1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003-2017 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).
53 int flag_incremental_link = 0
55 ; 0 means straightforward implementation of complex divide acceptable.
56 ; 1 means wide ranges of inputs must work for complex divide.
57 ; 2 means C99-like requirements for complex multiply and divide.
59 int flag_complex_method = 1
61 ; Language specific warning pass for unused results.
63 bool flag_warn_unused_result = false
68 ; Nonzero if we should write GIMPLE bytecode for link-time optimization.
72 ; Nonzero if we should write GIMPLE bytecode for offload compilation.
74 int flag_generate_offload = 0
76 ; True to warn about any objects definitions whose size is larger
77 ; than N bytes. Also want about function definitions whose returned
78 ; values are larger than N bytes, where N is 'larger_than_size'.
83 HOST_WIDE_INT larger_than_size
85 ; True to warn about any function whose frame size is larger
88 bool warn_frame_larger_than
91 HOST_WIDE_INT frame_larger_than_size
93 ; Nonzero means we should be saving declaration info into a .X file.
95 int flag_gen_aux_info = 0
97 ; Nonzero if we are compiling code for a shared library, zero for
102 ; These two are really VEC(char_p,heap) *.
105 void *flag_instrument_functions_exclude_functions
108 void *flag_instrument_functions_exclude_files
110 ; Generic structs (e.g. templates not explicitly specialized)
111 ; may not have a compilation unit associated with them, and so
112 ; may need to be treated differently from ordinary structs.
114 ; Structs only handled by reference (indirectly), will also usually
115 ; not need as much debugging information.
118 enum debug_struct_file debug_struct_ordinary[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
121 enum debug_struct_file debug_struct_generic[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
123 ; True if we should exit after parsing options.
125 bool exit_after_options
127 ; Type(s) of debugging information we are producing (if any). See
128 ; flag-types.h for the definitions of the different possible types of
129 ; debugging information.
131 enum debug_info_type write_symbols = NO_DEBUG
133 ; Level of debugging information we are producing. See flag-types.h
134 ; for the definitions of the different possible levels.
136 enum debug_info_levels debug_info_level = DINFO_LEVEL_NONE
138 ; Nonzero means use GNU-only extensions in the generated symbolic
139 ; debugging information. Currently, this only has an effect when
140 ; write_symbols is set to DBX_DEBUG, XCOFF_DEBUG, or DWARF_DEBUG.
142 bool use_gnu_debug_info_extensions
144 ; Original value of maximum field alignment in bytes, specified via
145 ; -fpack-struct=<value>.
147 unsigned int initial_max_fld_align = TARGET_DEFAULT_PACK_STRUCT
149 ; Type of stack check.
151 enum stack_check_type flag_stack_check = NO_STACK_CHECK
153 ; True if stack usage information needs to be computed.
155 bool flag_stack_usage_info = false
157 ; -dA causes debug commentary information to be produced in
158 ; the generated assembly code (to make it more readable). This option
159 ; is generally only of use to those who actually need to read the
160 ; generated assembly code (perhaps while debugging the compiler itself).
161 ; Currently, this switch is only used by dwarf2out.c; however, it is intended
162 ; to be a catchall for printing debug information in the assembler file.
166 ; How many NOP insns to place at each function entry by default
168 HOST_WIDE_INT function_entry_patch_area_size
170 ; And how far the real asm entry point is into this area
172 HOST_WIDE_INT function_entry_patch_area_start
174 ; Balance between GNAT encodings and standard DWARF to emit.
176 enum dwarf_gnat_encodings gnat_encodings = DWARF_GNAT_ENCODINGS_DEFAULT
178 ; -dP causes the rtl to be emitted as a comment in assembly.
180 int flag_dump_rtl_in_asm
182 ; Whether -da was passed (used only in handle_common_deferred_options).
184 bool flag_dump_all_passed
186 ; Other flags saying which kinds of debugging dump have been requested.
189 int rtl_dump_and_exit
192 int flag_print_asm_name
194 ; Name of top-level original source file (what was input to cpp).
195 ; This comes from the #-command at the beginning of the actual input.
196 ; If there isn't any there, then this is the cc1 input file name.
198 const char *main_input_filename
200 ; Pointer to base name in main_input_filename, with directories and a
201 ; single final extension removed, and the length of this base
205 const char *main_input_basename
208 int main_input_baselength
210 ; Which options have been printed by --help.
214 ; Which enums have been printed by --help. 0 = not printed, no
215 ; relevant options seen, 1 = relevant option seen, not yet printed, 2
218 char *help_enum_printed
220 ; The number of columns for --help output.
222 unsigned int help_columns
224 ; Whether this options structure has been through finish_options
226 bool flag_opts_finished
228 ; What the sanitizer should instrument
230 unsigned int flag_sanitize
232 ; What sanitizers should recover from errors
234 unsigned int flag_sanitize_recover = (SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT | SANITIZE_KERNEL_ADDRESS) & ~(SANITIZE_UNREACHABLE | SANITIZE_RETURN)
236 ; What the coverage sanitizers should instrument
238 unsigned int flag_sanitize_coverage
240 ; Flag whether a prefix has been added to dump_base_name
242 bool dump_base_name_prefixed = false
244 ; Flag whether HSA generation has been explicitely disabled
246 bool flag_disable_hsa = false
258 Driver Alias(coverage)
264 Common Separate Alias(d)
267 Common Joined Alias(d)
270 Common Separate Alias(dumpbase)
273 Common Separate Alias(dumpdir)
276 Driver Separate Alias(e)
279 Driver Joined Alias(e)
282 Common Warning Alias(Wextra)
285 Driver Separate Alias(Xassembler)
288 Driver JoinedOrMissing Alias(Xassembler)
291 Driver Separate Alias(Xlinker)
294 Driver JoinedOrMissing Alias(Xlinker)
297 Driver Separate Alias(u)
300 Driver Joined Alias(u)
303 Common Driver Var(help_flag)
304 Display this information.
307 Common Driver Report Joined
308 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params.
311 Driver Separate Alias(x)
314 Driver Joined Alias(x)
317 Driver Separate Alias(L)
320 Driver Joined Alias(L)
322 -no-canonical-prefixes
323 Driver Alias(no-canonical-prefixes)
325 -no-standard-libraries
326 Driver Alias(nostdlib)
329 Driver Var(no_sysroot_suffix)
338 Common Driver Separate Alias(o) MissingArgError(missing filename after %qs)
341 Common Driver Joined Alias(o) MissingArgError(missing filename after %qs)
344 Driver Alias(pass-exit-codes)
347 Common Alias(Wpedantic)
350 Common Alias(pedantic-errors)
356 Driver Alias(static-pie)
362 Driver Separate Alias(B)
365 Driver JoinedOrMissing Alias(B)
371 Driver Separate Alias(print-file-name=)
374 Driver JoinedOrMissing Alias(print-file-name=)
376 -print-libgcc-file-name
377 Driver Alias(print-libgcc-file-name)
379 -print-multi-directory
380 Driver Alias(print-multi-directory)
383 Driver Alias(print-multi-lib)
385 -print-multi-os-directory
386 Driver Alias(print-multi-os-directory)
389 Driver Alias(print-multiarch)
392 Driver Separate Alias(print-prog-name=)
395 Driver JoinedOrMissing Alias(print-prog-name=)
398 Driver Alias(print-search-dirs)
401 Driver Alias(print-sysroot)
403 -print-sysroot-headers-suffix
404 Driver Alias(print-sysroot-headers-suffix)
410 Driver Alias(save-temps)
416 Driver Separate Alias(specs=)
419 Driver Joined Alias(specs=)
425 Driver Alias(symbolic)
429 Alias for --help=target.
437 ;; The driver used to convert options such as --help into forms such
438 ;; as -fhelp; the following four entries are for compatibility with
439 ;; any direct uses of those (undocumented) -f forms
441 Common Driver Alias(-help)
444 Common Driver Joined Alias(-help=)
447 Common Driver Alias(-target-help)
450 Common Driver Alias(-version)
454 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters.
457 Common Joined Alias(-param)
460 Driver Separate Alias(-sysroot=)
463 Driver JoinedOrMissing
469 Driver Joined Separate
475 Driver Joined Separate
481 Common JoinedOrMissing Optimization
482 -O<number> Set optimization level to <number>.
486 Optimize for space rather than speed.
490 Optimize for speed disregarding exact standards compliance.
494 Optimize for debugging experience rather than speed or size.
506 Driver Joined Separate
512 Driver Joined Separate
533 Common RejectNegative Warning Alias(Wextra)
534 This switch is deprecated; use -Wextra instead.
537 Driver JoinedOrMissing RejectNegative
540 Driver JoinedOrMissing RejectNegative
543 Driver JoinedOrMissing RejectNegative
546 Common Var(warn_aggregate_return) Warning
547 Warn about returning structures, unions or arrays.
549 Waggressive-loop-optimizations
550 Common Var(warn_aggressive_loop_optimizations) Init(1) Warning
551 Warn if a loop with constant number of iterations triggers undefined behavior.
554 Common Var(warn_array_bounds) Warning
555 Warn if an array is accessed out of bounds.
558 Common Joined RejectNegative UInteger Var(warn_array_bounds) Warning IntegerRange(0, 2)
559 Warn if an array is accessed out of bounds.
562 Common Var(warn_attributes) Init(1) Warning
563 Warn about inappropriate attribute usage.
566 Common Var(warn_attributes) Init(1) Warning
567 Warn about type safety and similar errors in attribute alias and related.
570 Common Var(warn_cast_align) Warning
571 Warn about pointer casts which increase alignment.
574 Common Var(warn_cast_align,2) Warning
575 Warn about pointer casts which increase alignment.
578 Common Var(warn_cpp) Init(1) Warning
579 Warn when a #warning directive is encountered.
581 Wdeprecated-declarations
582 Common Var(warn_deprecated_decl) Init(1) Warning
583 Warn about uses of __attribute__((deprecated)) declarations.
585 Wdisabled-optimization
586 Common Var(warn_disabled_optimization) Warning
587 Warn when an optimization pass is disabled.
590 Common Var(warnings_are_errors)
591 Treat all warnings as errors.
595 Treat specified warning as error.
598 Common Var(extra_warnings) Warning
599 Print extra (possibly unwanted) warnings.
602 Common Var(flag_fatal_errors)
603 Exit on the first error occurred.
606 Common RejectNegative Joined UInteger Warning
607 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes.
