1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
5 ; This file is part of GCC.
7 ; GCC is free software; you can redistribute it and/or modify it under
8 ; the terms of the GNU General Public License as published by the Free
9 ; Software Foundation; either version 2, or (at your option) any later
12 ; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 ; WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 ; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 ; You should have received a copy of the GNU General Public License
18 ; along with GCC; see the file COPYING. If not, write to the Free
19 ; Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
22 ; See the GCC internals manual 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 Var(warn_inline) Warning
115 Warn when an inlined function cannot be inlined
118 Common RejectNegative Joined UInteger Warning
119 -Wlarger-than-<number> Warn if an object is larger than <number> bytes
122 Common Warning Var(warn_logical_op)
123 Warn when a logical operator is suspicously always evaluating to true or false
125 Wunsafe-loop-optimizations
126 Common Var(warn_unsafe_loop_optimizations) Warning
127 Warn if the loop cannot be optimized due to nontrivial assumptions.
130 Common Var(warn_missing_noreturn) Warning
131 Warn about functions which might be candidates for __attribute__((noreturn))
134 Common Var(warn_overflow) Init(1) Warning
135 Warn about overflow in arithmetic expressions
138 Common Var(warn_packed) Warning
139 Warn when the packed attribute has no effect on struct layout
142 Common Var(warn_padded) Warning
143 Warn when padding is required to align structure members
146 Common Var(warn_shadow) Warning
147 Warn when one local variable shadows another
150 Common Var(warn_stack_protect) Warning
151 Warn when not issuing stack smashing protection for some reason
155 Warn about code which might break strict aliasing rules
158 Common Joined UInteger Warning
159 Warn about code which might break strict aliasing rules
163 Warn about optimizations that assume that signed overflow is undefined
166 Common Joined UInteger Warning
167 Warn about optimizations that assume that signed overflow is undefined
170 Common Var(warn_switch) Warning
171 Warn about enumerated switches, with no default, missing a case
174 Common Var(warn_switch_default) Warning
175 Warn about enumerated switches missing a \"default:\" statement
178 Common Var(warn_switch_enum) Warning
179 Warn about all enumerated switches missing a specific case
182 Common Var(warn_system_headers) Warning
183 Do not suppress warnings from system headers
186 Common Var(warn_uninitialized) Warning
187 Warn about uninitialized automatic variables
190 Common Var(warn_notreached) Warning
191 Warn about code that will never be executed
195 Enable all -Wunused- warnings
198 Common Var(warn_unused_function) Warning
199 Warn when a function is unused
202 Common Var(warn_unused_label) Warning
203 Warn when a label is unused
206 Common Var(warn_unused_parameter) Warning
207 Warn when a function parameter is unused
210 Common Var(warn_unused_value) Warning
211 Warn when an expression value is unused
214 Common Var(warn_unused_variable) Warning
215 Warn when a variable is unused
217 Wvolatile-register-var
218 Common Var(warn_register_var) Warning
219 Warn when a register variable is declared volatile
222 Common RejectNegative Var(warn_coverage_mismatch) Warning
223 Warn instead of error in case profiles in -fprofile-use do not match
227 -aux-info <file> Emit declaration information into <file>
240 -d<letters> Enable dumps from specific passes of the compiler
244 -dumpbase <file> Set the file basename to be used for dumps
246 ; The version of the C++ ABI in use. The following values are allowed:
248 ; 0: The version of the ABI believed most conformant with the C++ ABI
249 ; specification. This ABI may change as bugs are discovered and fixed.
250 ; Therefore, 0 will not necessarily indicate the same ABI in different
253 ; 1: The version of the ABI first used in G++ 3.2.
255 ; Additional positive integers will be assigned as new versions of
256 ; the ABI become the default version of the ABI.
258 Common Joined UInteger Var(flag_abi_version) Init(2)
261 Common Report Var(align_functions,0)
262 Align the start of functions
265 Common RejectNegative Joined UInteger
268 Common Report Var(align_jumps,0) Optimization
269 Align labels which are only reached by jumping
272 Common RejectNegative Joined UInteger
275 Common Report Var(align_labels,0) Optimization
279 Common RejectNegative Joined UInteger
282 Common Report Var(align_loops) Optimization
283 Align the start of loops
286 Common RejectNegative Joined UInteger
288 ; This flag is only tested if alias checking is enabled.
