1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009
4 ; Free Software Foundation, Inc.
6 ; This file is part of GCC.
8 ; GCC is free software; you can redistribute it and/or modify it under
9 ; the terms of the GNU General Public License as published by the Free
10 ; Software Foundation; either version 3, or (at your option) any later
13 ; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 ; WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 ; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 ; You should have received a copy of the GNU General Public License
19 ; along with GCC; see the file COPYING3. If not see
20 ; <http://www.gnu.org/licenses/>.
22 ; See the GCC internals manual (options.texi) for a description of this file's format.
24 ; Please try to keep this file in ASCII collating order.
28 Display this information
32 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params
36 Alias for --help=target
38 ;; The following four 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).
55 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
61 Common Joined Separate UInteger
62 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
65 Common JoinedOrMissing Optimization
66 -O<number> Set optimization level to <number>
70 Optimize for space rather than speed
73 Common RejectNegative Var(extra_warnings) Warning
74 This switch is deprecated; use -Wextra instead
77 Common Var(warn_aggregate_return) Warning
78 Warn about returning structures, unions or arrays
81 Common Var(warn_array_bounds) Warning
82 Warn if an array is accessed out of bounds
85 Common Var(warn_attributes) Init(1) Warning
86 Warn about inappropriate attribute usage
89 Common Var(warn_cast_align) Warning
90 Warn about pointer casts which increase alignment
92 Wdeprecated-declarations
93 Common Var(warn_deprecated_decl) Init(1) Warning
94 Warn about uses of __attribute__((deprecated)) declarations
96 Wdisabled-optimization
97 Common Var(warn_disabled_optimization) Warning
98 Warn when an optimization pass is disabled
101 Common Var(warnings_are_errors)
102 Treat all warnings as errors
106 Treat specified warning as error
109 Common Var(extra_warnings) Warning
110 Print extra (possibly unwanted) warnings
113 Common Var(flag_fatal_errors)
114 Exit on the first error occurred
117 Common RejectNegative Joined UInteger
118 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes
121 Common Var(warn_inline) Warning
122 Warn when an inlined function cannot be inlined
125 Common RejectNegative Joined UInteger Warning
128 Common RejectNegative Joined UInteger Warning
129 -Wlarger-than=<number> Warn if an object is larger than <number> bytes
131 Wunsafe-loop-optimizations
132 Common Var(warn_unsafe_loop_optimizations) Warning
133 Warn if the loop cannot be optimized due to nontrivial assumptions.
136 Common Var(warn_missing_noreturn) Warning
137 Warn about functions which might be candidates for __attribute__((noreturn))
140 Common Var(warn_mudflap) Init(1) Warning
141 Warn about constructs not instrumented by -fmudflap
144 Common Var(warn_overflow) Init(1) Warning
145 Warn about overflow in arithmetic expressions
148 Common Var(warn_packed) Warning
149 Warn when the packed attribute has no effect on struct layout
152 Common Var(warn_padded) Warning
153 Warn when padding is required to align structure members
156 Common Var(warn_shadow) Warning
157 Warn when one local variable shadows another
160 Common Var(warn_stack_protect) Warning
161 Warn when not issuing stack smashing protection for some reason
165 Warn about code which might break strict aliasing rules
168 Common Joined UInteger Var(warn_strict_aliasing) Init(-1) Warning
169 Warn about code which might break strict aliasing rules
173 Warn about optimizations that assume that signed overflow is undefined
176 Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
177 Warn about optimizations that assume that signed overflow is undefined
180 Common Var(warn_switch) Warning
181 Warn about enumerated switches, with no default, missing a case
184 Common Var(warn_switch_default) Warning
185 Warn about enumerated switches missing a \"default:\" statement
188 Common Var(warn_switch_enum) Warning
189 Warn about all enumerated switches missing a specific case
192 Common Var(warn_system_headers) Warning
193 Do not suppress warnings from system headers
196 Common Var(warn_type_limits) Init(-1) Warning
197 Warn if a comparison is always true or always false due to the limited range of the data type
200 Common Var(warn_uninitialized) Init(-1) Warning
201 Warn about uninitialized automatic variables
204 Common Var(warn_notreached) Warning
205 Warn about code that will never be executed
208 Common Var(warn_unused) Init(0) Warning
209 Enable all -Wunused- warnings
212 Common Var(warn_unused_function) Init(-1) Warning
213 Warn when a function is unused
216 Common Var(warn_unused_label) Init(-1) Warning
217 Warn when a label is unused
220 Common Var(warn_unused_parameter) Init(-1) Warning
221 Warn when a function parameter is unused
224 Common Var(warn_unused_value) Init(-1) Warning
225 Warn when an expression value is unused
228 Common Var(warn_unused_variable) Init(-1) Warning
229 Warn when a variable is unused
232 Common RejectNegative Var(warn_coverage_mismatch) Warning
233 Warn instead of error in case profiles in -fprofile-use do not match
237 -aux-info <file> Emit declaration information into <file>
250 -d<letters> Enable dumps from specific passes of the compiler
254 -dumpbase <file> Set the file basename to be used for dumps
256 ; The version of the C++ ABI in use. The following values are allowed:
258 ; 0: The version of the ABI believed most conformant with the C++ ABI
259 ; specification. This ABI may change as bugs are discovered and fixed.
