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
550 fguess-branch-probability
551 Common Report Var(flag_guess_branch_prob) Optimization
552 Enable guessing of branch probabilities
554 ; Nonzero means ignore `#ident' directives. 0 means handle them.
555 ; Generate position-independent code for executables if possible
556 ; On SVR4 targets, it also controls whether or not to emit a
557 ; string identifying the compiler.
559 Common Report Var(flag_no_ident,0)
560 Process #ident directives
563 Common Report Var(flag_if_conversion) Optimization
564 Perform conversion of conditional jumps to branchless equivalents
567 Common Report Var(flag_if_conversion2) Optimization
568 Perform conversion of conditional jumps to conditional execution
570 ; -finhibit-size-directive inhibits output of .size for ELF.
571 ; This is used only for compiling crtstuff.c,
572 ; and it may be extended to other effects
573 ; needed for crtstuff.c on other systems.
574 finhibit-size-directive
575 Common Report Var(flag_inhibit_size_directive)
576 Do not generate .size directives
579 Common Report Var(flag_indirect_inlining)
580 Perform indirect inlining
582 ; Nonzero means that functions declared `inline' will be treated
583 ; as `static'. Prevents generation of zillions of copies of unused
584 ; static inline functions; instead, `inlines' are written out
585 ; only when actually used. Used in conjunction with -g. Also
586 ; does the right thing with #pragma interface.
588 Common Report Var(flag_no_inline,0) Init(0)
589 Pay attention to the \"inline\" keyword
591 finline-small-functions
592 Common Report Var(flag_inline_small_functions) Optimization
593 Integrate simple functions into their callers when code size is known to not growth
596 Common Report Var(flag_inline_functions) Optimization
597 Integrate simple functions into their callers
599 finline-functions-called-once
600 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
601 Integrate functions called once into their callers
604 Common RejectNegative Joined UInteger
607 Common RejectNegative Joined UInteger
608 -finline-limit=<number> Limit the size of inlined functions to <number>
610 finstrument-functions
611 Common Report Var(flag_instrument_function_entry_exit)
612 Instrument function entry and exit with profiling calls
614 finstrument-functions-exclude-function-list=
615 Common RejectNegative Joined
616 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
618 finstrument-functions-exclude-file-list=
619 Common RejectNegative Joined
620 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
623 Common Report Var(flag_ipa_cp) Optimization
624 Perform Interprocedural constant propagation
627 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
628 Discover pure and const functions
631 Common Report Var(flag_ipa_pta) Init(0) Optimization
632 Perform interprocedural points-to analysis
635 Common Report Var(flag_ipa_reference) Init(0) Optimization
636 Discover readonly and non addressable static variables
639 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
640 Type based escape and alias analysis
643 Common Report Var(flag_ipa_matrix_reorg) Optimization
644 Perform matrix layout flattening and transposing based
645 on profiling information.
648 Common Report Var(flag_ipa_struct_reorg)
649 Perform structure layout optimizations based
650 on profiling information.