610 Common Var(warn_free_nonheap_object) Init(1) Warning
611 Warn when attempting to free a non-heap object.
614 Common Var(warn_hsa) Init(1) Warning
615 Warn when a function cannot be expanded to HSAIL.
617 Wimplicit-fallthrough
618 Common Alias(Wimplicit-fallthrough=,3,0) Warning
620 Wimplicit-fallthrough=
621 Common Var(warn_implicit_fallthrough) RejectNegative Joined UInteger Warning IntegerRange(0, 5)
622 Warn when a switch case falls through.
625 Common Var(warn_inline) Warning
626 Warn when an inlined function cannot be inlined.
628 Winvalid-memory-model
629 Common Var(warn_invalid_memory_model) Init(1) Warning
630 Warn when an atomic memory model parameter is known to be outside the valid range.
633 Common RejectNegative Joined Warning Undocumented Alias(Wlarger-than=)
636 Common RejectNegative Joined UInteger Warning
637 -Wlarger-than=<number> Warn if an object is larger than <number> bytes.
640 Var(warn_nonnull_compare) Warning
641 Warn if comparing pointer parameter with nonnull attribute with NULL.
644 Common Var(warn_null_dereference) Warning
645 Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior.
647 Wunsafe-loop-optimizations
648 Common Var(warn_unsafe_loop_optimizations) Warning
649 Warn if the loop cannot be optimized due to nontrivial assumptions.
652 Common Warning Alias(Wsuggest-attribute=noreturn)
655 Common Var(warn_odr_violations) Init(1) Warning
656 Warn about some C++ One Definition Rule violations during link time optimization.
659 Common Var(warn_overflow) Init(1) Warning
660 Warn about overflow in arithmetic expressions.
663 Common Var(warn_lto_type_mismatch) Init(1) Warning
664 During link time optimization warn about mismatched types of global declarations.
667 Common Var(warn_packed) Warning
668 Warn when the packed attribute has no effect on struct layout.
671 Common Var(warn_padded) Warning
672 Warn when padding is required to align structure members.
675 Common Var(pedantic) Init(0) Warning
676 Issue warnings needed for strict compliance to the standard.
679 Common Var(warn_return_local_addr) Init(1) Warning
680 Warn about returning a pointer/reference to a local or temporary variable.
683 Common Var(warn_shadow) Warning
684 Warn when one variable shadows another. Same as -Wshadow=global.
687 Common Warning Alias(Wshadow)
688 Warn when one variable shadows another (globally).
691 Common Var(warn_shadow_local) Warning EnabledBy(Wshadow)
692 Warn when one local variable shadows another local variable or parameter.
695 Common Warning Undocumented Alias(Wshadow=local)
697 Wshadow=compatible-local
698 Common Var(warn_shadow_compatible_local) Warning EnabledBy(Wshadow=local)
699 Warn when one local variable shadows another local variable or parameter of compatible type.
701 Wshadow-compatible-local
702 Common Warning Undocumented Alias(Wshadow=compatible-local)
705 Common Var(warn_stack_protect) Warning
706 Warn when not issuing stack smashing protection for some reason.
709 Common Joined RejectNegative UInteger Var(warn_stack_usage) Warning
710 -Wstack-usage=<number> Warn if stack usage might be larger than specified amount.
714 Warn about code which might break strict aliasing rules.
717 Common Joined RejectNegative UInteger Var(warn_strict_aliasing) Warning
718 Warn about code which might break strict aliasing rules.
722 Warn about optimizations that assume that signed overflow is undefined.
725 Common Joined RejectNegative UInteger Var(warn_strict_overflow) Warning
726 Warn about optimizations that assume that signed overflow is undefined.
728 Wsuggest-attribute=cold
729 Common Var(warn_suggest_attribute_cold) Warning
730 Warn about functions which might be candidates for __attribute__((cold)).
732 Wsuggest-attribute=const
733 Common Var(warn_suggest_attribute_const) Warning
734 Warn about functions which might be candidates for __attribute__((const)).
736 Wsuggest-attribute=pure
737 Common Var(warn_suggest_attribute_pure) Warning
738 Warn about functions which might be candidates for __attribute__((pure)).
740 Wsuggest-attribute=noreturn
741 Common Var(warn_suggest_attribute_noreturn) Warning
742 Warn about functions which might be candidates for __attribute__((noreturn)).
745 Common Var(warn_suggest_final_types) Warning
746 Warn about C++ polymorphic types where adding final keyword would improve code quality.
748 Wsuggest-final-methods
749 Common Var(warn_suggest_final_methods) Warning
750 Warn about C++ virtual methods where adding final keyword would improve code quality.
753 Common Var(warn_switch_unreachable) Warning Init(1)
754 Warn about statements between switch's controlling expression and the first
758 Common Var(warn_system_headers) Warning
759 Do not suppress warnings from system headers.
762 Common Var(warn_trampolines) Warning
763 Warn whenever a trampoline is generated.
766 Common Var(warn_type_limits) Warning EnabledBy(Wextra)
767 Warn if a comparison is always true or always false due to the limited range of the data type.
770 Common Var(warn_uninitialized) Warning EnabledBy(Wextra)
771 Warn about uninitialized automatic variables.
774 Common Var(warn_maybe_uninitialized) Warning EnabledBy(Wuninitialized)
775 Warn about maybe uninitialized automatic variables.
778 Common Ignore Warning
779 Does nothing. Preserved for backward compatibility.
782 Common Var(warn_unused) Init(0) Warning
783 Enable all -Wunused- warnings.
785 Wunused-but-set-parameter
786 Common Var(warn_unused_but_set_parameter) Warning EnabledBy(Wunused && Wextra)
787 Warn when a function parameter is only set, otherwise unused.
789 Wunused-but-set-variable
790 Common Var(warn_unused_but_set_variable) Warning EnabledBy(Wunused)
791 Warn when a variable is only set, otherwise unused.
794 Common Var(warn_unused_function) Warning EnabledBy(Wunused)
795 Warn when a function is unused.
798 Common Var(warn_unused_label) Warning EnabledBy(Wunused)
799 Warn when a label is unused.
802 Common Var(warn_unused_parameter) Warning EnabledBy(Wunused && Wextra)
803 Warn when a function parameter is unused.
806 Common Var(warn_unused_value) Warning EnabledBy(Wunused)
807 Warn when an expression value is unused.
810 Common Var(warn_unused_variable) Warning EnabledBy(Wunused)
811 Warn when a variable is unused.
814 Common Var(warn_coverage_mismatch) Init(1) Warning
815 Warn in case profiles in -fprofile-use do not match.
817 Wvector-operation-performance
818 Common Var(warn_vector_operation_performance) Warning
819 Warn when a vector operation is compiled outside the SIMD.
834 Common Separate Var(aux_info_file_name)
835 -aux-info <file> Emit declaration information into <file>.
838 Common Joined Alias(aux-info)
841 Common Separate RejectDriver Var(aux_base_name)
844 Common Separate RejectDriver
854 -d<letters> Enable dumps from specific passes of the compiler.
857 Common Separate Var(dump_base_name)
858 -dumpbase <file> Set the file basename to be used for dumps.
861 Common Separate Var(dump_dir_name)
862 -dumpdir <dir> Set the directory name to be used for dumps.
877 Driver Joined Separate
879 ; This option has historically been passed down to the linker by an
880 ; accident of a %{e*} spec, so ensure it continues to be passed down
881 ; as a single option. The supported option for this purpose is
882 ; -rdynamic. See PR 47390.
886 ; The version of the C++ ABI in use. The following values are allowed:
888 ; 0: The version of the ABI believed most conformant with the C++ ABI
889 ; specification. This ABI may change as bugs are discovered and fixed.
890 ; Therefore, 0 will not necessarily indicate the same ABI in different
893 ; 1: The version of the ABI first used in G++ 3.2. No longer selectable.
895 ; 2: The version of the ABI first used in G++ 3.4, and the default
898 ; 3: The version of the ABI that fixes the missing underscore
899 ; in template non-type arguments of pointer type.
901 ; 4: The version of the ABI that introduces unambiguous mangling of
902 ; vector types. First selectable in G++ 4.5.
904 ; 5: The version of the ABI that ignores attribute const/noreturn
905 ; in function pointer mangling, and corrects mangling of decltype and
906 ; function parameters used in other parameters and the return type.
907 ; First selectable in G++ 4.6.
909 ; 6: The version of the ABI that doesn't promote scoped enums to int and
910 ; changes the mangling of template argument packs, const/static_cast,
911 ; prefix ++ and --, and a class scope function used as a template
913 ; First selectable in G++ 4.7.
915 ; 7: The version of the ABI that treats nullptr_t as a builtin type and
916 ; corrects the mangling of lambdas in default argument scope.
917 ; First selectable in G++ 4.8.
919 ; 8: The version of the ABI that corrects the substitution behavior of
920 ; function types with function-cv-qualifiers.
921 ; First selectable in G++ 4.9 and default in G++ 5.
923 ; 9: The version of the ABI that corrects the alignment of nullptr_t.
924 ; First selectable and default in G++ 5.2.
926 ; 10: The version of the ABI that mangles attributes that affect type
927 ; identity, such as ia32 calling convention attributes (stdcall, etc.)
928 ; Default in G++ 6 (set in c_common_post_options).
930 ; 11: The version of the ABI that corrects mangling of sizeof... expressions
931 ; and introduces new inheriting constructor handling.
934 ; 12: Corrects the calling convention for classes with only deleted copy/move
938 ; Additional positive integers will be assigned as new versions of
939 ; the ABI become the default version of the ABI.
941 Common Joined RejectNegative UInteger Var(flag_abi_version) Init(0)
942 The version of the C++ ABI in use.
944 faggressive-loop-optimizations
945 Common Report Var(flag_aggressive_loop_optimizations) Optimization Init(1)
946 Aggressively optimize loops using language constraints.
949 Common Report Var(align_functions,0) Optimization UInteger
950 Align the start of functions.
953 Common RejectNegative Joined UInteger Var(align_functions)
955 flimit-function-alignment
956 Common Report Var(flag_limit_function_alignment) Optimization Init(0)
959 Common Report Var(align_jumps,0) Optimization UInteger
960 Align labels which are only reached by jumping.
963 Common RejectNegative Joined UInteger Var(align_jumps)
966 Common Report Var(align_labels,0) Optimization UInteger
970 Common RejectNegative Joined UInteger Var(align_labels)
973 Common Report Var(align_loops,0) Optimization UInteger
974 Align the start of loops.
977 Common RejectNegative Joined UInteger Var(align_loops)
981 Does nothing. Preserved for backward compatibility.
985 Does nothing. Preserved for backward compatibility.
987 fargument-noalias-global
989 Does nothing. Preserved for backward compatibility.
991 fargument-noalias-anything
993 Does nothing. Preserved for backward compatibility.
996 Common Driver Report Joined
997 Select what to sanitize.
1000 Common Report Joined
1001 Select what to coverage sanitize.
1003 fasan-shadow-offset=
1004 Common Joined RejectNegative Var(common_deferred_options) Defer
1005 -fasan-shadow-offset=<number> Use custom shadow memory offset.
