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 Var(flag_conserve_stack,0) Optimization
390 Do not perform optimizations increasing noticeably stack usage
393 Common Report Var(flag_cprop_registers) Optimization
394 Perform a register copy-propagation optimization pass
397 Common Report Var(flag_crossjumping) Optimization
398 Perform cross-jumping optimization
401 Common Report Var(flag_cse_follow_jumps) Optimization
402 When running CSE, follow jumps to their targets
405 Common Report Var(flag_cse_skip_blocks) Optimization
406 When running CSE, follow conditional jumps
409 Common Report Var(flag_cx_limited_range) Optimization
410 Omit range reduction step when performing complex division
413 Common Report Var(flag_cx_fortran_rules) Optimization
414 Complex multiplication and division follow Fortran rules
417 Common Report Var(flag_data_sections) Optimization
418 Place data items into their own section
422 List all available debugging counters with their limits and counts.
425 Common RejectNegative Joined
426 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
429 Common Joined RejectNegative
430 Map one directory name to another in debug information
432 ; Nonzero for -fdefer-pop: don't pop args after each function call
433 ; instead save them up to pop many calls' args with one insns.
435 Common Report Var(flag_defer_pop) Optimization
436 Defer popping functions args from stack until later
439 Common Report Var(flag_delayed_branch) Optimization
440 Attempt to fill delay slots of branch instructions
442 fdelete-null-pointer-checks
443 Common Report Var(flag_delete_null_pointer_checks) Optimization
444 Delete useless null pointer checks
446 fdiagnostics-show-location=
447 Common Joined RejectNegative
448 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
450 fdiagnostics-show-option
452 Amend appropriate diagnostic messages with the command line option that controls them
455 Common Joined RejectNegative
456 -fdump-<type> Dump various compiler internals to a file
459 Common Report Var(flag_dump_noaddr)
460 Suppress output of addresses in debugging dumps
463 Common Report Var(flag_dump_unnumbered) VarExists
464 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
467 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
468 Enable CFI tables via GAS assembler directives.
471 Common Report Var(flag_early_inlining) Init(1) Optimization
472 Perform early inlining
474 feliminate-dwarf2-dups
475 Common Report Var(flag_eliminate_dwarf2_dups)
476 Perform DWARF2 duplicate elimination
478 feliminate-unused-debug-symbols
479 Common Report Var(flag_debug_only_used_symbols)
480 Perform unused type elimination in debug info
482 feliminate-unused-debug-types
483 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
484 Perform unused type elimination in debug info
486 femit-class-debug-always
487 Common Report Var(flag_emit_class_debug_always) Init(0)
488 Do not suppress C++ class debug information.
491 Common Report Var(flag_exceptions) Optimization
492 Enable exception handling
494 fexpensive-optimizations
495 Common Report Var(flag_expensive_optimizations) Optimization
496 Perform a number of minor, expensive optimizations
502 Common Report Var(flag_finite_math_only) Optimization
503 Assume no NaNs or infinities are generated
506 Common Joined RejectNegative
507 -ffixed-<register> Mark <register> as being unavailable to the compiler
510 Common Report Var(flag_float_store) Optimization
511 Don't allocate floats and doubles in extended-precision registers
515 Does nothing. Preserved for backward compatibility.
518 Common Report Var(flag_forward_propagate) Optimization
519 Perform a forward propagation pass on RTL
521 ; Nonzero means don't put addresses of constant functions in registers.
522 ; Used for compiling the Unix kernel, where strange substitutions are
523 ; done on the assembly output.
525 Common Report Var(flag_no_function_cse,0)
526 Allow function addresses to be held in registers
529 Common Report Var(flag_function_sections)
530 Place each function into its own section
533 Common Report Var(flag_gcse) Optimization
534 Perform global common subexpression elimination
537 Common Report Var(flag_gcse_lm) Init(1) Optimization
538 Perform enhanced load motion during global common subexpression elimination
541 Common Report Var(flag_gcse_sm) Init(0) Optimization
542 Perform store motion after global common subexpression elimination
545 Common Report Var(flag_gcse_las) Init(0) Optimization
546 Perform redundant load after store elimination in global common subexpression
550 Common Report Var(flag_gcse_after_reload) Optimization
551 Perform global common subexpression elimination after register allocation
554 ; This option is not documented yet as its semantics will change.