289 ; 0 if pointer arguments may alias each other. True in C.
290 ; 1 if pointer arguments may not alias each other but may alias
292 ; 2 if pointer arguments may not alias each other and may not
293 ; alias global variables.
294 ; 3 if pointer arguments may not alias anything. True in Fortran.
295 ; Set by the front end.
297 Common Report Var(flag_argument_noalias,0) Optimization
298 Specify that arguments may alias each other and globals
301 Common Report Var(flag_argument_noalias,1) VarExists Optimization
302 Assume arguments may alias globals but not each other
304 fargument-noalias-global
305 Common Report Var(flag_argument_noalias,2) VarExists Optimization
306 Assume arguments alias neither each other nor globals
308 fargument-noalias-anything
309 Common Report Var(flag_argument_noalias,3) VarExists Optimization
310 Assume arguments alias no other storage
312 fasynchronous-unwind-tables
313 Common Report Var(flag_asynchronous_unwind_tables) Optimization
314 Generate unwind tables that are exact at each instruction boundary
316 ; -fcheck-bounds causes gcc to generate array bounds checks.
317 ; For C, C++ and ObjC: defaults off.
318 ; For Java: defaults to on.
319 ; For Fortran: defaults to off.
321 Common Report Var(flag_bounds_check)
322 Generate code to check bounds before indexing arrays
325 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
326 Replace add, compare, branch with branch on count register
328 fbranch-probabilities
329 Common Report Var(flag_branch_probabilities) Optimization
330 Use profiling information for branch probabilities
332 fbranch-target-load-optimize
333 Common Report Var(flag_branch_target_load_optimize) Optimization
334 Perform branch target load optimization before prologue / epilogue threading
336 fbranch-target-load-optimize2
337 Common Report Var(flag_branch_target_load_optimize2) Optimization
338 Perform branch target load optimization after prologue / epilogue threading
341 Common Report Var(flag_btr_bb_exclusive) Optimization
342 Restrict target load migration not to re-use registers in any basic block
345 Common Joined RejectNegative
346 -fcall-saved-<register> Mark <register> as being preserved across functions
349 Common Joined RejectNegative
350 -fcall-used-<register> Mark <register> as being corrupted by function calls
352 ; Nonzero for -fcaller-saves: allocate values in regs that need to
353 ; be saved across function calls, if that produces overall better code.
354 ; Optional now, so people can test it.
356 Common Report Var(flag_caller_saves) Optimization
357 Save registers around function calls
360 Common Report Var(flag_check_data_deps)
361 Compare the results of several data dependence analyzers.
364 Common Report Var(flag_no_common,0) Optimization
365 Do not put uninitialized globals in the common section
368 Common Report Var(flag_cprop_registers) Optimization
369 Perform a register copy-propagation optimization pass
372 Common Report Var(flag_crossjumping) Optimization
373 Perform cross-jumping optimization
376 Common Report Var(flag_cse_follow_jumps) Optimization
377 When running CSE, follow jumps to their targets
380 Common Report Var(flag_cse_skip_blocks) Optimization
381 When running CSE, follow conditional jumps
384 Common Report Var(flag_cx_limited_range) Optimization
385 Omit range reduction step when performing complex division
388 Common Report Var(flag_data_sections) Optimization
389 Place data items into their own section
391 ; Nonzero for -fdefer-pop: don't pop args after each function call
392 ; instead save them up to pop many calls' args with one insns.
