1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003-2018 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 (options.texi) for a description of this file's format.
23 ; Please try to keep this file in ASCII collating order.
37 ; Not used directly to control optimizations, only to save -Ofast
38 ; setting for "optimize" attributes.
42 ; True if this is the lto front end. This is used to disable gimple
43 ; generation and lowering passes that are normally run on the output
44 ; of a front end. These passes must be bypassed for lto since they
45 ; have already been done before the gimple was written.
49 ; This variable is set to non-0 only by LTO front-end. 1 indicates that
50 ; the output produced will be used for incrmeental linking (thus weak symbols
51 ; can still be bound) and 2 indicates that the IL is going to be linked and
52 ; and output to LTO object file.
54 enum incremental_link flag_incremental_link = INCREMENTAL_LINK_NONE
56 ; 0 means straightforward implementation of complex divide acceptable.
57 ; 1 means wide ranges of inputs must work for complex divide.
58 ; 2 means C99-like requirements for complex multiply and divide.
60 int flag_complex_method = 1
62 ; Language specific warning pass for unused results.
64 bool flag_warn_unused_result = false
69 ; Nonzero if we should write GIMPLE bytecode for link-time optimization.
73 ; Nonzero if we should write GIMPLE bytecode for offload compilation.
75 int flag_generate_offload = 0
77 ; Nonzero means we should be saving declaration info into a .X file.
79 int flag_gen_aux_info = 0
81 ; Nonzero if we are compiling code for a shared library, zero for
86 ; These two are really VEC(char_p,heap) *.
89 void *flag_instrument_functions_exclude_functions
92 void *flag_instrument_functions_exclude_files
94 ; Generic structs (e.g. templates not explicitly specialized)
95 ; may not have a compilation unit associated with them, and so
96 ; may need to be treated differently from ordinary structs.
98 ; Structs only handled by reference (indirectly), will also usually
99 ; not need as much debugging information.
102 enum debug_struct_file debug_struct_ordinary[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
105 enum debug_struct_file debug_struct_generic[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
107 ; True if we should exit after parsing options.
109 bool exit_after_options
111 ; Type(s) of debugging information we are producing (if any). See
112 ; flag-types.h for the definitions of the different possible types of
113 ; debugging information.
115 enum debug_info_type write_symbols = NO_DEBUG
117 ; Level of debugging information we are producing. See flag-types.h
118 ; for the definitions of the different possible levels.
120 enum debug_info_levels debug_info_level = DINFO_LEVEL_NONE
122 ; Nonzero means use GNU-only extensions in the generated symbolic
123 ; debugging information. Currently, this only has an effect when
124 ; write_symbols is set to DBX_DEBUG or XCOFF_DEBUG.
126 bool use_gnu_debug_info_extensions
128 ; Original value of maximum field alignment in bytes, specified via
129 ; -fpack-struct=<value>.
131 unsigned int initial_max_fld_align = TARGET_DEFAULT_PACK_STRUCT
133 ; Type of stack check.
135 enum stack_check_type flag_stack_check = NO_STACK_CHECK
137 ; True if stack usage information needs to be computed.
139 bool flag_stack_usage_info = false
141 ; -dA causes debug commentary information to be produced in
142 ; the generated assembly code (to make it more readable). This option
143 ; is generally only of use to those who actually need to read the
144 ; generated assembly code (perhaps while debugging the compiler itself).
145 ; Currently, this switch is only used by dwarf2out.c; however, it is intended
146 ; to be a catchall for printing debug information in the assembler file.
150 ; How many NOP insns to place at each function entry by default
152 HOST_WIDE_INT function_entry_patch_area_size
154 ; And how far the real asm entry point is into this area
156 HOST_WIDE_INT function_entry_patch_area_start
158 ; Balance between GNAT encodings and standard DWARF to emit.
160 enum dwarf_gnat_encodings gnat_encodings = DWARF_GNAT_ENCODINGS_DEFAULT
162 ; -dP causes the rtl to be emitted as a comment in assembly.
164 int flag_dump_rtl_in_asm
166 ; Whether -da was passed (used only in handle_common_deferred_options).
168 bool flag_dump_all_passed
170 ; Other flags saying which kinds of debugging dump have been requested.
173 int rtl_dump_and_exit
176 int flag_print_asm_name
178 ; Name of top-level original source file (what was input to cpp).
179 ; This comes from the #-command at the beginning of the actual input.
180 ; If there isn't any there, then this is the cc1 input file name.
182 const char *main_input_filename
184 ; Pointer to base name in main_input_filename, with directories and a
185 ; single final extension removed, and the length of this base
189 const char *main_input_basename
192 int main_input_baselength
194 ; Which options have been printed by --help.
198 ; Which enums have been printed by --help. 0 = not printed, no
199 ; relevant options seen, 1 = relevant option seen, not yet printed, 2
202 char *help_enum_printed
204 ; The number of columns for --help output.
206 unsigned int help_columns
208 ; Whether this options structure has been through finish_options
210 bool flag_opts_finished
212 ; What the sanitizer should instrument
214 unsigned int flag_sanitize
216 ; What sanitizers should recover from errors
218 unsigned int flag_sanitize_recover = (SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT | SANITIZE_KERNEL_ADDRESS) & ~(SANITIZE_UNREACHABLE | SANITIZE_RETURN)
220 ; What the coverage sanitizers should instrument
222 unsigned int flag_sanitize_coverage
224 ; Flag whether a prefix has been added to dump_base_name
226 bool dump_base_name_prefixed = false
228 ; Flag whether HSA generation has been explicitely disabled
230 bool flag_disable_hsa = false
242 Common Driver Joined Undocumented
243 Provide bash completion for options starting with provided string.
246 Driver Alias(coverage)
252 Common Separate Alias(d)
255 Common Joined Alias(d)
258 Common Separate Alias(dumpbase)
261 Common Separate Alias(dumpdir)
264 Driver Separate Alias(e)
267 Driver Joined Alias(e)
270 Common Warning Alias(Wextra)
273 Driver Separate Alias(Xassembler)
276 Driver JoinedOrMissing Alias(Xassembler)
279 Driver Separate Alias(Xlinker)
282 Driver JoinedOrMissing Alias(Xlinker)
285 Driver Separate Alias(u)
288 Driver Joined Alias(u)
291 Common Driver Var(help_flag)
292 Display this information.
295 Common Driver Report Joined
296 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params.
299 Driver Separate Alias(x)
302 Driver Joined Alias(x)
305 Driver Separate Alias(L)
308 Driver Joined Alias(L)
310 -no-canonical-prefixes
311 Driver Alias(no-canonical-prefixes)
313 -no-standard-libraries
314 Driver Alias(nostdlib)
317 Driver Var(no_sysroot_suffix)
326 Common Driver Separate Alias(o) MissingArgError(missing filename after %qs)
329 Common Driver Joined Alias(o) MissingArgError(missing filename after %qs)
332 Driver Alias(pass-exit-codes)
335 Common Alias(Wpedantic)
338 Common Alias(pedantic-errors)
344 Driver Alias(static-pie)
350 Driver Separate Alias(B)
353 Driver JoinedOrMissing Alias(B)
359 Driver Separate Alias(print-file-name=)
362 Driver JoinedOrMissing Alias(print-file-name=)
364 -print-libgcc-file-name
365 Driver Alias(print-libgcc-file-name)
367 -print-multi-directory
368 Driver Alias(print-multi-directory)
371 Driver Alias(print-multi-lib)
373 -print-multi-os-directory
374 Driver Alias(print-multi-os-directory)
377 Driver Alias(print-multiarch)
380 Driver Separate Alias(print-prog-name=)
383 Driver JoinedOrMissing Alias(print-prog-name=)
386 Driver Alias(print-search-dirs)
389 Driver Alias(print-sysroot)
391 -print-sysroot-headers-suffix
392 Driver Alias(print-sysroot-headers-suffix)
398 Driver Alias(save-temps)
404 Driver Separate Alias(specs=)
407 Driver Joined Alias(specs=)
413 Driver Alias(symbolic)
417 Alias for --help=target.
425 ;; The driver used to convert options such as --help into forms such
426 ;; as -fhelp; the following four entries are for compatibility with
427 ;; any direct uses of those (undocumented) -f forms
429 Common Driver Alias(-help)
432 Common Driver Joined Alias(-help=)
435 Common Driver Alias(-target-help)
438 Common Driver Alias(-version)
442 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters.
445 Common Joined Alias(-param)
448 Driver Separate Alias(-sysroot=)
451 Driver JoinedOrMissing
457 Driver Joined Separate
463 Driver Joined Separate
469 Common JoinedOrMissing Optimization
470 -O<number> Set optimization level to <number>.
474 Optimize for space rather than speed.
478 Optimize for speed disregarding exact standards compliance.
482 Optimize for debugging experience rather than speed or size.
494 Driver Joined Separate
500 Driver Joined Separate
521 Common RejectNegative Warning Alias(Wextra)
522 This switch is deprecated; use -Wextra instead.
525 Driver JoinedOrMissing RejectNegative
528 Driver JoinedOrMissing RejectNegative
531 Driver JoinedOrMissing RejectNegative
534 Common Var(warn_aggregate_return) Warning
535 Warn about returning structures, unions or arrays.
537 Waggressive-loop-optimizations
538 Common Var(warn_aggressive_loop_optimizations) Init(1) Warning
539 Warn if a loop with constant number of iterations triggers undefined behavior.
542 Common Var(warn_array_bounds) Warning
543 Warn if an array is accessed out of bounds.
546 Common Joined RejectNegative UInteger Var(warn_array_bounds) Warning IntegerRange(0, 2)
547 Warn if an array is accessed out of bounds.
550 Common Var(warn_attributes) Init(1) Warning
551 Warn about inappropriate attribute usage.
554 Common Var(warn_attributes) Init(1) Warning
555 Warn about type safety and similar errors in attribute alias and related.
558 Common Var(warn_cannot_profile) Init(1) Warning
559 Warn when profiling instrumentation was requested, but could not be applied to
563 Common Var(warn_cast_align) Warning
564 Warn about pointer casts which increase alignment.
567 Common Var(warn_cast_align,2) Warning
568 Warn about pointer casts which increase alignment.
571 Common Var(warn_cpp) Init(1) Warning
572 Warn when a #warning directive is encountered.
574 Wdeprecated-declarations
575 Common Var(warn_deprecated_decl) Init(1) Warning
576 Warn about uses of __attribute__((deprecated)) declarations.
578 Wdisabled-optimization
579 Common Var(warn_disabled_optimization) Warning
580 Warn when an optimization pass is disabled.
583 Common Var(warnings_are_errors)
584 Treat all warnings as errors.
588 Treat specified warning as error.
591 Common Var(extra_warnings) Warning
592 Print extra (possibly unwanted) warnings.
595 Common Var(flag_fatal_errors)
596 Exit on the first error occurred.
599 Common RejectNegative Joined Host_Wide_Int ByteSize Warning Var(warn_frame_larger_than_size) Init(HOST_WIDE_INT_MAX)
600 -Wframe-larger-than=<byte-size> Warn if a function's stack frame requires in excess of <byte-size>.
