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 3, 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 COPYING3. If not see
19 ; <http://www.gnu.org/licenses/>.
21 ; See the GCC internals manual for a description of this file's format.
23 ; Please try to keep this file in ASCII collating order.
27 Display this information
31 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params
35 Alias for --help=target
37 ;; The following three entries are to work around the gcc driver
38 ;; program's insatiable desire to turn options starting with a
39 ;; double dash (--) into options starting with a dash f (-f).
51 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
57 Common Joined Separate UInteger
58 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
61 Common JoinedOrMissing
62 -O<number> Set optimization level to <number>
66 Optimize for space rather than speed
70 This switch is deprecated; use -Wextra instead
73 Common Var(warn_aggregate_return) Warning
74 Warn about returning structures, unions or arrays
77 Common Var(warn_array_bounds) Warning
78 Warn if an array is accessed out of bounds
81 Common Var(warn_attributes) Init(1) Warning
82 Warn about inappropriate attribute usage
85 Common Var(warn_cast_align) Warning
86 Warn about pointer casts which increase alignment
88 Wdeprecated-declarations
89 Common Var(warn_deprecated_decl) Init(1) Warning
90 Warn about uses of __attribute__((deprecated)) declarations
92 Wdisabled-optimization
93 Common Var(warn_disabled_optimization) Warning
94 Warn when an optimization pass is disabled
97 Common Var(warnings_are_errors)
98 Treat all warnings as errors
102 Treat specified warning as error
106 Print extra (possibly unwanted) warnings
109 Common Var(flag_fatal_errors)
110 Exit on the first error occurred
113 Common Var(warn_inline) Warning
114 Warn when an inlined function cannot be inlined
117 Common RejectNegative Joined UInteger Warning
118 -Wlarger-than-<number> Warn if an object is larger than <number> bytes
121 Common Warning Var(warn_logical_op)
122 Warn when a logical operator is suspicously always evaluating to true or false
124 Wunsafe-loop-optimizations
125 Common Var(warn_unsafe_loop_optimizations) Warning
126 Warn if the loop cannot be optimized due to nontrivial assumptions.
129 Common Var(warn_missing_noreturn) Warning
130 Warn about functions which might be candidates for __attribute__((noreturn))
133 Common Var(warn_overflow) Init(1) Warning
134 Warn about overflow in arithmetic expressions
137 Common Var(warn_packed) Warning
138 Warn when the packed attribute has no effect on struct layout
141 Common Var(warn_padded) Warning
142 Warn when padding is required to align structure members
145 Common Var(warn_shadow) Warning
146 Warn when one local variable shadows another
149 Common Var(warn_stack_protect) Warning
150 Warn when not issuing stack smashing protection for some reason
154 Warn about code which might break strict aliasing rules
157 Common Joined UInteger Warning
158 Warn about code which might break strict aliasing rules
162 Warn about optimizations that assume that signed overflow is undefined
165 Common Joined UInteger Warning
166 Warn about optimizations that assume that signed overflow is undefined
169 Common Var(warn_switch) Warning
170 Warn about enumerated switches, with no default, missing a case
173 Common Var(warn_switch_default) Warning
174 Warn about enumerated switches missing a \"default:\" statement
177 Common Var(warn_switch_enum) Warning
178 Warn about all enumerated switches missing a specific case
181 Common Var(warn_system_headers) Warning
182 Do not suppress warnings from system headers
185 Common Var(warn_uninitialized) Warning
186 Warn about uninitialized automatic variables
189 Common Var(warn_notreached) Warning
190 Warn about code that will never be executed
194 Enable all -Wunused- warnings
197 Common Var(warn_unused_function) Warning
198 Warn when a function is unused
201 Common Var(warn_unused_label) Warning
202 Warn when a label is unused
205 Common Var(warn_unused_parameter) Warning
206 Warn when a function parameter is unused
209 Common Var(warn_unused_value) Warning
210 Warn when an expression value is unused
213 Common Var(warn_unused_variable) Warning
214 Warn when a variable is unused
216 Wvolatile-register-var
217 Common Var(warn_register_var) Warning
218 Warn when a register variable is declared volatile
221 Common RejectNegative Var(warn_coverage_mismatch) Warning
222 Warn instead of error in case profiles in -fprofile-use do not match
226 -aux-info <file> Emit declaration information into <file>
239 -d<letters> Enable dumps from specific passes of the compiler
243 -dumpbase <file> Set the file basename to be used for dumps
245 ; The version of the C++ ABI in use. The following values are allowed:
247 ; 0: The version of the ABI believed most conformant with the C++ ABI
248 ; specification. This ABI may change as bugs are discovered and fixed.