394 Common Report Var(flag_defer_pop) Optimization
395 Defer popping functions args from stack until later
398 Common Report Var(flag_delayed_branch) Optimization
399 Attempt to fill delay slots of branch instructions
401 fdelete-null-pointer-checks
402 Common Report Var(flag_delete_null_pointer_checks) Optimization
403 Delete useless null pointer checks
405 fdiagnostics-show-location=
406 Common Joined RejectNegative
407 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
409 fdiagnostics-show-option
411 Amend appropriate diagnostic messages with the command line option that controls them
414 Common Joined RejectNegative
415 -fdump-<type> Dump various compiler internals to a file
418 Common Report Var(flag_dump_noaddr)
419 Suppress output of addresses in debugging dumps
422 Common Report Var(flag_dump_unnumbered) VarExists
423 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
426 Common Report Var(flag_early_inlining) Init(1) Optimization
427 Perform early inlining
429 feliminate-dwarf2-dups
430 Common Report Var(flag_eliminate_dwarf2_dups)
431 Perform DWARF2 duplicate elimination
433 feliminate-unused-debug-symbols
434 Common Report Var(flag_debug_only_used_symbols)
435 Perform unused type elimination in debug info
437 feliminate-unused-debug-types
438 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
439 Perform unused type elimination in debug info
441 femit-class-debug-always
442 Common Report Var(flag_emit_class_debug_always) Init(1)
443 Do not suppress C++ class debug information.
446 Common Report Var(flag_exceptions) Optimization
447 Enable exception handling
449 fexpensive-optimizations
450 Common Report Var(flag_expensive_optimizations) Optimization
451 Perform a number of minor, expensive optimizations
457 Common Report Var(flag_finite_math_only) Optimization
458 Assume no NaNs or infinities are generated
461 Common Joined RejectNegative
462 -ffixed-<register> Mark <register> as being unavailable to the compiler
465 Common Report Var(flag_float_store) Optimization
466 Don't allocate floats and doubles in extended-precision registers
468 ; Nonzero for -fforce-addr: load memory address into a register before
469 ; reference to memory. This makes better cse but slower compilation.
471 Common Report Var(flag_force_addr) Optimization
472 Copy memory address constants into registers before use
475 Common Report Var(flag_forward_propagate) Optimization
476 Perform a forward propagation pass on RTL
478 ; Nonzero means don't put addresses of constant functions in registers.
479 ; Used for compiling the Unix kernel, where strange substitutions are
480 ; done on the assembly output.
482 Common Report Var(flag_no_function_cse,0)
483 Allow function addresses to be held in registers
486 Common Report Var(flag_function_sections)
487 Place each function into its own section
490 Common Report Var(flag_gcse) Optimization
491 Perform global common subexpression elimination
494 Common Report Var(flag_gcse_lm) Init(1) Optimization
495 Perform enhanced load motion during global common subexpression elimination
498 Common Report Var(flag_gcse_sm) Init(0) Optimization
499 Perform store motion after global common subexpression elimination
502 Common Report Var(flag_gcse_las) Init(0) Optimization
503 Perform redundant load after store elimination in global common subexpression
507 Common Report Var(flag_gcse_after_reload) Optimization
508 Perform global common subexpression elimination after register allocation
511 fguess-branch-probability
512 Common Report Var(flag_guess_branch_prob) Optimization
513 Enable guessing of branch probabilities
515 ; Nonzero means ignore `#ident' directives. 0 means handle them.
516 ; Generate position-independent code for executables if possible
517 ; On SVR4 targets, it also controls whether or not to emit a
518 ; string identifying the compiler.
520 Common Report Var(flag_no_ident,0)
521 Process #ident directives
524 Common Report Var(flag_if_conversion) Optimization
525 Perform conversion of conditional jumps to branchless equivalents
528 Common Report Var(flag_if_conversion2) Optimization
529 Perform conversion of conditional jumps to conditional execution
531 ; -finhibit-size-directive inhibits output of .size for ELF.
532 ; This is used only for compiling crtstuff.c,
533 ; and it may be extended to other effects
534 ; needed for crtstuff.c on other systems.
535 finhibit-size-directive
536 Common Report Var(flag_inhibit_size_directive)
537 Do not generate .size directives
539 ; Nonzero means that functions declared `inline' will be treated
540 ; as `static'. Prevents generation of zillions of copies of unused
541 ; static inline functions; instead, `inlines' are written out
542 ; only when actually used. Used in conjunction with -g. Also
543 ; does the right thing with #pragma interface.