603 Common Var(warn_free_nonheap_object) Init(1) Warning
604 Warn when attempting to free a non-heap object.
607 Common Var(warn_hsa) Init(1) Warning
608 Warn when a function cannot be expanded to HSAIL.
610 Wimplicit-fallthrough
611 Common Alias(Wimplicit-fallthrough=,3,0) Warning
613 Wimplicit-fallthrough=
614 Common Var(warn_implicit_fallthrough) RejectNegative Joined UInteger Warning IntegerRange(0, 5)
615 Warn when a switch case falls through.
618 Common Var(warn_inline) Warning
619 Warn when an inlined function cannot be inlined.
621 Winvalid-memory-model
622 Common Var(warn_invalid_memory_model) Init(1) Warning
623 Warn when an atomic memory model parameter is known to be outside the valid range.
626 Common RejectNegative Joined Warning Undocumented Alias(Wlarger-than=)
629 Common RejectNegative Joined Host_Wide_Int ByteSize Warning Var(warn_larger_than_size) Init(HOST_WIDE_INT_MAX)
630 -Wlarger-than=<byte-size> Warn if an object's size exceeds <byte-size>.
633 Var(warn_nonnull_compare) Warning
634 Warn if comparing pointer parameter with nonnull attribute with NULL.
637 Common Var(warn_null_dereference) Warning
638 Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior.
640 Wunsafe-loop-optimizations
641 Common Ignore Warning
642 Does nothing. Preserved for backward compatibility.
645 Common Warning Alias(Wsuggest-attribute=noreturn)
648 Common Var(warn_odr_violations) Init(1) Warning
649 Warn about some C++ One Definition Rule violations during link time optimization.
652 Common Var(warn_overflow) Init(1) Warning
653 Warn about overflow in arithmetic expressions.
656 Common Var(warn_lto_type_mismatch) Init(1) Warning
657 During link time optimization warn about mismatched types of global declarations.
660 Common Var(warn_packed) Warning
661 Warn when the packed attribute has no effect on struct layout.
664 Common Var(warn_padded) Warning
665 Warn when padding is required to align structure members.
668 Common Var(pedantic) Init(0) Warning
669 Issue warnings needed for strict compliance to the standard.
672 Common Var(warn_return_local_addr) Init(1) Warning
673 Warn about returning a pointer/reference to a local or temporary variable.
676 Common Var(warn_shadow) Warning
677 Warn when one variable shadows another. Same as -Wshadow=global.
680 Common Warning Alias(Wshadow)
681 Warn when one variable shadows another (globally).
684 Common Var(warn_shadow_local) Warning EnabledBy(Wshadow)
685 Warn when one local variable shadows another local variable or parameter.
688 Common Warning Undocumented Alias(Wshadow=local)
690 Wshadow=compatible-local
691 Common Var(warn_shadow_compatible_local) Warning EnabledBy(Wshadow=local)
692 Warn when one local variable shadows another local variable or parameter of compatible type.
694 Wshadow-compatible-local
695 Common Warning Undocumented Alias(Wshadow=compatible-local)
698 Common Var(warn_stack_protect) Warning
699 Warn when not issuing stack smashing protection for some reason.
702 Common Joined RejectNegative Host_Wide_Int ByteSize Var(warn_stack_usage) Warning Init(HOST_WIDE_INT_MAX)
703 -Wstack-usage=<byte-size> Warn if stack usage might exceed <byte-size>.
707 Warn about code which might break strict aliasing rules.
710 Common Joined RejectNegative UInteger Var(warn_strict_aliasing) Warning
711 Warn about code which might break strict aliasing rules.
715 Warn about optimizations that assume that signed overflow is undefined.
718 Common Joined RejectNegative UInteger Var(warn_strict_overflow) Warning
719 Warn about optimizations that assume that signed overflow is undefined.
721 Wsuggest-attribute=cold
722 Common Var(warn_suggest_attribute_cold) Warning
723 Warn about functions which might be candidates for __attribute__((cold)).
725 Wsuggest-attribute=const
726 Common Var(warn_suggest_attribute_const) Warning
727 Warn about functions which might be candidates for __attribute__((const)).
729 Wsuggest-attribute=pure
730 Common Var(warn_suggest_attribute_pure) Warning
731 Warn about functions which might be candidates for __attribute__((pure)).
733 Wsuggest-attribute=noreturn
734 Common Var(warn_suggest_attribute_noreturn) Warning
735 Warn about functions which might be candidates for __attribute__((noreturn)).
737 Wsuggest-attribute=malloc
738 Common Var(warn_suggest_attribute_malloc) Warning
739 Warn about functions which might be candidates for __attribute__((malloc)).
742 Common Var(warn_suggest_final_types) Warning
743 Warn about C++ polymorphic types where adding final keyword would improve code quality.
745 Wsuggest-final-methods
746 Common Var(warn_suggest_final_methods) Warning
747 Warn about C++ virtual methods where adding final keyword would improve code quality.
750 Common Var(warn_switch_unreachable) Warning Init(1)
751 Warn about statements between switch's controlling expression and the first
755 Common Var(warn_system_headers) Warning
756 Do not suppress warnings from system headers.
759 Common Var(warn_trampolines) Warning
760 Warn whenever a trampoline is generated.
763 Common Var(warn_type_limits) Warning EnabledBy(Wextra)
764 Warn if a comparison is always true or always false due to the limited range of the data type.
767 Common Var(warn_uninitialized) Warning EnabledBy(Wextra)
768 Warn about uninitialized automatic variables.
771 Common Var(warn_maybe_uninitialized) Warning EnabledBy(Wuninitialized)
772 Warn about maybe uninitialized automatic variables.
775 Common Ignore Warning
776 Does nothing. Preserved for backward compatibility.
779 Common Var(warn_unused) Init(0) Warning
780 Enable all -Wunused- warnings.
782 Wunused-but-set-parameter
783 Common Var(warn_unused_but_set_parameter) Warning EnabledBy(Wunused && Wextra)
784 Warn when a function parameter is only set, otherwise unused.
786 Wunused-but-set-variable
787 Common Var(warn_unused_but_set_variable) Warning EnabledBy(Wunused)
788 Warn when a variable is only set, otherwise unused.
791 Common Var(warn_unused_function) Warning EnabledBy(Wunused)
792 Warn when a function is unused.
795 Common Var(warn_unused_label) Warning EnabledBy(Wunused)
796 Warn when a label is unused.
799 Common Var(warn_unused_parameter) Warning EnabledBy(Wunused && Wextra)
800 Warn when a function parameter is unused.
803 Common Var(warn_unused_value) Warning EnabledBy(Wunused)
804 Warn when an expression value is unused.
807 Common Var(warn_unused_variable) Warning EnabledBy(Wunused)
808 Warn when a variable is unused.
811 Common Var(warn_coverage_mismatch) Init(1) Warning
812 Warn in case profiles in -fprofile-use do not match.
814 Wvector-operation-performance
815 Common Var(warn_vector_operation_performance) Warning
816 Warn when a vector operation is compiled outside the SIMD.
831 Common Separate Var(aux_info_file_name)
832 -aux-info <file> Emit declaration information into <file>.
835 Common Joined Alias(aux-info)
838 Common Separate RejectDriver Var(aux_base_name)
841 Common Separate RejectDriver
851 -d<letters> Enable dumps from specific passes of the compiler.
854 Common Separate Var(dump_base_name)
855 -dumpbase <file> Set the file basename to be used for dumps.
858 Common Separate Var(dump_dir_name)
859 -dumpdir <dir> Set the directory name to be used for dumps.
874 Driver Joined Separate
876 ; This option has historically been passed down to the linker by an
877 ; accident of a %{e*} spec, so ensure it continues to be passed down
878 ; as a single option. The supported option for this purpose is
879 ; -rdynamic. See PR 47390.
883 ; The version of the C++ ABI in use. The following values are allowed:
885 ; 0: The version of the ABI believed most conformant with the C++ ABI
886 ; specification. This ABI may change as bugs are discovered and fixed.
887 ; Therefore, 0 will not necessarily indicate the same ABI in different
890 ; 1: The version of the ABI first used in G++ 3.2. No longer selectable.
892 ; 2: The version of the ABI first used in G++ 3.4, and the default
895 ; 3: The version of the ABI that fixes the missing underscore
896 ; in template non-type arguments of pointer type.
898 ; 4: The version of the ABI that introduces unambiguous mangling of
899 ; vector types. First selectable in G++ 4.5.
901 ; 5: The version of the ABI that ignores attribute const/noreturn
902 ; in function pointer mangling, and corrects mangling of decltype and
903 ; function parameters used in other parameters and the return type.
904 ; First selectable in G++ 4.6.
906 ; 6: The version of the ABI that doesn't promote scoped enums to int and
907 ; changes the mangling of template argument packs, const/static_cast,
908 ; prefix ++ and --, and a class scope function used as a template
910 ; First selectable in G++ 4.7.
912 ; 7: The version of the ABI that treats nullptr_t as a builtin type and
913 ; corrects the mangling of lambdas in default argument scope.
914 ; First selectable in G++ 4.8.
916 ; 8: The version of the ABI that corrects the substitution behavior of
917 ; function types with function-cv-qualifiers.
918 ; First selectable in G++ 4.9 and default in G++ 5.
920 ; 9: The version of the ABI that corrects the alignment of nullptr_t.
921 ; First selectable and default in G++ 5.2.
923 ; 10: The version of the ABI that mangles attributes that affect type
924 ; identity, such as ia32 calling convention attributes (stdcall, etc.)
925 ; Default in G++ 6 (set in c_common_post_options).
927 ; 11: The version of the ABI that corrects mangling of sizeof... expressions
928 ; and introduces new inheriting constructor handling.
931 ; 12: Corrects the calling convention for classes with only deleted copy/move
932 ; constructors and changes passing/returning of empty records.
933 ; Default in G++ 8.1.
935 ; 13: Fixes the accidental change in 12 to the calling convention for classes
936 ; with deleted copy constructor and trivial move constructor.
937 ; Default in G++ 8.2.
939 ; Additional positive integers will be assigned as new versions of
940 ; the ABI become the default version of the ABI.
942 Common Joined RejectNegative UInteger Var(flag_abi_version) Init(0)
943 The version of the C++ ABI in use.
945 faggressive-loop-optimizations
946 Common Report Var(flag_aggressive_loop_optimizations) Optimization Init(1)
947 Aggressively optimize loops using language constraints.
950 Common Report Var(flag_align_functions) Optimization
951 Align the start of functions.
954 Common RejectNegative Joined Var(str_align_functions) Optimization
956 flimit-function-alignment
957 Common Report Var(flag_limit_function_alignment) Optimization Init(0)
960 Common Report Var(flag_align_jumps) Optimization
961 Align labels which are only reached by jumping.
964 Common RejectNegative Joined Var(str_align_jumps) Optimization
967 Common Report Var(flag_align_labels) Optimization
971 Common RejectNegative Joined Var(str_align_labels) Optimization
974 Common Report Var(flag_align_loops) Optimization
975 Align the start of loops.
978 Common RejectNegative Joined Var(str_align_loops) Optimization
982 Does nothing. Preserved for backward compatibility.
986 Does nothing. Preserved for backward compatibility.
988 fargument-noalias-global
990 Does nothing. Preserved for backward compatibility.
992 fargument-noalias-anything
994 Does nothing. Preserved for backward compatibility.
997 Common Driver Report Joined
998 Select what to sanitize.
1001 Common Report Joined
1002 Select type of coverage sanitization.
1004 fasan-shadow-offset=
1005 Common Joined RejectNegative Var(common_deferred_options) Defer
1006 -fasan-shadow-offset=<number> Use custom shadow memory offset.