260 ; Therefore, 0 will not necessarily indicate the same ABI in different
263 ; 1: The version of the ABI first used in G++ 3.2.
265 ; 2: The version of the ABI first used in G++ 3.4.
267 ; Additional positive integers will be assigned as new versions of
268 ; the ABI become the default version of the ABI.
270 Common Joined UInteger Var(flag_abi_version) Init(2)
273 Common Report Var(align_functions,0) Optimization UInteger
274 Align the start of functions
277 Common RejectNegative Joined UInteger
280 Common Report Var(align_jumps,0) Optimization UInteger
281 Align labels which are only reached by jumping
284 Common RejectNegative Joined UInteger
287 Common Report Var(align_labels,0) Optimization UInteger
291 Common RejectNegative Joined UInteger
294 Common Report Var(align_loops) Optimization UInteger
295 Align the start of loops
298 Common RejectNegative Joined UInteger
300 ; This flag is only tested if alias checking is enabled.
301 ; 0 if pointer arguments may alias each other. True in C.
302 ; 1 if pointer arguments may not alias each other but may alias
304 ; 2 if pointer arguments may not alias each other and may not
305 ; alias global variables.
306 ; 3 if pointer arguments may not alias anything. True in Fortran.
307 ; Set by the front end.
309 Common Report Var(flag_argument_noalias,0) Optimization
310 Specify that arguments may alias each other and globals
313 Common Report Var(flag_argument_noalias,1) VarExists Optimization
314 Assume arguments may alias globals but not each other
316 fargument-noalias-global
317 Common Report Var(flag_argument_noalias,2) VarExists Optimization
318 Assume arguments alias neither each other nor globals
320 fargument-noalias-anything
321 Common Report Var(flag_argument_noalias,3) VarExists Optimization
322 Assume arguments alias no other storage
324 fasynchronous-unwind-tables
325 Common Report Var(flag_asynchronous_unwind_tables) Optimization
326 Generate unwind tables that are exact at each instruction boundary
329 Common Report Var(flag_auto_inc_dec) Init(1)
330 Generate auto-inc/dec instructions
332 ; -fcheck-bounds causes gcc to generate array bounds checks.
333 ; For C, C++ and ObjC: defaults off.
334 ; For Java: defaults to on.
335 ; For Fortran: defaults to off.
337 Common Report Var(flag_bounds_check)
338 Generate code to check bounds before indexing arrays
341 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
342 Replace add, compare, branch with branch on count register
344 fbranch-probabilities
345 Common Report Var(flag_branch_probabilities) Optimization
346 Use profiling information for branch probabilities
348 fbranch-target-load-optimize
349 Common Report Var(flag_branch_target_load_optimize) Optimization
350 Perform branch target load optimization before prologue / epilogue threading
352 fbranch-target-load-optimize2
353 Common Report Var(flag_branch_target_load_optimize2) Optimization
354 Perform branch target load optimization after prologue / epilogue threading
357 Common Report Var(flag_btr_bb_exclusive) Optimization
358 Restrict target load migration not to re-use registers in any basic block
361 Common Joined RejectNegative
362 -fcall-saved-<register> Mark <register> as being preserved across functions
365 Common Joined RejectNegative
366 -fcall-used-<register> Mark <register> as being corrupted by function calls
368 ; Nonzero for -fcaller-saves: allocate values in regs that need to
369 ; be saved across function calls, if that produces overall better code.
370 ; Optional now, so people can test it.
372 Common Report Var(flag_caller_saves) Optimization
373 Save registers around function calls
376 Common Report Var(flag_check_data_deps)
377 Compare the results of several data dependence analyzers.
380 Common Report Var(flag_no_common,0) Optimization
381 Do not put uninitialized globals in the common section
384 Common JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
385 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump
387 fcompare-debug-second
388 Common RejectNegative Var(flag_compare_debug)
389 Run only the second compilation of -fcompare-debug
392 Common Var(flag_conserve_stack) Optimization
393 Do not perform optimizations increasing noticeably stack usage
396 Common Report Var(flag_cprop_registers) Optimization
397 Perform a register copy-propagation optimization pass
400 Common Report Var(flag_crossjumping) Optimization
401 Perform cross-jumping optimization
404 Common Report Var(flag_cse_follow_jumps) Optimization
405 When running CSE, follow jumps to their targets
409 Does nothing. Preserved for backward compatibility.
412 Common Report Var(flag_cx_limited_range) Optimization
413 Omit range reduction step when performing complex division
416 Common Report Var(flag_cx_fortran_rules) Optimization
417 Complex multiplication and division follow Fortran rules
420 Common Report Var(flag_data_sections) Optimization
421 Place data items into their own section
425 List all available debugging counters with their limits and counts.
428 Common RejectNegative Joined
429 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
432 Common Joined RejectNegative
433 Map one directory name to another in debug information
435 ; Nonzero for -fdefer-pop: don't pop args after each function call
436 ; instead save them up to pop many calls' args with one insns.