545 Common Report Var(flag_no_inline,0) Init(2)
546 Pay attention to the \"inline\" keyword
549 Common Report Var(flag_inline_functions) Optimization
550 Integrate simple functions into their callers
552 finline-functions-called-once
553 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
554 Integrate functions called once into their callers
557 Common RejectNegative Joined UInteger
560 Common RejectNegative Joined UInteger
561 -finline-limit=<number> Limit the size of inlined functions to <number>
563 finstrument-functions
564 Common Report Var(flag_instrument_function_entry_exit)
565 Instrument function entry and exit with profiling calls
568 Common Report Var(flag_ipa_cp) Optimization
569 Perform Interprocedural constant propagation
572 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
573 Discover pure and const functions
576 Common Report Var(flag_ipa_pta) Init(0) Optimization
577 Perform interprocedural points-to analysis
580 Common Report Var(flag_ipa_reference) Init(0) Optimization
581 Discover readonly and non addressable static variables
584 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
585 Type based escape and alias analysis
588 Common Report Var(flag_ivopts) Init(1) Optimization
589 Optimize induction variables on trees
592 Common Var(flag_jump_tables) Init(1) Optimization
593 Use jump tables for sufficiently large switch statements
595 fkeep-inline-functions
596 Common Report Var(flag_keep_inline_functions)
597 Generate code for functions even if they are fully inlined
600 Common Report Var(flag_keep_static_consts) Init(1)
601 Emit static const variables even if they are not used
604 Common Report Var(flag_leading_underscore) Init(-1)
605 Give external symbols a leading underscore
609 Does nothing. Preserved for backward compatibility.
612 Common Report Var(flag_errno_math) Init(1)
613 Set errno after built-in math functions
616 Common Report Var(mem_report)
617 Report on permanent memory allocation
619 ; This will attempt to merge constant section constants, if 1 only
620 ; string constants and constants from constant pool, if 2 also constant
623 Common Report Var(flag_merge_constants,2) Init(1) Optimization
624 Attempt to merge identical constants and constant variables
627 Common Report Var(flag_merge_constants,1) VarExists Optimization
628 Attempt to merge identical constants across compilation units
631 Common RejectNegative Joined UInteger
632 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
635 Common Report Var(flag_modulo_sched) Optimization
636 Perform SMS based modulo scheduling before the first scheduling pass
638 fmove-loop-invariants
639 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
640 Move loop invariant computations out of loops
643 Common RejectNegative Report Var(flag_mudflap)
644 Add mudflap bounds-checking instrumentation for single-threaded program
647 Common RejectNegative Report VarExists Var(flag_mudflap,2)
648 Add mudflap bounds-checking instrumentation for multi-threaded program
651 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
652 Ignore read operations when inserting mudflap instrumentation
654 freschedule-modulo-scheduled-loops
655 Common Report Var(flag_resched_modulo_sched) Optimization
656 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
659 Common Report Var(flag_non_call_exceptions) Optimization
660 Support synchronous non-call exceptions
663 Common Report Var(flag_omit_frame_pointer) Optimization
664 When possible do not generate stack frames
666 foptimize-register-move
667 Common Report Var(flag_regmove) Optimization
668 Do the full register move optimization pass
670 foptimize-sibling-calls
671 Common Report Var(flag_optimize_sibling_calls) Optimization
672 Optimize sibling and tail recursive calls
675 Common Report Var(pre_ipa_mem_report)
676 Report on memory allocation before interprocedural optimization
679 Common Report Var(post_ipa_mem_report)
680 Report on memory allocation before interprocedural optimization
683 Common Report Var(flag_pack_struct) Optimization
684 Pack structure members together without holes
687 Common RejectNegative Joined UInteger Optimization
688 -fpack-struct=<number> Set initial maximum structure member alignment
691 Common Report Var(flag_pcc_struct_return,1) VarExists
692 Return small aggregates in memory, not registers
695 Common Report Var(flag_peel_loops) Optimization
699 Common Report Var(flag_no_peephole,0) Optimization
700 Enable machine specific peephole optimizations
703 Common Report Var(flag_peephole2) Optimization
704 Enable an RTL peephole pass before sched2
707 Common Report Var(flag_pic,2)
708 Generate position-independent code if possible (large mode)
711 Common Report Var(flag_pie,2)
712 Generate position-independent code for executables if possible (large mode)
715 Common Report Var(flag_pic,1) VarExists
716 Generate position-independent code if possible (small mode)
719 Common Report Var(flag_pie,1) VarExists
720 Generate position-independent code for executables if possible (small mode)
722 fprefetch-loop-arrays
723 Common Report Var(flag_prefetch_loop_arrays) Optimization
724 Generate prefetch instructions, if available, for arrays in loops
727 Common Report Var(profile_flag)
728 Enable basic program profiling code
731 Common Report Var(profile_arc_flag)
732 Insert arc-based program profiling code
736 Enable common options for generating profile info for profile feedback directed optimizations
740 Enable common options for performing profile feedback directed optimizations
743 Common Report Var(flag_profile_values)
744 Insert code to profile values of expressions
750 Common Joined RejectNegative
751 -frandom-seed=<string> Make compile reproducible using <string>
753 ; This switch causes the command line that was used to create an
754 ; object file to be recorded into the object file. The exact format
755 ; of this recording is target and binary file format dependent.