653 Common Report Var(flag_ivopts) Init(1) Optimization
654 Optimize induction variables on trees
657 Common Var(flag_jump_tables) Init(1) Optimization
658 Use jump tables for sufficiently large switch statements
660 fkeep-inline-functions
661 Common Report Var(flag_keep_inline_functions)
662 Generate code for functions even if they are fully inlined
665 Common Report Var(flag_keep_static_consts) Init(1)
666 Emit static const variables even if they are not used
669 Common Report Var(flag_leading_underscore) Init(-1)
670 Give external symbols a leading underscore
674 Does nothing. Preserved for backward compatibility.
677 Common Report Var(flag_errno_math) Init(1) Optimization
678 Set errno after built-in math functions
681 Common Report Var(mem_report)
682 Report on permanent memory allocation
684 ; This will attempt to merge constant section constants, if 1 only
685 ; string constants and constants from constant pool, if 2 also constant
688 Common Report Var(flag_merge_constants,2) Init(1) Optimization
689 Attempt to merge identical constants and constant variables
692 Common Report Var(flag_merge_constants,1) VarExists Optimization
693 Attempt to merge identical constants across compilation units
696 Common Report Var(flag_merge_debug_strings) Init(1)
697 Attempt to merge identical debug strings across compilation units
700 Common RejectNegative Joined UInteger
701 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
704 Common Report Var(flag_modulo_sched) Optimization
705 Perform SMS based modulo scheduling before the first scheduling pass
707 fmodulo-sched-allow-regmoves
708 Common Report Var(flag_modulo_sched_allow_regmoves)
709 Perform SMS based modulo scheduling with register moves allowed
711 fmove-loop-invariants
712 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
713 Move loop invariant computations out of loops
716 Common RejectNegative Report Var(flag_mudflap)
717 Add mudflap bounds-checking instrumentation for single-threaded program
720 Common RejectNegative Report VarExists Var(flag_mudflap,2)
721 Add mudflap bounds-checking instrumentation for multi-threaded program
724 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
725 Ignore read operations when inserting mudflap instrumentation
728 Common Var(flag_dce) Init(1) Optimization
729 Use the RTL dead code elimination pass
732 Common Var(flag_dse) Init(1) Optimization
733 Use the RTL dead store elimination pass
735 freschedule-modulo-scheduled-loops
736 Common Report Var(flag_resched_modulo_sched) Optimization
737 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
740 Common Report Var(flag_non_call_exceptions) Optimization
741 Support synchronous non-call exceptions
744 Common Report Var(flag_omit_frame_pointer) Optimization
745 When possible do not generate stack frames
747 foptimize-register-move
748 Common Report Var(flag_regmove) Optimization
749 Do the full register move optimization pass
751 foptimize-sibling-calls
752 Common Report Var(flag_optimize_sibling_calls) Optimization
753 Optimize sibling and tail recursive calls
756 Common Report Var(pre_ipa_mem_report)
757 Report on memory allocation before interprocedural optimization
760 Common Report Var(post_ipa_mem_report)
761 Report on memory allocation before interprocedural optimization
764 Common Report Var(flag_pack_struct) Optimization
765 Pack structure members together without holes
768 Common RejectNegative Joined UInteger Optimization
769 -fpack-struct=<number> Set initial maximum structure member alignment
772 Common Report Var(flag_pcc_struct_return,1) VarExists
773 Return small aggregates in memory, not registers
776 Common Report Var(flag_peel_loops) Optimization
780 Common Report Var(flag_no_peephole,0) Optimization
781 Enable machine specific peephole optimizations
784 Common Report Var(flag_peephole2) Optimization
785 Enable an RTL peephole pass before sched2
788 Common Report Var(flag_pic,2)
789 Generate position-independent code if possible (large mode)
792 Common Report Var(flag_pie,2)
793 Generate position-independent code for executables if possible (large mode)
796 Common Report Var(flag_pic,1) VarExists
797 Generate position-independent code if possible (small mode)
800 Common Report Var(flag_pie,1) VarExists
801 Generate position-independent code for executables if possible (small mode)
803 fpredictive-commoning
804 Common Report Var(flag_predictive_commoning) Optimization
805 Run predictive commoning optimization.
807 fprefetch-loop-arrays
808 Common Report Var(flag_prefetch_loop_arrays) Optimization
809 Generate prefetch instructions, if available, for arrays in loops
812 Common Report Var(profile_flag)
813 Enable basic program profiling code
816 Common Report Var(profile_arc_flag)
817 Insert arc-based program profiling code
820 Common Joined RejectNegative
821 Set the top-level directory for storing the profile data.
822 The default is 'pwd'.
826 Enable common options for generating profile info for profile feedback directed optimizations
829 Common Joined RejectNegative
830 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
833 Common Var(flag_profile_use)
834 Enable common options for performing profile feedback directed optimizations
837 Common Joined RejectNegative
838 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
841 Common Report Var(flag_profile_values)
842 Insert code to profile values of expressions
848 Common Joined RejectNegative
849 -frandom-seed=<string> Make compile reproducible using <string>
851 ; This switch causes the command line that was used to create an
852 ; object file to be recorded into the object file. The exact format
853 ; of this recording is target and binary file format dependent.
854 ; It is related to the -fverbose-asm switch, but that switch only
855 ; records information in the assembler output file as comments, so
856 ; they never reach the object file.
