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
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
98 Common Var(warnings_are_errors)
99 Treat all warnings as errors
103 Treat specified warning as error
107 Print extra (possibly unwanted) warnings
110 Common Var(flag_fatal_errors)
111 Exit on the first error occurred
114 Common RejectNegative Joined UInteger
115 -Wframe-larger-than=@var{len} Warn whenever a function's stack frame requires
116 more than @var{len} bytes. The computation done to determine
117 the stack frame size is approximate and not conservative.
118 The actual requirements may be somewhat greater than @var{len}
119 even if you do not get a warning. In addition, any space allocated
120 via @code{alloca}, variable-length arrays, or related constructs
121 is not included by the compiler when determining
122 whether or not to issue a warning.
125 Common Var(warn_inline) Warning
126 Warn when an inlined function cannot be inlined
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_overflow) Init(1) Warning
146 Warn about overflow in arithmetic expressions
149 Common Var(warn_packed) Warning
150 Warn when the packed attribute has no effect on struct layout
153 Common Var(warn_padded) Warning
154 Warn when padding is required to align structure members
157 Common Var(warn_shadow) Warning
158 Warn when one local variable shadows another
161 Common Var(warn_stack_protect) Warning
162 Warn when not issuing stack smashing protection for some reason
166 Warn about code which might break strict aliasing rules
169 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
170 Warn about code which might break strict aliasing rules
174 Warn about optimizations that assume that signed overflow is undefined
177 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
178 Warn about optimizations that assume that signed overflow is undefined
181 Common Var(warn_switch) Warning
182 Warn about enumerated switches, with no default, missing a case
185 Common Var(warn_switch_default) Warning
186 Warn about enumerated switches missing a \"default:\" statement
189 Common Var(warn_switch_enum) Warning
190 Warn about all enumerated switches missing a specific case
193 Common Var(warn_system_headers) Warning
194 Do not suppress warnings from system headers
197 Common Var(warn_type_limits) Init(-1) Warning
198 Warn if a comparison is always true or always false due to the limited range of the data type
201 Common Var(warn_uninitialized) Warning
202 Warn about uninitialized automatic variables
205 Common Var(warn_notreached) Warning
206 Warn about code that will never be executed
210 Enable all -Wunused- warnings
213 Common Var(warn_unused_function) Warning
214 Warn when a function is unused
217 Common Var(warn_unused_label) Warning
218 Warn when a label is unused
221 Common Var(warn_unused_parameter) Warning
222 Warn when a function parameter is unused
225 Common Var(warn_unused_value) Warning
226 Warn when an expression value is unused
229 Common Var(warn_unused_variable) Warning
230 Warn when a variable is unused
232 Wvolatile-register-var
233 Common Var(warn_register_var) Warning
234 Warn when a register variable is declared volatile
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)
279 Align the start of functions
282 Common RejectNegative Joined UInteger
285 Common Report Var(align_jumps,0) Optimization
286 Align labels which are only reached by jumping
289 Common RejectNegative Joined UInteger
292 Common Report Var(align_labels,0) Optimization
296 Common RejectNegative Joined UInteger
299 Common Report Var(align_loops) Optimization
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_data_sections) Optimization
410 Place data items into their own section
414 List all available debugging counters with their limits and counts.
417 Common RejectNegative Joined
418 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
421 Common Joined RejectNegative
422 Map one directory name to another in debug information
424 ; Nonzero for -fdefer-pop: don't pop args after each function call
425 ; instead save them up to pop many calls' args with one insns.