556 Common Report Var(flag_graphite)
557 Enable in and out of Graphite representation
560 Common Report Var(flag_loop_strip_mine) Optimization
561 Enable Loop Strip Mining transformation
564 Common Report Var(flag_loop_interchange) Optimization
565 Enable Loop Interchange transformation
568 Common Report Var(flag_loop_block) Optimization
569 Enable Loop Blocking transformation
571 ; This option is not documented as it does not perform any useful optimization.
573 Common Report Var(flag_graphite_identity) Optimization
574 Enable Graphite Identity transformation
576 fguess-branch-probability
577 Common Report Var(flag_guess_branch_prob) Optimization
578 Enable guessing of branch probabilities
580 ; Nonzero means ignore `#ident' directives. 0 means handle them.
581 ; Generate position-independent code for executables if possible
582 ; On SVR4 targets, it also controls whether or not to emit a
583 ; string identifying the compiler.
585 Common Report Var(flag_no_ident,0)
586 Process #ident directives
589 Common Report Var(flag_if_conversion) Optimization
590 Perform conversion of conditional jumps to branchless equivalents
593 Common Report Var(flag_if_conversion2) Optimization
594 Perform conversion of conditional jumps to conditional execution
596 ; -finhibit-size-directive inhibits output of .size for ELF.
597 ; This is used only for compiling crtstuff.c,
598 ; and it may be extended to other effects
599 ; needed for crtstuff.c on other systems.
600 finhibit-size-directive
601 Common Report Var(flag_inhibit_size_directive)
602 Do not generate .size directives
605 Common Report Var(flag_indirect_inlining)
606 Perform indirect inlining
608 ; Nonzero means that functions declared `inline' will be treated
609 ; as `static'. Prevents generation of zillions of copies of unused
610 ; static inline functions; instead, `inlines' are written out
611 ; only when actually used. Used in conjunction with -g. Also
612 ; does the right thing with #pragma interface.
614 Common Report Var(flag_no_inline,0) Init(0)
615 Pay attention to the \"inline\" keyword
617 finline-small-functions
618 Common Report Var(flag_inline_small_functions) Optimization
619 Integrate simple functions into their callers when code size is known to not growth
622 Common Report Var(flag_inline_functions) Optimization
623 Integrate simple functions into their callers
625 finline-functions-called-once
626 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
627 Integrate functions called once into their callers
630 Common RejectNegative Joined UInteger
633 Common RejectNegative Joined UInteger
634 -finline-limit=<number> Limit the size of inlined functions to <number>
636 finstrument-functions
637 Common Report Var(flag_instrument_function_entry_exit)
638 Instrument function entry and exit with profiling calls
640 finstrument-functions-exclude-function-list=
641 Common RejectNegative Joined
642 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
644 finstrument-functions-exclude-file-list=
645 Common RejectNegative Joined
646 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
649 Common Report Var(flag_ipa_cp) Optimization
650 Perform Interprocedural constant propagation
653 Common Report Var(flag_ipa_cp_clone) Optimization
654 Perform cloning to make Interprocedural constant propagation stronger
657 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
658 Discover pure and const functions
661 Common Report Var(flag_ipa_pta) Init(0) Optimization
662 Perform interprocedural points-to analysis
665 Common Report Var(flag_ipa_reference) Init(0) Optimization
666 Discover readonly and non addressable static variables
669 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
670 Type based escape and alias analysis
673 Common Report Var(flag_ipa_matrix_reorg) Optimization
674 Perform matrix layout flattening and transposing based
675 on profiling information.
678 Common Report Var(flag_ipa_struct_reorg)
679 Perform structure layout optimizations based
680 on profiling information.