858 Common Report Var(flag_record_gcc_switches)
859 Record gcc command line switches in the object file.
862 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
863 Return small aggregates in registers
866 Common Report Var(flag_regmove) Optimization
867 Enables a register move optimization
870 Common Report Var(flag_rename_registers) Init(2) Optimization
871 Perform a register renaming optimization pass
874 Common Report Var(flag_reorder_blocks) Optimization
875 Reorder basic blocks to improve code placement
877 freorder-blocks-and-partition
878 Common Report Var(flag_reorder_blocks_and_partition) Optimization
879 Reorder basic blocks and partition into hot and cold sections
882 Common Report Var(flag_reorder_functions) Optimization
883 Reorder functions to improve code placement
885 frerun-cse-after-loop
886 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
887 Add a common subexpression elimination pass after loop optimizations
891 Does nothing. Preserved for backward compatibility.
894 Common Report Var(flag_rounding_math) Optimization
895 Disable optimizations that assume default FP rounding behavior
898 Common Report Var(flag_schedule_interblock) Init(1) Optimization
899 Enable scheduling across basic blocks
902 Common Report Var(flag_schedule_speculative) Init(1) Optimization
903 Allow speculative motion of non-loads
906 Common Report Var(flag_schedule_speculative_load) Optimization
907 Allow speculative motion of some loads
909 fsched-spec-load-dangerous
910 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
911 Allow speculative motion of more loads
914 Common RejectNegative Joined
915 -fsched-verbose=<number> Set the verbosity level of the scheduler
917 fsched2-use-superblocks
918 Common Report Var(flag_sched2_use_superblocks) Optimization
919 If scheduling post reload, do superblock scheduling
922 Common Report Var(flag_sched2_use_traces) Optimization
923 If scheduling post reload, do trace scheduling
926 Common Report Var(flag_schedule_insns) Optimization
927 Reschedule instructions before register allocation
930 Common Report Var(flag_schedule_insns_after_reload) Optimization
931 Reschedule instructions after register allocation
933 ; sched_stalled_insns means that insns can be moved prematurely from the queue
934 ; of stalled insns into the ready list.
936 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
937 Allow premature scheduling of queued insns
939 fsched-stalled-insns=
940 Common RejectNegative Joined UInteger
941 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
943 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
944 ; be examined for a dependency on a stalled insn that is candidate for
945 ; premature removal from the queue of stalled insns into the ready list (has
946 ; an effect only if the flag 'sched_stalled_insns' is set).
947 fsched-stalled-insns-dep
948 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
949 Set dependence distance checking in premature scheduling of queued insns
951 fsched-stalled-insns-dep=
952 Common RejectNegative Joined UInteger
953 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
956 Common Report Var(flag_section_anchors) Optimization
957 Access data in the same section from shared anchor points
959 frtl-abstract-sequences
960 Common Report Var(flag_rtl_seqabstr) Optimization
961 Perform sequence abstraction optimization on RTL
964 Common Report Var(flag_see) Init(0)
965 Eliminate redundant sign extensions using LCM.
968 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
969 Show column numbers in diagnostics, when available. Default off
972 Common Report Var(flag_signaling_nans) Optimization
973 Disable optimizations observable by IEEE signaling NaNs
976 Common Report Var(flag_signed_zeros) Init(1) Optimization
977 Disable floating point optimizations that ignore the IEEE signedness of zero
979 fsingle-precision-constant
980 Common Report Var(flag_single_precision_constant) Optimization
981 Convert floating point constants to single precision constants
983 fsplit-ivs-in-unroller
984 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
985 Split lifetimes of induction variables when loops are unrolled
988 Common Report Var(flag_split_wide_types) Optimization
989 Split wide types into independent registers
991 fvariable-expansion-in-unroller
992 Common Report Var(flag_variable_expansion_in_unroller) Optimization
993 Apply variable expansion when loops are unrolled
995 ; Emit code to probe the stack, to help detect stack overflow; also
996 ; may cause large objects to be allocated dynamically.
998 Common Report Var(flag_stack_check)
999 Insert stack checking code into the program
1004 fstack-limit-register=
1005 Common RejectNegative Joined
1006 -fstack-limit-register=<register> Trap if the stack goes past <register>
1008 fstack-limit-symbol=
1009 Common RejectNegative Joined
1010 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1013 Common Report Var(flag_stack_protect, 1)
1014 Use propolice as a stack protection method
1016 fstack-protector-all
1017 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1018 Use a stack protection method for every function
1022 Does nothing. Preserved for backward compatibility.
1024 ; Nonzero if we should do (language-dependent) alias analysis.
1025 ; Typically, this analysis will assume that expressions of certain
1026 ; types do not alias expressions of certain other types. Only used
1027 ; if alias analysis (in general) is enabled.