427 Common Report Var(flag_defer_pop) Optimization
428 Defer popping functions args from stack until later
431 Common Report Var(flag_delayed_branch) Optimization
432 Attempt to fill delay slots of branch instructions
434 fdelete-null-pointer-checks
435 Common Report Var(flag_delete_null_pointer_checks) Optimization
436 Delete useless null pointer checks
438 fdiagnostics-show-location=
439 Common Joined RejectNegative
440 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
442 fdiagnostics-show-option
444 Amend appropriate diagnostic messages with the command line option that controls them
447 Common Joined RejectNegative
448 -fdump-<type> Dump various compiler internals to a file
451 Common Report Var(flag_dump_noaddr)
452 Suppress output of addresses in debugging dumps
455 Common Report Var(flag_dump_unnumbered) VarExists
456 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
459 Common Report Var(flag_early_inlining) Init(1) Optimization
460 Perform early inlining
462 feliminate-dwarf2-dups
463 Common Report Var(flag_eliminate_dwarf2_dups)
464 Perform DWARF2 duplicate elimination
466 feliminate-unused-debug-symbols
467 Common Report Var(flag_debug_only_used_symbols)
468 Perform unused type elimination in debug info
470 feliminate-unused-debug-types
471 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
472 Perform unused type elimination in debug info
474 femit-class-debug-always
475 Common Report Var(flag_emit_class_debug_always) Init(0)
476 Do not suppress C++ class debug information.
479 Common Report Var(flag_exceptions) Optimization
480 Enable exception handling
482 fexpensive-optimizations
483 Common Report Var(flag_expensive_optimizations) Optimization
484 Perform a number of minor, expensive optimizations
490 Common Report Var(flag_finite_math_only) Optimization
491 Assume no NaNs or infinities are generated
494 Common Joined RejectNegative
495 -ffixed-<register> Mark <register> as being unavailable to the compiler
498 Common Report Var(flag_float_store) Optimization
499 Don't allocate floats and doubles in extended-precision registers
503 Does nothing. Preserved for backward compatibility.
506 Common Report Var(flag_forward_propagate) Optimization
507 Perform a forward propagation pass on RTL
509 ; Nonzero means don't put addresses of constant functions in registers.
510 ; Used for compiling the Unix kernel, where strange substitutions are
511 ; done on the assembly output.
513 Common Report Var(flag_no_function_cse,0)
514 Allow function addresses to be held in registers
517 Common Report Var(flag_function_sections)
518 Place each function into its own section
521 Common Report Var(flag_gcse) Optimization
522 Perform global common subexpression elimination
525 Common Report Var(flag_gcse_lm) Init(1) Optimization
526 Perform enhanced load motion during global common subexpression elimination
529 Common Report Var(flag_gcse_sm) Init(0) Optimization
530 Perform store motion after global common subexpression elimination
533 Common Report Var(flag_gcse_las) Init(0) Optimization
534 Perform redundant load after store elimination in global common subexpression
538 Common Report Var(flag_gcse_after_reload) Optimization
539 Perform global common subexpression elimination after register allocation
542 fguess-branch-probability
543 Common Report Var(flag_guess_branch_prob) Optimization
544 Enable guessing of branch probabilities
546 ; Nonzero means ignore `#ident' directives. 0 means handle them.
547 ; Generate position-independent code for executables if possible
548 ; On SVR4 targets, it also controls whether or not to emit a
549 ; string identifying the compiler.
551 Common Report Var(flag_no_ident,0)
552 Process #ident directives
555 Common Report Var(flag_if_conversion) Optimization
556 Perform conversion of conditional jumps to branchless equivalents
559 Common Report Var(flag_if_conversion2) Optimization
560 Perform conversion of conditional jumps to conditional execution
562 ; -finhibit-size-directive inhibits output of .size for ELF.
563 ; This is used only for compiling crtstuff.c,
564 ; and it may be extended to other effects
565 ; needed for crtstuff.c on other systems.
566 finhibit-size-directive
567 Common Report Var(flag_inhibit_size_directive)
568 Do not generate .size directives
570 ; Nonzero means that functions declared `inline' will be treated
571 ; as `static'. Prevents generation of zillions of copies of unused
572 ; static inline functions; instead, `inlines' are written out
573 ; only when actually used. Used in conjunction with -g. Also
574 ; does the right thing with #pragma interface.