756 ; It is related to the -fverbose-asm switch, but that switch only
757 ; records information in the assembler output file as comments, so
758 ; they never reach the object file.
760 Common Report Var(flag_record_gcc_switches)
761 Record gcc command line switches in the object file.
764 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
765 Return small aggregates in registers
768 Common Report Var(flag_regmove) Optimization
769 Enables a register move optimization
772 Common Report Var(flag_rename_registers) Init(2) Optimization
773 Perform a register renaming optimization pass
776 Common Report Var(flag_reorder_blocks) Optimization
777 Reorder basic blocks to improve code placement
779 freorder-blocks-and-partition
780 Common Report Var(flag_reorder_blocks_and_partition) Optimization
781 Reorder basic blocks and partition into hot and cold sections
784 Common Report Var(flag_reorder_functions) Optimization
785 Reorder functions to improve code placement
787 frerun-cse-after-loop
788 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
789 Add a common subexpression elimination pass after loop optimizations
793 Does nothing. Preserved for backward compatibility.
796 Common Report Var(flag_rounding_math) Optimization
797 Disable optimizations that assume default FP rounding behavior
800 Common Report Var(flag_schedule_interblock) Init(1) Optimization
801 Enable scheduling across basic blocks
804 Common Report Var(flag_schedule_speculative) Init(1) Optimization
805 Allow speculative motion of non-loads
808 Common Report Var(flag_schedule_speculative_load) Optimization
809 Allow speculative motion of some loads
811 fsched-spec-load-dangerous
812 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
813 Allow speculative motion of more loads
816 Common RejectNegative Joined
817 -fsched-verbose=<number> Set the verbosity level of the scheduler
819 fsched2-use-superblocks
820 Common Report Var(flag_sched2_use_superblocks) Optimization
821 If scheduling post reload, do superblock scheduling
824 Common Report Var(flag_sched2_use_traces) Optimization
825 If scheduling post reload, do trace scheduling
828 Common Report Var(flag_schedule_insns) Optimization
829 Reschedule instructions before register allocation
832 Common Report Var(flag_schedule_insns_after_reload) Optimization
833 Reschedule instructions after register allocation
835 ; sched_stalled_insns means that insns can be moved prematurely from the queue
836 ; of stalled insns into the ready list.
838 Common Report Var(flag_sched_stalled_insns) Optimization
839 Allow premature scheduling of queued insns
841 fsched-stalled-insns=
842 Common RejectNegative Joined UInteger
843 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
845 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
846 ; be examined for a dependency on a stalled insn that is candidate for
847 ; premature removal from the queue of stalled insns into the ready list (has
848 ; an effect only if the flag 'sched_stalled_insns' is set).
849 fsched-stalled-insns-dep
850 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
851 Set dependence distance checking in premature scheduling of queued insns
853 fsched-stalled-insns-dep=
854 Common RejectNegative Joined UInteger
855 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
858 Common Report Var(flag_section_anchors) Optimization
859 Access data in the same section from shared anchor points
861 frtl-abstract-sequences
862 Common Report Var(flag_rtl_seqabstr) Optimization
863 Perform sequence abstraction optimization on RTL
866 Common Report Var(flag_see) Init(0)
867 Eliminate redundant sign extensions using LCM.
870 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
871 Show column numbers in diagnostics, when available. Default on
874 Common Report Var(flag_signaling_nans) Optimization
875 Disable optimizations observable by IEEE signaling NaNs
878 Common Report Var(flag_signed_zeros) Init(1) Optimization
879 Disable floating point optimizations that ignore the IEEE signedness of zero
881 fsingle-precision-constant
882 Common Report Var(flag_single_precision_constant) Optimization
883 Convert floating point constants to single precision constants
885 fsplit-ivs-in-unroller
886 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
887 Split lifetimes of induction variables when loops are unrolled
890 Common Report Var(flag_split_wide_types) Optimization
891 Split wide types into independent registers
893 fvariable-expansion-in-unroller
894 Common Report Var(flag_variable_expansion_in_unroller) Optimization
895 Apply variable expansion when loops are unrolled
897 ; Emit code to probe the stack, to help detect stack overflow; also
898 ; may cause large objects to be allocated dynamically.
