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_uninitialized) Warning
198 Warn about uninitialized automatic variables
201 Common Var(warn_notreached) Warning
202 Warn about code that will never be executed
206 Enable all -Wunused- warnings
209 Common Var(warn_unused_function) Warning
210 Warn when a function is unused
213 Common Var(warn_unused_label) Warning
214 Warn when a label is unused
217 Common Var(warn_unused_parameter) Warning
218 Warn when a function parameter is unused
221 Common Var(warn_unused_value) Warning
222 Warn when an expression value is unused
225 Common Var(warn_unused_variable) Warning
226 Warn when a variable is unused
228 Wvolatile-register-var
229 Common Var(warn_register_var) Warning
230 Warn when a register variable is declared volatile
233 Common RejectNegative Var(warn_coverage_mismatch) Warning
234 Warn instead of error in case profiles in -fprofile-use do not match
238 -aux-info <file> Emit declaration information into <file>
251 -d<letters> Enable dumps from specific passes of the compiler
255 -dumpbase <file> Set the file basename to be used for dumps
257 ; The version of the C++ ABI in use. The following values are allowed:
259 ; 0: The version of the ABI believed most conformant with the C++ ABI
260 ; specification. This ABI may change as bugs are discovered and fixed.
261 ; Therefore, 0 will not necessarily indicate the same ABI in different
264 ; 1: The version of the ABI first used in G++ 3.2.
266 ; 2: The version of the ABI first used in G++ 3.4.
268 ; Additional positive integers will be assigned as new versions of
269 ; the ABI become the default version of the ABI.
271 Common Joined UInteger Var(flag_abi_version) Init(2)
274 Common Report Var(align_functions,0)
275 Align the start of functions
278 Common RejectNegative Joined UInteger
281 Common Report Var(align_jumps,0) Optimization
282 Align labels which are only reached by jumping
285 Common RejectNegative Joined UInteger
288 Common Report Var(align_labels,0) Optimization
292 Common RejectNegative Joined UInteger
295 Common Report Var(align_loops) Optimization
296 Align the start of loops
299 Common RejectNegative Joined UInteger
301 ; This flag is only tested if alias checking is enabled.
302 ; 0 if pointer arguments may alias each other. True in C.
303 ; 1 if pointer arguments may not alias each other but may alias
305 ; 2 if pointer arguments may not alias each other and may not
306 ; alias global variables.
307 ; 3 if pointer arguments may not alias anything. True in Fortran.
308 ; Set by the front end.
310 Common Report Var(flag_argument_noalias,0) Optimization
311 Specify that arguments may alias each other and globals
314 Common Report Var(flag_argument_noalias,1) VarExists Optimization
315 Assume arguments may alias globals but not each other
317 fargument-noalias-global
318 Common Report Var(flag_argument_noalias,2) VarExists Optimization
319 Assume arguments alias neither each other nor globals
321 fargument-noalias-anything
322 Common Report Var(flag_argument_noalias,3) VarExists Optimization
323 Assume arguments alias no other storage
325 fasynchronous-unwind-tables
326 Common Report Var(flag_asynchronous_unwind_tables) Optimization
327 Generate unwind tables that are exact at each instruction boundary
330 Common Report Var(flag_auto_inc_dec) Init(1)
331 Generate auto-inc/dec instructions
333 ; -fcheck-bounds causes gcc to generate array bounds checks.
334 ; For C, C++ and ObjC: defaults off.
335 ; For Java: defaults to on.
336 ; For Fortran: defaults to off.
338 Common Report Var(flag_bounds_check)
339 Generate code to check bounds before indexing arrays
342 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
343 Replace add, compare, branch with branch on count register
345 fbranch-probabilities
346 Common Report Var(flag_branch_probabilities) Optimization
347 Use profiling information for branch probabilities
349 fbranch-target-load-optimize
350 Common Report Var(flag_branch_target_load_optimize) Optimization
351 Perform branch target load optimization before prologue / epilogue threading
353 fbranch-target-load-optimize2
354 Common Report Var(flag_branch_target_load_optimize2) Optimization
355 Perform branch target load optimization after prologue / epilogue threading
358 Common Report Var(flag_btr_bb_exclusive) Optimization
359 Restrict target load migration not to re-use registers in any basic block
362 Common Joined RejectNegative
363 -fcall-saved-<register> Mark <register> as being preserved across functions
366 Common Joined RejectNegative
367 -fcall-used-<register> Mark <register> as being corrupted by function calls
369 ; Nonzero for -fcaller-saves: allocate values in regs that need to
370 ; be saved across function calls, if that produces overall better code.
