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
317 Common Report Var(flag_auto_inc_dec) Init(1)
318 Generate auto-inc/dec instructions
320 ; -fcheck-bounds causes gcc to generate array bounds checks.
321 ; For C, C++ and ObjC: defaults off.
322 ; For Java: defaults to on.
323 ; For Fortran: defaults to off.
325 Common Report Var(flag_bounds_check)
326 Generate code to check bounds before indexing arrays
329 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
330 Replace add, compare, branch with branch on count register
332 fbranch-probabilities
333 Common Report Var(flag_branch_probabilities) Optimization
334 Use profiling information for branch probabilities
336 fbranch-target-load-optimize
337 Common Report Var(flag_branch_target_load_optimize) Optimization
338 Perform branch target load optimization before prologue / epilogue threading
340 fbranch-target-load-optimize2
341 Common Report Var(flag_branch_target_load_optimize2) Optimization
342 Perform branch target load optimization after prologue / epilogue threading
345 Common Report Var(flag_btr_bb_exclusive) Optimization
346 Restrict target load migration not to re-use registers in any basic block
349 Common Joined RejectNegative
350 -fcall-saved-<register> Mark <register> as being preserved across functions
353 Common Joined RejectNegative
354 -fcall-used-<register> Mark <register> as being corrupted by function calls
356 ; Nonzero for -fcaller-saves: allocate values in regs that need to
357 ; be saved across function calls, if that produces overall better code.
358 ; Optional now, so people can test it.
360 Common Report Var(flag_caller_saves) Optimization
361 Save registers around function calls
364 Common Report Var(flag_check_data_deps)
365 Compare the results of several data dependence analyzers.
368 Common Report Var(flag_no_common,0) Optimization
369 Do not put uninitialized globals in the common section
372 Common Report Var(flag_cprop_registers) Optimization
373 Perform a register copy-propagation optimization pass
376 Common Report Var(flag_crossjumping) Optimization
377 Perform cross-jumping optimization
380 Common Report Var(flag_cse_follow_jumps) Optimization
381 When running CSE, follow jumps to their targets
384 Common Report Var(flag_cse_skip_blocks) Optimization
385 When running CSE, follow conditional jumps
388 Common Report Var(flag_cx_limited_range) Optimization
389 Omit range reduction step when performing complex division
392 Common Report Var(flag_data_sections) Optimization
393 Place data items into their own section
396 Common RejectNegative Joined
397 -fdbg-cnt=<counter>:<limit> Set the debug counter limit.
399 ; Nonzero for -fdefer-pop: don't pop args after each function call
400 ; instead save them up to pop many calls' args with one insns.
402 Common Report Var(flag_defer_pop) Optimization
403 Defer popping functions args from stack until later
406 Common Report Var(flag_delayed_branch) Optimization
407 Attempt to fill delay slots of branch instructions
409 fdelete-null-pointer-checks
410 Common Report Var(flag_delete_null_pointer_checks) Optimization
411 Delete useless null pointer checks
413 fdiagnostics-show-location=
414 Common Joined RejectNegative
415 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
417 fdiagnostics-show-option
419 Amend appropriate diagnostic messages with the command line option that controls them
422 Common Joined RejectNegative
423 -fdump-<type> Dump various compiler internals to a file
426 Common Report Var(flag_dump_noaddr)
427 Suppress output of addresses in debugging dumps
430 Common Report Var(flag_dump_unnumbered) VarExists
431 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
434 Common Report Var(flag_early_inlining) Init(1) Optimization
435 Perform early inlining
437 feliminate-dwarf2-dups
438 Common Report Var(flag_eliminate_dwarf2_dups)
439 Perform DWARF2 duplicate elimination
441 feliminate-unused-debug-symbols
442 Common Report Var(flag_debug_only_used_symbols)
443 Perform unused type elimination in debug info
445 feliminate-unused-debug-types
446 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
447 Perform unused type elimination in debug info
449 femit-class-debug-always
450 Common Report Var(flag_emit_class_debug_always) Init(1)
451 Do not suppress C++ class debug information.
454 Common Report Var(flag_exceptions) Optimization
455 Enable exception handling
457 fexpensive-optimizations
458 Common Report Var(flag_expensive_optimizations) Optimization
459 Perform a number of minor, expensive optimizations
465 Common Report Var(flag_finite_math_only) Optimization
466 Assume no NaNs or infinities are generated
469 Common Joined RejectNegative
470 -ffixed-<register> Mark <register> as being unavailable to the compiler
473 Common Report Var(flag_float_store) Optimization
474 Don't allocate floats and doubles in extended-precision registers
476 ; Nonzero for -fforce-addr: load memory address into a register before
477 ; reference to memory. This makes better cse but slower compilation.