1009 Common Joined RejectNegative Var(common_deferred_options) Defer
1010 -fsanitize-sections=<sec1,sec2,...> Sanitize global variables
1011 in user-defined sections.
1014 Common Report Joined
1015 After diagnosing undefined behavior attempt to continue execution.
1019 This switch is deprecated; use -fsanitize-recover= instead.
1021 fsanitize-address-use-after-scope
1022 Common Driver Report Var(flag_sanitize_address_use_after_scope) Init(0)
1024 fsanitize-undefined-trap-on-error
1025 Common Driver Report Var(flag_sanitize_undefined_trap_on_error) Init(0)
1026 Use trap instead of a library function for undefined behavior sanitization.
1028 fasynchronous-unwind-tables
1029 Common Report Var(flag_asynchronous_unwind_tables) Optimization
1030 Generate unwind tables that are exact at each instruction boundary.
1033 Common Report Var(flag_auto_inc_dec) Init(1) Optimization
1034 Generate auto-inc/dec instructions.
1037 Common Report Var(flag_auto_profile)
1038 Use sample profile information for call graph node weights. The default
1039 profile file is fbdata.afdo in 'pwd'.
1042 Common Joined RejectNegative Var(auto_profile_file)
1043 Use sample profile information for call graph node weights. The profile
1044 file is specified in the argument.
1046 ; -fcheck-bounds causes gcc to generate array bounds checks.
1047 ; For C, C++ and ObjC: defaults off.
1048 ; For Java: defaults to on.
1049 ; For Fortran: defaults to off.
1051 Common Report Var(flag_bounds_check)
1052 Generate code to check bounds before indexing arrays.
1055 Common Report Var(flag_branch_on_count_reg) Optimization
1056 Replace add, compare, branch with branch on count register.
1058 fbranch-probabilities
1059 Common Report Var(flag_branch_probabilities) Optimization
1060 Use profiling information for branch probabilities.
1062 fbranch-target-load-optimize
1063 Common Report Var(flag_branch_target_load_optimize) Optimization
1064 Perform branch target load optimization before prologue / epilogue threading.
1066 fbranch-target-load-optimize2
1067 Common Report Var(flag_branch_target_load_optimize2) Optimization
1068 Perform branch target load optimization after prologue / epilogue threading.
1071 Common Report Var(flag_btr_bb_exclusive) Optimization
1072 Restrict target load migration not to re-use registers in any basic block.
1075 Common Joined RejectNegative Var(common_deferred_options) Defer
1076 -fcall-saved-<register> Mark <register> as being preserved across functions.
1079 Common Joined RejectNegative Var(common_deferred_options) Defer
1080 -fcall-used-<register> Mark <register> as being corrupted by function calls.
1082 ; Nonzero for -fcaller-saves: allocate values in regs that need to
1083 ; be saved across function calls, if that produces overall better code.
1084 ; Optional now, so people can test it.
1086 Common Report Var(flag_caller_saves) Optimization
1087 Save registers around function calls.
1090 Common Report Var(flag_check_data_deps)
1091 This switch is deprecated; do not use.
1094 Common Var(flag_check_new)
1095 Check the return value of new in C++.
1098 Common Var(flag_checking) Init(CHECKING_P ? ENABLE_EXTRA_CHECKING ? 2 : 1 : 0)
1099 Perform internal consistency checkings.
1102 Common Joined RejectNegative UInteger Var(flag_checking)
1103 Perform internal consistency checkings.
1106 Common Report Var(flag_code_hoisting) Optimization
1107 Enable code hoisting.
1109 fcombine-stack-adjustments
1110 Common Report Var(flag_combine_stack_adjustments) Optimization
1111 Looks for opportunities to reduce stack adjustments and stack references.
1114 Common Report Var(flag_no_common,0)
1115 Do not put uninitialized globals in the common section.
1119 ; Converted by the driver to -fcompare-debug= options.
1122 Common Driver JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
1123 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump.
1125 fcompare-debug-second
1126 Common Driver RejectNegative Var(flag_compare_debug)
1127 Run only the second compilation of -fcompare-debug.
1130 Common Report Var(flag_compare_elim_after_reload) Optimization
1131 Perform comparison elimination after register allocation has finished.
1134 Common Var(flag_conserve_stack) Optimization
1135 Do not perform optimizations increasing noticeably stack usage.
1138 Common Report Var(flag_cprop_registers) Optimization
1139 Perform a register copy-propagation optimization pass.
1142 Common Report Var(flag_crossjumping) Optimization
1143 Perform cross-jumping optimization.
1146 Common Report Var(flag_cse_follow_jumps) Optimization
1147 When running CSE, follow jumps to their targets.
1151 Does nothing. Preserved for backward compatibility.
1154 Common Report Var(flag_cx_limited_range) Optimization SetByCombined
1155 Omit range reduction step when performing complex division.
1158 Common Report Var(flag_cx_fortran_rules) Optimization
1159 Complex multiplication and division follow Fortran rules.
1162 Common Report Var(flag_data_sections)
1163 Place data items into their own section.
1166 Common Report Var(common_deferred_options) Defer
1167 List all available debugging counters with their limits and counts.
1170 Common RejectNegative Joined Var(common_deferred_options) Defer
1171 -fdbg-cnt=<counter>[:<lower_limit>]:<upper_limit>[,<counter>:...] Set the debug counter limit.
1174 Common Joined RejectNegative Var(common_deferred_options) Defer
1175 -fdebug-prefix-map=<old>=<new> Map one directory name to another in debug information.
1178 Common Joined RejectNegative Var(common_deferred_options) Defer
1179 -ffile-prefix-map=<old>=<new> Map one directory name to another in compilation result.
1181 fdebug-types-section
1182 Common Report Var(flag_debug_types_section) Init(0)
1183 Output .debug_types section when using DWARF v4 debuginfo.
1185 ; Nonzero for -fdefer-pop: don't pop args after each function call
1186 ; instead save them up to pop many calls' args with one insns.
1188 Common Report Var(flag_defer_pop) Optimization
1189 Defer popping functions args from stack until later.
1192 Common Report Var(flag_delayed_branch) Optimization
1193 Attempt to fill delay slots of branch instructions.
1195 fdelete-dead-exceptions
1196 Common Report Var(flag_delete_dead_exceptions) Init(0) Optimization
1197 Delete dead instructions that may throw exceptions.
1199 fdelete-null-pointer-checks
1200 Common Report Var(flag_delete_null_pointer_checks) Init(-1) Optimization
1201 Delete useless null pointer checks.
1203 fdevirtualize-at-ltrans
1204 Common Report Var(flag_ltrans_devirtualize)
1205 Stream extra data to support more aggressive devirtualization in LTO local transformation mode.
1207 fdevirtualize-speculatively
1208 Common Report Var(flag_devirtualize_speculatively) Optimization
1209 Perform speculative devirtualization.
1212 Common Report Var(flag_devirtualize) Optimization
1213 Try to convert virtual calls to direct ones.
1215 fdiagnostics-show-location=
1216 Common Joined RejectNegative Enum(diagnostic_prefixing_rule)
1217 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics.
1219 ; Required for these enum values.
1224 Name(diagnostic_prefixing_rule) Type(int)
1227 Enum(diagnostic_prefixing_rule) String(once) Value(DIAGNOSTICS_SHOW_PREFIX_ONCE)
1230 Enum(diagnostic_prefixing_rule) String(every-line) Value(DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE)
1232 fdiagnostics-show-caret
1233 Common Var(flag_diagnostics_show_caret) Init(1)
1234 Show the source line with a caret indicating the column.
1236 fdiagnostics-show-line-numbers
1237 Common Var(flag_diagnostics_show_line_numbers) Init(1)
1238 Show line numbers in the left margin when showing source
1241 Common Alias(fdiagnostics-color=,always,never)
1245 Driver Common Joined RejectNegative Var(flag_diagnostics_show_color) Enum(diagnostic_color_rule) Init(DIAGNOSTICS_COLOR_NO)
1246 -fdiagnostics-color=[never|always|auto] Colorize diagnostics.
1248 ; Required for these enum values.
1253 Name(diagnostic_color_rule) Type(int)
1256 Enum(diagnostic_color_rule) String(never) Value(DIAGNOSTICS_COLOR_NO)
1259 Enum(diagnostic_color_rule) String(always) Value(DIAGNOSTICS_COLOR_YES)
1262 Enum(diagnostic_color_rule) String(auto) Value(DIAGNOSTICS_COLOR_AUTO)
1264 fdiagnostics-parseable-fixits
1265 Common Var(flag_diagnostics_parseable_fixits)
1266 Print fix-it hints in machine-readable form.
1268 fdiagnostics-generate-patch
1269 Common Var(flag_diagnostics_generate_patch)
1270 Print fix-it hints to stderr in unified diff format.
1272 fdiagnostics-show-option
1273 Common Var(flag_diagnostics_show_option) Init(1)
1274 Amend appropriate diagnostic messages with the command line option that controls them.
1277 Common Joined RejectNegative Var(common_deferred_options) Defer
1278 -fdisable-[tree|rtl|ipa]-<pass>=range1+range2 disables an optimization pass.
1281 Common Joined RejectNegative Var(common_deferred_options) Defer
1282 -fenable-[tree|rtl|ipa]-<pass>=range1+range2 enables an optimization pass.
1285 Common Joined RejectNegative Var(common_deferred_options) Defer
1286 -fdump-<type> Dump various compiler internals to a file.
1289 Driver RejectNegative
1292 Common RejectNegative Joined Var(flag_dump_final_insns)
1293 -fdump-final-insns=filename Dump to filename the insns at the end of translation.
1296 Common RejectNegative Joined Var(flag_dump_go_spec)
1297 -fdump-go-spec=filename Write all declarations to file as Go code.
1300 Common Report Var(flag_dump_noaddr)
1301 Suppress output of addresses in debugging dumps.
1304 Common Driver Var(flag_report_bug)
1305 Collect and dump debug information into temporary file if ICE in C/C++
1308 fdump-internal-locations
1309 Common Var(flag_dump_locations) Init(0)
1310 Dump detailed information on GCC's internal representation of source code locations.
1313 Common Var(flag_dump_passes) Init(0)
1314 Dump optimization passes.
1317 Common Report Var(flag_dump_unnumbered)
1318 Suppress output of instruction numbers, line number notes and addresses in debugging dumps.
1320 fdump-unnumbered-links
1321 Common Report Var(flag_dump_unnumbered_links)
1322 Suppress output of previous and next insn numbers in debugging dumps.
1325 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
1326 Enable CFI tables via GAS assembler directives.
1329 Common Report Var(flag_early_inlining) Init(1) Optimization
1330 Perform early inlining.
1332 feliminate-dwarf2-dups
1334 Does nothing. Preserved for backward compatibility.
1337 Common Report Var(flag_ipa_sra) Init(0) Optimization
1338 Perform interprocedural reduction of aggregates.
1340 feliminate-unused-debug-symbols
1341 Common Report Var(flag_debug_only_used_symbols)
1342 Perform unused symbol elimination in debug info.
1344 feliminate-unused-debug-types
1345 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
1346 Perform unused type elimination in debug info.
1348 femit-class-debug-always
1349 Common Report Var(flag_emit_class_debug_always) Init(0)
1350 Do not suppress C++ class debug information.
1353 Common Report Var(flag_exceptions) Optimization
1354 Enable exception handling.
1356 fexpensive-optimizations
1357 Common Report Var(flag_expensive_optimizations) Optimization
1358 Perform a number of minor, expensive optimizations.
1361 Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision_cmdline) Init(EXCESS_PRECISION_DEFAULT) SetByCombined
1362 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision.