249 ; Therefore, 0 will not necessarily indicate the same ABI in different
252 ; 1: The version of the ABI first used in G++ 3.2.
254 ; Additional positive integers will be assigned as new versions of
255 ; the ABI become the default version of the ABI.
257 Common Joined UInteger Var(flag_abi_version) Init(2)
260 Common Report Var(align_functions,0)
261 Align the start of functions
264 Common RejectNegative Joined UInteger
267 Common Report Var(align_jumps,0) Optimization
268 Align labels which are only reached by jumping
271 Common RejectNegative Joined UInteger
274 Common Report Var(align_labels,0) Optimization
278 Common RejectNegative Joined UInteger
281 Common Report Var(align_loops) Optimization
282 Align the start of loops
285 Common RejectNegative Joined UInteger
287 ; This flag is only tested if alias checking is enabled.
288 ; 0 if pointer arguments may alias each other. True in C.
289 ; 1 if pointer arguments may not alias each other but may alias
291 ; 2 if pointer arguments may not alias each other and may not
292 ; alias global variables.
293 ; 3 if pointer arguments may not alias anything. True in Fortran.
294 ; Set by the front end.
296 Common Report Var(flag_argument_noalias,0) Optimization
297 Specify that arguments may alias each other and globals
300 Common Report Var(flag_argument_noalias,1) VarExists Optimization
301 Assume arguments may alias globals but not each other
303 fargument-noalias-global
304 Common Report Var(flag_argument_noalias,2) VarExists Optimization
305 Assume arguments alias neither each other nor globals
307 fargument-noalias-anything
308 Common Report Var(flag_argument_noalias,3) VarExists Optimization
309 Assume arguments alias no other storage
311 fasynchronous-unwind-tables
312 Common Report Var(flag_asynchronous_unwind_tables) Optimization
313 Generate unwind tables that are exact at each instruction boundary
316 Common Report Var(flag_auto_inc_dec) Init(1)
317 Generate auto-inc/dec instructions
319 ; -fcheck-bounds causes gcc to generate array bounds checks.
320 ; For C, C++ and ObjC: defaults off.
321 ; For Java: defaults to on.
322 ; For Fortran: defaults to off.
324 Common Report Var(flag_bounds_check)
325 Generate code to check bounds before indexing arrays
328 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
329 Replace add, compare, branch with branch on count register
331 fbranch-probabilities
332 Common Report Var(flag_branch_probabilities) Optimization
333 Use profiling information for branch probabilities
335 fbranch-target-load-optimize
336 Common Report Var(flag_branch_target_load_optimize) Optimization
337 Perform branch target load optimization before prologue / epilogue threading
339 fbranch-target-load-optimize2
340 Common Report Var(flag_branch_target_load_optimize2) Optimization
341 Perform branch target load optimization after prologue / epilogue threading
344 Common Report Var(flag_btr_bb_exclusive) Optimization
345 Restrict target load migration not to re-use registers in any basic block
348 Common Joined RejectNegative
349 -fcall-saved-<register> Mark <register> as being preserved across functions
352 Common Joined RejectNegative
353 -fcall-used-<register> Mark <register> as being corrupted by function calls
355 ; Nonzero for -fcaller-saves: allocate values in regs that need to
356 ; be saved across function calls, if that produces overall better code.
357 ; Optional now, so people can test it.