683 Common Report Var(flag_ira) Init(0)
684 Use integrated register allocator.
687 Common Joined RejectNegative
688 -fira-algorithm=[CB|priority] Set the used IRA algorithm
691 Common Joined RejectNegative
692 -fira-region=[one|all|mixed] Set regions for IRA
695 Common Report Var(flag_ira_coalesce) Init(0)
696 Do optimistic coalescing.
698 fira-share-save-slots
699 Common Report Var(flag_ira_share_save_slots) Init(1)
700 Share slots for saving different hard registers.
702 fira-share-spill-slots
703 Common Report Var(flag_ira_share_spill_slots) Init(1)
704 Share stack slots for spilled pseudo-registers.
707 Common RejectNegative Joined UInteger
708 -fira-verbose=<number> Control IRA's level of diagnostic messages.
711 Common Report Var(flag_ivopts) Init(1) Optimization
712 Optimize induction variables on trees
715 Common Var(flag_jump_tables) Init(1) Optimization
716 Use jump tables for sufficiently large switch statements
718 fkeep-inline-functions
719 Common Report Var(flag_keep_inline_functions)
720 Generate code for functions even if they are fully inlined
723 Common Report Var(flag_keep_static_consts) Init(1)
724 Emit static const variables even if they are not used
727 Common Report Var(flag_leading_underscore) Init(-1)
728 Give external symbols a leading underscore
732 Does nothing. Preserved for backward compatibility.
735 Common Report Var(flag_errno_math) Init(1) Optimization
736 Set errno after built-in math functions
739 Common Report Var(mem_report)
740 Report on permanent memory allocation
742 ; This will attempt to merge constant section constants, if 1 only
743 ; string constants and constants from constant pool, if 2 also constant
746 Common Report Var(flag_merge_constants,2) Init(1) Optimization
747 Attempt to merge identical constants and constant variables
750 Common Report Var(flag_merge_constants,1) VarExists Optimization
751 Attempt to merge identical constants across compilation units
754 Common Report Var(flag_merge_debug_strings) Init(1)
755 Attempt to merge identical debug strings across compilation units
758 Common RejectNegative Joined UInteger
759 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
762 Common Report Var(flag_modulo_sched) Optimization
763 Perform SMS based modulo scheduling before the first scheduling pass
765 fmodulo-sched-allow-regmoves
766 Common Report Var(flag_modulo_sched_allow_regmoves)
767 Perform SMS based modulo scheduling with register moves allowed
769 fmove-loop-invariants
770 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
771 Move loop invariant computations out of loops
774 Common RejectNegative Report Var(flag_mudflap)
775 Add mudflap bounds-checking instrumentation for single-threaded program
778 Common RejectNegative Report VarExists Var(flag_mudflap,2)
779 Add mudflap bounds-checking instrumentation for multi-threaded program
782 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
783 Ignore read operations when inserting mudflap instrumentation
786 Common Var(flag_dce) Init(1) Optimization
787 Use the RTL dead code elimination pass
790 Common Var(flag_dse) Init(1) Optimization
791 Use the RTL dead store elimination pass
793 freschedule-modulo-scheduled-loops
794 Common Report Var(flag_resched_modulo_sched) Optimization
795 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
798 Common Report Var(flag_non_call_exceptions) Optimization
799 Support synchronous non-call exceptions
802 Common Report Var(flag_omit_frame_pointer) Optimization
803 When possible do not generate stack frames
805 foptimize-register-move
806 Common Report Var(flag_regmove) Optimization
807 Do the full register move optimization pass
809 foptimize-sibling-calls
810 Common Report Var(flag_optimize_sibling_calls) Optimization
811 Optimize sibling and tail recursive calls
814 Common Report Var(pre_ipa_mem_report)
815 Report on memory allocation before interprocedural optimization
818 Common Report Var(post_ipa_mem_report)
819 Report on memory allocation before interprocedural optimization
822 Common Report Var(flag_pack_struct) Optimization
823 Pack structure members together without holes
826 Common RejectNegative Joined UInteger Optimization
827 -fpack-struct=<number> Set initial maximum structure member alignment
830 Common Report Var(flag_pcc_struct_return,1) VarExists
831 Return small aggregates in memory, not registers
834 Common Report Var(flag_peel_loops) Optimization
838 Common Report Var(flag_no_peephole,0) Optimization
839 Enable machine specific peephole optimizations