1365 Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess precision style %qs)
1368 Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)
1371 Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
1373 ; Whether we permit the extended set of values for FLT_EVAL_METHOD
1374 ; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C99/C11.
1375 fpermitted-flt-eval-methods=
1376 Common Joined RejectNegative Enum(permitted_flt_eval_methods) Var(flag_permitted_flt_eval_methods) Init(PERMITTED_FLT_EVAL_METHODS_DEFAULT)
1377 -fpermitted-flt-eval-methods=[c11|ts-18661] Specify which values of FLT_EVAL_METHOD are permitted.
1380 Name(permitted_flt_eval_methods) Type(enum permitted_flt_eval_methods) UnknownError(unknown specification for the set of FLT_EVAL_METHOD values to permit %qs)
1383 Enum(permitted_flt_eval_methods) String(c11) Value(PERMITTED_FLT_EVAL_METHODS_C11)
1386 Enum(permitted_flt_eval_methods) String(ts-18661-3) Value(PERMITTED_FLT_EVAL_METHODS_TS_18661)
1392 Common Var(flag_fat_lto_objects)
1393 Output lto objects containing both the intermediate language and binary output.
1396 Common Report Var(flag_finite_math_only) Optimization SetByCombined
1397 Assume no NaNs or infinities are generated.
1400 Common Joined RejectNegative Var(common_deferred_options) Defer
1401 -ffixed-<register> Mark <register> as being unavailable to the compiler.
1404 Common Report Var(flag_float_store) Optimization
1405 Don't allocate floats and doubles in extended-precision registers.
1409 Does nothing. Preserved for backward compatibility.
1412 Common Report Var(flag_forward_propagate) Optimization
1413 Perform a forward propagation pass on RTL.
1416 Common Joined RejectNegative Enum(fp_contract_mode) Var(flag_fp_contract_mode) Init(FP_CONTRACT_FAST) Optimization
1417 -ffp-contract=[off|on|fast] Perform floating-point expression contraction.
1420 Name(fp_contract_mode) Type(enum fp_contract_mode) UnknownError(unknown floating point contraction style %qs)
1423 Enum(fp_contract_mode) String(off) Value(FP_CONTRACT_OFF)
1425 ; Not implemented, fall back to conservative FP_CONTRACT_OFF.
1427 Enum(fp_contract_mode) String(on) Value(FP_CONTRACT_OFF)
1430 Enum(fp_contract_mode) String(fast) Value(FP_CONTRACT_FAST)
1432 ffp-int-builtin-inexact
1433 Common Report Var(flag_fp_int_builtin_inexact) Init(1) Optimization
1434 Allow built-in functions ceil, floor, round, trunc to raise \"inexact\" exceptions.
1436 ; Nonzero means don't put addresses of constant functions in registers.
1437 ; Used for compiling the Unix kernel, where strange substitutions are
1438 ; done on the assembly output.
1440 Common Report Var(flag_no_function_cse,0) Optimization
1441 Allow function addresses to be held in registers.
1444 Common Report Var(flag_function_sections)
1445 Place each function into its own section.
1448 Common Report Var(flag_gcse) Optimization
1449 Perform global common subexpression elimination.
1452 Common Report Var(flag_gcse_lm) Init(1) Optimization
1453 Perform enhanced load motion during global common subexpression elimination.
1456 Common Report Var(flag_gcse_sm) Init(0) Optimization
1457 Perform store motion after global common subexpression elimination.
1460 Common Report Var(flag_gcse_las) Init(0) Optimization
1461 Perform redundant load after store elimination in global common subexpression
1465 Common Report Var(flag_gcse_after_reload) Optimization
1466 Perform global common subexpression elimination after register allocation has
1470 Name(dwarf_gnat_encodings) Type(int)
1473 Enum(dwarf_gnat_encodings) String(all) Value(DWARF_GNAT_ENCODINGS_ALL)
1476 Enum(dwarf_gnat_encodings) String(gdb) Value(DWARF_GNAT_ENCODINGS_GDB)
1479 Enum(dwarf_gnat_encodings) String(minimal) Value(DWARF_GNAT_ENCODINGS_MINIMAL)
1482 Common Enum(dwarf_gnat_encodings) Joined RejectNegative Report Undocumented Var(gnat_encodings)
1483 -fgnat-encodings=[all|gdb|minimal] Select the balance between GNAT encodings and standard DWARF emitted in the debug information
1485 ; This option is not documented yet as its semantics will change.
1487 Common Report Var(flag_graphite) Optimization
1488 Enable in and out of Graphite representation.
1491 Common Report Var(flag_graphite_identity) Optimization
1492 Enable Graphite Identity transformation.
1494 fhoist-adjacent-loads
1495 Common Report Var(flag_hoist_adjacent_loads) Optimization
1496 Enable hoisting adjacent loads to encourage generating conditional move
1500 Common Undocumented Report Var(flag_keep_gc_roots_live) Optimization
1501 ; Always keep a pointer to a live memory block
1503 floop-parallelize-all
1504 Common Report Var(flag_loop_parallelize_all) Optimization
1505 Mark all loops as parallel.
1508 Common Alias(floop-nest-optimize)
1509 Enable loop nest transforms. Same as -floop-nest-optimize.
1512 Common Report Var(flag_loop_interchange) Optimization
1513 Enable loop interchange on trees.
1516 Common Alias(floop-nest-optimize)
1517 Enable loop nest transforms. Same as -floop-nest-optimize.
1519 floop-unroll-and-jam
1520 Common Report Var(flag_unroll_jam) Optimization
1521 Perform unroll-and-jam on loops.
1524 Common Report Var(flag_tm)
1525 Enable support for GNU transactional memory.
1528 Common Report Var(flag_gnu_unique) Init(1)
1529 Use STB_GNU_UNIQUE if supported by the assembler.
1533 Does nothing. Preserved for backward compatibility.
1536 Common Report Var(flag_loop_nest_optimize) Optimization
1537 Enable the loop nest optimizer.
1539 fstrict-volatile-bitfields
1540 Common Report Var(flag_strict_volatile_bitfields) Init(-1) Optimization
1541 Force bitfield accesses to match their type width.
1544 Common Report Var(flag_store_merging) Optimization
1545 Merge adjacent stores.
1547 fguess-branch-probability
1548 Common Report Var(flag_guess_branch_prob) Optimization
1549 Enable guessing of branch probabilities.
1551 ; Nonzero means ignore `#ident' directives. 0 means handle them.
1552 ; Generate position-independent code for executables if possible
1553 ; On SVR4 targets, it also controls whether or not to emit a
1554 ; string identifying the compiler.
1556 Common Report Var(flag_no_ident,0)
1557 Process #ident directives.
1560 Common Report Var(flag_if_conversion) Optimization
1561 Perform conversion of conditional jumps to branchless equivalents.
1564 Common Report Var(flag_if_conversion2) Optimization
1565 Perform conversion of conditional jumps to conditional execution.
1568 Common Joined RejectNegative Enum(stack_reuse_level) Var(flag_stack_reuse) Init(SR_ALL) Optimization
1569 -fstack-reuse=[all|named_vars|none] Set stack reuse level for local variables.
1572 Name(stack_reuse_level) Type(enum stack_reuse_level) UnknownError(unknown Stack Reuse Level %qs)
1575 Enum(stack_reuse_level) String(all) Value(SR_ALL)
1578 Enum(stack_reuse_level) String(named_vars) Value(SR_NAMED_VARS)
1581 Enum(stack_reuse_level) String(none) Value(SR_NONE)
1583 ftree-loop-if-convert
1584 Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
1585 Convert conditional jumps in innermost loops to branchless equivalents.
1587 ftree-loop-if-convert-stores
1589 Does nothing. Preserved for backward compatibility.
1591 ; -finhibit-size-directive inhibits output of .size for ELF.
1592 ; This is used only for compiling crtstuff.c,
1593 ; and it may be extended to other effects
1594 ; needed for crtstuff.c on other systems.
1595 finhibit-size-directive
1596 Common Report Var(flag_inhibit_size_directive)
1597 Do not generate .size directives.
1600 Common Report Var(flag_indirect_inlining) Optimization
1601 Perform indirect inlining.
1603 ; General flag to enable inlining. Specifying -fno-inline will disable
1604 ; all inlining apart from always-inline functions.
1606 Common Report Var(flag_no_inline,0) Init(0) Optimization
1607 Enable inlining of function declared \"inline\", disabling disables all inlining.
1609 finline-small-functions
1610 Common Report Var(flag_inline_small_functions) Optimization
1611 Integrate functions into their callers when code size is known not to grow.
1614 Common Report Var(flag_inline_functions) Optimization
1615 Integrate functions not declared \"inline\" into their callers when profitable.
1617 finline-functions-called-once
1618 Common Report Var(flag_inline_functions_called_once) Optimization
1619 Integrate functions only required by their single caller.
1622 Common RejectNegative Joined Alias(finline-limit=)
1625 Common RejectNegative Joined UInteger
1626 -finline-limit=<number> Limit the size of inlined functions to <number>.
1629 Common Report Var(flag_inline_atomics) Init(1) Optimization
1630 Inline __atomic operations when a lock free instruction sequence is available.
1633 Common RejectNegative Alias(fcf-protection=,full)
1636 Common Report Joined RejectNegative Enum(cf_protection_level) Var(flag_cf_protection) Init(CF_NONE)
1637 -fcf-protection=[full|branch|return|none] Instrument functions with checks to verify jump/call/return control-flow transfer
1638 instructions have valid targets.
1641 Name(cf_protection_level) Type(enum cf_protection_level) UnknownError(unknown Control-Flow Protection Level %qs)
1644 Enum(cf_protection_level) String(full) Value(CF_FULL)
1647 Enum(cf_protection_level) String(branch) Value(CF_BRANCH)
1650 Enum(cf_protection_level) String(return) Value(CF_RETURN)
1653 Enum(cf_protection_level) String(none) Value(CF_NONE)
1655 finstrument-functions
1656 Common Report Var(flag_instrument_function_entry_exit)
1657 Instrument function entry and exit with profiling calls.
1659 finstrument-functions-exclude-function-list=
1660 Common RejectNegative Joined
1661 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions.
1663 finstrument-functions-exclude-file-list=
1664 Common RejectNegative Joined
1665 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files.