359 Common Report Var(flag_caller_saves) Optimization
360 Save registers around function calls
363 Common Report Var(flag_check_data_deps)
364 Compare the results of several data dependence analyzers.
367 Common Report Var(flag_no_common,0) Optimization
368 Do not put uninitialized globals in the common section
371 Common Report Var(flag_cprop_registers) Optimization
372 Perform a register copy-propagation optimization pass
375 Common Report Var(flag_crossjumping) Optimization
376 Perform cross-jumping optimization
379 Common Report Var(flag_cse_follow_jumps) Optimization
380 When running CSE, follow jumps to their targets
383 Common Report Var(flag_cse_skip_blocks) Optimization
384 When running CSE, follow conditional jumps
387 Common Report Var(flag_cx_limited_range) Optimization
388 Omit range reduction step when performing complex division
391 Common Report Var(flag_data_sections) Optimization
392 Place data items into their own section
396 List all available debugging counters with their limits and counts.
399 Common RejectNegative Joined
400 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
402 ; Nonzero for -fdefer-pop: don't pop args after each function call
403 ; instead save them up to pop many calls' args with one insns.
405 Common Report Var(flag_defer_pop) Optimization
406 Defer popping functions args from stack until later
409 Common Report Var(flag_delayed_branch) Optimization
410 Attempt to fill delay slots of branch instructions
412 fdelete-null-pointer-checks
413 Common Report Var(flag_delete_null_pointer_checks) Optimization
414 Delete useless null pointer checks
416 fdiagnostics-show-location=
417 Common Joined RejectNegative
418 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
420 fdiagnostics-show-option
422 Amend appropriate diagnostic messages with the command line option that controls them
425 Common Joined RejectNegative
426 -fdump-<type> Dump various compiler internals to a file
429 Common Report Var(flag_dump_noaddr)
430 Suppress output of addresses in debugging dumps
433 Common Report Var(flag_dump_unnumbered) VarExists
434 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
437 Common Report Var(flag_early_inlining) Init(1) Optimization
438 Perform early inlining
440 feliminate-dwarf2-dups
441 Common Report Var(flag_eliminate_dwarf2_dups)
442 Perform DWARF2 duplicate elimination
444 feliminate-unused-debug-symbols
445 Common Report Var(flag_debug_only_used_symbols)
446 Perform unused type elimination in debug info
448 feliminate-unused-debug-types
449 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
450 Perform unused type elimination in debug info
452 femit-class-debug-always
453 Common Report Var(flag_emit_class_debug_always) Init(1)
454 Do not suppress C++ class debug information.
457 Common Report Var(flag_exceptions) Optimization
458 Enable exception handling
460 fexpensive-optimizations
461 Common Report Var(flag_expensive_optimizations) Optimization
462 Perform a number of minor, expensive optimizations
468 Common Report Var(flag_finite_math_only) Optimization
469 Assume no NaNs or infinities are generated
472 Common Joined RejectNegative
473 -ffixed-<register> Mark <register> as being unavailable to the compiler
476 Common Report Var(flag_float_store) Optimization
477 Don't allocate floats and doubles in extended-precision registers
479 ; Nonzero for -fforce-addr: load memory address into a register before
480 ; reference to memory. This makes better cse but slower compilation.
482 Common Report Var(flag_force_addr) Optimization
483 Copy memory address constants into registers before use
486 Common Report Var(flag_forward_propagate) Optimization
487 Perform a forward propagation pass on RTL
489 ; Nonzero means don't put addresses of constant functions in registers.
490 ; Used for compiling the Unix kernel, where strange substitutions are
491 ; done on the assembly output.