371 ; Optional now, so people can test it.
373 Common Report Var(flag_caller_saves) Optimization
374 Save registers around function calls
377 Common Report Var(flag_check_data_deps)
378 Compare the results of several data dependence analyzers.
381 Common Report Var(flag_no_common,0) Optimization
382 Do not put uninitialized globals in the common section
385 Common Report Var(flag_cprop_registers) Optimization
386 Perform a register copy-propagation optimization pass
389 Common Report Var(flag_crossjumping) Optimization
390 Perform cross-jumping optimization
393 Common Report Var(flag_cse_follow_jumps) Optimization
394 When running CSE, follow jumps to their targets
397 Common Report Var(flag_cse_skip_blocks) Optimization
398 When running CSE, follow conditional jumps
401 Common Report Var(flag_cx_limited_range) Optimization
402 Omit range reduction step when performing complex division
405 Common Report Var(flag_data_sections) Optimization
406 Place data items into their own section
410 List all available debugging counters with their limits and counts.
413 Common RejectNegative Joined
414 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
417 Common Joined RejectNegative
418 Map one directory name to another in debug information
420 ; Nonzero for -fdefer-pop: don't pop args after each function call
421 ; instead save them up to pop many calls' args with one insns.
423 Common Report Var(flag_defer_pop) Optimization
424 Defer popping functions args from stack until later
427 Common Report Var(flag_delayed_branch) Optimization
428 Attempt to fill delay slots of branch instructions
430 fdelete-null-pointer-checks
431 Common Report Var(flag_delete_null_pointer_checks) Optimization
432 Delete useless null pointer checks
434 fdiagnostics-show-location=
435 Common Joined RejectNegative
436 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
438 fdiagnostics-show-option
440 Amend appropriate diagnostic messages with the command line option that controls them
443 Common Joined RejectNegative
444 -fdump-<type> Dump various compiler internals to a file
447 Common Report Var(flag_dump_noaddr)
448 Suppress output of addresses in debugging dumps
451 Common Report Var(flag_dump_unnumbered) VarExists
452 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
455 Common Report Var(flag_early_inlining) Init(1) Optimization
456 Perform early inlining
458 feliminate-dwarf2-dups
459 Common Report Var(flag_eliminate_dwarf2_dups)
460 Perform DWARF2 duplicate elimination
462 feliminate-unused-debug-symbols
463 Common Report Var(flag_debug_only_used_symbols)
464 Perform unused type elimination in debug info
466 feliminate-unused-debug-types
467 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
468 Perform unused type elimination in debug info
470 femit-class-debug-always
471 Common Report Var(flag_emit_class_debug_always) Init(0)
472 Do not suppress C++ class debug information.
475 Common Report Var(flag_exceptions) Optimization
476 Enable exception handling
478 fexpensive-optimizations
479 Common Report Var(flag_expensive_optimizations) Optimization
480 Perform a number of minor, expensive optimizations
486 Common Report Var(flag_finite_math_only) Optimization
487 Assume no NaNs or infinities are generated
490 Common Joined RejectNegative
491 -ffixed-<register> Mark <register> as being unavailable to the compiler
494 Common Report Var(flag_float_store) Optimization
495 Don't allocate floats and doubles in extended-precision registers
499 Does nothing. Preserved for backward compatibility.
502 Common Report Var(flag_forward_propagate) Optimization
503 Perform a forward propagation pass on RTL
505 ; Nonzero means don't put addresses of constant functions in registers.
506 ; Used for compiling the Unix kernel, where strange substitutions are
507 ; done on the assembly output.