576 Common Report Var(flag_no_inline,0) Init(2)
577 Pay attention to the \"inline\" keyword
579 finline-small-functions
580 Common Report Var(flag_inline_small_functions) Optimization
581 Integrate simple functions into their callers when code size is known to not growth
584 Common Report Var(flag_inline_functions) Optimization
585 Integrate simple functions into their callers
587 finline-functions-called-once
588 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
589 Integrate functions called once into their callers
592 Common RejectNegative Joined UInteger
595 Common RejectNegative Joined UInteger
596 -finline-limit=<number> Limit the size of inlined functions to <number>
598 finstrument-functions
599 Common Report Var(flag_instrument_function_entry_exit)
600 Instrument function entry and exit with profiling calls
602 finstrument-functions-exclude-function-list=
603 Common RejectNegative Joined
604 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
606 finstrument-functions-exclude-file-list=
607 Common RejectNegative Joined
608 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
611 Common Report Var(flag_ipa_cp) Optimization
612 Perform Interprocedural constant propagation
615 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
616 Discover pure and const functions
619 Common Report Var(flag_ipa_pta) Init(0) Optimization
620 Perform interprocedural points-to analysis
623 Common Report Var(flag_ipa_reference) Init(0) Optimization
624 Discover readonly and non addressable static variables
627 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
628 Type based escape and alias analysis
631 Common Report Var(flag_ipa_matrix_reorg) Optimization
632 Perform matrix layout flattening and transposing based
633 on profiling information.
636 Common Report Var(flag_ipa_struct_reorg)
637 Perform structure layout optimizations based
638 on profiling information.
641 Common Report Var(flag_ivopts) Init(1) Optimization
642 Optimize induction variables on trees
645 Common Var(flag_jump_tables) Init(1) Optimization
646 Use jump tables for sufficiently large switch statements
648 fkeep-inline-functions
649 Common Report Var(flag_keep_inline_functions)
650 Generate code for functions even if they are fully inlined
653 Common Report Var(flag_keep_static_consts) Init(1)
654 Emit static const variables even if they are not used
657 Common Report Var(flag_leading_underscore) Init(-1)
658 Give external symbols a leading underscore
662 Does nothing. Preserved for backward compatibility.
665 Common Report Var(flag_errno_math) Init(1)
666 Set errno after built-in math functions
669 Common Report Var(mem_report)
670 Report on permanent memory allocation
672 ; This will attempt to merge constant section constants, if 1 only
673 ; string constants and constants from constant pool, if 2 also constant
676 Common Report Var(flag_merge_constants,2) Init(1) Optimization
677 Attempt to merge identical constants and constant variables
680 Common Report Var(flag_merge_constants,1) VarExists Optimization
681 Attempt to merge identical constants across compilation units
684 Common Report Var(flag_merge_debug_strings) Init(1)
685 Attempt to merge identical debug strings across compilation units
688 Common RejectNegative Joined UInteger
689 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
692 Common Report Var(flag_modulo_sched) Optimization
693 Perform SMS based modulo scheduling before the first scheduling pass
695 fmodulo-sched-allow-regmoves
696 Common Report Var(flag_modulo_sched_allow_regmoves)
697 Perform SMS based modulo scheduling with register moves allowed
699 fmove-loop-invariants
700 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
701 Move loop invariant computations out of loops