1668 Common Report Var(flag_ipa_cp) Optimization
1669 Perform interprocedural constant propagation.
1672 Common Report Var(flag_ipa_cp_clone) Optimization
1673 Perform cloning to make Interprocedural constant propagation stronger.
1677 Does nothing. Preserved for backward compatibility.
1680 Common Report Var(flag_ipa_bit_cp) Optimization
1681 Perform interprocedural bitwise constant propagation.
1684 Common Report Var(flag_ipa_profile) Init(0) Optimization
1685 Perform interprocedural profile propagation.
1688 Common Report Var(flag_ipa_pta) Init(0) Optimization
1689 Perform interprocedural points-to analysis.
1692 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
1693 Discover pure and const functions.
1696 Common Report Var(flag_ipa_icf) Optimization
1697 Perform Identical Code Folding for functions and read-only variables.
1700 Common Report Var(flag_ipa_icf_functions) Optimization
1701 Perform Identical Code Folding for functions.
1704 Common Report Var(flag_ipa_icf_variables) Optimization
1705 Perform Identical Code Folding for variables.
1708 Common Report Var(flag_ipa_reference) Init(0) Optimization
1709 Discover readonly and non addressable static variables.
1713 Does nothing. Preserved for backward compatibility.
1717 Does nothing. Preserved for backward compatibility.
1720 Common Report Var(flag_ipa_vrp) Optimization
1721 Perform IPA Value Range Propagation.
1724 Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization
1725 -fira-algorithm=[CB|priority] Set the used IRA algorithm.
1728 Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)
1731 Enum(ira_algorithm) String(CB) Value(IRA_ALGORITHM_CB)
1734 Enum(ira_algorithm) String(priority) Value(IRA_ALGORITHM_PRIORITY)
1737 Common Joined RejectNegative Enum(ira_region) Var(flag_ira_region) Init(IRA_REGION_AUTODETECT) Optimization
1738 -fira-region=[one|all|mixed] Set regions for IRA.
1741 Name(ira_region) Type(enum ira_region) UnknownError(unknown IRA region %qs)
1744 Enum(ira_region) String(one) Value(IRA_REGION_ONE)
1747 Enum(ira_region) String(all) Value(IRA_REGION_ALL)
1750 Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)
1753 Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
1754 Use IRA based register pressure calculation
1755 in RTL hoist optimizations.
1758 Common Report Var(flag_ira_loop_pressure) Optimization
1759 Use IRA based register pressure calculation
1760 in RTL loop optimizations.
1762 fira-share-save-slots
1763 Common Report Var(flag_ira_share_save_slots) Init(1) Optimization
1764 Share slots for saving different hard registers.
1766 fira-share-spill-slots
1767 Common Report Var(flag_ira_share_spill_slots) Init(1) Optimization
1768 Share stack slots for spilled pseudo-registers.
1771 Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
1772 -fira-verbose=<number> Control IRA's level of diagnostic messages.
1775 Common Report Var(flag_ivopts) Init(1) Optimization
1776 Optimize induction variables on trees.
1779 Common Var(flag_jump_tables) Init(1) Optimization
1780 Use jump tables for sufficiently large switch statements.
1782 fkeep-inline-functions
1783 Common Report Var(flag_keep_inline_functions)
1784 Generate code for functions even if they are fully inlined.
1786 fkeep-static-functions
1787 Common Report Var(flag_keep_static_functions)
1788 Generate code for static functions even if they are never called.
1791 Common Report Var(flag_keep_static_consts) Init(1)
1792 Emit static const variables even if they are not used.
1795 Common Report Var(flag_leading_underscore) Init(-1)
1796 Give external symbols a leading underscore.
1800 Does nothing. Preserved for backward compatibility.
1803 Common Report Var(flag_lra_remat) Optimization
1804 Do CFG-sensitive rematerialization in LRA.
1808 Enable link-time optimization.
1811 Common RejectNegative Joined Var(flag_lto)
1812 Link-time optimization with number of parallel jobs or jobserver.
1815 Name(lto_partition_model) Type(enum lto_partition_model) UnknownError(unknown LTO partitioning model %qs)
1818 Enum(lto_partition_model) String(none) Value(LTO_PARTITION_NONE)
1821 Enum(lto_partition_model) String(one) Value(LTO_PARTITION_ONE)
1824 Enum(lto_partition_model) String(balanced) Value(LTO_PARTITION_BALANCED)
1827 Enum(lto_partition_model) String(1to1) Value(LTO_PARTITION_1TO1)
1830 Enum(lto_partition_model) String(max) Value(LTO_PARTITION_MAX)
1833 Common Joined RejectNegative Enum(lto_partition_model) Var(flag_lto_partition) Init(LTO_PARTITION_BALANCED)
1834 Specify the algorithm to partition symbols and vars at linktime.
1836 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
1837 flto-compression-level=
1838 Common Joined RejectNegative UInteger Var(flag_lto_compression_level) Init(-1) IntegerRange(0, 9)
1839 -flto-compression-level=<number> Use zlib compression level <number> for IL.
1841 flto-odr-type-merging
1842 Common Report Var(flag_lto_odr_type_mering) Init(1)
1843 Merge C++ types using One Definition Rule.
1846 Common Report Var(flag_lto_report) Init(0)
1847 Report various link-time optimization statistics.
1850 Common Report Var(flag_lto_report_wpa) Init(0)
1851 Report various link-time optimization statistics for WPA only.
1854 Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
1855 Set errno after built-in math functions.
1858 Common Joined RejectNegative UInteger Var(flag_max_errors)
1859 -fmax-errors=<number> Maximum number of errors to report.
1862 Common Report Var(mem_report)
1863 Report on permanent memory allocation.
1866 Common Report Var(mem_report_wpa)
1867 Report on permanent memory allocation in WPA only.
1869 ; This will attempt to merge constant section constants, if 1 only
1870 ; string constants and constants from constant pool, if 2 also constant
1872 fmerge-all-constants
1873 Common Report Var(flag_merge_constants,2) Init(1)
1874 Attempt to merge identical constants and constant variables.
1877 Common Report Var(flag_merge_constants,1)
1878 Attempt to merge identical constants across compilation units.
1880 fmerge-debug-strings
1881 Common Report Var(flag_merge_debug_strings) Init(1)
1882 Attempt to merge identical debug strings across compilation units.
1885 Common RejectNegative Joined UInteger
1886 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping.
1889 Common Report Var(flag_modulo_sched) Optimization
1890 Perform SMS based modulo scheduling before the first scheduling pass.
1892 fmodulo-sched-allow-regmoves
1893 Common Report Var(flag_modulo_sched_allow_regmoves) Optimization
1894 Perform SMS based modulo scheduling with register moves allowed.
1896 fmove-loop-invariants
1897 Common Report Var(flag_move_loop_invariants) Optimization
1898 Move loop invariant computations out of loops.
1901 Common Var(flag_dce) Init(1) Optimization
1902 Use the RTL dead code elimination pass.
1905 Common Var(flag_dse) Init(1) Optimization
1906 Use the RTL dead store elimination pass.
1908 freschedule-modulo-scheduled-loops
1909 Common Report Var(flag_resched_modulo_sched) Optimization
1910 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling.
1912 fnon-call-exceptions
1913 Common Report Var(flag_non_call_exceptions) Optimization
1914 Support synchronous non-call exceptions.
1917 Common Driver Joined MissingArgError(options or targets missing after %qs)
1918 -foffload=<targets>=<options> Specify offloading targets and options for them.
1921 Common Joined RejectNegative Enum(offload_abi) Var(flag_offload_abi) Init(OFFLOAD_ABI_UNSET)
1922 -foffload-abi=[lp64|ilp32] Set the ABI to use in an offload compiler.
1925 Name(offload_abi) Type(enum offload_abi) UnknownError(unknown offload ABI %qs)
1928 Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
1931 Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
1934 Common Report Var(flag_omit_frame_pointer) Optimization
1935 When possible do not generate stack frames.
1938 Common Report Var(flag_opt_info) Optimization
1939 Enable all optimization info dumps on stderr.
1942 Common Joined RejectNegative Var(common_deferred_options) Defer
1943 -fopt-info[-<type>=filename] Dump compiler optimization details.
1945 fsave-optimization-record
1946 Common Report Var(flag_save_optimization_record) Optimization
1947 Write a SRCFILE.opt-record.json file detailing what optimizations were performed.
1949 foptimize-register-move
1951 Does nothing. Preserved for backward compatibility.
1953 foptimize-sibling-calls
1954 Common Report Var(flag_optimize_sibling_calls) Optimization
1955 Optimize sibling and tail recursive calls.
1958 Common Report Var(flag_partial_inlining) Optimization
1959 Perform partial inlining.
1962 Common Report Var(pre_ipa_mem_report)
1963 Report on memory allocation before interprocedural optimization.
1965 fpost-ipa-mem-report
1966 Common Report Var(post_ipa_mem_report)
1967 Report on memory allocation before interprocedural optimization.
1970 Common Report Var(flag_pack_struct) Optimization
1971 Pack structure members together without holes.
1974 Common RejectNegative Joined UInteger Optimization
1975 -fpack-struct=<number> Set initial maximum structure member alignment.
1978 Common Report Var(flag_pcc_struct_return,1) Init(DEFAULT_PCC_STRUCT_RETURN)
1979 Return small aggregates in memory, not registers.
1982 Common Report Var(flag_peel_loops) Optimization
1983 Perform loop peeling.
1986 Common Report Var(flag_no_peephole,0) Optimization
1987 Enable machine specific peephole optimizations.
1990 Common Report Var(flag_peephole2) Optimization
1991 Enable an RTL peephole pass before sched2.
1994 Common Report Var(flag_pic,2) Negative(fPIE) Init(-1)
1995 Generate position-independent code if possible (large mode).
1998 Common Report Var(flag_pie,2) Negative(fpic) Init(-1)
1999 Generate position-independent code for executables if possible (large mode).
2002 Common Report Var(flag_pic,1) Negative(fpie) Init(-1)
2003 Generate position-independent code if possible (small mode).
2006 Common Report Var(flag_pie,1) Negative(fPIC) Init(-1)
2007 Generate position-independent code for executables if possible (small mode).
2010 Common Report Var(flag_plt) Init(1) Optimization
2011 Use PLT for PIC calls (-fno-plt: load the address from GOT at call site).
2014 Common Joined RejectNegative Var(common_deferred_options) Defer
2015 Specify a plugin to load.
2018 Common Joined RejectNegative Var(common_deferred_options) Defer
2019 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>.
2021 fpredictive-commoning
2022 Common Report Var(flag_predictive_commoning) Optimization
2023 Run predictive commoning optimization.
2025 fprefetch-loop-arrays
2026 Common Report Var(flag_prefetch_loop_arrays) Init(-1) Optimization
2027 Generate prefetch instructions, if available, for arrays in loops.
2030 Common Report Var(profile_flag)
2031 Enable basic program profiling code.
2034 Common Report Var(profile_abs_path_flag)
2035 Generate absolute source path names for gcov.
2038 Common Report Var(profile_arc_flag)
2039 Insert arc-based program profiling code.
2042 Common Joined RejectNegative Var(profile_data_prefix)
2043 Set the top-level directory for storing the profile data.
2044 The default is 'pwd'.
2047 Common Report Var(flag_profile_correction)
2048 Enable correction of flow inconsistent profile data input.
2051 Common Joined RejectNegative Enum(profile_update) Var(flag_profile_update) Init(PROFILE_UPDATE_SINGLE)
2052 -fprofile-update=[single|atomic|prefer-atomic] Set the profile update method.