509 Common Report Var(flag_no_function_cse,0)
510 Allow function addresses to be held in registers
513 Common Report Var(flag_function_sections)
514 Place each function into its own section
517 Common Report Var(flag_gcse) Optimization
518 Perform global common subexpression elimination
521 Common Report Var(flag_gcse_lm) Init(1) Optimization
522 Perform enhanced load motion during global common subexpression elimination
525 Common Report Var(flag_gcse_sm) Init(0) Optimization
526 Perform store motion after global common subexpression elimination
529 Common Report Var(flag_gcse_las) Init(0) Optimization
530 Perform redundant load after store elimination in global common subexpression
534 Common Report Var(flag_gcse_after_reload) Optimization
535 Perform global common subexpression elimination after register allocation
538 fguess-branch-probability
539 Common Report Var(flag_guess_branch_prob) Optimization
540 Enable guessing of branch probabilities
542 ; Nonzero means ignore `#ident' directives. 0 means handle them.
543 ; Generate position-independent code for executables if possible
544 ; On SVR4 targets, it also controls whether or not to emit a
545 ; string identifying the compiler.
547 Common Report Var(flag_no_ident,0)
548 Process #ident directives
551 Common Report Var(flag_if_conversion) Optimization
552 Perform conversion of conditional jumps to branchless equivalents
555 Common Report Var(flag_if_conversion2) Optimization
556 Perform conversion of conditional jumps to conditional execution
558 ; -finhibit-size-directive inhibits output of .size for ELF.
559 ; This is used only for compiling crtstuff.c,
560 ; and it may be extended to other effects
561 ; needed for crtstuff.c on other systems.
562 finhibit-size-directive
563 Common Report Var(flag_inhibit_size_directive)
564 Do not generate .size directives
566 ; Nonzero means that functions declared `inline' will be treated
567 ; as `static'. Prevents generation of zillions of copies of unused
568 ; static inline functions; instead, `inlines' are written out
569 ; only when actually used. Used in conjunction with -g. Also
570 ; does the right thing with #pragma interface.
572 Common Report Var(flag_no_inline,0) Init(2)
573 Pay attention to the \"inline\" keyword
575 finline-small-functions
576 Common Report Var(flag_inline_small_functions) Optimization
577 Integrate simple functions into their callers when code size is known to not growth
580 Common Report Var(flag_inline_functions) Optimization
581 Integrate simple functions into their callers
583 finline-functions-called-once
584 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
585 Integrate functions called once into their callers
588 Common RejectNegative Joined UInteger
591 Common RejectNegative Joined UInteger
592 -finline-limit=<number> Limit the size of inlined functions to <number>
594 finstrument-functions
595 Common Report Var(flag_instrument_function_entry_exit)
596 Instrument function entry and exit with profiling calls
598 finstrument-functions-exclude-function-list=
599 Common RejectNegative Joined
600 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
602 finstrument-functions-exclude-file-list=
603 Common RejectNegative Joined
604 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
607 Common Report Var(flag_ipa_cp) Optimization
608 Perform Interprocedural constant propagation
611 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
612 Discover pure and const functions
615 Common Report Var(flag_ipa_pta) Init(0) Optimization
616 Perform interprocedural points-to analysis
619 Common Report Var(flag_ipa_reference) Init(0) Optimization
620 Discover readonly and non addressable static variables
623 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
624 Type based escape and alias analysis
627 Common Report Var(flag_ipa_matrix_reorg) Optimization
628 Perform matrix layout flattening and transposing based
629 on profiling information.
632 Common Report Var(flag_ipa_struct_reorg)
633 Perform structure layout optimizations based
634 on profiling information.
