Var(flag_gcse) Optimization
530 Perform global common subexpression elimination
533 Common Report Var(flag_gcse_lm) Init(1) Optimization
534 Perform enhanced load motion during global common subexpression elimination
537 Common Report Var(flag_gcse_sm) Init(0) Optimization
538 Perform store motion after global common subexpression elimination
541 Common Report Var(flag_gcse_las) Init(0) Optimization
542 Perform redundant load after store elimination in global common subexpression
546 Common Report Var(flag_gcse_after_reload) Optimization
547 Perform global common subexpression elimination after register allocation
551 Common Report Var(flag_graphite)
552 Enable in and out of Graphite representation
555 Common Report Var(flag_loop_strip_mine) Optimization
556 Enable Loop Strip Mining transformation
559 Common Report Var(flag_loop_interchange) Optimization
560 Enable Loop Interchange transformation
563 Common Report Var(flag_loop_block) Optimization
564 Enable Loop Blocking transformation
566 fguess-branch-probability
567 Common Report Var(flag_guess_branch_prob) Optimization
568 Enable guessing of branch probabilities
570 ; Nonzero means ignore `#ident' directives. 0 means handle them.
571 ; Generate position-independent code for executables if possible
572 ; On SVR4 targets, it also controls whether or not to emit a
573 ; string identifying the compiler.
575 Common Report Var(flag_no_ident,0)
576 Process #ident directives
579 Common Report Var(flag_if_conversion) Optimization
580 Perform conversion of conditional jumps to branchless equivalents
583 Common Report Var(flag_if_conversion2) Optimization
584 Perform conversion of conditional jumps to conditional execution
586 ; -finhibit-size-directive inhibits output of .size for ELF.
587 ; This is used only for compiling crtstuff.c,
588 ; and it may be extended to other effects
589 ; needed for crtstuff.c on other systems.
590 finhibit-size-directive
591 Common Report Var(flag_inhibit_size_directive)
592 Do not generate .size directives
595 Common Report Var(flag_indirect_inlining)
596 Perform indirect inlining
598 ; Nonzero means that functions declared `inline' will be treated
599 ; as `static'. Prevents generation of zillions of copies of unused
600 ; static inline functions; instead, `inlines' are written out
601 ; only when actually used. Used in conjunction with -g. Also
602 ; does the right thing with #pragma interface.
604 Common Report Var(flag_no_inline,0) Init(0)
605 Pay attention to the \"inline\" keyword
607 finline-small-functions
608 Common Report Var(flag_inline_small_functions) Optimization
609 Integrate simple functions into their callers when code size is known to not growth
612 Common Report Var(flag_inline_functions) Optimization
613 Integrate simple functions into their callers
615 finline-functions-called-once
616 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
617 Integrate functions called once into their callers
620 Common RejectNegative Joined UInteger
623 Common RejectNegative Joined UInteger
624 -finline-limit=<number> Limit the size of inlined functions to <number>
626 finstrument-functions
627 Common Report Var(flag_instrument_function_entry_exit)
628 Instrument function entry and exit with profiling calls
630 finstrument-functions-exclude-function-list=
631 Common RejectNegative Joined
632 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
634 finstrument-functions-exclude-file-list=
635 Common RejectNegative Joined
636 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
639 Common Report Var(flag_ipa_cp) Optimization
640 Perform Interprocedural constant propagation
643 Common Report Var(flag_ipa_cp_clone) Optimization
644 Perform cloning to make Interprocedural constant propagation stronger
647 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
648 Discover pure and const functions
651 Common Report Var(flag_ipa_pta) Init(0) Optimization
652 Perform interprocedural points-to analysis
655 Common Report Var(flag_ipa_reference) Init(0) Optimization
656 Discover readonly and non addressable static variables
659 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
660 Type based escape and alias analysis
663 Common Report Var(flag_ipa_matrix_reorg) Optimization
664 Perform matrix layout flattening and transposing based
665 on profiling information.
668 Common Report Var(flag_ipa_struct_reorg)
669 Perform structure layout optimizations based
670 on profiling information.