479 Common Report Var(flag_force_addr) Optimization
480 Copy memory address constants into registers before use
483 Common Report Var(flag_forward_propagate) Optimization
484 Perform a forward propagation pass on RTL
486 ; Nonzero means don't put addresses of constant functions in registers.
487 ; Used for compiling the Unix kernel, where strange substitutions are
488 ; done on the assembly output.
490 Common Report Var(flag_no_function_cse,0)
491 Allow function addresses to be held in registers
494 Common Report Var(flag_function_sections)
495 Place each function into its own section
498 Common Report Var(flag_gcse) Optimization
499 Perform global common subexpression elimination
502 Common Report Var(flag_gcse_lm) Init(1) Optimization
503 Perform enhanced load motion during global common subexpression elimination
506 Common Report Var(flag_gcse_sm) Init(0) Optimization
507 Perform store motion after global common subexpression elimination
510 Common Report Var(flag_gcse_las) Init(0) Optimization
511 Perform redundant load after store elimination in global common subexpression
515 Common Report Var(flag_gcse_after_reload) Optimization
516 Perform global common subexpression elimination after register allocation
519 fguess-branch-probability
520 Common Report Var(flag_guess_branch_prob) Optimization
521 Enable guessing of branch probabilities
523 ; Nonzero means ignore `#ident' directives. 0 means handle them.
524 ; Generate position-independent code for executables if possible
525 ; On SVR4 targets, it also controls whether or not to emit a
526 ; string identifying the compiler.
528 Common Report Var(flag_no_ident,0)
529 Process #ident directives
532 Common Report Var(flag_if_conversion) Optimization
533 Perform conversion of conditional jumps to branchless equivalents
536 Common Report Var(flag_if_conversion2) Optimization
537 Perform conversion of conditional jumps to conditional execution
539 ; -finhibit-size-directive inhibits output of .size for ELF.
540 ; This is used only for compiling crtstuff.c,
541 ; and it may be extended to other effects
542 ; needed for crtstuff.c on other systems.
543 finhibit-size-directive
544 Common Report Var(flag_inhibit_size_directive)
545 Do not generate .size directives
547 ; Nonzero means that functions declared `inline' will be treated
548 ; as `static'. Prevents generation of zillions of copies of unused
549 ; static inline functions; instead, `inlines' are written out
550 ; only when actually used. Used in conjunction with -g. Also
551 ; does the right thing with #pragma interface.
553 Common Report Var(flag_no_inline,0) Init(2)
554 Pay attention to the \"inline\" keyword
557 Common Report Var(flag_inline_functions) Optimization
558 Integrate simple functions into their callers
560 finline-functions-called-once
561 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
562 Integrate functions called once into their callers
565 Common RejectNegative Joined UInteger
568 Common RejectNegative Joined UInteger
569 -finline-limit=<number> Limit the size of inlined functions to <number>
571 finstrument-functions
572 Common Report Var(flag_instrument_function_entry_exit)
573 Instrument function entry and exit with profiling calls
576 Common Report Var(flag_ipa_cp) Optimization
577 Perform Interprocedural constant propagation
580 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
581 Discover pure and const functions
584 Common Report Var(flag_ipa_pta) Init(0) Optimization
585 Perform interprocedural points-to analysis
588 Common Report Var(flag_ipa_reference) Init(0) Optimization
589 Discover readonly and non addressable static variables
592 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
593 Type based escape and alias analysis
596 Common Report Var(flag_ipa_matrix_reorg)
597 Perform matrix layout flattening and transposing based
598 on profiling information.