637 Common Report Var(flag_ivopts) Init(1) Optimization
638 Optimize induction variables on trees
641 Common Var(flag_jump_tables) Init(1) Optimization
642 Use jump tables for sufficiently large switch statements
644 fkeep-inline-functions
645 Common Report Var(flag_keep_inline_functions)
646 Generate code for functions even if they are fully inlined
649 Common Report Var(flag_keep_static_consts) Init(1)
650 Emit static const variables even if they are not used
653 Common Report Var(flag_leading_underscore) Init(-1)
654 Give external symbols a leading underscore
658 Does nothing. Preserved for backward compatibility.
661 Common Report Var(flag_errno_math) Init(1)
662 Set errno after built-in math functions
665 Common Report Var(mem_report)
666 Report on permanent memory allocation
668 ; This will attempt to merge constant section constants, if 1 only
669 ; string constants and constants from constant pool, if 2 also constant
672 Common Report Var(flag_merge_constants,2) Init(1) Optimization
673 Attempt to merge identical constants and constant variables
676 Common Report Var(flag_merge_constants,1) VarExists Optimization
677 Attempt to merge identical constants across compilation units
680 Common Report Var(flag_merge_debug_strings) Init(1)
681 Attempt to merge identical debug strings across compilation units
684 Common RejectNegative Joined UInteger
685 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
688 Common Report Var(flag_modulo_sched) Optimization
689 Perform SMS based modulo scheduling before the first scheduling pass
691 fmodulo-sched-allow-regmoves
692 Common Report Var(flag_modulo_sched_allow_regmoves)
693 Perform SMS based modulo scheduling with register moves allowed
695 fmove-loop-invariants
696 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
697 Move loop invariant computations out of loops
700 Common RejectNegative Report Var(flag_mudflap)
701 Add mudflap bounds-checking instrumentation for single-threaded program
704 Common RejectNegative Report VarExists Var(flag_mudflap,2)
705 Add mudflap bounds-checking instrumentation for multi-threaded program
708 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
709 Ignore read operations when inserting mudflap instrumentation
712 Common Var(flag_dce) Init(1) Optimization
713 Use the RTL dead code elimination pass
716 Common Var(flag_dse) Init(1) Optimization
717 Use the RTL dead store elimination pass
719 freschedule-modulo-scheduled-loops
720 Common Report Var(flag_resched_modulo_sched) Optimization
721 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
724 Common Report Var(flag_non_call_exceptions) Optimization
725 Support synchronous non-call exceptions
728 Common Report Var(flag_omit_frame_pointer) Optimization
729 When possible do not generate stack frames
732 Common Report Var(flag_openmp_ssa)
733 Expand OpenMP operations on SSA form
735 foptimize-register-move
736 Common Report Var(flag_regmove) Optimization
737 Do the full register move optimization pass
739 foptimize-sibling-calls
740 Common Report Var(flag_optimize_sibling_calls) Optimization
741 Optimize sibling and tail recursive calls
744 Common Report Var(pre_ipa_mem_report)
745 Report on memory allocation before interprocedural optimization
748 Common Report Var(post_ipa_mem_report)
749 Report on memory allocation before interprocedural optimization
752 Common Report Var(flag_pack_struct) Optimization
753 Pack structure members together without holes
756 Common RejectNegative Joined UInteger Optimization
757 -fpack-struct=<number> Set initial maximum structure member alignment
760 Common Report Var(flag_pcc_struct_return,1) VarExists
761 Return small aggregates in memory, not registers
764 Common Report Var(flag_peel_loops) Optimization
768 Common Report Var(flag_no_peephole,0) Optimization
769 Enable machine specific peephole optimizations
772 Common Report Var(flag_peephole2) Optimization
773 Enable an RTL peephole pass before sched2
776 Common Report Var(flag_pic,2)
777 Generate position-independent code if possible (large mode)
780 Common Report Var(flag_pie,2)
781 Generate position-independent code for executables if possible (large mode)
784 Common Report Var(flag_pic,1) VarExists
785 Generate position-independent code if possible (small mode)
788 Common Report Var(flag_pie,1) VarExists
789 Generate position-independent code for executables if possible (small mode)
791 fpredictive-commoning
792 Common Report Var(flag_predictive_commoning) Optimization
793 Run predictive commoning optimization.
795 fprefetch-loop-arrays
796 Common Report Var(flag_prefetch_loop_arrays) Optimization
797 Generate prefetch instructions, if available, for arrays in loops
800 Common Report Var(profile_flag)
801 Enable basic program profiling code
804 Common Report Var(profile_arc_flag)
805 Insert arc-based program profiling code
809 Enable common options for generating profile info for profile feedback directed optimizations
813 Enable common options for performing profile feedback directed optimizations
816 Common Report Var(flag_profile_values)
817 Insert code to profile values of expressions
823 Common Joined RejectNegative
824 -frandom-seed=<string> Make compile reproducible using <string>
826 ; This switch causes the command line that was used to create an
827 ; object file to be recorded into the object file. The exact format
828 ; of this recording is target and binary file format dependent.
829 ; It is related to the -fverbose-asm switch, but that switch only
830 ; records information in the assembler output file as comments, so
831 ; they never reach the object file.