704 Common RejectNegative Report Var(flag_mudflap)
705 Add mudflap bounds-checking instrumentation for single-threaded program
708 Common RejectNegative Report VarExists Var(flag_mudflap,2)
709 Add mudflap bounds-checking instrumentation for multi-threaded program
712 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
713 Ignore read operations when inserting mudflap instrumentation
716 Common Var(flag_dce) Init(1) Optimization
717 Use the RTL dead code elimination pass
720 Common Var(flag_dse) Init(1) Optimization
721 Use the RTL dead store elimination pass
723 freschedule-modulo-scheduled-loops
724 Common Report Var(flag_resched_modulo_sched) Optimization
725 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
728 Common Report Var(flag_non_call_exceptions) Optimization
729 Support synchronous non-call exceptions
732 Common Report Var(flag_omit_frame_pointer) Optimization
733 When possible do not generate stack frames
736 Common Report Var(flag_openmp_ssa)
737 Expand OpenMP operations on SSA form
739 foptimize-register-move
740 Common Report Var(flag_regmove) Optimization
741 Do the full register move optimization pass
743 foptimize-sibling-calls
744 Common Report Var(flag_optimize_sibling_calls) Optimization
745 Optimize sibling and tail recursive calls
748 Common Report Var(pre_ipa_mem_report)
749 Report on memory allocation before interprocedural optimization
752 Common Report Var(post_ipa_mem_report)
753 Report on memory allocation before interprocedural optimization
756 Common Report Var(flag_pack_struct) Optimization
757 Pack structure members together without holes
760 Common RejectNegative Joined UInteger Optimization
761 -fpack-struct=<number> Set initial maximum structure member alignment
764 Common Report Var(flag_pcc_struct_return,1) VarExists
765 Return small aggregates in memory, not registers
768 Common Report Var(flag_peel_loops) Optimization
772 Common Report Var(flag_no_peephole,0) Optimization
773 Enable machine specific peephole optimizations
776 Common Report Var(flag_peephole2) Optimization
777 Enable an RTL peephole pass before sched2
780 Common Report Var(flag_pic,2)
781 Generate position-independent code if possible (large mode)
784 Common Report Var(flag_pie,2)
785 Generate position-independent code for executables if possible (large mode)
788 Common Report Var(flag_pic,1) VarExists
789 Generate position-independent code if possible (small mode)
792 Common Report Var(flag_pie,1) VarExists
793 Generate position-independent code for executables if possible (small mode)
795 fpredictive-commoning
796 Common Report Var(flag_predictive_commoning) Optimization
797 Run predictive commoning optimization.
799 fprefetch-loop-arrays
800 Common Report Var(flag_prefetch_loop_arrays) Optimization
801 Generate prefetch instructions, if available, for arrays in loops
804 Common Report Var(profile_flag)
805 Enable basic program profiling code
808 Common Report Var(profile_arc_flag)
809 Insert arc-based program profiling code
813 Enable common options for generating profile info for profile feedback directed optimizations
817 Enable common options for performing profile feedback directed optimizations
820 Common Report Var(flag_profile_values)
821 Insert code to profile values of expressions
827 Common Joined RejectNegative
828 -frandom-seed=<string> Make compile reproducible using <string>
830 ; This switch causes the command line that was used to create an
831 ; object file to be recorded into the object file. The exact format
832 ; of this recording is target and binary file format dependent.
833 ; It is related to the -fverbose-asm switch, but that switch only
834 ; records information in the assembler output file as comments, so
835 ; they never reach the object file.