601 Common Report Var(flag_ivopts) Init(1) Optimization
602 Optimize induction variables on trees
605 Common Var(flag_jump_tables) Init(1) Optimization
606 Use jump tables for sufficiently large switch statements
608 fkeep-inline-functions
609 Common Report Var(flag_keep_inline_functions)
610 Generate code for functions even if they are fully inlined
613 Common Report Var(flag_keep_static_consts) Init(1)
614 Emit static const variables even if they are not used
617 Common Report Var(flag_leading_underscore) Init(-1)
618 Give external symbols a leading underscore
622 Does nothing. Preserved for backward compatibility.
625 Common Report Var(flag_errno_math) Init(1)
626 Set errno after built-in math functions
629 Common Report Var(mem_report)
630 Report on permanent memory allocation
632 ; This will attempt to merge constant section constants, if 1 only
633 ; string constants and constants from constant pool, if 2 also constant
636 Common Report Var(flag_merge_constants,2) Init(1) Optimization
637 Attempt to merge identical constants and constant variables
640 Common Report Var(flag_merge_constants,1) VarExists Optimization
641 Attempt to merge identical constants across compilation units
644 Common RejectNegative Joined UInteger
645 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
648 Common Report Var(flag_modulo_sched) Optimization
649 Perform SMS based modulo scheduling before the first scheduling pass
651 fmove-loop-invariants
652 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
653 Move loop invariant computations out of loops
656 Common RejectNegative Report Var(flag_mudflap)
657 Add mudflap bounds-checking instrumentation for single-threaded program
660 Common RejectNegative Report VarExists Var(flag_mudflap,2)
661 Add mudflap bounds-checking instrumentation for multi-threaded program
664 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
665 Ignore read operations when inserting mudflap instrumentation
668 Common Var(flag_dce) Init(1)
669 Use the RTL dead code elimination pass
672 Common Var(flag_dse) Init(1)
673 Use the RTL dead store elimination pass
675 freschedule-modulo-scheduled-loops
676 Common Report Var(flag_resched_modulo_sched) Optimization
677 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
680 Common Report Var(flag_non_call_exceptions) Optimization
681 Support synchronous non-call exceptions
684 Common Report Var(flag_omit_frame_pointer) Optimization
685 When possible do not generate stack frames
687 foptimize-register-move
688 Common Report Var(flag_regmove) Optimization
689 Do the full register move optimization pass
691 foptimize-sibling-calls
692 Common Report Var(flag_optimize_sibling_calls) Optimization
693 Optimize sibling and tail recursive calls
696 Common Report Var(pre_ipa_mem_report)
697 Report on memory allocation before interprocedural optimization
700 Common Report Var(post_ipa_mem_report)
701 Report on memory allocation before interprocedural optimization
704 Common Report Var(flag_pack_struct) Optimization
705 Pack structure members together without holes
708 Common RejectNegative Joined UInteger Optimization
709 -fpack-struct=<number> Set initial maximum structure member alignment
712 Common Report Var(flag_pcc_struct_return,1) VarExists
713 Return small aggregates in memory, not registers
716 Common Report Var(flag_peel_loops) Optimization
720 Common Report Var(flag_no_peephole,0) Optimization
721 Enable machine specific peephole optimizations
724 Common Report Var(flag_peephole2) Optimization
725 Enable an RTL peephole pass before sched2
728 Common Report Var(flag_pic,2)
729 Generate position-independent code if possible (large mode)
732 Common Report Var(flag_pie,2)
733 Generate position-independent code for executables if possible (large mode)
736 Common Report Var(flag_pic,1) VarExists
737 Generate position-independent code if possible (small mode)
740 Common Report Var(flag_pie,1) VarExists
741 Generate position-independent code for executables if possible (small mode)
743 fpredictive-commoning
744 Common Report Var(flag_predictive_commoning)
745 Run predictive commoning optimization.
747 fprefetch-loop-arrays
748 Common Report Var(flag_prefetch_loop_arrays) Optimization
749 Generate prefetch instructions, if available, for arrays in loops
752 Common Report Var(profile_flag)
753 Enable basic program profiling code
756 Common Report Var(profile_arc_flag)
757 Insert arc-based program profiling code
761 Enable common options for generating profile info for profile feedback directed optimizations
765 Enable common options for performing profile feedback directed optimizations
768 Common Report Var(flag_profile_values)
769 Insert code to profile values of expressions
775 Common Joined RejectNegative
776 -frandom-seed=<string> Make compile reproducible using <string>
778 ; This switch causes the command line that was used to create an
779 ; object file to be recorded into the object file. The exact format
780 ; of this recording is target and binary file format dependent.