833 Common Report Var(flag_record_gcc_switches)
834 Record gcc command line switches in the object file.
837 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
838 Return small aggregates in registers
841 Common Report Var(flag_regmove) Optimization
842 Enables a register move optimization
845 Common Report Var(flag_rename_registers) Init(2) Optimization
846 Perform a register renaming optimization pass
849 Common Report Var(flag_reorder_blocks) Optimization
850 Reorder basic blocks to improve code placement
852 freorder-blocks-and-partition
853 Common Report Var(flag_reorder_blocks_and_partition) Optimization
854 Reorder basic blocks and partition into hot and cold sections
857 Common Report Var(flag_reorder_functions) Optimization
858 Reorder functions to improve code placement
860 frerun-cse-after-loop
861 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
862 Add a common subexpression elimination pass after loop optimizations
866 Does nothing. Preserved for backward compatibility.
869 Common Report Var(flag_rounding_math) Optimization
870 Disable optimizations that assume default FP rounding behavior
873 Common Report Var(flag_schedule_interblock) Init(1) Optimization
874 Enable scheduling across basic blocks
877 Common Report Var(flag_schedule_speculative) Init(1) Optimization
878 Allow speculative motion of non-loads
881 Common Report Var(flag_schedule_speculative_load) Optimization
882 Allow speculative motion of some loads
884 fsched-spec-load-dangerous
885 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
886 Allow speculative motion of more loads
889 Common RejectNegative Joined
890 -fsched-verbose=<number> Set the verbosity level of the scheduler
892 fsched2-use-superblocks
893 Common Report Var(flag_sched2_use_superblocks) Optimization
894 If scheduling post reload, do superblock scheduling
897 Common Report Var(flag_sched2_use_traces) Optimization
898 If scheduling post reload, do trace scheduling
901 Common Report Var(flag_schedule_insns) Optimization
902 Reschedule instructions before register allocation
905 Common Report Var(flag_schedule_insns_after_reload) Optimization
906 Reschedule instructions after register allocation
908 ; sched_stalled_insns means that insns can be moved prematurely from the queue
909 ; of stalled insns into the ready list.
911 Common Report Var(flag_sched_stalled_insns) Optimization
912 Allow premature scheduling of queued insns
914 fsched-stalled-insns=
915 Common RejectNegative Joined UInteger
916 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
918 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
919 ; be examined for a dependency on a stalled insn that is candidate for
920 ; premature removal from the queue of stalled insns into the ready list (has
921 ; an effect only if the flag 'sched_stalled_insns' is set).
922 fsched-stalled-insns-dep
923 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
924 Set dependence distance checking in premature scheduling of queued insns
926 fsched-stalled-insns-dep=
927 Common RejectNegative Joined UInteger
928 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
931 Common Report Var(flag_section_anchors) Optimization
932 Access data in the same section from shared anchor points
934 frtl-abstract-sequences
935 Common Report Var(flag_rtl_seqabstr) Optimization
936 Perform sequence abstraction optimization on RTL
939 Common Report Var(flag_see) Init(0)
940 Eliminate redundant sign extensions using LCM.
943 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(0)
944 Show column numbers in diagnostics, when available. Default off
947 Common Report Var(flag_signaling_nans) Optimization
948 Disable optimizations observable by IEEE signaling NaNs
951 Common Report Var(flag_signed_zeros) Init(1) Optimization
952 Disable floating point optimizations that ignore the IEEE signedness of zero
954 fsingle-precision-constant
955 Common Report Var(flag_single_precision_constant) Optimization
956 Convert floating point constants to single precision constants
958 fsplit-ivs-in-unroller
959 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
960 Split lifetimes of induction variables when loops are unrolled
963 Common Report Var(flag_split_wide_types) Optimization
964 Split wide types into independent registers
966 fvariable-expansion-in-unroller
967 Common Report Var(flag_variable_expansion_in_unroller) Optimization
968 Apply variable expansion when loops are unrolled
970 ; Emit code to probe the stack, to help detect stack overflow; also
971 ; may cause large objects to be allocated dynamically.
973 Common Report Var(flag_stack_check)
974 Insert stack checking code into the program
979 fstack-limit-register=
980 Common RejectNegative Joined
981 -fstack-limit-register=<register> Trap if the stack goes past <register>
984 Common RejectNegative Joined
985 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
988 Common Report Var(flag_stack_protect, 1)
989 Use propolice as a stack protection method
992 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
993 Use a stack protection method for every function
997 Does nothing. Preserved for backward compatibility.
999 ; Nonzero if we should do (language-dependent) alias analysis.