900 Common Report Var(flag_stack_check)
901 Insert stack checking code into the program
906 fstack-limit-register=
907 Common RejectNegative Joined
908 -fstack-limit-register=<register> Trap if the stack goes past <register>
911 Common RejectNegative Joined
912 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
915 Common Report Var(flag_stack_protect, 1)
916 Use propolice as a stack protection method
919 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
920 Use a stack protection method for every function
924 Does nothing. Preserved for backward compatibility.
926 ; Nonzero if we should do (language-dependent) alias analysis.
927 ; Typically, this analysis will assume that expressions of certain
928 ; types do not alias expressions of certain other types. Only used
929 ; if alias analysis (in general) is enabled.
931 Common Report Var(flag_strict_aliasing) Optimization
932 Assume strict aliasing rules apply
935 Common Report Var(flag_strict_overflow)
936 Treat signed overflow as undefined
939 Common Report Var(flag_syntax_only)
940 Check for syntax errors, then stop
943 Common Report Var(flag_test_coverage)
944 Create data files needed by \"gcov\"
947 Common Report Var(flag_thread_jumps) Optimization
948 Perform jump threading optimizations
951 Common Report Var(time_report)
952 Report the time taken by each compiler pass
955 Common Joined RejectNegative
956 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
959 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
960 Reorder top level functions, variables, and asms
963 Common Report Var(flag_tracer)
964 Perform superblock formation via tail duplication
966 ; Zero means that floating-point math operations cannot generate a
967 ; (user-visible) trap. This is the case, for example, in nonstop
968 ; IEEE 754 arithmetic.
970 Common Report Var(flag_trapping_math) Init(1) Optimization
971 Assume floating-point operations can trap
974 Common Report Var(flag_trapv) Optimization
975 Trap for signed overflow in addition, subtraction and multiplication
978 Common Report Var(flag_tree_ccp) Optimization
979 Enable SSA-CCP optimization on trees
982 Common Report Var(flag_tree_store_ccp) Optimization
983 Enable SSA-CCP optimization for stores and loads
986 Common Report Var(flag_tree_ch) Optimization
987 Enable loop header copying on trees
990 Common Report Var(flag_tree_copyrename) Optimization
991 Replace SSA temporaries with better names in copies
994 Common Report Var(flag_tree_copy_prop) Optimization
995 Enable copy propagation on trees
997 ftree-store-copy-prop
998 Common Report Var(flag_tree_store_copy_prop) Optimization
999 Enable copy propagation for stores and loads
1002 Common Report Var(flag_tree_dce) Optimization
1003 Enable SSA dead code elimination optimization on trees
1005 ftree-dominator-opts
1006 Common Report Var(flag_tree_dom) Optimization
1007 Enable dominator optimizations
1010 Common Report Var(flag_tree_dse) Optimization
1011 Enable dead store elimination
1014 Common Report Var(flag_tree_fre) Optimization
1015 Enable Full Redundancy Elimination (FRE) on trees
1018 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1019 Enable loop invariant motion on trees
1022 Common Report Var(flag_tree_loop_linear) Optimization
1023 Enable linear loop transforms on trees
1026 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1027 Create canonical induction variables in loops
1030 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1031 Enable loop optimizations on tree level
1034 Common Report Var(flag_tree_pre) Optimization
1035 Enable SSA-PRE optimization on trees
1038 Common Report Var(flag_tree_salias) Optimization
1039 Perform structural alias analysis
1042 Common Report Var(flag_tree_sink) Optimization
1043 Enable SSA code sinking on trees
1046 Common Report Var(flag_tree_sra) Optimization
1047 Perform scalar replacement of aggregates
1050 Common Report Var(flag_tree_ter) Optimization
1051 Replace temporary expressions in the SSA->normal pass
1054 Common Report Var(flag_tree_live_range_split) Optimization
1055 Perform live range splitting during the SSA->normal pass
1058 Common Report Var(flag_tree_vrp) Init(0) Optimization
1059 Perform Value Range Propagation on trees
1062 Common Report Var(flag_unit_at_a_time) Optimization
1063 Compile whole compilation unit at a time
1066 Common Report Var(flag_unroll_loops) Optimization
1067 Perform loop unrolling when iteration count is known
1070 Common Report Var(flag_unroll_all_loops) Optimization
1071 Perform loop unrolling for all loops
1073 ; Nonzero means that loop optimizer may assume that the induction variables
1074 ; that control loops do not overflow and that the loops with nontrivial
1075 ; exit condition are not infinite
1076 funsafe-loop-optimizations
1077 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1078 Allow loop optimizations to assume that the loops behave in normal way
1080 ; Nonzero means that unsafe floating-point math optimizations are allowed
1081 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1082 ; are allowed to assume that their arguments and results are "normal"
1083 ; (e.g., nonnegative for SQRT).