781 ; It is related to the -fverbose-asm switch, but that switch only
782 ; records information in the assembler output file as comments, so
783 ; they never reach the object file.
785 Common Report Var(flag_record_gcc_switches)
786 Record gcc command line switches in the object file.
789 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
790 Return small aggregates in registers
793 Common Report Var(flag_regmove) Optimization
794 Enables a register move optimization
797 Common Report Var(flag_rename_registers) Init(2) Optimization
798 Perform a register renaming optimization pass
801 Common Report Var(flag_reorder_blocks) Optimization
802 Reorder basic blocks to improve code placement
804 freorder-blocks-and-partition
805 Common Report Var(flag_reorder_blocks_and_partition) Optimization
806 Reorder basic blocks and partition into hot and cold sections
809 Common Report Var(flag_reorder_functions) Optimization
810 Reorder functions to improve code placement
812 frerun-cse-after-loop
813 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
814 Add a common subexpression elimination pass after loop optimizations
818 Does nothing. Preserved for backward compatibility.
821 Common Report Var(flag_rounding_math) Optimization
822 Disable optimizations that assume default FP rounding behavior
825 Common Report Var(flag_schedule_interblock) Init(1) Optimization
826 Enable scheduling across basic blocks
829 Common Report Var(flag_schedule_speculative) Init(1) Optimization
830 Allow speculative motion of non-loads
833 Common Report Var(flag_schedule_speculative_load) Optimization
834 Allow speculative motion of some loads
836 fsched-spec-load-dangerous
837 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
838 Allow speculative motion of more loads
841 Common RejectNegative Joined
842 -fsched-verbose=<number> Set the verbosity level of the scheduler
844 fsched2-use-superblocks
845 Common Report Var(flag_sched2_use_superblocks) Optimization
846 If scheduling post reload, do superblock scheduling
849 Common Report Var(flag_sched2_use_traces) Optimization
850 If scheduling post reload, do trace scheduling
853 Common Report Var(flag_schedule_insns) Optimization
854 Reschedule instructions before register allocation
857 Common Report Var(flag_schedule_insns_after_reload) Optimization
858 Reschedule instructions after register allocation
860 ; sched_stalled_insns means that insns can be moved prematurely from the queue
861 ; of stalled insns into the ready list.
863 Common Report Var(flag_sched_stalled_insns) Optimization
864 Allow premature scheduling of queued insns
866 fsched-stalled-insns=
867 Common RejectNegative Joined UInteger
868 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
870 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
871 ; be examined for a dependency on a stalled insn that is candidate for
872 ; premature removal from the queue of stalled insns into the ready list (has
873 ; an effect only if the flag 'sched_stalled_insns' is set).
874 fsched-stalled-insns-dep
875 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
876 Set dependence distance checking in premature scheduling of queued insns
878 fsched-stalled-insns-dep=
879 Common RejectNegative Joined UInteger
880 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
883 Common Report Var(flag_section_anchors) Optimization
884 Access data in the same section from shared anchor points
886 frtl-abstract-sequences
887 Common Report Var(flag_rtl_seqabstr) Optimization
888 Perform sequence abstraction optimization on RTL
891 Common Report Var(flag_see) Init(0)
892 Eliminate redundant sign extensions using LCM.
895 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
896 Show column numbers in diagnostics, when available. Default on
899 Common Report Var(flag_signaling_nans) Optimization
900 Disable optimizations observable by IEEE signaling NaNs
903 Common Report Var(flag_signed_zeros) Init(1) Optimization
904 Disable floating point optimizations that ignore the IEEE signedness of zero
906 fsingle-precision-constant
907 Common Report Var(flag_single_precision_constant) Optimization
908 Convert floating point constants to single precision constants
910 fsplit-ivs-in-unroller
911 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
912 Split lifetimes of induction variables when loops are unrolled
915 Common Report Var(flag_split_wide_types) Optimization
916 Split wide types into independent registers
918 fvariable-expansion-in-unroller
919 Common Report Var(flag_variable_expansion_in_unroller) Optimization
920 Apply variable expansion when loops are unrolled
922 ; Emit code to probe the stack, to help detect stack overflow; also
923 ; may cause large objects to be allocated dynamically.