1000 ; Typically, this analysis will assume that expressions of certain
1001 ; types do not alias expressions of certain other types. Only used
1002 ; if alias analysis (in general) is enabled.
1004 Common Report Var(flag_strict_aliasing) Optimization
1005 Assume strict aliasing rules apply
1008 Common Report Var(flag_strict_overflow)
1009 Treat signed overflow as undefined
1012 Common Report Var(flag_syntax_only)
1013 Check for syntax errors, then stop
1016 Common Report Var(flag_test_coverage)
1017 Create data files needed by \"gcov\"
1020 Common Report Var(flag_thread_jumps) Optimization
1021 Perform jump threading optimizations
1024 Common Report Var(time_report)
1025 Report the time taken by each compiler pass
1028 Common Joined RejectNegative
1029 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1032 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
1033 Reorder top level functions, variables, and asms
1036 Common Report Var(flag_tracer)
1037 Perform superblock formation via tail duplication
1039 ; Zero means that floating-point math operations cannot generate a
1040 ; (user-visible) trap. This is the case, for example, in nonstop
1041 ; IEEE 754 arithmetic.
1043 Common Report Var(flag_trapping_math) Init(1) Optimization
1044 Assume floating-point operations can trap
1047 Common Report Var(flag_trapv) Optimization
1048 Trap for signed overflow in addition, subtraction and multiplication
1051 Common Report Var(flag_tree_ccp) Optimization
1052 Enable SSA-CCP optimization on trees
1055 Common Report Var(flag_tree_store_ccp) Optimization
1056 Enable SSA-CCP optimization for stores and loads
1059 Common Report Var(flag_tree_ch) Optimization
1060 Enable loop header copying on trees
1063 Common Report Var(flag_tree_copyrename) Optimization
1064 Replace SSA temporaries with better names in copies
1067 Common Report Var(flag_tree_copy_prop) Optimization
1068 Enable copy propagation on trees
1070 ftree-store-copy-prop
1072 Does nothing. Preserved for backward compatibility.
1075 Common Report Var(flag_tree_cselim) Init(2) Optimization
1076 Transform condition stores into unconditional ones
1079 Common Report Var(flag_tree_dce) Optimization
1080 Enable SSA dead code elimination optimization on trees
1082 ftree-dominator-opts
1083 Common Report Var(flag_tree_dom) Optimization
1084 Enable dominator optimizations
1087 Common Report Var(flag_tree_dse) Optimization
1088 Enable dead store elimination
1091 Common Report Var(flag_tree_fre) Optimization
1092 Enable Full Redundancy Elimination (FRE) on trees
1095 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1096 Enable loop invariant motion on trees
1099 Common Report Var(flag_tree_loop_linear) Optimization
1100 Enable linear loop transforms on trees
1103 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1104 Create canonical induction variables in loops
1107 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1108 Enable loop optimizations on tree level
1110 ftree-parallelize-loops=
1111 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1112 Enable automatic parallelization of loops
1115 Common Report Var(flag_tree_pre) Optimization
1116 Enable SSA-PRE optimization on trees
1119 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1120 Enable reassociation on tree level
1123 Common Report Var(flag_tree_salias) Optimization
1124 Perform structural alias analysis
1127 Common Report Var(flag_tree_sink) Optimization
1128 Enable SSA code sinking on trees
1131 Common Report Var(flag_tree_sra) Optimization
1132 Perform scalar replacement of aggregates
1135 Common Report Var(flag_tree_ter) Optimization
1136 Replace temporary expressions in the SSA->normal pass
1139 Common Report Var(flag_tree_live_range_split) Optimization
1140 Perform live range splitting during the SSA->normal pass
1143 Common Report Var(flag_tree_vrp) Init(0) Optimization
1144 Perform Value Range Propagation on trees
1147 Common Report Var(flag_unit_at_a_time) Optimization
1148 Compile whole compilation unit at a time
1151 Common Report Var(flag_unroll_loops) Optimization
1152 Perform loop unrolling when iteration count is known
1155 Common Report Var(flag_unroll_all_loops) Optimization
1156 Perform loop unrolling for all loops
1158 ; Nonzero means that loop optimizer may assume that the induction variables
1159 ; that control loops do not overflow and that the loops with nontrivial
1160 ; exit condition are not infinite
1161 funsafe-loop-optimizations
1162 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1163 Allow loop optimizations to assume that the loops behave in normal way
1166 Common Report Var(flag_associative_math)
1167 Allow optimization for floating-point arithmetic which may change the
1168 result of the operation due to rounding.