1084 funsafe-math-optimizations
1085 Common Report Var(flag_unsafe_math_optimizations) Optimization
1086 Allow math optimizations that may violate IEEE or ISO standards
1089 Common Report Var(flag_unswitch_loops) Optimization
1090 Perform loop unswitching
1093 Common Report Var(flag_unwind_tables) Optimization
1094 Just generate unwind tables for exception handling
1097 Common Report Var(flag_var_tracking) VarExists Optimization
1098 Perform variable tracking
1101 Common Report Var(flag_tree_vectorize) Optimization
1102 Enable loop vectorization on trees
1104 ftree-vect-loop-version
1105 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1106 Enable loop versioning when doing loop vectorization on trees
1108 ftree-vectorizer-verbose=
1109 Common RejectNegative Joined
1110 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1113 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1114 Enable copy propagation of scalar-evolution information.
1116 ; -fverbose-asm causes extra commentary information to be produced in
1117 ; the generated assembly code (to make it more readable). This option
1118 ; is generally only of use to those who actually need to read the
1119 ; generated assembly code (perhaps while debugging the compiler itself).
1120 ; -fno-verbose-asm, the default, causes the extra information
1121 ; to not be added and is useful when comparing two assembler files.
1123 Common Report Var(flag_verbose_asm)
1124 Add extra commentary to assembler output
1127 Common Joined RejectNegative
1128 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1132 Common Report Var(flag_value_profile_transformations) Optimization
1133 Use expression value profiles in optimizations
1136 Common Report Var(flag_web) Init(2) Optimization
1137 Construct webs and split unrelated uses of single variable
1140 Common Report Var(flag_whole_program) Init(0) Optimization
1141 Perform whole program optimizations
1144 Common Report Var(flag_wrapv) Optimization
1145 Assume signed arithmetic overflow wraps around
1147 fzero-initialized-in-bss
1148 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1149 Put zero initialized data in the bss section
1152 Common JoinedOrMissing
1153 Generate debug information in default format
1156 Common JoinedOrMissing Negative(gdwarf-2)
1157 Generate debug information in COFF format
1160 Common JoinedOrMissing Negative(gstabs)
1161 Generate debug information in DWARF v2 format
1164 Common JoinedOrMissing
1165 Generate debug information in default extended format
1168 Common JoinedOrMissing Negative(gstabs+)
1169 Generate debug information in STABS format
1172 Common JoinedOrMissing Negative(gvms)
1173 Generate debug information in extended STABS format
1176 Common JoinedOrMissing Negative(gxcoff)
1177 Generate debug information in VMS format
1180 Common JoinedOrMissing Negative(gxcoff+)
1181 Generate debug information in XCOFF format
1184 Common JoinedOrMissing Negative(gcoff)
1185 Generate debug information in extended XCOFF format
1188 Common Joined Separate
1189 -o <file> Place output into <file>
1192 Common Var(profile_flag)
1193 Enable function profiling
1196 Common Var(pedantic)
1197 Issue warnings needed for strict compliance to the standard
1201 Like -pedantic but issue them as errors
1204 Common Var(quiet_flag)
1205 Do not display functions compiled or elapsed time
1208 Common Var(version_flag)
1209 Display the compiler's version
1212 Common Var(inhibit_warnings)
1215 ; This comment is to ensure we retain the blank line above.