673 Common Report Var(flag_ira) Init(0)
674 Use integrated register allocator.
677 Common Joined RejectNegative
678 -fira-algorithm=[regional|CB|mixed] Set the used IRA algorithm
681 Common Report Var(flag_ira_coalesce) Init(0)
682 Do optimistic coalescing.
684 fira-share-save-slots
685 Common Report Var(flag_ira_share_save_slots) Init(1)
686 Share slots for saving different hard registers.
688 fira-share-spill-slots
689 Common Report Var(flag_ira_share_spill_slots) Init(1)
690 Share stack slots for spilled pseudo-registers.
693 Common RejectNegative Joined UInteger
694 -fira-verbose=<number> Control IRA's level of diagnostic messages.
697 Common Report Var(flag_ivopts) Init(1) Optimization
698 Optimize induction variables on trees
701 Common Var(flag_jump_tables) Init(1) Optimization
702 Use jump tables for sufficiently large switch statements
704 fkeep-inline-functions
705 Common Report Var(flag_keep_inline_functions)
706 Generate code for functions even if they are fully inlined
709 Common Report Var(flag_keep_static_consts) Init(1)
710 Emit static const variables even if they are not used
713 Common Report Var(flag_leading_underscore) Init(-1)
714 Give external symbols a leading underscore
718 Does nothing. Preserved for backward compatibility.
721 Common Report Var(flag_errno_math) Init(1) Optimization
722 Set errno after built-in math functions
725 Common Report Var(mem_report)
726 Report on permanent memory allocation
728 ; This will attempt to merge constant section constants, if 1 only
729 ; string constants and constants from constant pool, if 2 also constant
732 Common Report Var(flag_merge_constants,2) Init(1) Optimization
733 Attempt to merge identical constants and constant variables
736 Common Report Var(flag_merge_constants,1) VarExists Optimization
737 Attempt to merge identical constants across compilation units
740 Common Report Var(flag_merge_debug_strings) Init(1)
741 Attempt to merge identical debug strings across compilation units
744 Common RejectNegative Joined UInteger
745 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
748 Common Report Var(flag_modulo_sched) Optimization
749 Perform SMS based modulo scheduling before the first scheduling pass
751 fmodulo-sched-allow-regmoves
752 Common Report Var(flag_modulo_sched_allow_regmoves)
753 Perform SMS based modulo scheduling with register moves allowed
755 fmove-loop-invariants
756 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
757 Move loop invariant computations out of loops
760 Common RejectNegative Report Var(flag_mudflap)
761 Add mudflap bounds-checking instrumentation for single-threaded program
764 Common RejectNegative Report VarExists Var(flag_mudflap,2)
765 Add mudflap bounds-checking instrumentation for multi-threaded program
768 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
769 Ignore read operations when inserting mudflap instrumentation
772 Common Var(flag_dce) Init(1) Optimization
773 Use the RTL dead code elimination pass
776 Common Var(flag_dse) Init(1) Optimization
777 Use the RTL dead store elimination pass
779 freschedule-modulo-scheduled-loops
780 Common Report Var(flag_resched_modulo_sched) Optimization
781 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
784 Common Report Var(flag_non_call_exceptions) Optimization
785 Support synchronous non-call exceptions
788 Common Report Var(flag_omit_frame_pointer) Optimization
789 When possible do not generate stack frames
791 foptimize-register-move
792 Common Report Var(flag_regmove) Optimization
793 Do the full register move optimization pass
795 foptimize-sibling-calls
796 Common Report Var(flag_optimize_sibling_calls) Optimization
797 Optimize sibling and tail recursive calls
800 Common Report Var(pre_ipa_mem_report)
801 Report on memory allocation before interprocedural optimization
804 Common Report Var(post_ipa_mem_report)
805 Report on memory allocation before interprocedural optimization
808 Common Report Var(flag_pack_struct) Optimization
809 Pack structure members together without holes
812 Common RejectNegative Joined UInteger Optimization
813 -fpack-struct=<number> Set initial maximum structure member alignment
816 Common Report Var(flag_pcc_struct_return,1) VarExists
817 Return small aggregates in memory, not registers
820 Common Report Var(flag_peel_loops) Optimization
824 Common Report Var(flag_no_peephole,0) Optimization
825 Enable machine specific peephole optimizations
828 Common Report Var(flag_peephole2) Optimization