438 Common Report Var(flag_defer_pop) Optimization
439 Defer popping functions args from stack until later
442 Common Report Var(flag_delayed_branch) Optimization
443 Attempt to fill delay slots of branch instructions
445 fdelete-null-pointer-checks
446 Common Report Var(flag_delete_null_pointer_checks) Init(1) Optimization
447 Delete useless null pointer checks
449 fdiagnostics-show-location=
450 Common Joined RejectNegative
451 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
453 fdiagnostics-show-option
455 Amend appropriate diagnostic messages with the command line option that controls them
458 Common Joined RejectNegative
459 -fdump-<type> Dump various compiler internals to a file
462 Common RejectNegative Joined Var(flag_dump_final_insns)
463 -fdump-final-insns=filename Dump to filename the insns at the end of translation
466 Common Report Var(flag_dump_noaddr)
467 Suppress output of addresses in debugging dumps
470 Common Report Var(flag_dump_unnumbered) VarExists
471 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
473 fdump-unnumbered-links
474 Common Report Var(flag_dump_unnumbered_links) VarExists
475 Suppress output of previous and next insn numbers in debugging dumps
478 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
479 Enable CFI tables via GAS assembler directives.
482 Common Report Var(flag_early_inlining) Init(1) Optimization
483 Perform early inlining
485 feliminate-dwarf2-dups
486 Common Report Var(flag_eliminate_dwarf2_dups)
487 Perform DWARF2 duplicate elimination
490 Common Report Var(flag_ipa_sra) Init(0) Optimization
491 Perform interprocedural reduction of aggregates
493 feliminate-unused-debug-symbols
494 Common Report Var(flag_debug_only_used_symbols)
495 Perform unused type elimination in debug info
497 feliminate-unused-debug-types
498 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
499 Perform unused type elimination in debug info
501 femit-class-debug-always
502 Common Report Var(flag_emit_class_debug_always) Init(0)
503 Do not suppress C++ class debug information.
506 Common Report Var(flag_enable_icf_debug)
507 Generate debug information to support Identical Code Folding (ICF)
510 Common Report Var(flag_exceptions) Optimization
511 Enable exception handling
513 fexpensive-optimizations
514 Common Report Var(flag_expensive_optimizations) Optimization
515 Perform a number of minor, expensive optimizations
518 Common Joined RejectNegative
519 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision
525 Common Report Var(flag_finite_math_only) Optimization
526 Assume no NaNs or infinities are generated
529 Common Joined RejectNegative
530 -ffixed-<register> Mark <register> as being unavailable to the compiler
533 Common Report Var(flag_float_store) Optimization
534 Don't allocate floats and doubles in extended-precision registers
538 Does nothing. Preserved for backward compatibility.
541 Common Report Var(flag_forward_propagate) Optimization
542 Perform a forward propagation pass on RTL
544 ; Nonzero means don't put addresses of constant functions in registers.
545 ; Used for compiling the Unix kernel, where strange substitutions are
546 ; done on the assembly output.
548 Common Report Var(flag_no_function_cse,0)
549 Allow function addresses to be held in registers
552 Common Report Var(flag_function_sections)
553 Place each function into its own section
556 Common Report Var(flag_gcse) Optimization
557 Perform global common subexpression elimination
560 Common Report Var(flag_gcse_lm) Init(1) Optimization
561 Perform enhanced load motion during global common subexpression elimination
564 Common Report Var(flag_gcse_sm) Init(0) Optimization
565 Perform store motion after global common subexpression elimination
568 Common Report Var(flag_gcse_las) Init(0) Optimization
569 Perform redundant load after store elimination in global common subexpression
573 Common Report Var(flag_gcse_after_reload) Optimization
574 Perform global common subexpression elimination after register allocation
577 ; This option is not documented yet as its semantics will change.
579 Common Report Var(flag_graphite)
580 Enable in and out of Graphite representation
583 Common Report Var(flag_graphite_identity) Optimization
584 Enable Graphite Identity transformation
586 floop-parallelize-all
587 Common Report Var(flag_loop_parallelize_all) Optimization
588 Mark all loops as parallel
591 Common Report Var(flag_loop_strip_mine) Optimization
592 Enable Loop Strip Mining transformation
595 Common Report Var(flag_loop_interchange) Optimization
596 Enable Loop Interchange transformation
599 Common Report Var(flag_loop_block) Optimization
600 Enable Loop Blocking transformation
602 fguess-branch-probability
603 Common Report Var(flag_guess_branch_prob) Optimization
604 Enable guessing of branch probabilities
606 ; Nonzero means ignore `#ident' directives. 0 means handle them.
607 ; Generate position-independent code for executables if possible
608 ; On SVR4 targets, it also controls whether or not to emit a
609 ; string identifying the compiler.
611 Common Report Var(flag_no_ident,0)
612 Process #ident directives
615 Common Report Var(flag_if_conversion) Optimization
616 Perform conversion of conditional jumps to branchless equivalents
619 Common Report Var(flag_if_conversion2) Optimization
620 Perform conversion of conditional jumps to conditional execution
622 ; -finhibit-size-directive inhibits output of .size for ELF.