1029 Common Report Var(flag_strict_aliasing) Optimization
1030 Assume strict aliasing rules apply
1033 Common Report Var(flag_strict_overflow)
1034 Treat signed overflow as undefined
1037 Common Report Var(flag_syntax_only)
1038 Check for syntax errors, then stop
1041 Common Report Var(flag_test_coverage)
1042 Create data files needed by \"gcov\"
1045 Common Report Var(flag_thread_jumps) Optimization
1046 Perform jump threading optimizations
1049 Common Report Var(time_report)
1050 Report the time taken by each compiler pass
1053 Common Joined RejectNegative
1054 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1057 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1058 Reorder top level functions, variables, and asms
1061 Common Report Var(flag_tracer)
1062 Perform superblock formation via tail duplication
1064 ; Zero means that floating-point math operations cannot generate a
1065 ; (user-visible) trap. This is the case, for example, in nonstop
1066 ; IEEE 754 arithmetic.
1068 Common Report Var(flag_trapping_math) Init(1) Optimization
1069 Assume floating-point operations can trap
1072 Common Report Var(flag_trapv) Optimization
1073 Trap for signed overflow in addition, subtraction and multiplication
1076 Common Report Var(flag_tree_ccp) Optimization
1077 Enable SSA-CCP optimization on trees
1080 Common Report Var(flag_tree_store_ccp) Optimization
1081 Enable SSA-CCP optimization for stores and loads
1084 Common Report Var(flag_tree_ch) Optimization
1085 Enable loop header copying on trees
1088 Common Report Var(flag_tree_copyrename) Optimization
1089 Replace SSA temporaries with better names in copies
1092 Common Report Var(flag_tree_copy_prop) Optimization
1093 Enable copy propagation on trees
1095 ftree-store-copy-prop
1097 Does nothing. Preserved for backward compatibility.
1100 Common Report Var(flag_tree_cselim) Init(2) Optimization
1101 Transform condition stores into unconditional ones
1103 ftree-switch-conversion
1104 Common Report Var(flag_tree_switch_conversion) Optimization
1105 Perform conversions of switch initializations.
1108 Common Report Var(flag_tree_dce) Optimization
1109 Enable SSA dead code elimination optimization on trees
1111 ftree-dominator-opts
1112 Common Report Var(flag_tree_dom) Optimization
1113 Enable dominator optimizations
1116 Common Report Var(flag_tree_dse) Optimization
1117 Enable dead store elimination
1120 Common Report Var(flag_tree_fre) Optimization
1121 Enable Full Redundancy Elimination (FRE) on trees
1123 ftree-loop-distribution
1124 Common Report Var(flag_tree_loop_distribution) Optimization
1125 Enable loop distribution on trees
1128 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1129 Enable loop invariant motion on trees
1132 Common Report Var(flag_tree_loop_linear) Optimization
1133 Enable linear loop transforms on trees
1136 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1137 Create canonical induction variables in loops
1140 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1141 Enable loop optimizations on tree level
1143 ftree-parallelize-loops=
1144 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1145 Enable automatic parallelization of loops
1148 Common Report Var(flag_tree_pre) Optimization
1149 Enable SSA-PRE optimization on trees
1152 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1153 Enable reassociation on tree level
1157 Does nothing. Preserved for backward compatibility.
1160 Common Report Var(flag_tree_sink) Optimization
1161 Enable SSA code sinking on trees
1164 Common Report Var(flag_tree_sra) Optimization
1165 Perform scalar replacement of aggregates
1168 Common Report Var(flag_tree_ter) Init(1) Optimization
1169 Replace temporary expressions in the SSA->normal pass
1172 Common Report Var(flag_tree_live_range_split) Optimization
1173 Perform live range splitting during the SSA->normal pass
1176 Common Report Var(flag_tree_vrp) Init(0) Optimization
1177 Perform Value Range Propagation on trees
1180 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1181 Compile whole compilation unit at a time
1184 Common Report Var(flag_unroll_loops) Optimization
1185 Perform loop unrolling when iteration count is known
1188 Common Report Var(flag_unroll_all_loops) Optimization
1189 Perform loop unrolling for all loops
1191 ; Nonzero means that loop optimizer may assume that the induction variables
1192 ; that control loops do not overflow and that the loops with nontrivial
1193 ; exit condition are not infinite
1194 funsafe-loop-optimizations
1195 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1196 Allow loop optimizations to assume that the loops behave in normal way
1199 Common Report Var(flag_associative_math)
1200 Allow optimization for floating-point arithmetic which may change the
1201 result of the operation due to rounding.