1008 Common Joined RejectNegative Var(common_deferred_options) Defer
1009 -fsanitize-sections=<sec1,sec2,...> Sanitize global variables
1010 in user-defined sections.
1013 Common Report Joined
1014 After diagnosing undefined behavior attempt to continue execution.
1018 This switch is deprecated; use -fsanitize-recover= instead.
1020 fsanitize-address-use-after-scope
1021 Common Driver Report Var(flag_sanitize_address_use_after_scope) Init(0)
1023 fsanitize-undefined-trap-on-error
1024 Common Driver Report Var(flag_sanitize_undefined_trap_on_error) Init(0)
1025 Use trap instead of a library function for undefined behavior sanitization.
1027 fasynchronous-unwind-tables
1028 Common Report Var(flag_asynchronous_unwind_tables) Optimization
1029 Generate unwind tables that are exact at each instruction boundary.
1032 Common Report Var(flag_auto_inc_dec) Init(1) Optimization
1033 Generate auto-inc/dec instructions.
1036 Common Report Var(flag_auto_profile)
1037 Use sample profile information for call graph node weights. The default
1038 profile file is fbdata.afdo in 'pwd'.
1041 Common Joined RejectNegative Var(auto_profile_file)
1042 Use sample profile information for call graph node weights. The profile
1043 file is specified in the argument.
1045 ; -fcheck-bounds causes gcc to generate array bounds checks.
1046 ; For C, C++ and ObjC: defaults off.
1047 ; For Java: defaults to on.
1048 ; For Fortran: defaults to off.
1050 Common Report Var(flag_bounds_check)
1051 Generate code to check bounds before indexing arrays.
1054 Common Report Var(flag_branch_on_count_reg) Optimization
1055 Replace add, compare, branch with branch on count register.
1057 fbranch-probabilities
1058 Common Report Var(flag_branch_probabilities) Optimization
1059 Use profiling information for branch probabilities.
1061 fbranch-target-load-optimize
1062 Common Report Var(flag_branch_target_load_optimize) Optimization
1063 Perform branch target load optimization before prologue / epilogue threading.
1065 fbranch-target-load-optimize2
1066 Common Report Var(flag_branch_target_load_optimize2) Optimization
1067 Perform branch target load optimization after prologue / epilogue threading.
1070 Common Report Var(flag_btr_bb_exclusive) Optimization
1071 Restrict target load migration not to re-use registers in any basic block.
1074 Common Joined RejectNegative Var(common_deferred_options) Defer
1075 -fcall-saved-<register> Mark <register> as being preserved across functions.
1078 Common Joined RejectNegative Var(common_deferred_options) Defer
1079 -fcall-used-<register> Mark <register> as being corrupted by function calls.
1081 ; Nonzero for -fcaller-saves: allocate values in regs that need to
1082 ; be saved across function calls, if that produces overall better code.
1083 ; Optional now, so people can test it.
1085 Common Report Var(flag_caller_saves) Optimization
1086 Save registers around function calls.
1089 Common Report Var(flag_check_data_deps)
1090 This switch is deprecated; do not use.
1093 Common Var(flag_check_new)
1094 Check the return value of new in C++.
1097 Common Var(flag_checking) Init(CHECKING_P ? ENABLE_EXTRA_CHECKING ? 2 : 1 : 0)
1098 Perform internal consistency checkings.
1101 Common Joined RejectNegative UInteger Var(flag_checking)
1102 Perform internal consistency checkings.
1105 Common Report Var(flag_code_hoisting) Optimization
1106 Enable code hoisting.
1108 fcombine-stack-adjustments
1109 Common Report Var(flag_combine_stack_adjustments) Optimization
1110 Looks for opportunities to reduce stack adjustments and stack references.
1113 Common Report Var(flag_no_common,0)
1114 Do not put uninitialized globals in the common section.
1118 ; Converted by the driver to -fcompare-debug= options.
1121 Common Driver JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
1122 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump.
1124 fcompare-debug-second
1125 Common Driver RejectNegative Var(flag_compare_debug)
1126 Run only the second compilation of -fcompare-debug.
1129 Common Report Var(flag_compare_elim_after_reload) Optimization
1130 Perform comparison elimination after register allocation has finished.
1133 Common Var(flag_conserve_stack) Optimization
1134 Do not perform optimizations increasing noticeably stack usage.
1137 Common Report Var(flag_cprop_registers) Optimization
1138 Perform a register copy-propagation optimization pass.
1141 Common Report Var(flag_crossjumping) Optimization
1142 Perform cross-jumping optimization.
1145 Common Report Var(flag_cse_follow_jumps) Optimization
1146 When running CSE, follow jumps to their targets.
1150 Does nothing. Preserved for backward compatibility.
1153 Common Report Var(flag_cx_limited_range) Optimization SetByCombined
1154 Omit range reduction step when performing complex division.
1157 Common Report Var(flag_cx_fortran_rules) Optimization
1158 Complex multiplication and division follow Fortran rules.
1161 Common Report Var(flag_data_sections)
1162 Place data items into their own section.
1165 Common Report Var(common_deferred_options) Defer
1166 List all available debugging counters with their limits and counts.
1169 Common RejectNegative Joined Var(common_deferred_options) Defer
1170 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
1173 Common Joined RejectNegative Var(common_deferred_options) Defer
1174 Map one directory name to another in debug information.
1176 fdebug-types-section
1177 Common Report Var(flag_debug_types_section) Init(0)
1178 Output .debug_types section when using DWARF v4 debuginfo.
1180 ; Nonzero for -fdefer-pop: don't pop args after each function call
1181 ; instead save them up to pop many calls' args with one insns.
1183 Common Report Var(flag_defer_pop) Optimization
1184 Defer popping functions args from stack until later.
1187 Common Report Var(flag_delayed_branch) Optimization
1188 Attempt to fill delay slots of branch instructions.
1190 fdelete-dead-exceptions
1191 Common Report Var(flag_delete_dead_exceptions) Init(0) Optimization
1192 Delete dead instructions that may throw exceptions.
1194 fdelete-null-pointer-checks
1195 Common Report Var(flag_delete_null_pointer_checks) Init(-1) Optimization
1196 Delete useless null pointer checks.
1198 fdevirtualize-at-ltrans
1199 Common Report Var(flag_ltrans_devirtualize)
1200 Stream extra data to support more aggressive devirtualization in LTO local transformation mode.
1202 fdevirtualize-speculatively
1203 Common Report Var(flag_devirtualize_speculatively) Optimization
1204 Perform speculative devirtualization.
1207 Common Report Var(flag_devirtualize) Optimization
1208 Try to convert virtual calls to direct ones.
1210 fdiagnostics-show-location=
1211 Common Joined RejectNegative Enum(diagnostic_prefixing_rule)
1212 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics.
1214 ; Required for these enum values.
1219 Name(diagnostic_prefixing_rule) Type(int)
1222 Enum(diagnostic_prefixing_rule) String(once) Value(DIAGNOSTICS_SHOW_PREFIX_ONCE)
1225 Enum(diagnostic_prefixing_rule) String(every-line) Value(DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE)
1227 fdiagnostics-show-caret
1228 Common Var(flag_diagnostics_show_caret) Init(1)
1229 Show the source line with a caret indicating the column.
1232 Common Alias(fdiagnostics-color=,always,never)
1236 Driver Common Joined RejectNegative Var(flag_diagnostics_show_color) Enum(diagnostic_color_rule) Init(DIAGNOSTICS_COLOR_NO)
1237 -fdiagnostics-color=[never|always|auto] Colorize diagnostics.
1239 ; Required for these enum values.
1244 Name(diagnostic_color_rule) Type(int)
1247 Enum(diagnostic_color_rule) String(never) Value(DIAGNOSTICS_COLOR_NO)
1250 Enum(diagnostic_color_rule) String(always) Value(DIAGNOSTICS_COLOR_YES)
1253 Enum(diagnostic_color_rule) String(auto) Value(DIAGNOSTICS_COLOR_AUTO)
1255 fdiagnostics-parseable-fixits
1256 Common Var(flag_diagnostics_parseable_fixits)
1257 Print fix-it hints in machine-readable form.
1259 fdiagnostics-generate-patch
1260 Common Var(flag_diagnostics_generate_patch)
1261 Print fix-it hints to stderr in unified diff format.
1263 fdiagnostics-show-option
1264 Common Var(flag_diagnostics_show_option) Init(1)
1265 Amend appropriate diagnostic messages with the command line option that controls them.
1268 Common Joined RejectNegative Var(common_deferred_options) Defer
1269 -fdisable-[tree|rtl|ipa]-<pass>=range1+range2 disables an optimization pass.
1272 Common Joined RejectNegative Var(common_deferred_options) Defer
1273 -fenable-[tree|rtl|ipa]-<pass>=range1+range2 enables an optimization pass.
1276 Common Joined RejectNegative Var(common_deferred_options) Defer
1277 -fdump-<type> Dump various compiler internals to a file.
1280 Driver RejectNegative
1283 Common RejectNegative Joined Var(flag_dump_final_insns)
1284 -fdump-final-insns=filename Dump to filename the insns at the end of translation.
1287 Common RejectNegative Joined Var(flag_dump_go_spec)
1288 -fdump-go-spec=filename Write all declarations to file as Go code.