623 ; This is used only for compiling crtstuff.c,
624 ; and it may be extended to other effects
625 ; needed for crtstuff.c on other systems.
626 finhibit-size-directive
627 Common Report Var(flag_inhibit_size_directive)
628 Do not generate .size directives
631 Common Report Var(flag_indirect_inlining)
632 Perform indirect inlining
634 ; Nonzero means that functions declared `inline' will be treated
635 ; as `static'. Prevents generation of zillions of copies of unused
636 ; static inline functions; instead, `inlines' are written out
637 ; only when actually used. Used in conjunction with -g. Also
638 ; does the right thing with #pragma interface.
640 Common Report Var(flag_no_inline,0) Init(0)
641 Pay attention to the \"inline\" keyword
643 finline-small-functions
644 Common Report Var(flag_inline_small_functions) Optimization
645 Integrate simple functions into their callers when code size is known to not growth
648 Common Report Var(flag_inline_functions) Optimization
649 Integrate simple functions into their callers
651 finline-functions-called-once
652 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
653 Integrate functions called once into their callers
656 Common RejectNegative Joined UInteger
659 Common RejectNegative Joined UInteger
660 -finline-limit=<number> Limit the size of inlined functions to <number>
662 finstrument-functions
663 Common Report Var(flag_instrument_function_entry_exit)
664 Instrument function entry and exit with profiling calls
666 finstrument-functions-exclude-function-list=
667 Common RejectNegative Joined
668 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
670 finstrument-functions-exclude-file-list=
671 Common RejectNegative Joined
672 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
675 Common Report Var(flag_ipa_cp) Optimization
676 Perform Interprocedural constant propagation
679 Common Report Var(flag_ipa_cp_clone) Optimization
680 Perform cloning to make Interprocedural constant propagation stronger
683 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
684 Discover pure and const functions
687 Common Report Var(flag_ipa_pta) Init(0) Optimization
688 Perform interprocedural points-to analysis
691 Common Report Var(flag_ipa_reference) Init(0) Optimization
692 Discover readonly and non addressable static variables
695 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
696 Type based escape and alias analysis
699 Common Report Var(flag_ipa_matrix_reorg) Optimization
700 Perform matrix layout flattening and transposing based
701 on profiling information.
704 Common Report Var(flag_ipa_struct_reorg)
705 Perform structure layout optimizations based
706 on profiling information.
709 Common Joined RejectNegative
710 -fira-algorithm=[CB|priority] Set the used IRA algorithm
713 Common Joined RejectNegative
714 -fira-region=[one|all|mixed] Set regions for IRA
717 Common Report Var(flag_ira_coalesce) Init(0)
718 Do optimistic coalescing.
721 Common Report Var(flag_ira_loop_pressure)
722 Use IRA based register pressure calculation
723 in RTL loop optimizations.
725 fira-share-save-slots
726 Common Report Var(flag_ira_share_save_slots) Init(1)
727 Share slots for saving different hard registers.
729 fira-share-spill-slots
730 Common Report Var(flag_ira_share_spill_slots) Init(1)
731 Share stack slots for spilled pseudo-registers.
734 Common RejectNegative Joined UInteger
735 -fira-verbose=<number> Control IRA's level of diagnostic messages.