842 Common Report Var(flag_peephole2) Optimization
843 Enable an RTL peephole pass before sched2
846 Common Report Var(flag_pic,2)
847 Generate position-independent code if possible (large mode)
850 Common Report Var(flag_pie,2)
851 Generate position-independent code for executables if possible (large mode)
854 Common Report Var(flag_pic,1) VarExists
855 Generate position-independent code if possible (small mode)
858 Common Report Var(flag_pie,1) VarExists
859 Generate position-independent code for executables if possible (small mode)
861 fpredictive-commoning
862 Common Report Var(flag_predictive_commoning) Optimization
863 Run predictive commoning optimization.
865 fprefetch-loop-arrays
866 Common Report Var(flag_prefetch_loop_arrays) Optimization
867 Generate prefetch instructions, if available, for arrays in loops
870 Common Report Var(profile_flag)
871 Enable basic program profiling code
874 Common Report Var(profile_arc_flag)
875 Insert arc-based program profiling code
878 Common Joined RejectNegative
879 Set the top-level directory for storing the profile data.
880 The default is 'pwd'.
883 Common Report Var(flag_profile_correction)
884 Enable correction of flow inconsistent profile data input
888 Enable common options for generating profile info for profile feedback directed optimizations
891 Common Joined RejectNegative
892 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
895 Common Var(flag_profile_use)
896 Enable common options for performing profile feedback directed optimizations
899 Common Joined RejectNegative
900 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
903 Common Report Var(flag_profile_values)
904 Insert code to profile values of expressions
910 Common Joined RejectNegative
911 -frandom-seed=<string> Make compile reproducible using <string>
913 ; This switch causes the command line that was used to create an
914 ; object file to be recorded into the object file. The exact format
915 ; of this recording is target and binary file format dependent.
916 ; It is related to the -fverbose-asm switch, but that switch only
917 ; records information in the assembler output file as comments, so
918 ; they never reach the object file.
920 Common Report Var(flag_record_gcc_switches)
921 Record gcc command line switches in the object file.
924 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
925 Return small aggregates in registers
928 Common Report Var(flag_regmove) Optimization
929 Enables a register move optimization
932 Common Report Var(flag_rename_registers) Init(2) Optimization
933 Perform a register renaming optimization pass
936 Common Report Var(flag_reorder_blocks) Optimization
937 Reorder basic blocks to improve code placement
939 freorder-blocks-and-partition
940 Common Report Var(flag_reorder_blocks_and_partition) Optimization
941 Reorder basic blocks and partition into hot and cold sections
944 Common Report Var(flag_reorder_functions) Optimization
945 Reorder functions to improve code placement
947 frerun-cse-after-loop
948 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
949 Add a common subexpression elimination pass after loop optimizations
953 Does nothing. Preserved for backward compatibility.
956 Common Report Var(flag_rounding_math) Optimization
957 Disable optimizations that assume default FP rounding behavior
960 Common Report Var(flag_schedule_interblock) Init(1) Optimization
961 Enable scheduling across basic blocks
964 Common Report Var(flag_schedule_speculative) Init(1) Optimization
965 Allow speculative motion of non-loads
968 Common Report Var(flag_schedule_speculative_load) Optimization
969 Allow speculative motion of some loads
971 fsched-spec-load-dangerous
972 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
973 Allow speculative motion of more loads
976 Common RejectNegative Joined
977 -fsched-verbose=<number> Set the verbosity level of the scheduler
979 fsched2-use-superblocks
980 Common Report Var(flag_sched2_use_superblocks) Optimization
981 If scheduling post reload, do superblock scheduling
984 Common Report Var(flag_sched2_use_traces) Optimization
985 If scheduling post reload, do trace scheduling
988 Common Report Var(flag_schedule_insns) Optimization
989 Reschedule instructions before register allocation
992 Common Report Var(flag_schedule_insns_after_reload) Optimization
993 Reschedule instructions after register allocation
995 ; This flag should be on when a target implements non-trivial
996 ; scheduling hooks, maybe saving some information for its own sake.