1204 Common Report Var(flag_reciprocal_math)
1205 Same as -fassociative-math for expressions which include division.
1207 ; Nonzero means that unsafe floating-point math optimizations are allowed
1208 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1209 ; are allowed to assume that their arguments and results are "normal"
1210 ; (e.g., nonnegative for SQRT).
1211 funsafe-math-optimizations
1212 Common Report Var(flag_unsafe_math_optimizations) Optimization
1213 Allow math optimizations that may violate IEEE or ISO standards
1216 Common Report Var(flag_unswitch_loops) Optimization
1217 Perform loop unswitching
1220 Common Report Var(flag_unwind_tables) Optimization
1221 Just generate unwind tables for exception handling
1224 Common Report Var(flag_var_tracking) VarExists Optimization
1225 Perform variable tracking
1227 fvar-tracking-uninit
1228 Common Report Var(flag_var_tracking_uninit) Optimization
1229 Perform variable tracking and also tag variables that are uninitialized
1232 Common Report Var(flag_tree_vectorize) Optimization
1233 Enable loop vectorization on trees
1236 Common Report Var(flag_vect_cost_model) Optimization
1237 Enable use of cost model in vectorization
1239 ftree-vect-loop-version
1240 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1241 Enable loop versioning when doing loop vectorization on trees
1243 ftree-vectorizer-verbose=
1244 Common RejectNegative Joined
1245 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1248 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1249 Enable copy propagation of scalar-evolution information.
1251 ; -fverbose-asm causes extra commentary information to be produced in
1252 ; the generated assembly code (to make it more readable). This option
1253 ; is generally only of use to those who actually need to read the
1254 ; generated assembly code (perhaps while debugging the compiler itself).
1255 ; -fno-verbose-asm, the default, causes the extra information
1256 ; to not be added and is useful when comparing two assembler files.
1258 Common Report Var(flag_verbose_asm)
1259 Add extra commentary to assembler output
1262 Common Joined RejectNegative
1263 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1267 Common Report Var(flag_value_profile_transformations) Optimization
1268 Use expression value profiles in optimizations
1271 Common Report Var(flag_web) Init(2) Optimization
1272 Construct webs and split unrelated uses of single variable
1274 ftree-builtin-call-dce
1275 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1276 Enable conditional dead code elimination for builtin calls
1279 Common Report Var(flag_whole_program) Init(0) Optimization
1280 Perform whole program optimizations
1283 Common Report Var(flag_wrapv) Optimization
1284 Assume signed arithmetic overflow wraps around
1286 fzero-initialized-in-bss
1287 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1288 Put zero initialized data in the bss section
1291 Common JoinedOrMissing
1292 Generate debug information in default format
1295 Common JoinedOrMissing Negative(gdwarf-2)
1296 Generate debug information in COFF format
1299 Common JoinedOrMissing Negative(gstabs)
1300 Generate debug information in DWARF v2 format
1303 Common JoinedOrMissing
1304 Generate debug information in default extended format
1307 Common JoinedOrMissing Negative(gstabs+)
1308 Generate debug information in STABS format
1311 Common JoinedOrMissing Negative(gvms)
1312 Generate debug information in extended STABS format
1315 Common JoinedOrMissing Negative(gxcoff)
1316 Generate debug information in VMS format
1319 Common JoinedOrMissing Negative(gxcoff+)
1320 Generate debug information in XCOFF format
1323 Common JoinedOrMissing Negative(gcoff)
1324 Generate debug information in extended XCOFF format
1327 Common Joined Separate
1328 -o <file> Place output into <file>
1331 Common Var(profile_flag)
1332 Enable function profiling
1335 Common Var(pedantic)
1336 Issue warnings needed for strict compliance to the standard
1340 Like -pedantic but issue them as errors
1343 Common Var(quiet_flag)
1344 Do not display functions compiled or elapsed time
1347 Common Var(version_flag)
1348 Display the compiler's version
1351 Common Var(inhibit_warnings)
1355 Common RejectNegative Negative(pie)
1356 Create a shared library
1359 Common RejectNegative Negative(shared)
1360 Create a position independent executable
1362 ; This comment is to ensure we retain the blank line above.