738 Common Report Var(flag_ivopts) Init(1) Optimization
739 Optimize induction variables on trees
742 Common Var(flag_jump_tables) Init(1) Optimization
743 Use jump tables for sufficiently large switch statements
745 fkeep-inline-functions
746 Common Report Var(flag_keep_inline_functions)
747 Generate code for functions even if they are fully inlined
750 Common Report Var(flag_keep_static_consts) Init(1)
751 Emit static const variables even if they are not used
754 Common Report Var(flag_leading_underscore) Init(-1)
755 Give external symbols a leading underscore
759 Does nothing. Preserved for backward compatibility.
763 Enable link-time optimization.
765 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
766 flto-compression-level=
767 Common Joined UInteger Var(flag_lto_compression_level) Init(-1)
768 -flto-compression-level=<number> Use zlib compression level <number> for IL
771 Common Report Var(flag_lto_report) Init(0) Optimization
772 Report various link-time optimization statistics
775 Common Report Var(flag_errno_math) Init(1) Optimization
776 Set errno after built-in math functions
779 Common Report Var(mem_report)
780 Report on permanent memory allocation
782 ; This will attempt to merge constant section constants, if 1 only
783 ; string constants and constants from constant pool, if 2 also constant
786 Common Report Var(flag_merge_constants,2) Init(1) Optimization
787 Attempt to merge identical constants and constant variables
790 Common Report Var(flag_merge_constants,1) VarExists Optimization
791 Attempt to merge identical constants across compilation units
794 Common Report Var(flag_merge_debug_strings) Init(1)
795 Attempt to merge identical debug strings across compilation units
798 Common RejectNegative Joined UInteger
799 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
802 Common Report Var(flag_modulo_sched) Optimization
803 Perform SMS based modulo scheduling before the first scheduling pass
805 fmodulo-sched-allow-regmoves
806 Common Report Var(flag_modulo_sched_allow_regmoves)
807 Perform SMS based modulo scheduling with register moves allowed
809 fmove-loop-invariants
810 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
811 Move loop invariant computations out of loops
814 Common RejectNegative Report Var(flag_mudflap)
815 Add mudflap bounds-checking instrumentation for single-threaded program
818 Common RejectNegative Report VarExists Var(flag_mudflap,2)
819 Add mudflap bounds-checking instrumentation for multi-threaded program
822 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
823 Ignore read operations when inserting mudflap instrumentation
826 Common Var(flag_dce) Init(1) Optimization
827 Use the RTL dead code elimination pass
830 Common Var(flag_dse) Init(1) Optimization
831 Use the RTL dead store elimination pass
833 freschedule-modulo-scheduled-loops
834 Common Report Var(flag_resched_modulo_sched) Optimization
835 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
838 Common Report Var(flag_non_call_exceptions) Optimization
839 Support synchronous non-call exceptions
842 Common Report Var(flag_omit_frame_pointer) Optimization
843 When possible do not generate stack frames
845 foptimize-register-move
846 Common Report Var(flag_regmove) Optimization
847 Do the full register move optimization pass
849 foptimize-sibling-calls
850 Common Report Var(flag_optimize_sibling_calls) Optimization
851 Optimize sibling and tail recursive calls
854 Common Report Var(pre_ipa_mem_report)
855 Report on memory allocation before interprocedural optimization
858 Common Report Var(post_ipa_mem_report)
859 Report on memory allocation before interprocedural optimization
862 Common Report Var(flag_pack_struct) Optimization
863 Pack structure members together without holes
866 Common RejectNegative Joined UInteger Optimization
867 -fpack-struct=<number> Set initial maximum structure member alignment
870 Common Report Var(flag_pcc_struct_return,1) VarExists
871 Return small aggregates in memory, not registers
874 Common Report Var(flag_peel_loops) Optimization
878 Common Report Var(flag_no_peephole,0) Optimization
879 Enable machine specific peephole optimizations
882 Common Report Var(flag_peephole2) Optimization
883 Enable an RTL peephole pass before sched2
886 Common Report Var(flag_pic,2)
887 Generate position-independent code if possible (large mode)
890 Common Report Var(flag_pie,2)
891 Generate position-independent code for executables if possible (large mode)
894 Common Report Var(flag_pic,1) VarExists
895 Generate position-independent code if possible (small mode)
898 Common Report Var(flag_pie,1) VarExists
899 Generate position-independent code for executables if possible (small mode)
902 Common Joined RejectNegative
903 Specify a plugin to load
906 Common Joined RejectNegative
907 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>
909 fpredictive-commoning
910 Common Report Var(flag_predictive_commoning) Optimization
911 Run predictive commoning optimization.
913 fprefetch-loop-arrays
914 Common Report Var(flag_prefetch_loop_arrays) Optimization
915 Generate prefetch instructions, if available, for arrays in loops
918 Common Report Var(profile_flag)
919 Enable basic program profiling code
922 Common Report Var(profile_arc_flag)
923 Insert arc-based program profiling code
926 Common Joined RejectNegative
927 Set the top-level directory for storing the profile data.
928 The default is 'pwd'.
931 Common Report Var(flag_profile_correction)
932 Enable correction of flow inconsistent profile data input
936 Enable common options for generating profile info for profile feedback directed optimizations
939 Common Joined RejectNegative
940 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=
943 Common Var(flag_profile_use)
944 Enable common options for performing profile feedback directed optimizations
947 Common Joined RejectNegative
948 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=
951 Common Report Var(flag_profile_values)
952 Insert code to profile values of expressions
958 Common Joined RejectNegative
959 -frandom-seed=<string> Make compile reproducible using <string>
961 ; This switch causes the command line that was used to create an
962 ; object file to be recorded into the object file. The exact format
963 ; of this recording is target and binary file format dependent.
964 ; It is related to the -fverbose-asm switch, but that switch only
965 ; records information in the assembler output file as comments, so
966 ; they never reach the object file.