925 Common Report Var(flag_stack_check)
926 Insert stack checking code into the program
931 fstack-limit-register=
932 Common RejectNegative Joined
933 -fstack-limit-register=<register> Trap if the stack goes past <register>
936 Common RejectNegative Joined
937 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
940 Common Report Var(flag_stack_protect, 1)
941 Use propolice as a stack protection method
944 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
945 Use a stack protection method for every function
949 Does nothing. Preserved for backward compatibility.
951 ; Nonzero if we should do (language-dependent) alias analysis.
952 ; Typically, this analysis will assume that expressions of certain
953 ; types do not alias expressions of certain other types. Only used
954 ; if alias analysis (in general) is enabled.
956 Common Report Var(flag_strict_aliasing) Optimization
957 Assume strict aliasing rules apply
960 Common Report Var(flag_strict_overflow)
961 Treat signed overflow as undefined
964 Common Report Var(flag_syntax_only)
965 Check for syntax errors, then stop
968 Common Report Var(flag_test_coverage)
969 Create data files needed by \"gcov\"
972 Common Report Var(flag_thread_jumps) Optimization
973 Perform jump threading optimizations
976 Common Report Var(time_report)
977 Report the time taken by each compiler pass
980 Common Joined RejectNegative
981 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
984 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
985 Reorder top level functions, variables, and asms
988 Common Report Var(flag_tracer)
989 Perform superblock formation via tail duplication
991 ; Zero means that floating-point math operations cannot generate a
992 ; (user-visible) trap. This is the case, for example, in nonstop
993 ; IEEE 754 arithmetic.
995 Common Report Var(flag_trapping_math) Init(1) Optimization
996 Assume floating-point operations can trap
999 Common Report Var(flag_trapv) Optimization
1000 Trap for signed overflow in addition, subtraction and multiplication
1003 Common Report Var(flag_tree_ccp) Optimization
1004 Enable SSA-CCP optimization on trees
1007 Common Report Var(flag_tree_store_ccp) Optimization
1008 Enable SSA-CCP optimization for stores and loads
1011 Common Report Var(flag_tree_ch) Optimization
1012 Enable loop header copying on trees
1015 Common Report Var(flag_tree_copyrename) Optimization
1016 Replace SSA temporaries with better names in copies
1019 Common Report Var(flag_tree_copy_prop) Optimization
1020 Enable copy propagation on trees
1022 ftree-store-copy-prop
1023 Common Report Var(flag_tree_store_copy_prop) Optimization
1024 Enable copy propagation for stores and loads
1027 Common Report Var(flag_tree_dce) Optimization
1028 Enable SSA dead code elimination optimization on trees
1030 ftree-dominator-opts
1031 Common Report Var(flag_tree_dom) Optimization
1032 Enable dominator optimizations
1035 Common Report Var(flag_tree_dse) Optimization
1036 Enable dead store elimination
1039 Common Report Var(flag_tree_fre) Optimization
1040 Enable Full Redundancy Elimination (FRE) on trees
1043 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1044 Enable loop invariant motion on trees
1047 Common Report Var(flag_tree_loop_linear) Optimization
1048 Enable linear loop transforms on trees
1051 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1052 Create canonical induction variables in loops
1055 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1056 Enable loop optimizations on tree level
1059 Common Report Var(flag_tree_pre) Optimization
1060 Enable SSA-PRE optimization on trees
1063 Common Report Var(flag_tree_salias) Optimization
1064 Perform structural alias analysis
1067 Common Report Var(flag_tree_sink) Optimization
1068 Enable SSA code sinking on trees
1071 Common Report Var(flag_tree_sra) Optimization
1072 Perform scalar replacement of aggregates
1075 Common Report Var(flag_tree_ter) Optimization
1076 Replace temporary expressions in the SSA->normal pass
1079 Common Report Var(flag_tree_live_range_split) Optimization
1080 Perform live range splitting during the SSA->normal pass
1083 Common Report Var(flag_tree_vrp) Init(0) Optimization
1084 Perform Value Range Propagation on trees
1087 Common Report Var(flag_unit_at_a_time) Optimization
1088 Compile whole compilation unit at a time
1091 Common Report Var(flag_unroll_loops) Optimization
1092 Perform loop unrolling when iteration count is known
1095 Common Report Var(flag_unroll_all_loops) Optimization
1096 Perform loop unrolling for all loops
1098 ; Nonzero means that loop optimizer may assume that the induction variables
1099 ; that control loops do not overflow and that the loops with nontrivial
1100 ; exit condition are not infinite
1101 funsafe-loop-optimizations
1102 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1103 Allow loop optimizations to assume that the loops behave in normal way
1105 ; Nonzero means that unsafe floating-point math optimizations are allowed
1106 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1107 ; are allowed to assume that their arguments and results are "normal"
1108 ; (e.g., nonnegative for SQRT).