2055 Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
2058 Enum(profile_update) String(single) Value(PROFILE_UPDATE_SINGLE)
2061 Enum(profile_update) String(atomic) Value(PROFILE_UPDATE_ATOMIC)
2064 Enum(profile_update) String(prefer-atomic) Value(PROFILE_UPDATE_PREFER_ATOMIC)
2068 Enable common options for generating profile info for profile feedback directed optimizations.
2071 Common Joined RejectNegative
2072 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=.
2075 Common Var(flag_profile_use)
2076 Enable common options for performing profile feedback directed optimizations.
2079 Common Joined RejectNegative
2080 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=.
2083 Common Report Var(flag_profile_values)
2084 Insert code to profile values of expressions.
2087 Common Report Var(profile_report)
2088 Report on consistency of profile.
2090 fprofile-reorder-functions
2091 Common Report Var(flag_profile_reorder_functions)
2092 Enable function reordering that improves code placement.
2094 fpatchable-function-entry=
2095 Common Joined Optimization
2096 Insert NOP instructions at each function entry.
2099 Common Var(common_deferred_options) Defer
2102 Common Joined RejectNegative Var(common_deferred_options) Defer
2103 -frandom-seed=<string> Make compile reproducible using <string>.
2105 ; This switch causes the command line that was used to create an
2106 ; object file to be recorded into the object file. The exact format
2107 ; of this recording is target and binary file format dependent.
2108 ; It is related to the -fverbose-asm switch, but that switch only
2109 ; records information in the assembler output file as comments, so
2110 ; they never reach the object file.
2111 frecord-gcc-switches
2112 Common Report Var(flag_record_gcc_switches)
2113 Record gcc command line switches in the object file.
2116 Common Report Var(flag_pcc_struct_return,0) Optimization
2117 Return small aggregates in registers.
2121 Does nothing. Preserved for backward compatibility.
2124 Common Report Var(flag_lifetime_dse,2) Init(2) Optimization
2125 Tell DSE that the storage for a C++ object is dead when the constructor
2126 starts and when the destructor finishes.
2129 Common Joined RejectNegative UInteger Var(flag_lifetime_dse) Optimization IntegerRange(0, 2)
2131 flive-range-shrinkage
2132 Common Report Var(flag_live_range_shrinkage) Init(0) Optimization
2133 Relief of register pressure through live range shrinkage.
2136 Common Report Var(flag_rename_registers) Init(2) Optimization
2137 Perform a register renaming optimization pass.
2140 Common Report Var(flag_schedule_fusion) Init(2) Optimization
2141 Perform a target dependent instruction fusion optimization pass.
2144 Common Report Var(flag_reorder_blocks) Optimization
2145 Reorder basic blocks to improve code placement.
2147 freorder-blocks-algorithm=
2148 Common Joined RejectNegative Enum(reorder_blocks_algorithm) Var(flag_reorder_blocks_algorithm) Init(REORDER_BLOCKS_ALGORITHM_SIMPLE) Optimization
2149 -freorder-blocks-algorithm=[simple|stc] Set the used basic block reordering algorithm.
2152 Name(reorder_blocks_algorithm) Type(enum reorder_blocks_algorithm) UnknownError(unknown basic block reordering algorithm %qs)
2155 Enum(reorder_blocks_algorithm) String(simple) Value(REORDER_BLOCKS_ALGORITHM_SIMPLE)
2158 Enum(reorder_blocks_algorithm) String(stc) Value(REORDER_BLOCKS_ALGORITHM_STC)
2160 freorder-blocks-and-partition
2161 Common Report Var(flag_reorder_blocks_and_partition) Optimization
2162 Reorder basic blocks and partition into hot and cold sections.
2165 Common Report Var(flag_reorder_functions) Optimization
2166 Reorder functions to improve code placement.
2168 frerun-cse-after-loop
2169 Common Report Var(flag_rerun_cse_after_loop) Optimization
2170 Add a common subexpression elimination pass after loop optimizations.
2174 Does nothing. Preserved for backward compatibility.
2177 Common Report Var(flag_rounding_math) Optimization SetByCombined
2178 Disable optimizations that assume default FP rounding behavior.
2181 Common Report Var(flag_schedule_interblock) Init(1) Optimization
2182 Enable scheduling across basic blocks.
2185 Common Report Var(flag_sched_pressure) Init(0) Optimization
2186 Enable register pressure sensitive insn scheduling.
2189 Common Report Var(flag_schedule_speculative) Init(1) Optimization
2190 Allow speculative motion of non-loads.
2193 Common Report Var(flag_schedule_speculative_load) Optimization
2194 Allow speculative motion of some loads.
2196 fsched-spec-load-dangerous
2197 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
2198 Allow speculative motion of more loads.
2201 Common RejectNegative Joined UInteger Var(sched_verbose_param) Init(1)
2202 -fsched-verbose=<number> Set the verbosity level of the scheduler.
2204 fsched2-use-superblocks
2205 Common Report Var(flag_sched2_use_superblocks) Optimization
2206 If scheduling post reload, do superblock scheduling.
2210 Does nothing. Preserved for backward compatibility.
2213 Common Report Var(flag_schedule_insns) Optimization
2214 Reschedule instructions before register allocation.
2217 Common Report Var(flag_schedule_insns_after_reload) Optimization
2218 Reschedule instructions after register allocation.
2220 ; This flag should be on when a target implements non-trivial
2221 ; scheduling hooks, maybe saving some information for its own sake.
2222 ; On IA64, for example, this is used for correct bundling.
2223 fselective-scheduling
2224 Common Report Var(flag_selective_scheduling) Optimization
2225 Schedule instructions using selective scheduling algorithm.
2227 fselective-scheduling2
2228 Common Report Var(flag_selective_scheduling2) Optimization
2229 Run selective scheduling after reload.
2232 Common Undocumented Joined Var(flag_self_test)
2233 Run self-tests, using the given path to locate test files.
2235 fsel-sched-pipelining
2236 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
2237 Perform software pipelining of inner loops during selective scheduling.
2239 fsel-sched-pipelining-outer-loops
2240 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
2241 Perform software pipelining of outer loops during selective scheduling.
2243 fsel-sched-reschedule-pipelined
2244 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
2245 Reschedule pipelined regions without pipelining.
2247 fsemantic-interposition
2248 Common Report Var(flag_semantic_interposition) Init(1)
2249 Allow interposing function (or variables) by ones with different semantics (or initializer) respectively by dynamic linker.
2251 ; sched_stalled_insns means that insns can be moved prematurely from the queue
2252 ; of stalled insns into the ready list.
2253 fsched-stalled-insns
2254 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
2255 Allow premature scheduling of queued insns.
2257 fsched-stalled-insns=
2258 Common RejectNegative Joined UInteger Optimization
2259 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled.
2261 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
2262 ; be examined for a dependency on a stalled insn that is candidate for
2263 ; premature removal from the queue of stalled insns into the ready list (has
2264 ; an effect only if the flag 'sched_stalled_insns' is set).
2265 fsched-stalled-insns-dep
2266 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
2267 Set dependence distance checking in premature scheduling of queued insns.
2269 fsched-stalled-insns-dep=
2270 Common RejectNegative Joined UInteger Optimization
2271 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns.
2273 fsched-group-heuristic
2274 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
2275 Enable the group heuristic in the scheduler.
2277 fsched-critical-path-heuristic
2278 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
2279 Enable the critical path heuristic in the scheduler.
2281 fsched-spec-insn-heuristic
2282 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
2283 Enable the speculative instruction heuristic in the scheduler.
2285 fsched-rank-heuristic
2286 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
2287 Enable the rank heuristic in the scheduler.
2289 fsched-last-insn-heuristic
2290 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
2291 Enable the last instruction heuristic in the scheduler.
2293 fsched-dep-count-heuristic
2294 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
2295 Enable the dependent count heuristic in the scheduler.
2298 Common Report Var(flag_section_anchors) Optimization
2299 Access data in the same section from shared anchor points.
2303 Does nothing. Preserved for backward compatibility.
2307 Does nothing. Preserved for backward compatibility.
2310 Common Report Var(flag_ree) Init(0)
2311 Turn on Redundant Extensions Elimination pass.
2314 Common Report Var(flag_show_column) Init(1)
2315 Show column numbers in diagnostics, when available. Default on.
2318 Common Report Var(flag_shrink_wrap) Optimization
2319 Emit function prologues only before parts of the function that need it,
2320 rather than at the top of the function.
2322 fshrink-wrap-separate
2323 Common Report Var(flag_shrink_wrap_separate) Init(1) Optimization
2324 Shrink-wrap parts of the prologue and epilogue separately.
2327 Common Report Var(flag_signaling_nans) Optimization SetByCombined
2328 Disable optimizations observable by IEEE signaling NaNs.
2331 Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
2332 Disable floating point optimizations that ignore the IEEE signedness of zero.
2334 fsingle-precision-constant
2335 Common Report Var(flag_single_precision_constant) Optimization
2336 Convert floating point constants to single precision constants.
2338 fsplit-ivs-in-unroller
2339 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
2340 Split lifetimes of induction variables when loops are unrolled.
2343 Common Report Var(flag_split_stack) Init(-1)
2344 Generate discontiguous stack frames.
2347 Common Report Var(flag_split_wide_types) Optimization
2348 Split wide types into independent registers.
2351 Common Report Var(flag_ssa_backprop) Init(1) Optimization
2352 Enable backward propagation of use properties at the SSA level.
2355 Common Report Var(flag_ssa_phiopt) Optimization
2356 Optimize conditional patterns using SSA PHI nodes.
2359 Common Report Var(flag_stdarg_opt) Init(1) Optimization
2360 Optimize amount of stdarg registers saved to stack at start of function.
2362 fvariable-expansion-in-unroller
2363 Common Report Var(flag_variable_expansion_in_unroller) Optimization
2364 Apply variable expansion when loops are unrolled.
2367 Common Report RejectNegative Joined Optimization
2368 -fstack-check=[no|generic|specific] Insert stack checking code into the program.
2371 Common Alias(fstack-check=, specific, no)
2372 Insert stack checking code into the program. Same as -fstack-check=specific.
2374 fstack-clash-protection
2375 Common Report Var(flag_stack_clash_protection) Optimization
2376 Insert code to probe each page of stack space as it is allocated to protect
2377 from stack-clash style attacks.
2380 Common Var(common_deferred_options) Defer
2382 fstack-limit-register=
2383 Common RejectNegative Joined Var(common_deferred_options) Defer
2384 -fstack-limit-register=<register> Trap if the stack goes past <register>.
2386 fstack-limit-symbol=
2387 Common RejectNegative Joined Var(common_deferred_options) Defer
2388 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>.
2391 Common Report Var(flag_stack_protect, 1) Init(-1) Optimization
2392 Use propolice as a stack protection method.
2394 fstack-protector-all
2395 Common Report RejectNegative Var(flag_stack_protect, 2) Init(-1) Optimization
2396 Use a stack protection method for every function.
2398 fstack-protector-strong
2399 Common Report RejectNegative Var(flag_stack_protect, 3) Init(-1) Optimization
2400 Use a smart stack protection method for certain functions.
2402 fstack-protector-explicit
2403 Common Report RejectNegative Var(flag_stack_protect, 4) Optimization
2404 Use stack protection method only for functions with the stack_protect attribute.
2407 Common RejectNegative Var(flag_stack_usage)
2408 Output stack usage information on a per-function basis.
2412 Does nothing. Preserved for backward compatibility.
2414 ; Nonzero if we should do (language-dependent) alias analysis.