1291 Common Report Var(flag_dump_noaddr)
1292 Suppress output of addresses in debugging dumps.
1295 Common Driver Var(flag_report_bug)
1296 Collect and dump debug information into temporary file if ICE in C/C++
1299 fdump-internal-locations
1300 Common Var(flag_dump_locations) Init(0)
1301 Dump detailed information on GCC's internal representation of source code locations.
1304 Common Var(flag_dump_passes) Init(0)
1305 Dump optimization passes.
1308 Common Report Var(flag_dump_unnumbered)
1309 Suppress output of instruction numbers, line number notes and addresses in debugging dumps.
1311 fdump-unnumbered-links
1312 Common Report Var(flag_dump_unnumbered_links)
1313 Suppress output of previous and next insn numbers in debugging dumps.
1316 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
1317 Enable CFI tables via GAS assembler directives.
1320 Common Report Var(flag_early_inlining) Init(1) Optimization
1321 Perform early inlining.
1323 feliminate-dwarf2-dups
1325 Does nothing. Preserved for backward compatibility.
1328 Common Report Var(flag_ipa_sra) Init(0) Optimization
1329 Perform interprocedural reduction of aggregates.
1331 feliminate-unused-debug-symbols
1332 Common Report Var(flag_debug_only_used_symbols)
1333 Perform unused symbol elimination in debug info.
1335 feliminate-unused-debug-types
1336 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
1337 Perform unused type elimination in debug info.
1339 femit-class-debug-always
1340 Common Report Var(flag_emit_class_debug_always) Init(0)
1341 Do not suppress C++ class debug information.
1344 Common Report Var(flag_exceptions) Optimization
1345 Enable exception handling.
1347 fexpensive-optimizations
1348 Common Report Var(flag_expensive_optimizations) Optimization
1349 Perform a number of minor, expensive optimizations.
1352 Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision_cmdline) Init(EXCESS_PRECISION_DEFAULT) SetByCombined
1353 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision.
1356 Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess precision style %qs)
1359 Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)
1362 Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
1364 ; Whether we permit the extended set of values for FLT_EVAL_METHOD
1365 ; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C99/C11.
1366 fpermitted-flt-eval-methods=
1367 Common Joined RejectNegative Enum(permitted_flt_eval_methods) Var(flag_permitted_flt_eval_methods) Init(PERMITTED_FLT_EVAL_METHODS_DEFAULT)
1368 -fpermitted-flt-eval-methods=[c11|ts-18661] Specify which values of FLT_EVAL_METHOD are permitted.
1371 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)
1374 Enum(permitted_flt_eval_methods) String(c11) Value(PERMITTED_FLT_EVAL_METHODS_C11)
1377 Enum(permitted_flt_eval_methods) String(ts-18661-3) Value(PERMITTED_FLT_EVAL_METHODS_TS_18661)
1383 Common Var(flag_fat_lto_objects)
1384 Output lto objects containing both the intermediate language and binary output.
1387 Common Report Var(flag_finite_math_only) Optimization SetByCombined
1388 Assume no NaNs or infinities are generated.
1391 Common Joined RejectNegative Var(common_deferred_options) Defer
1392 -ffixed-<register> Mark <register> as being unavailable to the compiler.
1395 Common Report Var(flag_float_store) Optimization
1396 Don't allocate floats and doubles in extended-precision registers.
1400 Does nothing. Preserved for backward compatibility.
1403 Common Report Var(flag_forward_propagate) Optimization
1404 Perform a forward propagation pass on RTL.
1407 Common Joined RejectNegative Enum(fp_contract_mode) Var(flag_fp_contract_mode) Init(FP_CONTRACT_FAST) Optimization
1408 -ffp-contract=[off|on|fast] Perform floating-point expression contraction.
1411 Name(fp_contract_mode) Type(enum fp_contract_mode) UnknownError(unknown floating point contraction style %qs)
1414 Enum(fp_contract_mode) String(off) Value(FP_CONTRACT_OFF)
1416 ; Not implemented, fall back to conservative FP_CONTRACT_OFF.
1418 Enum(fp_contract_mode) String(on) Value(FP_CONTRACT_OFF)
1421 Enum(fp_contract_mode) String(fast) Value(FP_CONTRACT_FAST)
1423 ffp-int-builtin-inexact
1424 Common Report Var(flag_fp_int_builtin_inexact) Init(1) Optimization
1425 Allow built-in functions ceil, floor, round, trunc to raise \"inexact\" exceptions.
1427 ; Nonzero means don't put addresses of constant functions in registers.
1428 ; Used for compiling the Unix kernel, where strange substitutions are
1429 ; done on the assembly output.
1431 Common Report Var(flag_no_function_cse,0) Optimization
1432 Allow function addresses to be held in registers.
1435 Common Report Var(flag_function_sections)
1436 Place each function into its own section.
1439 Common Report Var(flag_gcse) Optimization
1440 Perform global common subexpression elimination.
1443 Common Report Var(flag_gcse_lm) Init(1) Optimization
1444 Perform enhanced load motion during global common subexpression elimination.
1447 Common Report Var(flag_gcse_sm) Init(0) Optimization
1448 Perform store motion after global common subexpression elimination.
1451 Common Report Var(flag_gcse_las) Init(0) Optimization
1452 Perform redundant load after store elimination in global common subexpression
1456 Common Report Var(flag_gcse_after_reload) Optimization
1457 Perform global common subexpression elimination after register allocation has
1461 Name(dwarf_gnat_encodings) Type(int)
1464 Enum(dwarf_gnat_encodings) String(all) Value(DWARF_GNAT_ENCODINGS_ALL)
1467 Enum(dwarf_gnat_encodings) String(gdb) Value(DWARF_GNAT_ENCODINGS_GDB)
1470 Enum(dwarf_gnat_encodings) String(minimal) Value(DWARF_GNAT_ENCODINGS_MINIMAL)
1473 Common Enum(dwarf_gnat_encodings) Joined RejectNegative Report Undocumented Var(gnat_encodings)
1474 -fgnat-encodings=[all|gdb|minimal] Select the balance between GNAT encodings and standard DWARF emitted in the debug information
1476 ; This option is not documented yet as its semantics will change.
1478 Common Report Var(flag_graphite) Optimization
1479 Enable in and out of Graphite representation.
1482 Common Report Var(flag_graphite_identity) Optimization
1483 Enable Graphite Identity transformation.
1485 fhoist-adjacent-loads
1486 Common Report Var(flag_hoist_adjacent_loads) Optimization
1487 Enable hoisting adjacent loads to encourage generating conditional move
1491 Common Undocumented Report Var(flag_keep_gc_roots_live) Optimization
1492 ; Always keep a pointer to a live memory block
1494 floop-parallelize-all
1495 Common Report Var(flag_loop_parallelize_all) Optimization
1496 Mark all loops as parallel.
1499 Common Alias(floop-nest-optimize)
1500 Enable loop nest transforms. Same as -floop-nest-optimize.
1503 Common Alias(floop-nest-optimize)
1504 Enable loop nest transforms. Same as -floop-nest-optimize.
1507 Common Alias(floop-nest-optimize)
1508 Enable loop nest transforms. Same as -floop-nest-optimize.
1510 floop-unroll-and-jam
1511 Common Alias(floop-nest-optimize)
1512 Enable loop nest transforms. Same as -floop-nest-optimize.
1515 Common Report Var(flag_tm)
1516 Enable support for GNU transactional memory.
1519 Common Report Var(flag_gnu_unique) Init(1)
1520 Use STB_GNU_UNIQUE if supported by the assembler.
1524 Does nothing. Preserved for backward compatibility.
1527 Common Report Var(flag_loop_nest_optimize) Optimization
1528 Enable the loop nest optimizer.
1530 fstrict-volatile-bitfields
1531 Common Report Var(flag_strict_volatile_bitfields) Init(-1) Optimization
1532 Force bitfield accesses to match their type width.
1535 Common Report Var(flag_store_merging) Optimization
1536 Merge adjacent stores.
1538 fguess-branch-probability
1539 Common Report Var(flag_guess_branch_prob) Optimization
1540 Enable guessing of branch probabilities.
1542 ; Nonzero means ignore `#ident' directives. 0 means handle them.
1543 ; Generate position-independent code for executables if possible
1544 ; On SVR4 targets, it also controls whether or not to emit a
1545 ; string identifying the compiler.
1547 Common Report Var(flag_no_ident,0)
1548 Process #ident directives.
1551 Common Report Var(flag_if_conversion) Optimization
1552 Perform conversion of conditional jumps to branchless equivalents.
1555 Common Report Var(flag_if_conversion2) Optimization
1556 Perform conversion of conditional jumps to conditional execution.
1559 Common Joined RejectNegative Enum(stack_reuse_level) Var(flag_stack_reuse) Init(SR_ALL) Optimization
1560 -fstack-reuse=[all|named_vars|none] Set stack reuse level for local variables.
1563 Name(stack_reuse_level) Type(enum stack_reuse_level) UnknownError(unknown Stack Reuse Level %qs)
1566 Enum(stack_reuse_level) String(all) Value(SR_ALL)
1569 Enum(stack_reuse_level) String(named_vars) Value(SR_NAMED_VARS)
1572 Enum(stack_reuse_level) String(none) Value(SR_NONE)
1574 ftree-loop-if-convert
1575 Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
1576 Convert conditional jumps in innermost loops to branchless equivalents.
1578 ftree-loop-if-convert-stores
1580 Does nothing. Preserved for backward compatibility.
1582 ; -finhibit-size-directive inhibits output of .size for ELF.
1583 ; This is used only for compiling crtstuff.c,
1584 ; and it may be extended to other effects
1585 ; needed for crtstuff.c on other systems.
1586 finhibit-size-directive
1587 Common Report Var(flag_inhibit_size_directive)
1588 Do not generate .size directives.
1591 Common Report Var(flag_indirect_inlining) Optimization
1592 Perform indirect inlining.
1594 ; General flag to enable inlining. Specifying -fno-inline will disable
1595 ; all inlining apart from always-inline functions.
1597 Common Report Var(flag_no_inline,0) Init(0) Optimization
1598 Enable inlining of function declared \"inline\", disabling disables all inlining.
1600 finline-small-functions
1601 Common Report Var(flag_inline_small_functions) Optimization
1602 Integrate functions into their callers when code size is known not to grow.
1605 Common Report Var(flag_inline_functions) Optimization
1606 Integrate functions not declared \"inline\" into their callers when profitable.
1608 finline-functions-called-once
1609 Common Report Var(flag_inline_functions_called_once) Optimization
1610 Integrate functions only required by their single caller.
1613 Common RejectNegative Joined Alias(finline-limit=)
1616 Common RejectNegative Joined UInteger
1617 -finline-limit=<number> Limit the size of inlined functions to <number>.
1620 Common Report Var(flag_inline_atomics) Init(1) Optimization
1621 Inline __atomic operations when a lock free instruction sequence is available.
1624 Common RejectNegative Alias(fcf-protection=,full)
1627 Common Report Joined RejectNegative Enum(cf_protection_level) Var(flag_cf_protection) Init(CF_NONE)
1628 -fcf-protection=[full|branch|return|none] Instrument functions with checks to verify jump/call/return control-flow transfer
1629 instructions have valid targets.