493 Common Report Var(flag_no_function_cse,0)
494 Allow function addresses to be held in registers
497 Common Report Var(flag_function_sections)
498 Place each function into its own section
501 Common Report Var(flag_gcse) Optimization
502 Perform global common subexpression elimination
505 Common Report Var(flag_gcse_lm) Init(1) Optimization
506 Perform enhanced load motion during global common subexpression elimination
509 Common Report Var(flag_gcse_sm) Init(0) Optimization
510 Perform store motion after global common subexpression elimination
513 Common Report Var(flag_gcse_las) Init(0) Optimization
514 Perform redundant load after store elimination in global common subexpression
518 Common Report Var(flag_gcse_after_reload) Optimization
519 Perform global common subexpression elimination after register allocation
522 fguess-branch-probability
523 Common Report Var(flag_guess_branch_prob) Optimization
524 Enable guessing of branch probabilities
526 ; Nonzero means ignore `#ident' directives. 0 means handle them.
527 ; Generate position-independent code for executables if possible
528 ; On SVR4 targets, it also controls whether or not to emit a
529 ; string identifying the compiler.
531 Common Report Var(flag_no_ident,0)
532 Process #ident directives
535 Common Report Var(flag_if_conversion) Optimization
536 Perform conversion of conditional jumps to branchless equivalents
539 Common Report Var(flag_if_conversion2) Optimization
540 Perform conversion of conditional jumps to conditional execution
542 ; -finhibit-size-directive inhibits output of .size for ELF.
543 ; This is used only for compiling crtstuff.c,
544 ; and it may be extended to other effects
545 ; needed for crtstuff.c on other systems.
546 finhibit-size-directive
547 Common Report Var(flag_inhibit_size_directive)
548 Do not generate .size directives
550 ; Nonzero means that functions declared `inline' will be treated
551 ; as `static'. Prevents generation of zillions of copies of unused
552 ; static inline functions; instead, `inlines' are written out
553 ; only when actually used. Used in conjunction with -g. Also
554 ; does the right thing with #pragma interface.
556 Common Report Var(flag_no_inline,0) Init(2)
557 Pay attention to the \"inline\" keyword
560 Common Report Var(flag_inline_functions) Optimization
561 Integrate simple functions into their callers
563 finline-functions-called-once
564 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
565 Integrate functions called once into their callers
568 Common RejectNegative Joined UInteger
571 Common RejectNegative Joined UInteger
572 -finline-limit=<number> Limit the size of inlined functions to <number>
574 finstrument-functions
575 Common Report Var(flag_instrument_function_entry_exit)
576 Instrument function entry and exit with profiling calls
579 Common Report Var(flag_ipa_cp) Optimization
580 Perform Interprocedural constant propagation
583 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
584 Discover pure and const functions
587 Common Report Var(flag_ipa_pta) Init(0) Optimization
588 Perform interprocedural points-to analysis
591 Common Report Var(flag_ipa_reference) Init(0) Optimization
592 Discover readonly and non addressable static variables
595 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
596 Type based escape and alias analysis
599 Common Report Var(flag_ipa_matrix_reorg) Optimization
600 Perform matrix layout flattening and transposing based
601 on profiling information.