997 ; On IA64, for example, this is used for correct bundling.
998 fselective-scheduling
999 Common Report Var(flag_selective_scheduling) Optimization
1000 Schedule instructions using selective scheduling algorithm
1002 fselective-scheduling2
1003 Common Report Var(flag_selective_scheduling2) Optimization
1004 Run selective scheduling after reload
1006 fsel-sched-pipelining
1007 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1008 Perform software pipelining of inner loops during selective scheduling
1010 fsel-sched-pipelining-outer-loops
1011 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1012 Perform software pipelining of outer loops during selective scheduling
1014 fsel-sched-reschedule-pipelined
1015 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1016 Reschedule pipelined regions without pipelining
1018 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1019 ; of stalled insns into the ready list.
1020 fsched-stalled-insns
1021 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1022 Allow premature scheduling of queued insns
1024 fsched-stalled-insns=
1025 Common RejectNegative Joined UInteger
1026 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1028 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1029 ; be examined for a dependency on a stalled insn that is candidate for
1030 ; premature removal from the queue of stalled insns into the ready list (has
1031 ; an effect only if the flag 'sched_stalled_insns' is set).
1032 fsched-stalled-insns-dep
1033 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1034 Set dependence distance checking in premature scheduling of queued insns
1036 fsched-stalled-insns-dep=
1037 Common RejectNegative Joined UInteger
1038 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1041 Common Report Var(flag_section_anchors) Optimization
1042 Access data in the same section from shared anchor points
1044 frtl-abstract-sequences
1045 Common Report Var(flag_rtl_seqabstr) Optimization
1046 Perform sequence abstraction optimization on RTL
1049 Common Report Var(flag_see) Init(0)
1050 Eliminate redundant sign extensions using LCM.
1053 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
1054 Show column numbers in diagnostics, when available. Default off
1057 Common Report Var(flag_signaling_nans) Optimization
1058 Disable optimizations observable by IEEE signaling NaNs
1061 Common Report Var(flag_signed_zeros) Init(1) Optimization
1062 Disable floating point optimizations that ignore the IEEE signedness of zero
1064 fsingle-precision-constant
1065 Common Report Var(flag_single_precision_constant) Optimization
1066 Convert floating point constants to single precision constants
1068 fsplit-ivs-in-unroller
1069 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1070 Split lifetimes of induction variables when loops are unrolled
1073 Common Report Var(flag_split_wide_types) Optimization
1074 Split wide types into independent registers
1076 fvariable-expansion-in-unroller
1077 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1078 Apply variable expansion when loops are unrolled
1081 Common Report RejectNegative Joined
1082 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1086 Insert stack checking code into the program. Same as -fstack-check=specific
1091 fstack-limit-register=
1092 Common RejectNegative Joined
1093 -fstack-limit-register=<register> Trap if the stack goes past <register>
1095 fstack-limit-symbol=
1096 Common RejectNegative Joined
1097 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1100 Common Report Var(flag_stack_protect, 1)
1101 Use propolice as a stack protection method
1103 fstack-protector-all
1104 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1105 Use a stack protection method for every function
1109 Does nothing. Preserved for backward compatibility.
1111 ; Nonzero if we should do (language-dependent) alias analysis.
1112 ; Typically, this analysis will assume that expressions of certain
1113 ; types do not alias expressions of certain other types. Only used
1114 ; if alias analysis (in general) is enabled.
1116 Common Report Var(flag_strict_aliasing) Optimization
1117 Assume strict aliasing rules apply
1120 Common Report Var(flag_strict_overflow)
1121 Treat signed overflow as undefined
1124 Common Report Var(flag_syntax_only)
1125 Check for syntax errors, then stop
1128 Common Report Var(flag_test_coverage)
1129 Create data files needed by \"gcov\"
1132 Common Report Var(flag_thread_jumps) Optimization
1133 Perform jump threading optimizations
1136 Common Report Var(time_report)
1137 Report the time taken by each compiler pass
1140 Common Joined RejectNegative
1141 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1144 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1145 Reorder top level functions, variables, and asms
1148 Common Report Var(flag_tracer)
1149 Perform superblock formation via tail duplication
1151 ; Zero means that floating-point math operations cannot generate a
1152 ; (user-visible) trap. This is the case, for example, in nonstop
1153 ; IEEE 754 arithmetic.