829 Enable an RTL peephole pass before sched2
832 Common Report Var(flag_pic,2)
833 Generate position-independent code if possible (large mode)
836 Common Report Var(flag_pie,2)
837 Generate position-independent code for executables if possible (large mode)
840 Common Report Var(flag_pic,1) VarExists
841 Generate position-independent code if possible (small mode)
844 Common Report Var(flag_pie,1) VarExists
845 Generate position-independent code for executables if possible (small mode)
847 fpredictive-commoning
848 Common Report Var(flag_predictive_commoning) Optimization
849 Run predictive commoning optimization.
851 fprefetch-loop-arrays
852 Common Report Var(flag_prefetch_loop_arrays) Optimization
853 Generate prefetch instructions, if available, for arrays in loops
856 Common Report Var(profile_flag)
857 Enable basic program profiling code
860 Common Report Var(profile_arc_flag)
861 Insert arc-based program profiling code
864 Common Joined RejectNegative
865 Set the top-level directory for storing the profile data.
866 The default is 'pwd'.
869 Common Report Var(flag_profile_correction)
870 Enable correction of flow inconsistent profile data input
874 Enable common options for generating profile info for profile feedback directed optimizations
877 Common Joined RejectNegative
878 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
881 Common Var(flag_profile_use)
882 Enable common options for performing profile feedback directed optimizations
885 Common Joined RejectNegative
886 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
889 Common Report Var(flag_profile_values)
890 Insert code to profile values of expressions
896 Common Joined RejectNegative
897 -frandom-seed=<string> Make compile reproducible using <string>
899 ; This switch causes the command line that was used to create an
900 ; object file to be recorded into the object file. The exact format
901 ; of this recording is target and binary file format dependent.
902 ; It is related to the -fverbose-asm switch, but that switch only
903 ; records information in the assembler output file as comments, so
904 ; they never reach the object file.
906 Common Report Var(flag_record_gcc_switches)
907 Record gcc command line switches in the object file.
910 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
911 Return small aggregates in registers
914 Common Report Var(flag_regmove) Optimization
915 Enables a register move optimization
918 Common Report Var(flag_rename_registers) Init(2) Optimization
919 Perform a register renaming optimization pass
922 Common Report Var(flag_reorder_blocks) Optimization
923 Reorder basic blocks to improve code placement
925 freorder-blocks-and-partition
926 Common Report Var(flag_reorder_blocks_and_partition) Optimization
927 Reorder basic blocks and partition into hot and cold sections
930 Common Report Var(flag_reorder_functions) Optimization
931 Reorder functions to improve code placement
933 frerun-cse-after-loop
934 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
935 Add a common subexpression elimination pass after loop optimizations
939 Does nothing. Preserved for backward compatibility.
942 Common Report Var(flag_rounding_math) Optimization
943 Disable optimizations that assume default FP rounding behavior
946 Common Report Var(flag_schedule_interblock) Init(1) Optimization
947 Enable scheduling across basic blocks
950 Common Report Var(flag_schedule_speculative) Init(1) Optimization
951 Allow speculative motion of non-loads
954 Common Report Var(flag_schedule_speculative_load) Optimization
955 Allow speculative motion of some loads
957 fsched-spec-load-dangerous
958 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
959 Allow speculative motion of more loads
962 Common RejectNegative Joined
963 -fsched-verbose=<number> Set the verbosity level of the scheduler
965 fsched2-use-superblocks
966 Common Report Var(flag_sched2_use_superblocks) Optimization
967 If scheduling post reload, do superblock scheduling
970 Common Report Var(flag_sched2_use_traces) Optimization
971 If scheduling post reload, do trace scheduling
974 Common Report Var(flag_schedule_insns) Optimization
975 Reschedule instructions before register allocation
978 Common Report Var(flag_schedule_insns_after_reload) Optimization
979 Reschedule instructions after register allocation
981 ; This flag should be on when a target implements non-trivial
982 ; scheduling hooks, maybe saving some information for its own sake.