837 Common Report Var(flag_record_gcc_switches)
838 Record gcc command line switches in the object file.
841 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
842 Return small aggregates in registers
845 Common Report Var(flag_regmove) Optimization
846 Enables a register move optimization
849 Common Report Var(flag_rename_registers) Init(2) Optimization
850 Perform a register renaming optimization pass
853 Common Report Var(flag_reorder_blocks) Optimization
854 Reorder basic blocks to improve code placement
856 freorder-blocks-and-partition
857 Common Report Var(flag_reorder_blocks_and_partition) Optimization
858 Reorder basic blocks and partition into hot and cold sections
861 Common Report Var(flag_reorder_functions) Optimization
862 Reorder functions to improve code placement
864 frerun-cse-after-loop
865 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
866 Add a common subexpression elimination pass after loop optimizations
870 Does nothing. Preserved for backward compatibility.
873 Common Report Var(flag_rounding_math) Optimization
874 Disable optimizations that assume default FP rounding behavior
877 Common Report Var(flag_schedule_interblock) Init(1) Optimization
878 Enable scheduling across basic blocks
881 Common Report Var(flag_schedule_speculative) Init(1) Optimization
882 Allow speculative motion of non-loads
885 Common Report Var(flag_schedule_speculative_load) Optimization
886 Allow speculative motion of some loads
888 fsched-spec-load-dangerous
889 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
890 Allow speculative motion of more loads
893 Common RejectNegative Joined
894 -fsched-verbose=<number> Set the verbosity level of the scheduler
896 fsched2-use-superblocks
897 Common Report Var(flag_sched2_use_superblocks) Optimization
898 If scheduling post reload, do superblock scheduling
901 Common Report Var(flag_sched2_use_traces) Optimization
902 If scheduling post reload, do trace scheduling
905 Common Report Var(flag_schedule_insns) Optimization
906 Reschedule instructions before register allocation
909 Common Report Var(flag_schedule_insns_after_reload) Optimization
910 Reschedule instructions after register allocation
912 ; sched_stalled_insns means that insns can be moved prematurely from the queue
913 ; of stalled insns into the ready list.
915 Common Report Var(flag_sched_stalled_insns) Optimization
916 Allow premature scheduling of queued insns
918 fsched-stalled-insns=
919 Common RejectNegative Joined UInteger
920 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
922 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
923 ; be examined for a dependency on a stalled insn that is candidate for
924 ; premature removal from the queue of stalled insns into the ready list (has
925 ; an effect only if the flag 'sched_stalled_insns' is set).
926 fsched-stalled-insns-dep
927 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
928 Set dependence distance checking in premature scheduling of queued insns
930 fsched-stalled-insns-dep=
931 Common RejectNegative Joined UInteger
932 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
935 Common Report Var(flag_section_anchors) Optimization
936 Access data in the same section from shared anchor points
938 frtl-abstract-sequences
939 Common Report Var(flag_rtl_seqabstr) Optimization
940 Perform sequence abstraction optimization on RTL
943 Common Report Var(flag_see) Init(0)
944 Eliminate redundant sign extensions using LCM.
947 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
948 Show column numbers in diagnostics, when available. Default off
951 Common Report Var(flag_signaling_nans) Optimization
952 Disable optimizations observable by IEEE signaling NaNs
955 Common Report Var(flag_signed_zeros) Init(1) Optimization
956 Disable floating point optimizations that ignore the IEEE signedness of zero
958 fsingle-precision-constant
959 Common Report Var(flag_single_precision_constant) Optimization
960 Convert floating point constants to single precision constants
962 fsplit-ivs-in-unroller
963 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
964 Split lifetimes of induction variables when loops are unrolled
967 Common Report Var(flag_split_wide_types) Optimization
968 Split wide types into independent registers
970 fvariable-expansion-in-unroller
971 Common Report Var(flag_variable_expansion_in_unroller) Optimization
972 Apply variable expansion when loops are unrolled
974 ; Emit code to probe the stack, to help detect stack overflow; also
975 ; may cause large objects to be allocated dynamically.
977 Common Report Var(flag_stack_check)
978 Insert stack checking code into the program
983 fstack-limit-register=
984 Common RejectNegative Joined
985 -fstack-limit-register=<register> Trap if the stack goes past <register>
988 Common RejectNegative Joined
989 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
992 Common Report Var(flag_stack_protect, 1)
993 Use propolice as a stack protection method
996 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
997 Use a stack protection method for every function
1001 Does nothing. Preserved for backward compatibility.
1003 ; Nonzero if we should do (language-dependent) alias analysis.
1004 ; Typically, this analysis will assume that expressions of certain
1005 ; types do not alias expressions of certain other types. Only used
1006 ; if alias analysis (in general) is enabled.