604 Common Report Var(flag_ivopts) Init(1) Optimization
605 Optimize induction variables on trees
608 Common Var(flag_jump_tables) Init(1) Optimization
609 Use jump tables for sufficiently large switch statements
611 fkeep-inline-functions
612 Common Report Var(flag_keep_inline_functions)
613 Generate code for functions even if they are fully inlined
616 Common Report Var(flag_keep_static_consts) Init(1)
617 Emit static const variables even if they are not used
620 Common Report Var(flag_leading_underscore) Init(-1)
621 Give external symbols a leading underscore
625 Does nothing. Preserved for backward compatibility.
628 Common Report Var(flag_errno_math) Init(1)
629 Set errno after built-in math functions
632 Common Report Var(mem_report)
633 Report on permanent memory allocation
635 ; This will attempt to merge constant section constants, if 1 only
636 ; string constants and constants from constant pool, if 2 also constant
639 Common Report Var(flag_merge_constants,2) Init(1) Optimization
640 Attempt to merge identical constants and constant variables
643 Common Report Var(flag_merge_constants,1) VarExists Optimization
644 Attempt to merge identical constants across compilation units
647 Common RejectNegative Joined UInteger
648 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
651 Common Report Var(flag_modulo_sched) Optimization
652 Perform SMS based modulo scheduling before the first scheduling pass
654 fmove-loop-invariants
655 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
656 Move loop invariant computations out of loops
659 Common RejectNegative Report Var(flag_mudflap)
660 Add mudflap bounds-checking instrumentation for single-threaded program
663 Common RejectNegative Report VarExists Var(flag_mudflap,2)
664 Add mudflap bounds-checking instrumentation for multi-threaded program
667 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
668 Ignore read operations when inserting mudflap instrumentation
671 Common Var(flag_dce) Init(1) Optimization
672 Use the RTL dead code elimination pass
675 Common Var(flag_dse) Init(1) Optimization
676 Use the RTL dead store elimination pass
678 freschedule-modulo-scheduled-loops
679 Common Report Var(flag_resched_modulo_sched) Optimization
680 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
683 Common Report Var(flag_non_call_exceptions) Optimization
684 Support synchronous non-call exceptions
687 Common Report Var(flag_omit_frame_pointer) Optimization
688 When possible do not generate stack frames
690 foptimize-register-move
691 Common Report Var(flag_regmove) Optimization
692 Do the full register move optimization pass
694 foptimize-sibling-calls
695 Common Report Var(flag_optimize_sibling_calls) Optimization
696 Optimize sibling and tail recursive calls
699 Common Report Var(pre_ipa_mem_report)
700 Report on memory allocation before interprocedural optimization
703 Common Report Var(post_ipa_mem_report)
704 Report on memory allocation before interprocedural optimization
707 Common Report Var(flag_pack_struct) Optimization
708 Pack structure members together without holes
711 Common RejectNegative Joined UInteger Optimization
712 -fpack-struct=<number> Set initial maximum structure member alignment
715 Common Report Var(flag_pcc_struct_return,1) VarExists
716 Return small aggregates in memory, not registers
719 Common Report Var(flag_peel_loops) Optimization
723 Common Report Var(flag_no_peephole,0) Optimization
724 Enable machine specific peephole optimizations
727 Common Report Var(flag_peephole2) Optimization
728 Enable an RTL peephole pass before sched2
731 Common Report Var(flag_pic,2)
732 Generate position-independent code if possible (large mode)
735 Common Report Var(flag_pie,2)
736 Generate position-independent code for executables if possible (large mode)
739 Common Report Var(flag_pic,1) VarExists
740 Generate position-independent code if possible (small mode)
743 Common Report Var(flag_pie,1) VarExists
744 Generate position-independent code for executables if possible (small mode)
746 fpredictive-commoning
747 Common Report Var(flag_predictive_commoning) Optimization
748 Run predictive commoning optimization.
750 fprefetch-loop-arrays
751 Common Report Var(flag_prefetch_loop_arrays) Optimization
752 Generate prefetch instructions, if available, for arrays in loops
755 Common Report Var(profile_flag)
756 Enable basic program profiling code
759 Common Report Var(profile_arc_flag)
760 Insert arc-based program profiling code
764 Enable common options for generating profile info for profile feedback directed optimizations
768 Enable common options for performing profile feedback directed optimizations
771 Common Report Var(flag_profile_values)
772 Insert code to profile values of expressions
778 Common Joined RejectNegative
779 -frandom-seed=<string> Make compile reproducible using <string>
781 ; This switch causes the command line that was used to create an
782 ; object file to be recorded into the object file. The exact format
783 ; of this recording is target and binary file format dependent.
784 ; It is related to the -fverbose-asm switch, but that switch only
785 ; records information in the assembler output file as comments, so
786 ; they never reach the object file.