2415 ; Typically, this analysis will assume that expressions of certain
2416 ; types do not alias expressions of certain other types. Only used
2417 ; if alias analysis (in general) is enabled.
2419 Common Report Var(flag_strict_aliasing) Optimization
2420 Assume strict aliasing rules apply.
2424 Treat signed overflow as undefined. Negated as -fwrapv -fwrapv-pointer.
2427 Common Report Var(flag_sync_libcalls) Init(1)
2428 Implement __atomic operations via libcalls to legacy __sync functions.
2431 Common Report Var(flag_syntax_only)
2432 Check for syntax errors, then stop.
2435 Common Report Var(flag_test_coverage)
2436 Create data files needed by \"gcov\".
2439 Common Report Var(flag_thread_jumps) Optimization
2440 Perform jump threading optimizations.
2443 Common Report Var(time_report)
2444 Report the time taken by each compiler pass.
2446 ftime-report-details
2447 Common Report Var(time_report_details)
2448 Record times taken by sub-phases separately.
2451 Common Joined RejectNegative Enum(tls_model) Var(flag_tls_default) Init(TLS_MODEL_GLOBAL_DYNAMIC)
2452 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model.
2455 Name(tls_model) Type(enum tls_model) UnknownError(unknown TLS model %qs)
2458 Enum(tls_model) String(global-dynamic) Value(TLS_MODEL_GLOBAL_DYNAMIC)
2461 Enum(tls_model) String(local-dynamic) Value(TLS_MODEL_LOCAL_DYNAMIC)
2464 Enum(tls_model) String(initial-exec) Value(TLS_MODEL_INITIAL_EXEC)
2467 Enum(tls_model) String(local-exec) Value(TLS_MODEL_LOCAL_EXEC)
2470 Common Report Var(flag_toplevel_reorder) Init(2)
2471 Reorder top level functions, variables, and asms.
2474 Common Report Var(flag_tracer) Optimization
2475 Perform superblock formation via tail duplication.
2478 Common Report Var(flag_trampolines) Init(0)
2479 For targets that normally need trampolines for nested functions, always
2480 generate them instead of using descriptors.
2482 ; Zero means that floating-point math operations cannot generate a
2483 ; (user-visible) trap. This is the case, for example, in nonstop
2484 ; IEEE 754 arithmetic.
2486 Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
2487 Assume floating-point operations can trap.
2490 Common Report Var(flag_trapv) Optimization
2491 Trap for signed overflow in addition, subtraction and multiplication.
2494 Common Report Var(flag_tree_ccp) Optimization
2495 Enable SSA-CCP optimization on trees.
2498 Common Report Var(flag_tree_bit_ccp) Optimization
2499 Enable SSA-BIT-CCP optimization on trees.
2503 Does nothing. Preserved for backward compatibility.
2506 Common Report Var(flag_tree_ch) Optimization
2507 Enable loop header copying on trees.
2509 ftree-coalesce-inlined-vars
2510 Common Ignore RejectNegative
2511 Does nothing. Preserved for backward compatibility.
2514 Common Report Var(flag_tree_coalesce_vars) Optimization
2515 Enable SSA coalescing of user variables.
2519 Does nothing. Preserved for backward compatibility.
2522 Common Report Var(flag_tree_copy_prop) Optimization
2523 Enable copy propagation on trees.
2525 ftree-store-copy-prop
2527 Does nothing. Preserved for backward compatibility.
2530 Common Report Var(flag_tree_cselim) Init(2) Optimization
2531 Transform condition stores into unconditional ones.
2533 ftree-switch-conversion
2534 Common Report Var(flag_tree_switch_conversion) Optimization
2535 Perform conversions of switch initializations.
2538 Common Report Var(flag_tree_dce) Optimization
2539 Enable SSA dead code elimination optimization on trees.
2541 ftree-dominator-opts
2542 Common Report Var(flag_tree_dom) Optimization
2543 Enable dominator optimizations.
2546 Common Report Var(flag_tree_tail_merge) Optimization
2547 Enable tail merging on trees.
2550 Common Report Var(flag_tree_dse) Optimization
2551 Enable dead store elimination.
2554 Common Report Var(flag_tree_forwprop) Init(1) Optimization
2555 Enable forward propagation on trees.
2558 Common Report Var(flag_tree_fre) Optimization
2559 Enable Full Redundancy Elimination (FRE) on trees.
2562 Common Report Var(flag_optimize_strlen) Optimization
2563 Enable string length optimizations on trees.
2565 fisolate-erroneous-paths-dereference
2566 Common Report Var(flag_isolate_erroneous_paths_dereference) Optimization
2567 Detect paths that trigger erroneous or undefined behavior due to
2568 dereferencing a null pointer. Isolate those paths from the main control
2569 flow and turn the statement with erroneous or undefined behavior into a trap.
2571 fisolate-erroneous-paths-attribute
2572 Common Report Var(flag_isolate_erroneous_paths_attribute) Optimization
2573 Detect paths that trigger erroneous or undefined behavior due to a null value
2574 being used in a way forbidden by a returns_nonnull or nonnull
2575 attribute. Isolate those paths from the main control flow and turn the
2576 statement with erroneous or undefined behavior into a trap.
2578 ftree-loop-distribution
2579 Common Report Var(flag_tree_loop_distribution) Optimization
2580 Enable loop distribution on trees.
2582 ftree-loop-distribute-patterns
2583 Common Report Var(flag_tree_loop_distribute_patterns) Optimization
2584 Enable loop distribution for patterns transformed into a library call.
2587 Common Report Var(flag_tree_loop_im) Init(1) Optimization
2588 Enable loop invariant motion on trees.
2591 Common Alias(floop-nest-optimize)
2592 Enable loop nest transforms. Same as -floop-nest-optimize.
2595 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
2596 Create canonical induction variables in loops.
2599 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
2600 Enable loop optimizations on tree level.
2602 ftree-parallelize-loops=
2603 Common Report Joined RejectNegative UInteger Var(flag_tree_parallelize_loops) Init(1) Optimization
2604 -ftree-parallelize-loops=<number> Enable automatic parallelization of loops.
2607 Common Report Var(flag_tree_phiprop) Init(1) Optimization
2608 Enable hoisting loads from conditional pointers.
2611 Common Report Var(flag_tree_pre) Optimization
2612 Enable SSA-PRE optimization on trees.
2615 Common Report Var(flag_tree_partial_pre) Optimization
2616 In SSA-PRE optimization on trees, enable partial-partial redundancy elimination.
2619 Common Report Var(flag_tree_pta) Optimization
2620 Perform function-local points-to analysis on trees.
2623 Common Report Var(flag_tree_reassoc) Init(1) Optimization
2624 Enable reassociation on tree level.
2628 Does nothing. Preserved for backward compatibility.
2631 Common Report Var(flag_tree_sink) Optimization
2632 Enable SSA code sinking on trees.
2635 Common Report Var(flag_tree_slsr) Optimization
2636 Perform straight-line strength reduction.
2639 Common Report Var(flag_tree_sra) Optimization
2640 Perform scalar replacement of aggregates.
2643 Common Report Var(flag_tree_ter) Optimization
2644 Replace temporary expressions in the SSA->normal pass.
2647 Common Report Var(flag_tree_live_range_split) Optimization
2648 Perform live range splitting during the SSA->normal pass.
2651 Common Report Var(flag_tree_vrp) Init(0) Optimization
2652 Perform Value Range Propagation on trees.
2655 Common Report Var(flag_split_paths) Init(0) Optimization
2656 Split paths leading to loop backedges.
2658 funconstrained-commons
2659 Common Var(flag_unconstrained_commons) Optimization
2660 Assume common declarations may be overridden with ones with a larger
2664 Common Report Var(flag_unit_at_a_time) Init(1)
2665 Compile whole compilation unit at a time.
2668 Common Report Var(flag_unroll_loops) Optimization
2669 Perform loop unrolling when iteration count is known.
2672 Common Report Var(flag_unroll_all_loops) Optimization
2673 Perform loop unrolling for all loops.
2675 ; Nonzero means that loop optimizer may assume that the induction variables
2676 ; that control loops do not overflow and that the loops with nontrivial
2677 ; exit condition are not infinite
2678 funsafe-loop-optimizations
2680 Does nothing. Preserved for backward compatibility.
2683 Common Report Var(flag_associative_math) SetByCombined Optimization
2684 Allow optimization for floating-point arithmetic which may change the
2685 result of the operation due to rounding.
2688 Common Report Var(flag_reciprocal_math) SetByCombined Optimization
2689 Same as -fassociative-math for expressions which include division.
2691 ; Nonzero means that unsafe floating-point math optimizations are allowed
2692 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
2693 ; are allowed to assume that their arguments and results are "normal"
2694 ; (e.g., nonnegative for SQRT).
2695 funsafe-math-optimizations
2696 Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
2697 Allow math optimizations that may violate IEEE or ISO standards.
2700 Common Report Var(flag_unswitch_loops) Optimization
2701 Perform loop unswitching.
2704 Common Report Var(flag_split_loops) Optimization
2705 Perform loop splitting.
2708 Common Report Var(flag_unwind_tables) Optimization
2709 Just generate unwind tables for exception handling.
2712 Common Driver Negative(fuse-ld=gold)
2713 Use the bfd linker instead of the default linker.
2716 Common Driver Negative(fuse-ld=bfd)
2717 Use the gold linker instead of the default linker.
2720 Common Undocumented Var(flag_use_linker_plugin)
2722 ; Positive if we should track variables, negative if we should run
2723 ; the var-tracking pass only to discard debug annotations, zero if
2724 ; we're not to run it. When flag_var_tracking == 2 (AUTODETECT_VALUE) it
2725 ; will be set according to optimize, debug_info_level and debug_hooks
2726 ; in process_options ().
2728 Common Report Var(flag_var_tracking) Init(2) PerFunction
2729 Perform variable tracking.
2731 ; Positive if we should track variables at assignments, negative if
2732 ; we should run the var-tracking pass only to discard debug
2733 ; annotations. When flag_var_tracking_assignments ==
2734 ; AUTODETECT_VALUE it will be set according to flag_var_tracking.
2735 fvar-tracking-assignments
2736 Common Report Var(flag_var_tracking_assignments) Init(2) PerFunction
2737 Perform variable tracking by annotating assignments.
2739 ; Nonzero if we should toggle flag_var_tracking_assignments after
2740 ; processing options and computing its default. */
2741 fvar-tracking-assignments-toggle
2742 Common Report Var(flag_var_tracking_assignments_toggle) PerFunction
2743 Toggle -fvar-tracking-assignments.
2745 ; Positive if we should track uninitialized variables, negative if
2746 ; we should run the var-tracking pass only to discard debug
2747 ; annotations. When flag_var_tracking_uninit == AUTODETECT_VALUE it
2748 ; will be set according to flag_var_tracking.
2749 fvar-tracking-uninit
2750 Common Report Var(flag_var_tracking_uninit) PerFunction
2751 Perform variable tracking and also tag variables that are uninitialized.
2753 ; Alias to enable both -ftree-loop-vectorize and -ftree-slp-vectorize.