983 ; On IA64, for example, this is used for correct bundling.
984 fselective-scheduling
985 Common Report Var(flag_selective_scheduling) Optimization
986 Schedule instructions using selective scheduling algorithm
988 fselective-scheduling2
989 Common Report Var(flag_selective_scheduling2) Optimization
990 Run selective scheduling after reload
992 fsel-sched-pipelining
993 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
994 Perform software pipelining of inner loops during selective scheduling
996 fsel-sched-pipelining-outer-loops
997 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
998 Perform software pipelining of outer loops during selective scheduling
1000 fsel-sched-reschedule-pipelined
1001 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1002 Reschedule pipelined regions without pipelining
1004 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1005 ; of stalled insns into the ready list.
1006 fsched-stalled-insns
1007 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1008 Allow premature scheduling of queued insns
1010 fsched-stalled-insns=
1011 Common RejectNegative Joined UInteger
1012 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1014 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1015 ; be examined for a dependency on a stalled insn that is candidate for
1016 ; premature removal from the queue of stalled insns into the ready list (has
1017 ; an effect only if the flag 'sched_stalled_insns' is set).
1018 fsched-stalled-insns-dep
1019 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1020 Set dependence distance checking in premature scheduling of queued insns
1022 fsched-stalled-insns-dep=
1023 Common RejectNegative Joined UInteger
1024 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1027 Common Report Var(flag_section_anchors) Optimization
1028 Access data in the same section from shared anchor points
1030 frtl-abstract-sequences
1031 Common Report Var(flag_rtl_seqabstr) Optimization
1032 Perform sequence abstraction optimization on RTL
1035 Common Report Var(flag_see) Init(0)
1036 Eliminate redundant sign extensions using LCM.
1039 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
1040 Show column numbers in diagnostics, when available. Default off
1043 Common Report Var(flag_signaling_nans) Optimization
1044 Disable optimizations observable by IEEE signaling NaNs
1047 Common Report Var(flag_signed_zeros) Init(1) Optimization
1048 Disable floating point optimizations that ignore the IEEE signedness of zero
1050 fsingle-precision-constant
1051 Common Report Var(flag_single_precision_constant) Optimization
1052 Convert floating point constants to single precision constants
1054 fsplit-ivs-in-unroller
1055 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1056 Split lifetimes of induction variables when loops are unrolled
1059 Common Report Var(flag_split_wide_types) Optimization
1060 Split wide types into independent registers
1062 fvariable-expansion-in-unroller
1063 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1064 Apply variable expansion when loops are unrolled
1067 Common Report RejectNegative Joined
1068 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1072 Insert stack checking code into the program. Same as -fstack-check=specific
1077 fstack-limit-register=
1078 Common RejectNegative Joined
1079 -fstack-limit-register=<register> Trap if the stack goes past <register>
1081 fstack-limit-symbol=
1082 Common RejectNegative Joined
1083 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1086 Common Report Var(flag_stack_protect, 1)
1087 Use propolice as a stack protection method
1089 fstack-protector-all
1090 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1091 Use a stack protection method for every function
1095 Does nothing. Preserved for backward compatibility.
1097 ; Nonzero if we should do (language-dependent) alias analysis.
1098 ; Typically, this analysis will assume that expressions of certain
1099 ; types do not alias expressions of certain other types. Only used
1100 ; if alias analysis (in general) is enabled.
1102 Common Report Var(flag_strict_aliasing) Optimization
1103 Assume strict aliasing rules apply
1106 Common Report Var(flag_strict_overflow)
1107 Treat signed overflow as undefined
1110 Common Report Var(flag_syntax_only)
1111 Check for syntax errors, then stop
1114 Common Report Var(flag_test_coverage)
1115 Create data files needed by \"gcov\"
1118 Common Report Var(flag_thread_jumps) Optimization
1119 Perform jump threading optimizations
1122 Common Report Var(time_report)
1123 Report the time taken by each compiler pass
1126 Common Joined RejectNegative
1127 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1130 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1131 Reorder top level functions, variables, and asms
1134 Common Report Var(flag_tracer)
1135 Perform superblock formation via tail duplication
1137 ; Zero means that floating-point math operations cannot generate a
1138 ; (user-visible) trap. This is the case, for example, in nonstop
1139 ; IEEE 754 arithmetic.