788 Common Report Var(flag_record_gcc_switches)
789 Record gcc command line switches in the object file.
792 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
793 Return small aggregates in registers
796 Common Report Var(flag_regmove) Optimization
797 Enables a register move optimization
800 Common Report Var(flag_rename_registers) Init(2) Optimization
801 Perform a register renaming optimization pass
804 Common Report Var(flag_reorder_blocks) Optimization
805 Reorder basic blocks to improve code placement
807 freorder-blocks-and-partition
808 Common Report Var(flag_reorder_blocks_and_partition) Optimization
809 Reorder basic blocks and partition into hot and cold sections
812 Common Report Var(flag_reorder_functions) Optimization
813 Reorder functions to improve code placement
815 frerun-cse-after-loop
816 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
817 Add a common subexpression elimination pass after loop optimizations
821 Does nothing. Preserved for backward compatibility.
824 Common Report Var(flag_rounding_math) Optimization
825 Disable optimizations that assume default FP rounding behavior
828 Common Report Var(flag_schedule_interblock) Init(1) Optimization
829 Enable scheduling across basic blocks
832 Common Report Var(flag_schedule_speculative) Init(1) Optimization
833 Allow speculative motion of non-loads
836 Common Report Var(flag_schedule_speculative_load) Optimization
837 Allow speculative motion of some loads
839 fsched-spec-load-dangerous
840 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
841 Allow speculative motion of more loads
844 Common RejectNegative Joined
845 -fsched-verbose=<number> Set the verbosity level of the scheduler
847 fsched2-use-superblocks
848 Common Report Var(flag_sched2_use_superblocks) Optimization
849 If scheduling post reload, do superblock scheduling
852 Common Report Var(flag_sched2_use_traces) Optimization
853 If scheduling post reload, do trace scheduling
856 Common Report Var(flag_schedule_insns) Optimization
857 Reschedule instructions before register allocation
860 Common Report Var(flag_schedule_insns_after_reload) Optimization
861 Reschedule instructions after register allocation
863 ; sched_stalled_insns means that insns can be moved prematurely from the queue
864 ; of stalled insns into the ready list.
866 Common Report Var(flag_sched_stalled_insns) Optimization
867 Allow premature scheduling of queued insns
869 fsched-stalled-insns=
870 Common RejectNegative Joined UInteger
871 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
873 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
874 ; be examined for a dependency on a stalled insn that is candidate for
875 ; premature removal from the queue of stalled insns into the ready list (has
876 ; an effect only if the flag 'sched_stalled_insns' is set).
877 fsched-stalled-insns-dep
878 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
879 Set dependence distance checking in premature scheduling of queued insns
881 fsched-stalled-insns-dep=
882 Common RejectNegative Joined UInteger
883 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
886 Common Report Var(flag_section_anchors) Optimization
887 Access data in the same section from shared anchor points
889 frtl-abstract-sequences
890 Common Report Var(flag_rtl_seqabstr) Optimization
891 Perform sequence abstraction optimization on RTL
894 Common Report Var(flag_see) Init(0)
895 Eliminate redundant sign extensions using LCM.
898 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
899 Show column numbers in diagnostics, when available. Default on
902 Common Report Var(flag_signaling_nans) Optimization
903 Disable optimizations observable by IEEE signaling NaNs
906 Common Report Var(flag_signed_zeros) Init(1) Optimization
907 Disable floating point optimizations that ignore the IEEE signedness of zero
909 fsingle-precision-constant
910 Common Report Var(flag_single_precision_constant) Optimization
911 Convert floating point constants to single precision constants
913 fsplit-ivs-in-unroller
914 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
915 Split lifetimes of induction variables when loops are unrolled
918 Common Report Var(flag_split_wide_types) Optimization
919 Split wide types into independent registers
921 fvariable-expansion-in-unroller
922 Common Report Var(flag_variable_expansion_in_unroller) Optimization
923 Apply variable expansion when loops are unrolled
925 ; Emit code to probe the stack, to help detect stack overflow; also
926 ; may cause large objects to be allocated dynamically.
928 Common Report Var(flag_stack_check)
929 Insert stack checking code into the program
934 fstack-limit-register=
935 Common RejectNegative Joined
936 -fstack-limit-register=<register> Trap if the stack goes past <register>
939 Common RejectNegative Joined
940 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
943 Common Report Var(flag_stack_protect, 1)
944 Use propolice as a stack protection method
947 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
948 Use a stack protection method for every function
952 Does nothing. Preserved for backward compatibility.
954 ; Nonzero if we should do (language-dependent) alias analysis.