2755 Common Report Optimization
2756 Enable vectorization on trees.
2758 ftree-vectorizer-verbose=
2759 Common Joined RejectNegative Ignore
2760 Does nothing. Preserved for backward compatibility.
2762 ftree-loop-vectorize
2763 Common Report Var(flag_tree_loop_vectorize) Optimization EnabledBy(ftree-vectorize)
2764 Enable loop vectorization on trees.
2767 Common Report Var(flag_tree_slp_vectorize) Optimization EnabledBy(ftree-vectorize)
2768 Enable basic block vectorization (SLP) on trees.
2771 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_vect_cost_model) Init(VECT_COST_MODEL_DEFAULT) Optimization
2772 -fvect-cost-model=[unlimited|dynamic|cheap] Specifies the cost model for vectorization.
2775 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_simd_cost_model) Init(VECT_COST_MODEL_UNLIMITED) Optimization
2776 -fsimd-cost-model=[unlimited|dynamic|cheap] Specifies the vectorization cost model for code marked with a simd directive.
2779 Name(vect_cost_model) Type(enum vect_cost_model) UnknownError(unknown vectorizer cost model %qs)
2782 Enum(vect_cost_model) String(unlimited) Value(VECT_COST_MODEL_UNLIMITED)
2785 Enum(vect_cost_model) String(dynamic) Value(VECT_COST_MODEL_DYNAMIC)
2788 Enum(vect_cost_model) String(cheap) Value(VECT_COST_MODEL_CHEAP)
2791 Common Alias(fvect-cost-model=,dynamic,unlimited)
2792 Enables the dynamic vectorizer cost model. Preserved for backward compatibility.
2794 ftree-vect-loop-version
2796 Does nothing. Preserved for backward compatibility.
2799 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
2800 Enable copy propagation of scalar-evolution information.
2802 ; -fverbose-asm causes extra commentary information to be produced in
2803 ; the generated assembly code (to make it more readable). This option
2804 ; is generally only of use to those who actually need to read the
2805 ; generated assembly code (perhaps while debugging the compiler itself).
2806 ; -fno-verbose-asm, the default, causes the extra information
2807 ; to not be added and is useful when comparing two assembler files.
2809 Common Report Var(flag_verbose_asm)
2810 Add extra commentary to assembler output.
2813 Common Joined RejectNegative Enum(symbol_visibility) Var(default_visibility) Init(VISIBILITY_DEFAULT)
2814 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility.
2817 Name(symbol_visibility) Type(enum symbol_visibility) UnknownError(unrecognized visibility value %qs)
2820 Enum(symbol_visibility) String(default) Value(VISIBILITY_DEFAULT)
2823 Enum(symbol_visibility) String(internal) Value(VISIBILITY_INTERNAL)
2826 Enum(symbol_visibility) String(hidden) Value(VISIBILITY_HIDDEN)
2829 Enum(symbol_visibility) String(protected) Value(VISIBILITY_PROTECTED)
2832 Common Joined RejectNegative Enum(vtv_priority) Var(flag_vtable_verify) Init(VTV_NO_PRIORITY)
2833 Validate vtable pointers before using them.
2836 Name(vtv_priority) Type(enum vtv_priority) UnknownError(unknown vtable verify initialization priority %qs)
2839 Enum(vtv_priority) String(none) Value(VTV_NO_PRIORITY)
2842 Enum(vtv_priority) String(std) Value(VTV_STANDARD_PRIORITY)
2845 Enum(vtv_priority) String(preinit) Value(VTV_PREINIT_PRIORITY)
2848 Common Var(flag_vtv_counts)
2849 Output vtable verification counters.
2852 Common Var(flag_vtv_debug)
2853 Output vtable verification pointer sets information.
2856 Common Report Var(flag_value_profile_transformations) Optimization
2857 Use expression value profiles in optimizations.
2860 Common Report Var(flag_web) Init(2) Optimization
2861 Construct webs and split unrelated uses of single variable.
2863 ftree-builtin-call-dce
2864 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
2865 Enable conditional dead code elimination for builtin calls.
2868 Common Report Var(flag_whole_program) Init(0)
2869 Perform whole program optimizations.
2872 Common Report Var(flag_wrapv_pointer) Optimization
2873 Assume pointer overflow wraps around.
2876 Common Report Var(flag_wrapv) Optimization
2877 Assume signed arithmetic overflow wraps around.
2879 fzero-initialized-in-bss
2880 Common Report Var(flag_zero_initialized_in_bss) Init(1)
2881 Put zero initialized data in the bss section.
2884 Common Driver RejectNegative JoinedOrMissing
2885 Generate debug information in default format.
2888 Common Driver Var(dwarf2out_as_loc_support) Init(2)
2889 Assume assembler support for (DWARF2+) .loc directives
2892 Common Driver Var(dwarf2out_as_locview_support) Init(2)
2893 Assume assembler support for view in (DWARF2+) .loc directives
2896 Common Driver Ignore Warn(switch %qs no longer supported)
2897 Does nothing. Preserved for backward compatibility.
2900 Common Driver Ignore Warn(switch %qs no longer supported)
2901 Does nothing. Preserved for backward compatibility.
2904 Common Driver Ignore Warn(switch %qs no longer supported)
2905 Does nothing. Preserved for backward compatibility.
2908 Common Driver Ignore Warn(switch %qs no longer supported)
2909 Does nothing. Preserved for backward compatibility.
2912 Common Driver Var(debug_column_info,1) Init(1)
2913 Record DW_AT_decl_column and DW_AT_call_column in DWARF.
2916 Common Driver JoinedOrMissing Negative(gdwarf-)
2917 Generate debug information in default version of DWARF format.
2920 Common Driver Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
2921 Generate debug information in DWARF v2 (or later) format.
2924 Common Driver JoinedOrMissing
2925 Generate debug information in default extended format.
2928 Common Driver Var(debug_inline_points) Init(2)
2929 Generate extended entry point information for inlined functions
2931 ginternal-reset-location-views
2932 Common Driver Var(debug_internal_reset_location_views) Init(2)
2933 Compute locview reset points based on insn length estimates
2936 RejectNegative Joined Undocumented
2937 ; Catch the gno- prefix, so it doesn't backtrack to g<level>.
2940 Common Driver Negative(gpubnames) Var(debug_generate_pub_sections, 0) Init(-1)
2941 Don't generate DWARF pubnames and pubtypes sections.
2944 Common Driver Negative(ggnu-pubnames) Var(debug_generate_pub_sections, 1)
2945 Generate DWARF pubnames and pubtypes sections.
2948 Common Driver Negative(gno-pubnames) Var(debug_generate_pub_sections, 2)
2949 Generate DWARF pubnames and pubtypes sections with GNU extensions.
2951 grecord-gcc-switches
2952 Common Driver Var(dwarf_record_gcc_switches) Init(1)
2953 Record gcc command line switches in DWARF DW_AT_producer.
2956 Common Driver Var(dwarf_split_debug_info) Init(0)
2957 Generate debug information in separate .dwo files.
2960 Common Driver JoinedOrMissing Negative(gstabs+)
2961 Generate debug information in STABS format.
2964 Common Driver JoinedOrMissing Negative(gvms)
2965 Generate debug information in extended STABS format.
2967 gstatement-frontiers
2968 Common Driver Var(debug_nonbind_markers_p) Init(2)
2969 Emit progressive recommended breakpoint locations.
2972 Common Driver Report Var(dwarf_strict) Init(0)
2973 Don't emit DWARF additions beyond selected version.
2976 Common Driver Report Var(flag_gtoggle)
2977 Toggle debug information generation.
2979 gvariable-location-views
2980 Common Driver Var(debug_variable_location_views, 1) Init(2)
2981 Augment variable location lists with progressive views.
2983 gvariable-location-views=incompat5
2984 Common Driver RejectNegative Var(debug_variable_location_views, -1) Init(2)
2987 Common Driver JoinedOrMissing Negative(gxcoff)
2988 Generate debug information in VMS format.
2991 Common Driver JoinedOrMissing Negative(gxcoff+)
2992 Generate debug information in XCOFF format.
2995 Common Driver JoinedOrMissing Negative(gdwarf)
2996 Generate debug information in extended XCOFF format.
2999 Name(compressed_debug_sections) Type(int)
3001 ; Since -gz= is completely handled in specs, the values aren't used and we
3002 ; assign arbitrary constants.
3004 Enum(compressed_debug_sections) String(none) Value(0)
3007 Enum(compressed_debug_sections) String(zlib) Value(1)
3010 Enum(compressed_debug_sections) String(zlib-gnu) Value(2)
3014 Generate compressed debug sections.
3017 Common Driver RejectNegative Joined Enum(compressed_debug_sections)
3018 -gz=<format> Generate compressed debug sections in format <format>.
3021 Driver Joined Separate
3024 Common Joined Var(plugindir_string) Init(0)
3025 -iplugindir=<dir> Set <dir> to be the default plugin directory.
3028 Common Joined Separate RejectDriver Var(imultiarch) Init(0)
3029 -imultiarch <dir> Set <dir> to be the multiarch include subdirectory.
3032 Driver Joined Separate
3037 no-canonical-prefixes
3053 Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs)
3054 -o <file> Place output into <file>.
3057 Common Var(profile_flag)
3058 Enable function profiling.
3061 Driver Var(pass_exit_codes)
3064 Common Alias(Wpedantic)
3067 Common Var(flag_pedantic_errors)
3068 Like -pedantic but issue them as errors.
3074 Driver Var(use_pipes)
3077 Driver JoinedOrMissing Var(print_file_name)
3079 print-libgcc-file-name
3082 print-multi-directory
3083 Driver Var(print_multi_directory)
3086 Driver Var(print_multi_lib)
3088 print-multi-os-directory
3089 Driver Var(print_multi_os_directory)
3092 Driver Var(print_multiarch)
3095 Driver JoinedOrMissing Var(print_prog_name)
3098 Driver Var(print_search_dirs)
3101 Driver Var(print_sysroot)
3103 print-sysroot-headers-suffix
3104 Driver Var(print_sysroot_headers_suffix)
3107 Common Var(quiet_flag) RejectDriver
3108 Do not display functions compiled or elapsed time.
3126 Driver Var(report_times)
3129 Driver JoinedOrMissing
3132 Driver Joined Separate
3136 ; C option, but driver must not handle as "-u ndef".
3139 Common Driver Var(verbose_flag)
3140 Enable verbose output.
3143 Common Var(version_flag) RejectDriver
3144 Display the compiler's version.
3147 Common Var(inhibit_warnings)
3151 Driver Separate Var(wrapper_string)
3154 Driver Joined Separate
3157 Driver RejectNegative Negative(static-pie)
3158 Create a shared library.
3164 Driver Separate Alias(specs=)
3177 ; Documented for Fortran, but always accepted by driver.
3184 ; Documented for Go, but always accepted by driver.
3202 Driver RejectNegative Negative(shared)
3203 Don't create a dynamically linked position independent executable.
3206 Driver RejectNegative Negative(no-pie)
3207 Create a dynamically linked position independent executable.
3210 Driver RejectNegative Negative(pie)
3211 Create a static position independent executable.
3214 Driver Joined Separate
3217 Common Report Var(flag_ipa_ra) Optimization
3218 Use caller save register across calls if possible.
3220 ; This comment is to ensure we retain the blank line above.