1155 Common Report Var(flag_trapping_math) Init(1) Optimization
1156 Assume floating-point operations can trap
1159 Common Report Var(flag_trapv) Optimization
1160 Trap for signed overflow in addition, subtraction and multiplication
1163 Common Report Var(flag_tree_ccp) Optimization
1164 Enable SSA-CCP optimization on trees
1168 Does nothing. Preserved for backward compatibility.
1171 Common Report Var(flag_tree_ch) Optimization
1172 Enable loop header copying on trees
1175 Common Report Var(flag_tree_copyrename) Optimization
1176 Replace SSA temporaries with better names in copies
1179 Common Report Var(flag_tree_copy_prop) Optimization
1180 Enable copy propagation on trees
1182 ftree-store-copy-prop
1184 Does nothing. Preserved for backward compatibility.
1187 Common Report Var(flag_tree_cselim) Init(2) Optimization
1188 Transform condition stores into unconditional ones
1190 ftree-switch-conversion
1191 Common Report Var(flag_tree_switch_conversion) Optimization
1192 Perform conversions of switch initializations.
1195 Common Report Var(flag_tree_dce) Optimization
1196 Enable SSA dead code elimination optimization on trees
1198 ftree-dominator-opts
1199 Common Report Var(flag_tree_dom) Optimization
1200 Enable dominator optimizations
1203 Common Report Var(flag_tree_dse) Optimization
1204 Enable dead store elimination
1207 Common Report Var(flag_tree_fre) Optimization
1208 Enable Full Redundancy Elimination (FRE) on trees
1210 ftree-loop-distribution
1211 Common Report Var(flag_tree_loop_distribution) Optimization
1212 Enable loop distribution on trees
1215 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1216 Enable loop invariant motion on trees
1219 Common Report Var(flag_tree_loop_linear) Optimization
1220 Enable linear loop transforms on trees
1223 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1224 Create canonical induction variables in loops
1227 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1228 Enable loop optimizations on tree level
1230 ftree-parallelize-loops=
1231 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1232 Enable automatic parallelization of loops
1235 Common Report Var(flag_tree_pre) Optimization
1236 Enable SSA-PRE optimization on trees
1239 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1240 Enable reassociation on tree level
1244 Does nothing. Preserved for backward compatibility.
1247 Common Report Var(flag_tree_sink) Optimization
1248 Enable SSA code sinking on trees
1251 Common Report Var(flag_tree_sra) Optimization
1252 Perform scalar replacement of aggregates
1255 Common Report Var(flag_tree_ter) Init(1) Optimization
1256 Replace temporary expressions in the SSA->normal pass
1259 Common Report Var(flag_tree_live_range_split) Optimization
1260 Perform live range splitting during the SSA->normal pass
1263 Common Report Var(flag_tree_vrp) Init(0) Optimization
1264 Perform Value Range Propagation on trees
1267 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1268 Compile whole compilation unit at a time
1271 Common Report Var(flag_unroll_loops) Optimization
1272 Perform loop unrolling when iteration count is known
1275 Common Report Var(flag_unroll_all_loops) Optimization
1276 Perform loop unrolling for all loops
1278 ; Nonzero means that loop optimizer may assume that the induction variables
1279 ; that control loops do not overflow and that the loops with nontrivial
1280 ; exit condition are not infinite
1281 funsafe-loop-optimizations
1282 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1283 Allow loop optimizations to assume that the loops behave in normal way
1286 Common Report Var(flag_associative_math)
1287 Allow optimization for floating-point arithmetic which may change the
1288 result of the operation due to rounding.