1632 Name(cf_protection_level) Type(enum cf_protection_level) UnknownError(unknown Cotrol-Flow Protection Level %qs)
1635 Enum(cf_protection_level) String(full) Value(CF_FULL)
1638 Enum(cf_protection_level) String(branch) Value(CF_BRANCH)
1641 Enum(cf_protection_level) String(return) Value(CF_RETURN)
1644 Enum(cf_protection_level) String(none) Value(CF_NONE)
1646 finstrument-functions
1647 Common Report Var(flag_instrument_function_entry_exit)
1648 Instrument function entry and exit with profiling calls.
1650 finstrument-functions-exclude-function-list=
1651 Common RejectNegative Joined
1652 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions.
1654 finstrument-functions-exclude-file-list=
1655 Common RejectNegative Joined
1656 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files.
1659 Common Report Var(flag_ipa_cp) Optimization
1660 Perform interprocedural constant propagation.
1663 Common Report Var(flag_ipa_cp_clone) Optimization
1664 Perform cloning to make Interprocedural constant propagation stronger.
1668 Does nothing. Preserved for backward compatibility.
1671 Common Report Var(flag_ipa_bit_cp) Optimization
1672 Perform interprocedural bitwise constant propagation.
1675 Common Report Var(flag_ipa_profile) Init(0) Optimization
1676 Perform interprocedural profile propagation.
1679 Common Report Var(flag_ipa_pta) Init(0) Optimization
1680 Perform interprocedural points-to analysis.
1683 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
1684 Discover pure and const functions.
1687 Common Report Var(flag_ipa_icf) Optimization
1688 Perform Identical Code Folding for functions and read-only variables.
1691 Common Report Var(flag_ipa_icf_functions) Optimization
1692 Perform Identical Code Folding for functions.
1695 Common Report Var(flag_ipa_icf_variables) Optimization
1696 Perform Identical Code Folding for variables.
1699 Common Report Var(flag_ipa_reference) Init(0) Optimization
1700 Discover readonly and non addressable static variables.
1704 Does nothing. Preserved for backward compatibility.
1708 Does nothing. Preserved for backward compatibility.
1711 Common Report Var(flag_ipa_vrp) Optimization
1712 Perform IPA Value Range Propagation.
1715 Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization
1716 -fira-algorithm=[CB|priority] Set the used IRA algorithm.
1719 Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)
1722 Enum(ira_algorithm) String(CB) Value(IRA_ALGORITHM_CB)
1725 Enum(ira_algorithm) String(priority) Value(IRA_ALGORITHM_PRIORITY)
1728 Common Joined RejectNegative Enum(ira_region) Var(flag_ira_region) Init(IRA_REGION_AUTODETECT) Optimization
1729 -fira-region=[one|all|mixed] Set regions for IRA.
1732 Name(ira_region) Type(enum ira_region) UnknownError(unknown IRA region %qs)
1735 Enum(ira_region) String(one) Value(IRA_REGION_ONE)
1738 Enum(ira_region) String(all) Value(IRA_REGION_ALL)
1741 Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)
1744 Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
1745 Use IRA based register pressure calculation
1746 in RTL hoist optimizations.
1749 Common Report Var(flag_ira_loop_pressure) Optimization
1750 Use IRA based register pressure calculation
1751 in RTL loop optimizations.
1753 fira-share-save-slots
1754 Common Report Var(flag_ira_share_save_slots) Init(1) Optimization
1755 Share slots for saving different hard registers.
1757 fira-share-spill-slots
1758 Common Report Var(flag_ira_share_spill_slots) Init(1) Optimization
1759 Share stack slots for spilled pseudo-registers.
1762 Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
1763 -fira-verbose=<number> Control IRA's level of diagnostic messages.
1766 Common Report Var(flag_ivopts) Init(1) Optimization
1767 Optimize induction variables on trees.
1770 Common Var(flag_jump_tables) Init(1) Optimization
1771 Use jump tables for sufficiently large switch statements.
1773 fkeep-inline-functions
1774 Common Report Var(flag_keep_inline_functions)
1775 Generate code for functions even if they are fully inlined.
1777 fkeep-static-functions
1778 Common Report Var(flag_keep_static_functions)
1779 Generate code for static functions even if they are never called.
1782 Common Report Var(flag_keep_static_consts) Init(1)
1783 Emit static const variables even if they are not used.
1786 Common Report Var(flag_leading_underscore) Init(-1)
1787 Give external symbols a leading underscore.
1791 Does nothing. Preserved for backward compatibility.
1794 Common Report Var(flag_lra_remat) Optimization
1795 Do CFG-sensitive rematerialization in LRA.
1799 Enable link-time optimization.
1802 Common RejectNegative Joined Var(flag_lto)
1803 Link-time optimization with number of parallel jobs or jobserver.
1806 Name(lto_partition_model) Type(enum lto_partition_model) UnknownError(unknown LTO partitioning model %qs)
1809 Enum(lto_partition_model) String(none) Value(LTO_PARTITION_NONE)
1812 Enum(lto_partition_model) String(one) Value(LTO_PARTITION_ONE)
1815 Enum(lto_partition_model) String(balanced) Value(LTO_PARTITION_BALANCED)
1818 Enum(lto_partition_model) String(1to1) Value(LTO_PARTITION_1TO1)
1821 Enum(lto_partition_model) String(max) Value(LTO_PARTITION_MAX)
1824 Common Joined RejectNegative Enum(lto_partition_model) Var(flag_lto_partition) Init(LTO_PARTITION_BALANCED)
1825 Specify the algorithm to partition symbols and vars at linktime.
1827 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
1828 flto-compression-level=
1829 Common Joined RejectNegative UInteger Var(flag_lto_compression_level) Init(-1) IntegerRange(0, 9)
1830 -flto-compression-level=<number> Use zlib compression level <number> for IL.
1832 flto-odr-type-merging
1833 Common Report Var(flag_lto_odr_type_mering) Init(1)
1834 Merge C++ types using One Definition Rule.
1837 Common Report Var(flag_lto_report) Init(0)
1838 Report various link-time optimization statistics.
1841 Common Report Var(flag_lto_report_wpa) Init(0)
1842 Report various link-time optimization statistics for WPA only.
1845 Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
1846 Set errno after built-in math functions.
1849 Common Joined RejectNegative UInteger Var(flag_max_errors)
1850 -fmax-errors=<number> Maximum number of errors to report.
1853 Common Report Var(mem_report)
1854 Report on permanent memory allocation.
1857 Common Report Var(mem_report_wpa)
1858 Report on permanent memory allocation in WPA only.
1860 ; This will attempt to merge constant section constants, if 1 only
1861 ; string constants and constants from constant pool, if 2 also constant
1863 fmerge-all-constants
1864 Common Report Var(flag_merge_constants,2) Init(1)
1865 Attempt to merge identical constants and constant variables.
1868 Common Report Var(flag_merge_constants,1)
1869 Attempt to merge identical constants across compilation units.
1871 fmerge-debug-strings
1872 Common Report Var(flag_merge_debug_strings) Init(1)
1873 Attempt to merge identical debug strings across compilation units.
1876 Common RejectNegative Joined UInteger
1877 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping.
1880 Common Report Var(flag_modulo_sched) Optimization
1881 Perform SMS based modulo scheduling before the first scheduling pass.
1883 fmodulo-sched-allow-regmoves
1884 Common Report Var(flag_modulo_sched_allow_regmoves) Optimization
1885 Perform SMS based modulo scheduling with register moves allowed.
1887 fmove-loop-invariants
1888 Common Report Var(flag_move_loop_invariants) Optimization
1889 Move loop invariant computations out of loops.
1892 Common Var(flag_dce) Init(1) Optimization
1893 Use the RTL dead code elimination pass.
1896 Common Var(flag_dse) Init(1) Optimization
1897 Use the RTL dead store elimination pass.
1899 freschedule-modulo-scheduled-loops
1900 Common Report Var(flag_resched_modulo_sched) Optimization
1901 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling.
1903 fnon-call-exceptions
1904 Common Report Var(flag_non_call_exceptions) Optimization
1905 Support synchronous non-call exceptions.
1908 Common Driver Joined MissingArgError(options or targets missing after %qs)
1909 -foffload=<targets>=<options> Specify offloading targets and options for them.
1912 Common Joined RejectNegative Enum(offload_abi) Var(flag_offload_abi) Init(OFFLOAD_ABI_UNSET)
1913 -foffload-abi=[lp64|ilp32] Set the ABI to use in an offload compiler.
1916 Name(offload_abi) Type(enum offload_abi) UnknownError(unknown offload ABI %qs)
1919 Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
1922 Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
1925 Common Report Var(flag_omit_frame_pointer) Optimization
1926 When possible do not generate stack frames.
1929 Common Report Var(flag_opt_info) Optimization
1930 Enable all optimization info dumps on stderr.
1933 Common Joined RejectNegative Var(common_deferred_options) Defer
1934 -fopt-info[-<type>=filename] Dump compiler optimization details.
1936 foptimize-register-move
1938 Does nothing. Preserved for backward compatibility.
1940 foptimize-sibling-calls
1941 Common Report Var(flag_optimize_sibling_calls) Optimization
1942 Optimize sibling and tail recursive calls.
1945 Common Report Var(flag_partial_inlining) Optimization
1946 Perform partial inlining.
1949 Common Report Var(pre_ipa_mem_report)
1950 Report on memory allocation before interprocedural optimization.
1952 fpost-ipa-mem-report
1953 Common Report Var(post_ipa_mem_report)
1954 Report on memory allocation before interprocedural optimization.
1957 Common Report Var(flag_pack_struct) Optimization
1958 Pack structure members together without holes.
1961 Common RejectNegative Joined UInteger Optimization
1962 -fpack-struct=<number> Set initial maximum structure member alignment.