1008 Common Report Var(flag_strict_aliasing) Optimization
1009 Assume strict aliasing rules apply
1012 Common Report Var(flag_strict_overflow)
1013 Treat signed overflow as undefined
1016 Common Report Var(flag_syntax_only)
1017 Check for syntax errors, then stop
1020 Common Report Var(flag_test_coverage)
1021 Create data files needed by \"gcov\"
1024 Common Report Var(flag_thread_jumps) Optimization
1025 Perform jump threading optimizations
1028 Common Report Var(time_report)
1029 Report the time taken by each compiler pass
1032 Common Joined RejectNegative
1033 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1036 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
1037 Reorder top level functions, variables, and asms
1040 Common Report Var(flag_tracer)
1041 Perform superblock formation via tail duplication
1043 ; Zero means that floating-point math operations cannot generate a
1044 ; (user-visible) trap. This is the case, for example, in nonstop
1045 ; IEEE 754 arithmetic.
1047 Common Report Var(flag_trapping_math) Init(1) Optimization
1048 Assume floating-point operations can trap
1051 Common Report Var(flag_trapv) Optimization
1052 Trap for signed overflow in addition, subtraction and multiplication
1055 Common Report Var(flag_tree_ccp) Optimization
1056 Enable SSA-CCP optimization on trees
1059 Common Report Var(flag_tree_store_ccp) Optimization
1060 Enable SSA-CCP optimization for stores and loads
1063 Common Report Var(flag_tree_ch) Optimization
1064 Enable loop header copying on trees
1067 Common Report Var(flag_tree_copyrename) Optimization
1068 Replace SSA temporaries with better names in copies
1071 Common Report Var(flag_tree_copy_prop) Optimization
1072 Enable copy propagation on trees
1074 ftree-store-copy-prop
1076 Does nothing. Preserved for backward compatibility.
1079 Common Report Var(flag_tree_cselim) Init(2) Optimization
1080 Transform condition stores into unconditional ones
1083 Common Report Var(flag_tree_dce) Optimization
1084 Enable SSA dead code elimination optimization on trees
1086 ftree-dominator-opts
1087 Common Report Var(flag_tree_dom) Optimization
1088 Enable dominator optimizations
1091 Common Report Var(flag_tree_dse) Optimization
1092 Enable dead store elimination
1095 Common Report Var(flag_tree_fre) Optimization
1096 Enable Full Redundancy Elimination (FRE) on trees
1099 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1100 Enable loop invariant motion on trees
1103 Common Report Var(flag_tree_loop_linear) Optimization
1104 Enable linear loop transforms on trees
1107 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1108 Create canonical induction variables in loops
1111 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1112 Enable loop optimizations on tree level
1114 ftree-parallelize-loops=
1115 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1116 Enable automatic parallelization of loops
1119 Common Report Var(flag_tree_pre) Optimization
1120 Enable SSA-PRE optimization on trees
1123 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1124 Enable reassociation on tree level
1127 Common Report Var(flag_tree_salias) Optimization
1128 Perform structural alias analysis
1131 Common Report Var(flag_tree_sink) Optimization
1132 Enable SSA code sinking on trees
1135 Common Report Var(flag_tree_sra) Optimization
1136 Perform scalar replacement of aggregates
1139 Common Report Var(flag_tree_ter) Optimization
1140 Replace temporary expressions in the SSA->normal pass
1143 Common Report Var(flag_tree_live_range_split) Optimization
1144 Perform live range splitting during the SSA->normal pass
1147 Common Report Var(flag_tree_vrp) Init(0) Optimization
1148 Perform Value Range Propagation on trees
1151 Common Report Var(flag_unit_at_a_time) Optimization
1152 Compile whole compilation unit at a time
1155 Common Report Var(flag_unroll_loops) Optimization
1156 Perform loop unrolling when iteration count is known
1159 Common Report Var(flag_unroll_all_loops) Optimization
1160 Perform loop unrolling for all loops
1162 ; Nonzero means that loop optimizer may assume that the induction variables
1163 ; that control loops do not overflow and that the loops with nontrivial
1164 ; exit condition are not infinite
1165 funsafe-loop-optimizations
1166 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1167 Allow loop optimizations to assume that the loops behave in normal way
1170 Common Report Var(flag_associative_math)
1171 Allow optimization for floating-point arithmetic which may change the
1172 result of the operation due to rounding.