968 Common Report Var(flag_record_gcc_switches)
969 Record gcc command line switches in the object file.
972 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
973 Return small aggregates in registers
976 Common Report Var(flag_regmove) Optimization
977 Enables a register move optimization
980 Common Report Var(flag_rename_registers) Init(2) Optimization
981 Perform a register renaming optimization pass
984 Common Report Var(flag_reorder_blocks) Optimization
985 Reorder basic blocks to improve code placement
987 freorder-blocks-and-partition
988 Common Report Var(flag_reorder_blocks_and_partition) Optimization
989 Reorder basic blocks and partition into hot and cold sections
992 Common Report Var(flag_reorder_functions) Optimization
993 Reorder functions to improve code placement
995 frerun-cse-after-loop
996 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
997 Add a common subexpression elimination pass after loop optimizations
1001 Does nothing. Preserved for backward compatibility.
1004 Common Report Var(flag_rounding_math) Optimization
1005 Disable optimizations that assume default FP rounding behavior
1008 Common Report Var(flag_schedule_interblock) Init(1) Optimization
1009 Enable scheduling across basic blocks
1012 Common Report Var(flag_sched_pressure) Init(0) Optimization
1013 Enable register pressure sensitive insn scheduling
1016 Common Report Var(flag_schedule_speculative) Init(1) Optimization
1017 Allow speculative motion of non-loads
1020 Common Report Var(flag_schedule_speculative_load) Optimization
1021 Allow speculative motion of some loads
1023 fsched-spec-load-dangerous
1024 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
1025 Allow speculative motion of more loads
1028 Common RejectNegative Joined
1029 -fsched-verbose=<number> Set the verbosity level of the scheduler
1031 fsched2-use-superblocks
1032 Common Report Var(flag_sched2_use_superblocks) Optimization
1033 If scheduling post reload, do superblock scheduling
1036 Common Report Var(flag_sched2_use_traces) Optimization
1037 If scheduling post reload, do trace scheduling
1040 Common Report Var(flag_schedule_insns) Optimization
1041 Reschedule instructions before register allocation
1044 Common Report Var(flag_schedule_insns_after_reload) Optimization
1045 Reschedule instructions after register allocation
1047 ; This flag should be on when a target implements non-trivial
1048 ; scheduling hooks, maybe saving some information for its own sake.
1049 ; On IA64, for example, this is used for correct bundling.
1050 fselective-scheduling
1051 Common Report Var(flag_selective_scheduling) Optimization
1052 Schedule instructions using selective scheduling algorithm
1054 fselective-scheduling2
1055 Common Report Var(flag_selective_scheduling2) Optimization
1056 Run selective scheduling after reload
1058 fsel-sched-pipelining
1059 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
1060 Perform software pipelining of inner loops during selective scheduling
1062 fsel-sched-pipelining-outer-loops
1063 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
1064 Perform software pipelining of outer loops during selective scheduling
1066 fsel-sched-reschedule-pipelined
1067 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
1068 Reschedule pipelined regions without pipelining
1070 ; sched_stalled_insns means that insns can be moved prematurely from the queue
1071 ; of stalled insns into the ready list.
1072 fsched-stalled-insns
1073 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
1074 Allow premature scheduling of queued insns
1076 fsched-stalled-insns=
1077 Common RejectNegative Joined UInteger
1078 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
1080 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
1081 ; be examined for a dependency on a stalled insn that is candidate for
1082 ; premature removal from the queue of stalled insns into the ready list (has
1083 ; an effect only if the flag 'sched_stalled_insns' is set).
1084 fsched-stalled-insns-dep
1085 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
1086 Set dependence distance checking in premature scheduling of queued insns
1088 fsched-stalled-insns-dep=
1089 Common RejectNegative Joined UInteger
1090 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
1092 fsched-group-heuristic
1093 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
1094 Enable the group heuristic in the scheduler
1096 fsched-critical-path-heuristic
1097 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
1098 Enable the critical path heuristic in the scheduler
1100 fsched-spec-insn-heuristic
1101 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
1102 Enable the speculative instruction heuristic in the scheduler
1104 fsched-rank-heuristic
1105 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
1106 Enable the rank heuristic in the scheduler
1108 fsched-last-insn-heuristic
1109 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
1110 Enable the last instruction heuristic in the scheduler
1112 fsched-dep-count-heuristic
1113 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
1114 Enable the dependent count heuristic in the scheduler
1117 Common Report Var(flag_section_anchors) Optimization
1118 Access data in the same section from shared anchor points
1122 Does nothing. Preserved for backward compatibility.
1125 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
1126 Show column numbers in diagnostics, when available. Default on
1129 Common Report Var(flag_signaling_nans) Optimization
1130 Disable optimizations observable by IEEE signaling NaNs
1133 Common Report Var(flag_signed_zeros) Init(1) Optimization
1134 Disable floating point optimizations that ignore the IEEE signedness of zero
1136 fsingle-precision-constant
1137 Common Report Var(flag_single_precision_constant) Optimization
1138 Convert floating point constants to single precision constants
1140 fsplit-ivs-in-unroller
1141 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
1142 Split lifetimes of induction variables when loops are unrolled
1145 Common Report Var(flag_split_wide_types) Optimization
1146 Split wide types into independent registers
1148 fvariable-expansion-in-unroller
1149 Common Report Var(flag_variable_expansion_in_unroller) Optimization
1150 Apply variable expansion when loops are unrolled
1153 Common Report RejectNegative Joined
1154 -fstack-check=[no|generic|specific] Insert stack checking code into the program
1158 Insert stack checking code into the program. Same as -fstack-check=specific
1163 fstack-limit-register=
1164 Common RejectNegative Joined
1165 -fstack-limit-register=<register> Trap if the stack goes past <register>
1167 fstack-limit-symbol=
1168 Common RejectNegative Joined
1169 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
1172 Common Report Var(flag_stack_protect, 1)
1173 Use propolice as a stack protection method
1175 fstack-protector-all
1176 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
1177 Use a stack protection method for every function
1181 Does nothing. Preserved for backward compatibility.
1183 ; Nonzero if we should do (language-dependent) alias analysis.
1184 ; Typically, this analysis will assume that expressions of certain
1185 ; types do not alias expressions of certain other types. Only used
1186 ; if alias analysis (in general) is enabled.