1965 Common Report Var(flag_pcc_struct_return,1) Init(DEFAULT_PCC_STRUCT_RETURN)
1966 Return small aggregates in memory, not registers.
1969 Common Report Var(flag_peel_loops) Optimization
1970 Perform loop peeling.
1973 Common Report Var(flag_no_peephole,0) Optimization
1974 Enable machine specific peephole optimizations.
1977 Common Report Var(flag_peephole2) Optimization
1978 Enable an RTL peephole pass before sched2.
1981 Common Report Var(flag_pic,2) Negative(fPIE) Init(-1)
1982 Generate position-independent code if possible (large mode).
1985 Common Report Var(flag_pie,2) Negative(fpic) Init(-1)
1986 Generate position-independent code for executables if possible (large mode).
1989 Common Report Var(flag_pic,1) Negative(fpie) Init(-1)
1990 Generate position-independent code if possible (small mode).
1993 Common Report Var(flag_pie,1) Negative(fPIC) Init(-1)
1994 Generate position-independent code for executables if possible (small mode).
1997 Common Report Var(flag_plt) Init(1) Optimization
1998 Use PLT for PIC calls (-fno-plt: load the address from GOT at call site).
2001 Common Joined RejectNegative Var(common_deferred_options) Defer
2002 Specify a plugin to load.
2005 Common Joined RejectNegative Var(common_deferred_options) Defer
2006 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>.
2008 fpredictive-commoning
2009 Common Report Var(flag_predictive_commoning) Optimization
2010 Run predictive commoning optimization.
2012 fprefetch-loop-arrays
2013 Common Report Var(flag_prefetch_loop_arrays) Init(-1) Optimization
2014 Generate prefetch instructions, if available, for arrays in loops.
2017 Common Report Var(profile_flag)
2018 Enable basic program profiling code.
2021 Common Report Var(profile_abs_path_flag)
2022 Generate absolute source path names for gcov.
2025 Common Report Var(profile_arc_flag)
2026 Insert arc-based program profiling code.
2029 Common Joined RejectNegative Var(profile_data_prefix)
2030 Set the top-level directory for storing the profile data.
2031 The default is 'pwd'.
2034 Common Report Var(flag_profile_correction)
2035 Enable correction of flow inconsistent profile data input.
2038 Common Joined RejectNegative Enum(profile_update) Var(flag_profile_update) Init(PROFILE_UPDATE_SINGLE)
2039 -fprofile-update=[single|atomic|prefer-atomic] Set the profile update method.
2042 Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
2045 Enum(profile_update) String(single) Value(PROFILE_UPDATE_SINGLE)
2048 Enum(profile_update) String(atomic) Value(PROFILE_UPDATE_ATOMIC)
2051 Enum(profile_update) String(prefer-atomic) Value(PROFILE_UPDATE_PREFER_ATOMIC)
2055 Enable common options for generating profile info for profile feedback directed optimizations.
2058 Common Joined RejectNegative
2059 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=.
2062 Common Var(flag_profile_use)
2063 Enable common options for performing profile feedback directed optimizations.
2066 Common Joined RejectNegative
2067 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=.
2070 Common Report Var(flag_profile_values)
2071 Insert code to profile values of expressions.
2074 Common Report Var(profile_report)
2075 Report on consistency of profile.
2077 fprofile-reorder-functions
2078 Common Report Var(flag_profile_reorder_functions)
2079 Enable function reordering that improves code placement.
2081 fpatchable-function-entry=
2082 Common Joined Optimization
2083 Insert NOP instructions at each function entry.
2086 Common Var(common_deferred_options) Defer
2089 Common Joined RejectNegative Var(common_deferred_options) Defer
2090 -frandom-seed=<string> Make compile reproducible using <string>.
2092 ; This switch causes the command line that was used to create an
2093 ; object file to be recorded into the object file. The exact format
2094 ; of this recording is target and binary file format dependent.
2095 ; It is related to the -fverbose-asm switch, but that switch only
2096 ; records information in the assembler output file as comments, so
2097 ; they never reach the object file.
2098 frecord-gcc-switches
2099 Common Report Var(flag_record_gcc_switches)
2100 Record gcc command line switches in the object file.
2103 Common Report Var(flag_pcc_struct_return,0) Optimization
2104 Return small aggregates in registers.
2108 Does nothing. Preserved for backward compatibility.
2111 Common Report Var(flag_lifetime_dse,2) Init(2) Optimization
2112 Tell DSE that the storage for a C++ object is dead when the constructor
2113 starts and when the destructor finishes.
2116 Common Joined RejectNegative UInteger Var(flag_lifetime_dse) Optimization IntegerRange(0, 2)
2118 flive-range-shrinkage
2119 Common Report Var(flag_live_range_shrinkage) Init(0) Optimization
2120 Relief of register pressure through live range shrinkage.
2123 Common Report Var(flag_rename_registers) Init(2) Optimization
2124 Perform a register renaming optimization pass.
2127 Common Report Var(flag_schedule_fusion) Init(2) Optimization
2128 Perform a target dependent instruction fusion optimization pass.
2131 Common Report Var(flag_reorder_blocks) Optimization
2132 Reorder basic blocks to improve code placement.
2134 freorder-blocks-algorithm=
2135 Common Joined RejectNegative Enum(reorder_blocks_algorithm) Var(flag_reorder_blocks_algorithm) Init(REORDER_BLOCKS_ALGORITHM_SIMPLE) Optimization
2136 -freorder-blocks-algorithm=[simple|stc] Set the used basic block reordering algorithm.
2139 Name(reorder_blocks_algorithm) Type(enum reorder_blocks_algorithm) UnknownError(unknown basic block reordering algorithm %qs)
2142 Enum(reorder_blocks_algorithm) String(simple) Value(REORDER_BLOCKS_ALGORITHM_SIMPLE)
2145 Enum(reorder_blocks_algorithm) String(stc) Value(REORDER_BLOCKS_ALGORITHM_STC)
2147 freorder-blocks-and-partition
2148 Common Report Var(flag_reorder_blocks_and_partition) Optimization
2149 Reorder basic blocks and partition into hot and cold sections.
2152 Common Report Var(flag_reorder_functions) Optimization
2153 Reorder functions to improve code placement.
2155 frerun-cse-after-loop
2156 Common Report Var(flag_rerun_cse_after_loop) Optimization
2157 Add a common subexpression elimination pass after loop optimizations.
2161 Does nothing. Preserved for backward compatibility.
2164 Common Report Var(flag_rounding_math) Optimization SetByCombined
2165 Disable optimizations that assume default FP rounding behavior.
2168 Common Report Var(flag_schedule_interblock) Init(1) Optimization
2169 Enable scheduling across basic blocks.
2172 Common Report Var(flag_sched_pressure) Init(0) Optimization
2173 Enable register pressure sensitive insn scheduling.
2176 Common Report Var(flag_schedule_speculative) Init(1) Optimization
2177 Allow speculative motion of non-loads.
2180 Common Report Var(flag_schedule_speculative_load) Optimization
2181 Allow speculative motion of some loads.
2183 fsched-spec-load-dangerous
2184 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
2185 Allow speculative motion of more loads.
2188 Common RejectNegative Joined UInteger Var(sched_verbose_param) Init(1)
2189 -fsched-verbose=<number> Set the verbosity level of the scheduler.
2191 fsched2-use-superblocks
2192 Common Report Var(flag_sched2_use_superblocks) Optimization
2193 If scheduling post reload, do superblock scheduling.
2197 Does nothing. Preserved for backward compatibility.
2200 Common Report Var(flag_schedule_insns) Optimization
2201 Reschedule instructions before register allocation.
2204 Common Report Var(flag_schedule_insns_after_reload) Optimization
2205 Reschedule instructions after register allocation.
2207 ; This flag should be on when a target implements non-trivial
2208 ; scheduling hooks, maybe saving some information for its own sake.
2209 ; On IA64, for example, this is used for correct bundling.
2210 fselective-scheduling
2211 Common Report Var(flag_selective_scheduling) Optimization
2212 Schedule instructions using selective scheduling algorithm.
2214 fselective-scheduling2
2215 Common Report Var(flag_selective_scheduling2) Optimization
2216 Run selective scheduling after reload.
2219 Common Undocumented Joined Var(flag_self_test)
2220 Run self-tests, using the given path to locate test files.
2222 fsel-sched-pipelining
2223 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
2224 Perform software pipelining of inner loops during selective scheduling.
2226 fsel-sched-pipelining-outer-loops
2227 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
2228 Perform software pipelining of outer loops during selective scheduling.
2230 fsel-sched-reschedule-pipelined
2231 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
2232 Reschedule pipelined regions without pipelining.
2234 fsemantic-interposition
2235 Common Report Var(flag_semantic_interposition) Init(1)
2236 Allow interposing function (or variables) by ones with different semantics (or initializer) respectively by dynamic linker.
2238 ; sched_stalled_insns means that insns can be moved prematurely from the queue
2239 ; of stalled insns into the ready list.
2240 fsched-stalled-insns
2241 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
2242 Allow premature scheduling of queued insns.
2244 fsched-stalled-insns=
2245 Common RejectNegative Joined UInteger Optimization
2246 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled.
2248 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
2249 ; be examined for a dependency on a stalled insn that is candidate for
2250 ; premature removal from the queue of stalled insns into the ready list (has
2251 ; an effect only if the flag 'sched_stalled_insns' is set).
2252 fsched-stalled-insns-dep
2253 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
2254 Set dependence distance checking in premature scheduling of queued insns.
2256 fsched-stalled-insns-dep=
2257 Common RejectNegative Joined UInteger Optimization
2258 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns.
2260 fsched-group-heuristic
2261 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
2262 Enable the group heuristic in the scheduler.
2264 fsched-critical-path-heuristic
2265 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
2266 Enable the critical path heuristic in the scheduler.
2268 fsched-spec-insn-heuristic
2269 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
2270 Enable the speculative instruction heuristic in the scheduler.
2272 fsched-rank-heuristic
2273 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
2274 Enable the rank heuristic in the scheduler.
2276 fsched-last-insn-heuristic
2277 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
2278 Enable the last instruction heuristic in the scheduler.
2280 fsched-dep-count-heuristic
2281 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
2282 Enable the dependent count heuristic in the scheduler.
2285 Common Report Var(flag_section_anchors) Optimization
2286 Access data in the same section from shared anchor points.
2290 Does nothing. Preserved for backward compatibility.
2294 Does nothing. Preserved for backward compatibility.
2297 Common Report Var(flag_ree) Init(0)
2298 Turn on Redundant Extensions Elimination pass.
2301 Common Report Var(flag_show_column) Init(1)
2302 Show column numbers in diagnostics, when available. Default on.
2305 Common Report Var(flag_shrink_wrap) Optimization
2306 Emit function prologues only before parts of the function that need it,
2307 rather than at the top of the function.