1175 Common Report Var(flag_reciprocal_math)
1176 Same as -fassociative-math for expressions which include division.
1178 ; Nonzero means that unsafe floating-point math optimizations are allowed
1179 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1180 ; are allowed to assume that their arguments and results are "normal"
1181 ; (e.g., nonnegative for SQRT).
1182 funsafe-math-optimizations
1183 Common Report Var(flag_unsafe_math_optimizations) Optimization
1184 Allow math optimizations that may violate IEEE or ISO standards
1187 Common Report Var(flag_unswitch_loops) Optimization
1188 Perform loop unswitching
1191 Common Report Var(flag_unwind_tables) Optimization
1192 Just generate unwind tables for exception handling
1195 Common Report Var(flag_var_tracking) VarExists Optimization
1196 Perform variable tracking
1198 fvar-tracking-uninit
1199 Common Report Var(flag_var_tracking_uninit) Optimization
1200 Perform variable tracking and also tag variables that are uninitialized
1203 Common Report Var(flag_tree_vectorize) Optimization
1204 Enable loop vectorization on trees
1207 Common Report Var(flag_vect_cost_model) Optimization
1208 Enable use of cost model in vectorization
1210 ftree-vect-loop-version
1211 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1212 Enable loop versioning when doing loop vectorization on trees
1214 ftree-vectorizer-verbose=
1215 Common RejectNegative Joined
1216 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1219 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1220 Enable copy propagation of scalar-evolution information.
1222 ; -fverbose-asm causes extra commentary information to be produced in
1223 ; the generated assembly code (to make it more readable). This option
1224 ; is generally only of use to those who actually need to read the
1225 ; generated assembly code (perhaps while debugging the compiler itself).
1226 ; -fno-verbose-asm, the default, causes the extra information
1227 ; to not be added and is useful when comparing two assembler files.
1229 Common Report Var(flag_verbose_asm)
1230 Add extra commentary to assembler output
1233 Common Joined RejectNegative
1234 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1238 Common Report Var(flag_value_profile_transformations) Optimization
1239 Use expression value profiles in optimizations
1242 Common Report Var(flag_web) Init(2) Optimization
1243 Construct webs and split unrelated uses of single variable
1246 Common Report Var(flag_whole_program) Init(0) Optimization
1247 Perform whole program optimizations
1250 Common Report Var(flag_wrapv) Optimization
1251 Assume signed arithmetic overflow wraps around
1253 fzero-initialized-in-bss
1254 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1255 Put zero initialized data in the bss section
1258 Common JoinedOrMissing
1259 Generate debug information in default format
1262 Common JoinedOrMissing Negative(gdwarf-2)
1263 Generate debug information in COFF format
1266 Common JoinedOrMissing Negative(gstabs)
1267 Generate debug information in DWARF v2 format
1270 Common JoinedOrMissing
1271 Generate debug information in default extended format
1274 Common JoinedOrMissing Negative(gstabs+)
1275 Generate debug information in STABS format
1278 Common JoinedOrMissing Negative(gvms)
1279 Generate debug information in extended STABS format
1282 Common JoinedOrMissing Negative(gxcoff)
1283 Generate debug information in VMS format
1286 Common JoinedOrMissing Negative(gxcoff+)
1287 Generate debug information in XCOFF format
1290 Common JoinedOrMissing Negative(gcoff)
1291 Generate debug information in extended XCOFF format
1294 Common Joined Separate
1295 -o <file> Place output into <file>
1298 Common Var(profile_flag)
1299 Enable function profiling
1302 Common Var(pedantic)
1303 Issue warnings needed for strict compliance to the standard
1307 Like -pedantic but issue them as errors
1310 Common Var(quiet_flag)
1311 Do not display functions compiled or elapsed time
1314 Common Var(version_flag)
1315 Display the compiler's version
1318 Common Var(inhibit_warnings)
1322 Common RejectNegative Negative(pie)
1323 Create a shared library
1326 Common RejectNegative Negative(shared)
1327 Create a position independent executable
1329 ; This comment is to ensure we retain the blank line above.