1141 Common Report Var(flag_trapping_math) Init(1) Optimization
1142 Assume floating-point operations can trap
1145 Common Report Var(flag_trapv) Optimization
1146 Trap for signed overflow in addition, subtraction and multiplication
1149 Common Report Var(flag_tree_ccp) Optimization
1150 Enable SSA-CCP optimization on trees
1154 Does nothing. Preserved for backward compatibility.
1157 Common Report Var(flag_tree_ch) Optimization
1158 Enable loop header copying on trees
1161 Common Report Var(flag_tree_copyrename) Optimization
1162 Replace SSA temporaries with better names in copies
1165 Common Report Var(flag_tree_copy_prop) Optimization
1166 Enable copy propagation on trees
1168 ftree-store-copy-prop
1170 Does nothing. Preserved for backward compatibility.
1173 Common Report Var(flag_tree_cselim) Init(2) Optimization
1174 Transform condition stores into unconditional ones
1176 ftree-switch-conversion
1177 Common Report Var(flag_tree_switch_conversion) Optimization
1178 Perform conversions of switch initializations.
1181 Common Report Var(flag_tree_dce) Optimization
1182 Enable SSA dead code elimination optimization on trees
1184 ftree-dominator-opts
1185 Common Report Var(flag_tree_dom) Optimization
1186 Enable dominator optimizations
1189 Common Report Var(flag_tree_dse) Optimization
1190 Enable dead store elimination
1193 Common Report Var(flag_tree_fre) Optimization
1194 Enable Full Redundancy Elimination (FRE) on trees
1196 ftree-loop-distribution
1197 Common Report Var(flag_tree_loop_distribution) Optimization
1198 Enable loop distribution on trees
1201 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1202 Enable loop invariant motion on trees
1205 Common Report Var(flag_tree_loop_linear) Optimization
1206 Enable linear loop transforms on trees
1209 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1210 Create canonical induction variables in loops
1213 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1214 Enable loop optimizations on tree level
1216 ftree-parallelize-loops=
1217 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1218 Enable automatic parallelization of loops
1221 Common Report Var(flag_tree_pre) Optimization
1222 Enable SSA-PRE optimization on trees
1225 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1226 Enable reassociation on tree level
1230 Does nothing. Preserved for backward compatibility.
1233 Common Report Var(flag_tree_sink) Optimization
1234 Enable SSA code sinking on trees
1237 Common Report Var(flag_tree_sra) Optimization
1238 Perform scalar replacement of aggregates
1241 Common Report Var(flag_tree_ter) Init(1) Optimization
1242 Replace temporary expressions in the SSA->normal pass
1245 Common Report Var(flag_tree_live_range_split) Optimization
1246 Perform live range splitting during the SSA->normal pass
1249 Common Report Var(flag_tree_vrp) Init(0) Optimization
1250 Perform Value Range Propagation on trees
1253 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1254 Compile whole compilation unit at a time
1257 Common Report Var(flag_unroll_loops) Optimization
1258 Perform loop unrolling when iteration count is known
1261 Common Report Var(flag_unroll_all_loops) Optimization
1262 Perform loop unrolling for all loops
1264 ; Nonzero means that loop optimizer may assume that the induction variables
1265 ; that control loops do not overflow and that the loops with nontrivial
1266 ; exit condition are not infinite
1267 funsafe-loop-optimizations
1268 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1269 Allow loop optimizations to assume that the loops behave in normal way
1272 Common Report Var(flag_associative_math)
1273 Allow optimization for floating-point arithmetic which may change the
1274 result of the operation due to rounding.