1188 Common Report Var(flag_strict_aliasing) Optimization
1189 Assume strict aliasing rules apply
1192 Common Report Var(flag_strict_overflow)
1193 Treat signed overflow as undefined
1196 Common Report Var(flag_syntax_only)
1197 Check for syntax errors, then stop
1200 Common Report Var(flag_test_coverage)
1201 Create data files needed by \"gcov\"
1204 Common Report Var(flag_thread_jumps) Optimization
1205 Perform jump threading optimizations
1208 Common Report Var(time_report)
1209 Report the time taken by each compiler pass
1212 Common Joined RejectNegative
1213 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1216 Common Report Var(flag_toplevel_reorder) Init(2) Optimization
1217 Reorder top level functions, variables, and asms
1220 Common Report Var(flag_tracer)
1221 Perform superblock formation via tail duplication
1223 ; Zero means that floating-point math operations cannot generate a
1224 ; (user-visible) trap. This is the case, for example, in nonstop
1225 ; IEEE 754 arithmetic.
1227 Common Report Var(flag_trapping_math) Init(1) Optimization
1228 Assume floating-point operations can trap
1231 Common Report Var(flag_trapv) Optimization
1232 Trap for signed overflow in addition, subtraction and multiplication
1235 Common Report Var(flag_tree_ccp) Optimization
1236 Enable SSA-CCP optimization on trees
1240 Does nothing. Preserved for backward compatibility.
1243 Common Report Var(flag_tree_ch) Optimization
1244 Enable loop header copying on trees
1247 Common Report Var(flag_tree_copyrename) Optimization
1248 Replace SSA temporaries with better names in copies
1251 Common Report Var(flag_tree_copy_prop) Optimization
1252 Enable copy propagation on trees
1254 ftree-store-copy-prop
1256 Does nothing. Preserved for backward compatibility.
1259 Common Report Var(flag_tree_cselim) Init(2) Optimization
1260 Transform condition stores into unconditional ones
1262 ftree-switch-conversion
1263 Common Report Var(flag_tree_switch_conversion) Optimization
1264 Perform conversions of switch initializations.
1267 Common Report Var(flag_tree_dce) Optimization
1268 Enable SSA dead code elimination optimization on trees
1270 ftree-dominator-opts
1271 Common Report Var(flag_tree_dom) Optimization
1272 Enable dominator optimizations
1275 Common Report Var(flag_tree_dse) Optimization
1276 Enable dead store elimination
1279 Common Report Var(flag_tree_forwprop) Init(1) Optimization
1280 Enable forward propagation on trees
1283 Common Report Var(flag_tree_fre) Optimization
1284 Enable Full Redundancy Elimination (FRE) on trees
1286 ftree-loop-distribution
1287 Common Report Var(flag_tree_loop_distribution) Optimization
1288 Enable loop distribution on trees
1291 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1292 Enable loop invariant motion on trees
1295 Common Report Var(flag_tree_loop_linear) Optimization
1296 Enable linear loop transforms on trees
1299 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1300 Create canonical induction variables in loops
1303 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1304 Enable loop optimizations on tree level
1306 ftree-parallelize-loops=
1307 Common Report Joined UInteger Var(flag_tree_parallelize_loops) Init(1)
1308 Enable automatic parallelization of loops
1311 Common Report Var(flag_tree_phiprop) Init(1) Optimization
1312 Enable hoisting loads from conditional pointers.
1315 Common Report Var(flag_tree_pre) Optimization
1316 Enable SSA-PRE optimization on trees
1319 Common Report Var(flag_tree_pta) Init(1) Optimization
1320 Perform function-local points-to analysis on trees.
1323 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1324 Enable reassociation on tree level
1328 Does nothing. Preserved for backward compatibility.
1331 Common Report Var(flag_tree_sink) Optimization
1332 Enable SSA code sinking on trees
1335 Common Report Var(flag_tree_sra) Optimization
1336 Perform scalar replacement of aggregates
1339 Common Report Var(flag_tree_ter) Init(1) Optimization
1340 Replace temporary expressions in the SSA->normal pass
1343 Common Report Var(flag_tree_live_range_split) Optimization
1344 Perform live range splitting during the SSA->normal pass
1347 Common Report Var(flag_tree_vrp) Init(0) Optimization
1348 Perform Value Range Propagation on trees
1351 Common Report Var(flag_unit_at_a_time) Init(1) Optimization
1352 Compile whole compilation unit at a time
1355 Common Report Var(flag_unroll_loops) Optimization
1356 Perform loop unrolling when iteration count is known
1359 Common Report Var(flag_unroll_all_loops) Optimization
1360 Perform loop unrolling for all loops
1362 ; Nonzero means that loop optimizer may assume that the induction variables
1363 ; that control loops do not overflow and that the loops with nontrivial
1364 ; exit condition are not infinite
1365 funsafe-loop-optimizations
1366 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1367 Allow loop optimizations to assume that the loops behave in normal way
1370 Common Report Var(flag_associative_math)
1371 Allow optimization for floating-point arithmetic which may change the
1372 result of the operation due to rounding.