955 ; Typically, this analysis will assume that expressions of certain
956 ; types do not alias expressions of certain other types. Only used
957 ; if alias analysis (in general) is enabled.
959 Common Report Var(flag_strict_aliasing) Optimization
960 Assume strict aliasing rules apply
963 Common Report Var(flag_strict_overflow)
964 Treat signed overflow as undefined
967 Common Report Var(flag_syntax_only)
968 Check for syntax errors, then stop
971 Common Report Var(flag_test_coverage)
972 Create data files needed by \"gcov\"
975 Common Report Var(flag_thread_jumps) Optimization
976 Perform jump threading optimizations
979 Common Report Var(time_report)
980 Report the time taken by each compiler pass
983 Common Joined RejectNegative
984 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
987 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
988 Reorder top level functions, variables, and asms
991 Common Report Var(flag_tracer)
992 Perform superblock formation via tail duplication
994 ; Zero means that floating-point math operations cannot generate a
995 ; (user-visible) trap. This is the case, for example, in nonstop
996 ; IEEE 754 arithmetic.
998 Common Report Var(flag_trapping_math) Init(1) Optimization
999 Assume floating-point operations can trap
1002 Common Report Var(flag_trapv) Optimization
1003 Trap for signed overflow in addition, subtraction and multiplication
1006 Common Report Var(flag_tree_ccp) Optimization
1007 Enable SSA-CCP optimization on trees
1010 Common Report Var(flag_tree_store_ccp) Optimization
1011 Enable SSA-CCP optimization for stores and loads
1014 Common Report Var(flag_tree_ch) Optimization
1015 Enable loop header copying on trees
1018 Common Report Var(flag_tree_copyrename) Optimization
1019 Replace SSA temporaries with better names in copies
1022 Common Report Var(flag_tree_copy_prop) Optimization
1023 Enable copy propagation on trees
1025 ftree-store-copy-prop
1026 Common Report Var(flag_tree_store_copy_prop) Optimization
1027 Enable copy propagation for stores and loads
1030 Common Report Var(flag_tree_dce) Optimization
1031 Enable SSA dead code elimination optimization on trees
1033 ftree-dominator-opts
1034 Common Report Var(flag_tree_dom) Optimization
1035 Enable dominator optimizations
1038 Common Report Var(flag_tree_dse) Optimization
1039 Enable dead store elimination
1042 Common Report Var(flag_tree_fre) Optimization
1043 Enable Full Redundancy Elimination (FRE) on trees
1046 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1047 Enable loop invariant motion on trees
1050 Common Report Var(flag_tree_loop_linear) Optimization
1051 Enable linear loop transforms on trees
1054 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1055 Create canonical induction variables in loops
1058 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1059 Enable loop optimizations on tree level
1062 Common Report Var(flag_tree_pre) Optimization
1063 Enable SSA-PRE optimization on trees
1066 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1067 Enable reassociation on tree level
1070 Common Report Var(flag_tree_salias) Optimization
1071 Perform structural alias analysis
1074 Common Report Var(flag_tree_sink) Optimization
1075 Enable SSA code sinking on trees
1078 Common Report Var(flag_tree_sra) Optimization
1079 Perform scalar replacement of aggregates
1082 Common Report Var(flag_tree_ter) Optimization
1083 Replace temporary expressions in the SSA->normal pass
1086 Common Report Var(flag_tree_live_range_split) Optimization
1087 Perform live range splitting during the SSA->normal pass
1090 Common Report Var(flag_tree_vrp) Init(0) Optimization
1091 Perform Value Range Propagation on trees
1094 Common Report Var(flag_unit_at_a_time) Optimization
1095 Compile whole compilation unit at a time
1098 Common Report Var(flag_unroll_loops) Optimization
1099 Perform loop unrolling when iteration count is known
1102 Common Report Var(flag_unroll_all_loops) Optimization
1103 Perform loop unrolling for all loops
1105 ; Nonzero means that loop optimizer may assume that the induction variables
1106 ; that control loops do not overflow and that the loops with nontrivial
1107 ; exit condition are not infinite
1108 funsafe-loop-optimizations
1109 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1110 Allow loop optimizations to assume that the loops behave in normal way
1112 ; Nonzero means that unsafe floating-point math optimizations are allowed
1113 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1114 ; are allowed to assume that their arguments and results are "normal"
1115 ; (e.g., nonnegative for SQRT).