2309 fshrink-wrap-separate
2310 Common Report Var(flag_shrink_wrap_separate) Init(1) Optimization
2311 Shrink-wrap parts of the prologue and epilogue separately.
2314 Common Report Var(flag_signaling_nans) Optimization SetByCombined
2315 Disable optimizations observable by IEEE signaling NaNs.
2318 Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
2319 Disable floating point optimizations that ignore the IEEE signedness of zero.
2321 fsingle-precision-constant
2322 Common Report Var(flag_single_precision_constant) Optimization
2323 Convert floating point constants to single precision constants.
2325 fsplit-ivs-in-unroller
2326 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
2327 Split lifetimes of induction variables when loops are unrolled.
2330 Common Report Var(flag_split_stack) Init(-1)
2331 Generate discontiguous stack frames.
2334 Common Report Var(flag_split_wide_types) Optimization
2335 Split wide types into independent registers.
2338 Common Report Var(flag_ssa_backprop) Init(1) Optimization
2339 Enable backward propagation of use properties at the SSA level.
2342 Common Report Var(flag_ssa_phiopt) Optimization
2343 Optimize conditional patterns using SSA PHI nodes.
2346 Common Report Var(flag_stdarg_opt) Init(1) Optimization
2347 Optimize amount of stdarg registers saved to stack at start of function.
2349 fvariable-expansion-in-unroller
2350 Common Report Var(flag_variable_expansion_in_unroller) Optimization
2351 Apply variable expansion when loops are unrolled.
2354 Common Report RejectNegative Joined Optimization
2355 -fstack-check=[no|generic|specific] Insert stack checking code into the program.
2358 Common Alias(fstack-check=, specific, no)
2359 Insert stack checking code into the program. Same as -fstack-check=specific.
2361 fstack-clash-protection
2362 Common Report Var(flag_stack_clash_protection) Optimization
2363 Insert code to probe each page of stack space as it is allocated to protect
2364 from stack-clash style attacks.
2367 Common Var(common_deferred_options) Defer
2369 fstack-limit-register=
2370 Common RejectNegative Joined Var(common_deferred_options) Defer
2371 -fstack-limit-register=<register> Trap if the stack goes past <register>.
2373 fstack-limit-symbol=
2374 Common RejectNegative Joined Var(common_deferred_options) Defer
2375 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>.
2378 Common Report Var(flag_stack_protect, 1) Init(-1) Optimization
2379 Use propolice as a stack protection method.
2381 fstack-protector-all
2382 Common Report RejectNegative Var(flag_stack_protect, 2) Init(-1) Optimization
2383 Use a stack protection method for every function.
2385 fstack-protector-strong
2386 Common Report RejectNegative Var(flag_stack_protect, 3) Init(-1) Optimization
2387 Use a smart stack protection method for certain functions.
2389 fstack-protector-explicit
2390 Common Report RejectNegative Var(flag_stack_protect, 4) Optimization
2391 Use stack protection method only for functions with the stack_protect attribute.
2394 Common RejectNegative Var(flag_stack_usage)
2395 Output stack usage information on a per-function basis.
2399 Does nothing. Preserved for backward compatibility.
2401 ; Nonzero if we should do (language-dependent) alias analysis.
2402 ; Typically, this analysis will assume that expressions of certain
2403 ; types do not alias expressions of certain other types. Only used
2404 ; if alias analysis (in general) is enabled.
2406 Common Report Var(flag_strict_aliasing) Optimization
2407 Assume strict aliasing rules apply.
2410 Common NegativeAlias Alias(fwrapv)
2411 Treat signed overflow as undefined. Negated as -fwrapv.
2414 Common Report Var(flag_sync_libcalls) Init(1)
2415 Implement __atomic operations via libcalls to legacy __sync functions.
2418 Common Report Var(flag_syntax_only)
2419 Check for syntax errors, then stop.
2422 Common Report Var(flag_test_coverage)
2423 Create data files needed by \"gcov\".
2426 Common Report Var(flag_thread_jumps) Optimization
2427 Perform jump threading optimizations.
2430 Common Report Var(time_report)
2431 Report the time taken by each compiler pass.
2433 ftime-report-details
2434 Common Report Var(time_report_details)
2435 Record times taken by sub-phases separately.
2438 Common Joined RejectNegative Enum(tls_model) Var(flag_tls_default) Init(TLS_MODEL_GLOBAL_DYNAMIC)
2439 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model.
2442 Name(tls_model) Type(enum tls_model) UnknownError(unknown TLS model %qs)
2445 Enum(tls_model) String(global-dynamic) Value(TLS_MODEL_GLOBAL_DYNAMIC)
2448 Enum(tls_model) String(local-dynamic) Value(TLS_MODEL_LOCAL_DYNAMIC)
2451 Enum(tls_model) String(initial-exec) Value(TLS_MODEL_INITIAL_EXEC)
2454 Enum(tls_model) String(local-exec) Value(TLS_MODEL_LOCAL_EXEC)
2457 Common Report Var(flag_toplevel_reorder) Init(2)
2458 Reorder top level functions, variables, and asms.
2461 Common Report Var(flag_tracer) Optimization
2462 Perform superblock formation via tail duplication.
2465 Common Report Var(flag_trampolines) Init(0)
2466 For targets that normally need trampolines for nested functions, always
2467 generate them instead of using descriptors.
2469 ; Zero means that floating-point math operations cannot generate a
2470 ; (user-visible) trap. This is the case, for example, in nonstop
2471 ; IEEE 754 arithmetic.
2473 Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
2474 Assume floating-point operations can trap.
2477 Common Report Var(flag_trapv) Optimization
2478 Trap for signed overflow in addition, subtraction and multiplication.
2481 Common Report Var(flag_tree_ccp) Optimization
2482 Enable SSA-CCP optimization on trees.
2485 Common Report Var(flag_tree_bit_ccp) Optimization
2486 Enable SSA-BIT-CCP optimization on trees.
2490 Does nothing. Preserved for backward compatibility.
2493 Common Report Var(flag_tree_ch) Optimization
2494 Enable loop header copying on trees.
2496 ftree-coalesce-inlined-vars
2497 Common Ignore RejectNegative
2498 Does nothing. Preserved for backward compatibility.
2501 Common Report Var(flag_tree_coalesce_vars) Optimization
2502 Enable SSA coalescing of user variables.
2506 Does nothing. Preserved for backward compatibility.
2509 Common Report Var(flag_tree_copy_prop) Optimization
2510 Enable copy propagation on trees.
2512 ftree-store-copy-prop
2514 Does nothing. Preserved for backward compatibility.
2517 Common Report Var(flag_tree_cselim) Init(2) Optimization
2518 Transform condition stores into unconditional ones.
2520 ftree-switch-conversion
2521 Common Report Var(flag_tree_switch_conversion) Optimization
2522 Perform conversions of switch initializations.
2525 Common Report Var(flag_tree_dce) Optimization
2526 Enable SSA dead code elimination optimization on trees.
2528 ftree-dominator-opts
2529 Common Report Var(flag_tree_dom) Optimization
2530 Enable dominator optimizations.
2533 Common Report Var(flag_tree_tail_merge) Optimization
2534 Enable tail merging on trees.
2537 Common Report Var(flag_tree_dse) Optimization
2538 Enable dead store elimination.
2541 Common Report Var(flag_tree_forwprop) Init(1) Optimization
2542 Enable forward propagation on trees.
2545 Common Report Var(flag_tree_fre) Optimization
2546 Enable Full Redundancy Elimination (FRE) on trees.
2549 Common Report Var(flag_optimize_strlen) Optimization
2550 Enable string length optimizations on trees.
2552 fisolate-erroneous-paths-dereference
2553 Common Report Var(flag_isolate_erroneous_paths_dereference) Optimization
2554 Detect paths that trigger erroneous or undefined behavior due to
2555 dereferencing a null pointer. Isolate those paths from the main control
2556 flow and turn the statement with erroneous or undefined behavior into a trap.
2558 fisolate-erroneous-paths-attribute
2559 Common Report Var(flag_isolate_erroneous_paths_attribute) Optimization
2560 Detect paths that trigger erroneous or undefined behavior due to a null value
2561 being used in a way forbidden by a returns_nonnull or nonnull
2562 attribute. Isolate those paths from the main control flow and turn the
2563 statement with erroneous or undefined behavior into a trap.
2565 ftree-loop-distribution
2566 Common Report Var(flag_tree_loop_distribution) Optimization
2567 Enable loop distribution on trees.
2569 ftree-loop-distribute-patterns
2570 Common Report Var(flag_tree_loop_distribute_patterns) Optimization
2571 Enable loop distribution for patterns transformed into a library call.
2574 Common Report Var(flag_tree_loop_im) Init(1) Optimization
2575 Enable loop invariant motion on trees.
2578 Common Alias(floop-nest-optimize)
2579 Enable loop nest transforms. Same as -floop-nest-optimize.
2582 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
2583 Create canonical induction variables in loops.
2586 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
2587 Enable loop optimizations on tree level.
2589 ftree-parallelize-loops=
2590 Common Report Joined RejectNegative UInteger Var(flag_tree_parallelize_loops) Init(1) Optimization
2591 -ftree-parallelize-loops=<number> Enable automatic parallelization of loops.
2594 Common Report Var(flag_tree_phiprop) Init(1) Optimization
2595 Enable hoisting loads from conditional pointers.
2598 Common Report Var(flag_tree_pre) Optimization
2599 Enable SSA-PRE optimization on trees.
2602 Common Report Var(flag_tree_partial_pre) Optimization
2603 In SSA-PRE optimization on trees, enable partial-partial redundancy elimination.
2606 Common Report Var(flag_tree_pta) Optimization
2607 Perform function-local points-to analysis on trees.
2610 Common Report Var(flag_tree_reassoc) Init(1) Optimization
2611 Enable reassociation on tree level.
2615 Does nothing. Preserved for backward compatibility.
2618 Common Report Var(flag_tree_sink) Optimization
2619 Enable SSA code sinking on trees.
2622 Common Report Var(flag_tree_slsr) Optimization
2623 Perform straight-line strength reduction.
2626 Common Report Var(flag_tree_sra) Optimization
2627 Perform scalar replacement of aggregates.
2630 Common Report Var(flag_tree_ter) Optimization
2631 Replace temporary expressions in the SSA->normal pass.
2634 Common Report Var(flag_tree_live_range_split) Optimization
2635 Perform live range splitting during the SSA->normal pass.
2638 Common Report Var(flag_tree_vrp) Init(0) Optimization
2639 Perform Value Range Propagation on trees.
2642 Common Report Var(flag_split_paths) Init(0) Optimization
2643 Split paths leading to loop backedges.
2645 funconstrained-commons
2646 Common Var(flag_unconstrained_commons) Optimization
2647 Assume common declarations may be overridden with ones with a larger
2651 Common Report Var(flag_unit_at_a_time) Init(1)
2652 Compile whole compilation unit at a time.
2655 Common Report Var(flag_unroll_loops) Optimization
2656 Perform loop unrolling when iteration count is known.
2659 Common Report Var(flag_unroll_all_loops) Optimization
2660 Perform loop unrolling for all loops.
2662 ; Nonzero means that loop optimizer may assume that the induction variables
2663 ; that control loops do not overflow and that the loops with nontrivial
2664 ; exit condition are not infinite
2665 funsafe-loop-optimizations
2667 Does nothing. Preserved for backward compatibility.
2670 Common Report Var(flag_associative_math) SetByCombined Optimization
2671 Allow optimization for floating-point arithmetic which may change the
2672 result of the operation due to rounding.