1109 funsafe-math-optimizations
1110 Common Report Var(flag_unsafe_math_optimizations) Optimization
1111 Allow math optimizations that may violate IEEE or ISO standards
1114 Common Report Var(flag_unswitch_loops) Optimization
1115 Perform loop unswitching
1118 Common Report Var(flag_unwind_tables) Optimization
1119 Just generate unwind tables for exception handling
1122 Common Report Var(flag_var_tracking) VarExists Optimization
1123 Perform variable tracking
1126 Common Report Var(flag_tree_vectorize) Optimization
1127 Enable loop vectorization on trees
1130 Common Report Var(flag_vect_cost_model) Optimization
1131 Enable use of cost model in vectorization
1133 ftree-vect-loop-version
1134 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1135 Enable loop versioning when doing loop vectorization on trees
1137 ftree-vectorizer-verbose=
1138 Common RejectNegative Joined
1139 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1142 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1143 Enable copy propagation of scalar-evolution information.
1145 ; -fverbose-asm causes extra commentary information to be produced in
1146 ; the generated assembly code (to make it more readable). This option
1147 ; is generally only of use to those who actually need to read the
1148 ; generated assembly code (perhaps while debugging the compiler itself).
1149 ; -fno-verbose-asm, the default, causes the extra information
1150 ; to not be added and is useful when comparing two assembler files.
1152 Common Report Var(flag_verbose_asm)
1153 Add extra commentary to assembler output
1156 Common Joined RejectNegative
1157 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1161 Common Report Var(flag_value_profile_transformations) Optimization
1162 Use expression value profiles in optimizations
1165 Common Report Var(flag_web) Init(2) Optimization
1166 Construct webs and split unrelated uses of single variable
1169 Common Report Var(flag_whole_program) Init(0) Optimization
1170 Perform whole program optimizations
1173 Common Report Var(flag_wrapv) Optimization
1174 Assume signed arithmetic overflow wraps around
1176 fzero-initialized-in-bss
1177 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1178 Put zero initialized data in the bss section
1181 Common JoinedOrMissing
1182 Generate debug information in default format
1185 Common JoinedOrMissing Negative(gdwarf-2)
1186 Generate debug information in COFF format
1189 Common JoinedOrMissing Negative(gstabs)
1190 Generate debug information in DWARF v2 format
1193 Common JoinedOrMissing
1194 Generate debug information in default extended format
1197 Common JoinedOrMissing Negative(gstabs+)
1198 Generate debug information in STABS format
1201 Common JoinedOrMissing Negative(gvms)
1202 Generate debug information in extended STABS format
1205 Common JoinedOrMissing Negative(gxcoff)
1206 Generate debug information in VMS format
1209 Common JoinedOrMissing Negative(gxcoff+)
1210 Generate debug information in XCOFF format
1213 Common JoinedOrMissing Negative(gcoff)
1214 Generate debug information in extended XCOFF format
1217 Common Joined Separate
1218 -o <file> Place output into <file>
1221 Common Var(profile_flag)
1222 Enable function profiling
1225 Common Var(pedantic)
1226 Issue warnings needed for strict compliance to the standard
1230 Like -pedantic but issue them as errors
1233 Common Var(quiet_flag)
1234 Do not display functions compiled or elapsed time
1237 Common Var(version_flag)
1238 Display the compiler's version
1241 Common Var(inhibit_warnings)
1244 ; This comment is to ensure we retain the blank line above.