1116 funsafe-math-optimizations
1117 Common Report Var(flag_unsafe_math_optimizations) Optimization
1118 Allow math optimizations that may violate IEEE or ISO standards
1121 Common Report Var(flag_unswitch_loops) Optimization
1122 Perform loop unswitching
1125 Common Report Var(flag_unwind_tables) Optimization
1126 Just generate unwind tables for exception handling
1129 Common Report Var(flag_var_tracking) VarExists Optimization
1130 Perform variable tracking
1132 fvar-tracking-uninit
1133 Common Report Var(flag_var_tracking_uninit) Optimization
1134 Perform variable tracking and also tag variables that are uninitialized
1137 Common Report Var(flag_tree_vectorize) Optimization
1138 Enable loop vectorization on trees
1141 Common Report Var(flag_vect_cost_model) Optimization
1142 Enable use of cost model in vectorization
1144 ftree-vect-loop-version
1145 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1146 Enable loop versioning when doing loop vectorization on trees
1148 ftree-vectorizer-verbose=
1149 Common RejectNegative Joined
1150 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1153 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1154 Enable copy propagation of scalar-evolution information.
1156 ; -fverbose-asm causes extra commentary information to be produced in
1157 ; the generated assembly code (to make it more readable). This option
1158 ; is generally only of use to those who actually need to read the
1159 ; generated assembly code (perhaps while debugging the compiler itself).
1160 ; -fno-verbose-asm, the default, causes the extra information
1161 ; to not be added and is useful when comparing two assembler files.
1163 Common Report Var(flag_verbose_asm)
1164 Add extra commentary to assembler output
1167 Common Joined RejectNegative
1168 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1172 Common Report Var(flag_value_profile_transformations) Optimization
1173 Use expression value profiles in optimizations
1176 Common Report Var(flag_web) Init(2) Optimization
1177 Construct webs and split unrelated uses of single variable
1180 Common Report Var(flag_whole_program) Init(0) Optimization
1181 Perform whole program optimizations
1184 Common Report Var(flag_wrapv) Optimization
1185 Assume signed arithmetic overflow wraps around
1187 fzero-initialized-in-bss
1188 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1189 Put zero initialized data in the bss section
1192 Common JoinedOrMissing
1193 Generate debug information in default format
1196 Common JoinedOrMissing Negative(gdwarf-2)
1197 Generate debug information in COFF format
1200 Common JoinedOrMissing Negative(gstabs)
1201 Generate debug information in DWARF v2 format
1204 Common JoinedOrMissing
1205 Generate debug information in default extended format
1208 Common JoinedOrMissing Negative(gstabs+)
1209 Generate debug information in STABS format
1212 Common JoinedOrMissing Negative(gvms)
1213 Generate debug information in extended STABS format
1216 Common JoinedOrMissing Negative(gxcoff)
1217 Generate debug information in VMS format
1220 Common JoinedOrMissing Negative(gxcoff+)
1221 Generate debug information in XCOFF format
1224 Common JoinedOrMissing Negative(gcoff)
1225 Generate debug information in extended XCOFF format
1228 Common Joined Separate
1229 -o <file> Place output into <file>
1232 Common Var(profile_flag)
1233 Enable function profiling
1236 Common Var(pedantic)
1237 Issue warnings needed for strict compliance to the standard
1241 Like -pedantic but issue them as errors
1244 Common Var(quiet_flag)
1245 Do not display functions compiled or elapsed time
1248 Common Var(version_flag)
1249 Display the compiler's version
1252 Common Var(inhibit_warnings)
1255 ; This comment is to ensure we retain the blank line above.