1171 Common Report Var(flag_reciprocal_math)
1172 Same as -fassociative-math for expressions which include division.
1174 ; Nonzero means that unsafe floating-point math optimizations are allowed
1175 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1176 ; are allowed to assume that their arguments and results are "normal"
1177 ; (e.g., nonnegative for SQRT).
1178 funsafe-math-optimizations
1179 Common Report Var(flag_unsafe_math_optimizations) Optimization
1180 Allow math optimizations that may violate IEEE or ISO standards
1183 Common Report Var(flag_unswitch_loops) Optimization
1184 Perform loop unswitching
1187 Common Report Var(flag_unwind_tables) Optimization
1188 Just generate unwind tables for exception handling
1191 Common Report Var(flag_var_tracking) VarExists Optimization
1192 Perform variable tracking
1194 fvar-tracking-uninit
1195 Common Report Var(flag_var_tracking_uninit) Optimization
1196 Perform variable tracking and also tag variables that are uninitialized
1199 Common Report Var(flag_tree_vectorize) Optimization
1200 Enable loop vectorization on trees
1203 Common Report Var(flag_vect_cost_model) Optimization
1204 Enable use of cost model in vectorization
1206 ftree-vect-loop-version
1207 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1208 Enable loop versioning when doing loop vectorization on trees
1210 ftree-vectorizer-verbose=
1211 Common RejectNegative Joined
1212 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1215 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1216 Enable copy propagation of scalar-evolution information.
1218 ; -fverbose-asm causes extra commentary information to be produced in
1219 ; the generated assembly code (to make it more readable). This option
1220 ; is generally only of use to those who actually need to read the
1221 ; generated assembly code (perhaps while debugging the compiler itself).
1222 ; -fno-verbose-asm, the default, causes the extra information
1223 ; to not be added and is useful when comparing two assembler files.
1225 Common Report Var(flag_verbose_asm)
1226 Add extra commentary to assembler output
1229 Common Joined RejectNegative
1230 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1234 Common Report Var(flag_value_profile_transformations) Optimization
1235 Use expression value profiles in optimizations
1238 Common Report Var(flag_web) Init(2) Optimization
1239 Construct webs and split unrelated uses of single variable
1242 Common Report Var(flag_whole_program) Init(0) Optimization
1243 Perform whole program optimizations
1246 Common Report Var(flag_wrapv) Optimization
1247 Assume signed arithmetic overflow wraps around
1249 fzero-initialized-in-bss
1250 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1251 Put zero initialized data in the bss section
1254 Common JoinedOrMissing
1255 Generate debug information in default format
1258 Common JoinedOrMissing Negative(gdwarf-2)
1259 Generate debug information in COFF format
1262 Common JoinedOrMissing Negative(gstabs)
1263 Generate debug information in DWARF v2 format
1266 Common JoinedOrMissing
1267 Generate debug information in default extended format
1270 Common JoinedOrMissing Negative(gstabs+)
1271 Generate debug information in STABS format
1274 Common JoinedOrMissing Negative(gvms)
1275 Generate debug information in extended STABS format
1278 Common JoinedOrMissing Negative(gxcoff)
1279 Generate debug information in VMS format
1282 Common JoinedOrMissing Negative(gxcoff+)
1283 Generate debug information in XCOFF format
1286 Common JoinedOrMissing Negative(gcoff)
1287 Generate debug information in extended XCOFF format
1290 Common Joined Separate
1291 -o <file> Place output into <file>
1294 Common Var(profile_flag)
1295 Enable function profiling
1298 Common Var(pedantic)
1299 Issue warnings needed for strict compliance to the standard
1303 Like -pedantic but issue them as errors
1306 Common Var(quiet_flag)
1307 Do not display functions compiled or elapsed time
1310 Common Var(version_flag)
1311 Display the compiler's version
1314 Common Var(inhibit_warnings)
1318 Common RejectNegative Negative(pie)
1319 Create a shared library
1322 Common RejectNegative Negative(shared)
1323 Create a position independent executable
1325 ; This comment is to ensure we retain the blank line above.