1291 Common Report Var(flag_reciprocal_math)
1292 Same as -fassociative-math for expressions which include division.
1294 ; Nonzero means that unsafe floating-point math optimizations are allowed
1295 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1296 ; are allowed to assume that their arguments and results are "normal"
1297 ; (e.g., nonnegative for SQRT).
1298 funsafe-math-optimizations
1299 Common Report Var(flag_unsafe_math_optimizations) Optimization
1300 Allow math optimizations that may violate IEEE or ISO standards
1303 Common Report Var(flag_unswitch_loops) Optimization
1304 Perform loop unswitching
1307 Common Report Var(flag_unwind_tables) Optimization
1308 Just generate unwind tables for exception handling
1311 Common Report Var(flag_var_tracking) VarExists Optimization
1312 Perform variable tracking
1314 fvar-tracking-uninit
1315 Common Report Var(flag_var_tracking_uninit) Optimization
1316 Perform variable tracking and also tag variables that are uninitialized
1319 Common Report Var(flag_tree_vectorize) Optimization
1320 Enable loop vectorization on trees
1323 Common Report Var(flag_vect_cost_model) Optimization
1324 Enable use of cost model in vectorization
1326 ftree-vect-loop-version
1327 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1328 Enable loop versioning when doing loop vectorization on trees
1330 ftree-vectorizer-verbose=
1331 Common RejectNegative Joined
1332 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1335 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1336 Enable copy propagation of scalar-evolution information.
1338 ; -fverbose-asm causes extra commentary information to be produced in
1339 ; the generated assembly code (to make it more readable). This option
1340 ; is generally only of use to those who actually need to read the
1341 ; generated assembly code (perhaps while debugging the compiler itself).
1342 ; -fno-verbose-asm, the default, causes the extra information
1343 ; to not be added and is useful when comparing two assembler files.
1345 Common Report Var(flag_verbose_asm)
1346 Add extra commentary to assembler output
1349 Common Joined RejectNegative
1350 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1354 Common Report Var(flag_value_profile_transformations) Optimization
1355 Use expression value profiles in optimizations
1358 Common Report Var(flag_web) Init(2) Optimization
1359 Construct webs and split unrelated uses of single variable
1361 ftree-builtin-call-dce
1362 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1363 Enable conditional dead code elimination for builtin calls
1366 Common Report Var(flag_whole_program) Init(0) Optimization
1367 Perform whole program optimizations
1370 Common Report Var(flag_wrapv) Optimization
1371 Assume signed arithmetic overflow wraps around
1373 fzero-initialized-in-bss
1374 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1375 Put zero initialized data in the bss section
1378 Common JoinedOrMissing
1379 Generate debug information in default format
1382 Common JoinedOrMissing Negative(gdwarf-2)
1383 Generate debug information in COFF format
1386 Common JoinedOrMissing Negative(gstabs)
1387 Generate debug information in DWARF v2 format
1390 Common JoinedOrMissing
1391 Generate debug information in default extended format
1394 Common JoinedOrMissing Negative(gstabs+)
1395 Generate debug information in STABS format
1398 Common JoinedOrMissing Negative(gvms)
1399 Generate debug information in extended STABS format
1402 Common JoinedOrMissing Negative(gxcoff)
1403 Generate debug information in VMS format
1406 Common JoinedOrMissing Negative(gxcoff+)
1407 Generate debug information in XCOFF format
1410 Common JoinedOrMissing Negative(gcoff)
1411 Generate debug information in extended XCOFF format
1414 Common Joined Separate
1415 -o <file> Place output into <file>
1418 Common Var(profile_flag)
1419 Enable function profiling
1422 Common Var(pedantic)
1423 Issue warnings needed for strict compliance to the standard
1427 Like -pedantic but issue them as errors
1430 Common Var(quiet_flag)
1431 Do not display functions compiled or elapsed time
1434 Common Var(version_flag)
1435 Display the compiler's version
1438 Common Var(inhibit_warnings)
1442 Common RejectNegative Negative(pie)
1443 Create a shared library
1446 Common RejectNegative Negative(shared)
1447 Create a position independent executable
1449 ; This comment is to ensure we retain the blank line above.