1277 Common Report Var(flag_reciprocal_math)
1278 Same as -fassociative-math for expressions which include division.
1280 ; Nonzero means that unsafe floating-point math optimizations are allowed
1281 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1282 ; are allowed to assume that their arguments and results are "normal"
1283 ; (e.g., nonnegative for SQRT).
1284 funsafe-math-optimizations
1285 Common Report Var(flag_unsafe_math_optimizations) Optimization
1286 Allow math optimizations that may violate IEEE or ISO standards
1289 Common Report Var(flag_unswitch_loops) Optimization
1290 Perform loop unswitching
1293 Common Report Var(flag_unwind_tables) Optimization
1294 Just generate unwind tables for exception handling
1297 Common Report Var(flag_var_tracking) VarExists Optimization
1298 Perform variable tracking
1300 fvar-tracking-uninit
1301 Common Report Var(flag_var_tracking_uninit) Optimization
1302 Perform variable tracking and also tag variables that are uninitialized
1305 Common Report Var(flag_tree_vectorize) Optimization
1306 Enable loop vectorization on trees
1309 Common Report Var(flag_vect_cost_model) Optimization
1310 Enable use of cost model in vectorization
1312 ftree-vect-loop-version
1313 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1314 Enable loop versioning when doing loop vectorization on trees
1316 ftree-vectorizer-verbose=
1317 Common RejectNegative Joined
1318 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1321 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1322 Enable copy propagation of scalar-evolution information.
1324 ; -fverbose-asm causes extra commentary information to be produced in
1325 ; the generated assembly code (to make it more readable). This option
1326 ; is generally only of use to those who actually need to read the
1327 ; generated assembly code (perhaps while debugging the compiler itself).
1328 ; -fno-verbose-asm, the default, causes the extra information
1329 ; to not be added and is useful when comparing two assembler files.
1331 Common Report Var(flag_verbose_asm)
1332 Add extra commentary to assembler output
1335 Common Joined RejectNegative
1336 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1340 Common Report Var(flag_value_profile_transformations) Optimization
1341 Use expression value profiles in optimizations
1344 Common Report Var(flag_web) Init(2) Optimization
1345 Construct webs and split unrelated uses of single variable
1347 ftree-builtin-call-dce
1348 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1349 Enable conditional dead code elimination for builtin calls
1352 Common Report Var(flag_whole_program) Init(0) Optimization
1353 Perform whole program optimizations
1356 Common Report Var(flag_wrapv) Optimization
1357 Assume signed arithmetic overflow wraps around
1359 fzero-initialized-in-bss
1360 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1361 Put zero initialized data in the bss section
1364 Common JoinedOrMissing
1365 Generate debug information in default format
1368 Common JoinedOrMissing Negative(gdwarf-2)
1369 Generate debug information in COFF format
1372 Common JoinedOrMissing Negative(gstabs)
1373 Generate debug information in DWARF v2 format
1376 Common JoinedOrMissing
1377 Generate debug information in default extended format
1380 Common JoinedOrMissing Negative(gstabs+)
1381 Generate debug information in STABS format
1384 Common JoinedOrMissing Negative(gvms)
1385 Generate debug information in extended STABS format
1388 Common JoinedOrMissing Negative(gxcoff)
1389 Generate debug information in VMS format
1392 Common JoinedOrMissing Negative(gxcoff+)
1393 Generate debug information in XCOFF format
1396 Common JoinedOrMissing Negative(gcoff)
1397 Generate debug information in extended XCOFF format
1400 Common Joined Separate
1401 -o <file> Place output into <file>
1404 Common Var(profile_flag)
1405 Enable function profiling
1408 Common Var(pedantic)
1409 Issue warnings needed for strict compliance to the standard
1413 Like -pedantic but issue them as errors
1416 Common Var(quiet_flag)
1417 Do not display functions compiled or elapsed time
1420 Common Var(version_flag)
1421 Display the compiler's version
1424 Common Var(inhibit_warnings)
1428 Common RejectNegative Negative(pie)
1429 Create a shared library
1432 Common RejectNegative Negative(shared)
1433 Create a position independent executable
1435 ; This comment is to ensure we retain the blank line above.