1375 Common Report Var(flag_reciprocal_math)
1376 Same as -fassociative-math for expressions which include division.
1378 ; Nonzero means that unsafe floating-point math optimizations are allowed
1379 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1380 ; are allowed to assume that their arguments and results are "normal"
1381 ; (e.g., nonnegative for SQRT).
1382 funsafe-math-optimizations
1383 Common Report Var(flag_unsafe_math_optimizations) Optimization
1384 Allow math optimizations that may violate IEEE or ISO standards
1387 Common Report Var(flag_unswitch_loops) Optimization
1388 Perform loop unswitching
1391 Common Report Var(flag_unwind_tables) Optimization
1392 Just generate unwind tables for exception handling
1398 Common Report Var(flag_var_tracking) VarExists Optimization
1399 Perform variable tracking
1401 fvar-tracking-assignments
1402 Common Report Var(flag_var_tracking_assignments) VarExists Optimization
1403 Perform variable tracking by annotating assignments
1405 fvar-tracking-assignments-toggle
1406 Common Report Var(flag_var_tracking_assignments_toggle) VarExists Optimization
1407 Toggle -fvar-tracking-assignments
1409 fvar-tracking-uninit
1410 Common Report Var(flag_var_tracking_uninit) Optimization
1411 Perform variable tracking and also tag variables that are uninitialized
1414 Common Report Var(flag_tree_vectorize) Optimization
1415 Enable loop vectorization on trees
1418 Common Report Var(flag_tree_slp_vectorize) Init(2) Optimization
1419 Enable basic block vectorization (SLP) on trees
1422 Common Report Var(flag_vect_cost_model) Optimization
1423 Enable use of cost model in vectorization
1425 ftree-vect-loop-version
1426 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1427 Enable loop versioning when doing loop vectorization on trees
1429 ftree-vectorizer-verbose=
1430 Common RejectNegative Joined
1431 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1434 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1435 Enable copy propagation of scalar-evolution information.
1437 ; -fverbose-asm causes extra commentary information to be produced in
1438 ; the generated assembly code (to make it more readable). This option
1439 ; is generally only of use to those who actually need to read the
1440 ; generated assembly code (perhaps while debugging the compiler itself).
1441 ; -fno-verbose-asm, the default, causes the extra information
1442 ; to not be added and is useful when comparing two assembler files.
1444 Common Report Var(flag_verbose_asm)
1445 Add extra commentary to assembler output
1448 Common Joined RejectNegative
1449 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1453 Common Report Var(flag_value_profile_transformations) Optimization
1454 Use expression value profiles in optimizations
1457 Common Report Var(flag_web) Init(2) Optimization
1458 Construct webs and split unrelated uses of single variable
1461 Common Var(flag_whopr)
1462 Enable partitioned link-time optimization.
1464 ftree-builtin-call-dce
1465 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
1466 Enable conditional dead code elimination for builtin calls
1469 Common Report Var(flag_whole_program) Init(0) Optimization
1470 Perform whole program optimizations
1473 Common Report Var(flag_wrapv) Optimization
1474 Assume signed arithmetic overflow wraps around
1476 fzero-initialized-in-bss
1477 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1478 Put zero initialized data in the bss section
1481 Common JoinedOrMissing
1482 Generate debug information in default format
1485 Common JoinedOrMissing Negative(gdwarf-)
1486 Generate debug information in COFF format
1489 Common Joined UInteger Var(dwarf_version) Init(2) Negative(gstabs)
1490 Generate debug information in DWARF v2 (or later) format
1493 Common JoinedOrMissing
1494 Generate debug information in default extended format
1497 Common JoinedOrMissing Negative(gstabs+)
1498 Generate debug information in STABS format
1501 Common JoinedOrMissing Negative(gvms)
1502 Generate debug information in extended STABS format
1505 Common RejectNegative Var(dwarf_strict,0) Init(-1)
1506 Emit DWARF additions beyond selected version
1509 Common Report RejectNegative Var(dwarf_strict,1) VarExists
1510 Don't emit DWARF additions beyond selected version
1513 Common Report Var(flag_gtoggle)
1514 Toggle debug information generation
1517 Common JoinedOrMissing Negative(gxcoff)
1518 Generate debug information in VMS format
1521 Common JoinedOrMissing Negative(gxcoff+)
1522 Generate debug information in XCOFF format
1525 Common JoinedOrMissing Negative(gcoff)
1526 Generate debug information in extended XCOFF format
1529 Common Joined Separate
1530 -o <file> Place output into <file>
1533 Common Var(profile_flag)
1534 Enable function profiling
1537 Common Var(pedantic)
1538 Issue warnings needed for strict compliance to the standard
1542 Like -pedantic but issue them as errors
1545 Common Var(quiet_flag)
1546 Do not display functions compiled or elapsed time
1549 Common Var(version_flag)
1550 Display the compiler's version
1553 Common Var(inhibit_warnings)
1557 Common RejectNegative Negative(pie)
1558 Create a shared library
1561 Common RejectNegative Negative(shared)
1562 Create a position independent executable
1564 ; This comment is to ensure we retain the blank line above.