2675 Common Report Var(flag_reciprocal_math) SetByCombined Optimization
2676 Same as -fassociative-math for expressions which include division.
2678 ; Nonzero means that unsafe floating-point math optimizations are allowed
2679 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
2680 ; are allowed to assume that their arguments and results are "normal"
2681 ; (e.g., nonnegative for SQRT).
2682 funsafe-math-optimizations
2683 Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
2684 Allow math optimizations that may violate IEEE or ISO standards.
2687 Common Report Var(flag_unswitch_loops) Optimization
2688 Perform loop unswitching.
2691 Common Report Var(flag_split_loops) Optimization
2692 Perform loop splitting.
2695 Common Report Var(flag_unwind_tables) Optimization
2696 Just generate unwind tables for exception handling.
2699 Common Driver Negative(fuse-ld=gold)
2700 Use the bfd linker instead of the default linker.
2703 Common Driver Negative(fuse-ld=bfd)
2704 Use the gold linker instead of the default linker.
2707 Common Undocumented Var(flag_use_linker_plugin)
2709 ; Positive if we should track variables, negative if we should run
2710 ; the var-tracking pass only to discard debug annotations, zero if
2711 ; we're not to run it. When flag_var_tracking == 2 (AUTODETECT_VALUE) it
2712 ; will be set according to optimize, debug_info_level and debug_hooks
2713 ; in process_options ().
2715 Common Report Var(flag_var_tracking) Init(2) PerFunction
2716 Perform variable tracking.
2718 ; Positive if we should track variables at assignments, negative if
2719 ; we should run the var-tracking pass only to discard debug
2720 ; annotations. When flag_var_tracking_assignments ==
2721 ; AUTODETECT_VALUE it will be set according to flag_var_tracking.
2722 fvar-tracking-assignments
2723 Common Report Var(flag_var_tracking_assignments) Init(2) PerFunction
2724 Perform variable tracking by annotating assignments.
2726 ; Nonzero if we should toggle flag_var_tracking_assignments after
2727 ; processing options and computing its default. */
2728 fvar-tracking-assignments-toggle
2729 Common Report Var(flag_var_tracking_assignments_toggle) PerFunction
2730 Toggle -fvar-tracking-assignments.
2732 ; Positive if we should track uninitialized variables, negative if
2733 ; we should run the var-tracking pass only to discard debug
2734 ; annotations. When flag_var_tracking_uninit == AUTODETECT_VALUE it
2735 ; will be set according to flag_var_tracking.
2736 fvar-tracking-uninit
2737 Common Report Var(flag_var_tracking_uninit) PerFunction
2738 Perform variable tracking and also tag variables that are uninitialized.
2740 ; Alias to enable both -ftree-loop-vectorize and -ftree-slp-vectorize.
2742 Common Report Optimization
2743 Enable vectorization on trees.
2745 ftree-vectorizer-verbose=
2746 Common Joined RejectNegative Ignore
2747 Does nothing. Preserved for backward compatibility.
2749 ftree-loop-vectorize
2750 Common Report Var(flag_tree_loop_vectorize) Optimization EnabledBy(ftree-vectorize)
2751 Enable loop vectorization on trees.
2754 Common Report Var(flag_tree_slp_vectorize) Optimization EnabledBy(ftree-vectorize)
2755 Enable basic block vectorization (SLP) on trees.
2758 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_vect_cost_model) Init(VECT_COST_MODEL_DEFAULT) Optimization
2759 Specifies the cost model for vectorization.
2760 -fvect-cost-model=[unlimited|dynamic|cheap] Specifies the cost model for vectorization.
2763 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_simd_cost_model) Init(VECT_COST_MODEL_UNLIMITED) Optimization
2764 -fsimd-cost-model=[unlimited|dynamic|cheap] Specifies the vectorization cost model for code marked with a simd directive.
2767 Name(vect_cost_model) Type(enum vect_cost_model) UnknownError(unknown vectorizer cost model %qs)
2770 Enum(vect_cost_model) String(unlimited) Value(VECT_COST_MODEL_UNLIMITED)
2773 Enum(vect_cost_model) String(dynamic) Value(VECT_COST_MODEL_DYNAMIC)
2776 Enum(vect_cost_model) String(cheap) Value(VECT_COST_MODEL_CHEAP)
2779 Common Alias(fvect-cost-model=,dynamic,unlimited)
2780 Enables the dynamic vectorizer cost model. Preserved for backward compatibility.
2782 ftree-vect-loop-version
2784 Does nothing. Preserved for backward compatibility.
2787 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
2788 Enable copy propagation of scalar-evolution information.
2790 ; -fverbose-asm causes extra commentary information to be produced in
2791 ; the generated assembly code (to make it more readable). This option
2792 ; is generally only of use to those who actually need to read the
2793 ; generated assembly code (perhaps while debugging the compiler itself).
2794 ; -fno-verbose-asm, the default, causes the extra information
2795 ; to not be added and is useful when comparing two assembler files.
2797 Common Report Var(flag_verbose_asm)
2798 Add extra commentary to assembler output.
2801 Common Joined RejectNegative Enum(symbol_visibility) Var(default_visibility) Init(VISIBILITY_DEFAULT)
2802 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility.
2805 Name(symbol_visibility) Type(enum symbol_visibility) UnknownError(unrecognized visibility value %qs)
2808 Enum(symbol_visibility) String(default) Value(VISIBILITY_DEFAULT)
2811 Enum(symbol_visibility) String(internal) Value(VISIBILITY_INTERNAL)
2814 Enum(symbol_visibility) String(hidden) Value(VISIBILITY_HIDDEN)
2817 Enum(symbol_visibility) String(protected) Value(VISIBILITY_PROTECTED)
2820 Common Joined RejectNegative Enum(vtv_priority) Var(flag_vtable_verify) Init(VTV_NO_PRIORITY)
2821 Validate vtable pointers before using them.
2824 Name(vtv_priority) Type(enum vtv_priority) UnknownError(unknown vtable verify initialization priority %qs)
2827 Enum(vtv_priority) String(none) Value(VTV_NO_PRIORITY)
2830 Enum(vtv_priority) String(std) Value(VTV_STANDARD_PRIORITY)
2833 Enum(vtv_priority) String(preinit) Value(VTV_PREINIT_PRIORITY)
2836 Common Var(flag_vtv_counts)
2837 Output vtable verification counters.
2840 Common Var(flag_vtv_debug)
2841 Output vtable verification pointer sets information.
2844 Common Report Var(flag_value_profile_transformations) Optimization
2845 Use expression value profiles in optimizations.
2848 Common Report Var(flag_web) Init(2) Optimization
2849 Construct webs and split unrelated uses of single variable.
2851 ftree-builtin-call-dce
2852 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
2853 Enable conditional dead code elimination for builtin calls.
2856 Common Report Var(flag_whole_program) Init(0)
2857 Perform whole program optimizations.
2860 Common Report Var(flag_wrapv) Optimization
2861 Assume signed arithmetic overflow wraps around.
2863 fzero-initialized-in-bss
2864 Common Report Var(flag_zero_initialized_in_bss) Init(1)
2865 Put zero initialized data in the bss section.
2868 Common Driver RejectNegative JoinedOrMissing
2869 Generate debug information in default format.
2872 Common Driver JoinedOrMissing Negative(gdwarf)
2873 Generate debug information in COFF format.
2876 Common Driver Var(debug_column_info,1) Init(0)
2877 Record DW_AT_decl_column and DW_AT_call_column in DWARF.
2880 Common Driver JoinedOrMissing Negative(gdwarf-)
2881 Generate debug information in default version of DWARF format.
2884 Common Driver Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
2885 Generate debug information in DWARF v2 (or later) format.
2888 Common Driver JoinedOrMissing
2889 Generate debug information in default extended format.
2892 RejectNegative Joined Undocumented
2893 ; Catch the gno- prefix, so it doesn't backtrack to g<level>.
2896 Common Driver Negative(gpubnames) Var(debug_generate_pub_sections, 0) Init(-1)
2897 Don't generate DWARF pubnames and pubtypes sections.
2900 Common Driver Negative(ggnu-pubnames) Var(debug_generate_pub_sections, 1)
2901 Generate DWARF pubnames and pubtypes sections.
2904 Common Driver Negative(gno-pubnames) Var(debug_generate_pub_sections, 2)
2905 Generate DWARF pubnames and pubtypes sections with GNU extensions.
2907 grecord-gcc-switches
2908 Common Driver Var(dwarf_record_gcc_switches) Init(1)
2909 Record gcc command line switches in DWARF DW_AT_producer.
2912 Common Driver Var(dwarf_split_debug_info) Init(0)
2913 Generate debug information in separate .dwo files.
2916 Common Driver JoinedOrMissing Negative(gstabs+)
2917 Generate debug information in STABS format.
2920 Common Driver JoinedOrMissing Negative(gvms)
2921 Generate debug information in extended STABS format.
2924 Common Driver Report Var(dwarf_strict) Init(0)
2925 Don't emit DWARF additions beyond selected version.
2928 Common Driver Report Var(flag_gtoggle)
2929 Toggle debug information generation.
2932 Common Driver JoinedOrMissing Negative(gxcoff)
2933 Generate debug information in VMS format.
2936 Common Driver JoinedOrMissing Negative(gxcoff+)
2937 Generate debug information in XCOFF format.
2940 Common Driver JoinedOrMissing Negative(gcoff)
2941 Generate debug information in extended XCOFF format.
2944 Name(compressed_debug_sections) Type(int)
2946 ; Since -gz= is completely handled in specs, the values aren't used and we
2947 ; assign arbitrary constants.
2949 Enum(compressed_debug_sections) String(none) Value(0)
2952 Enum(compressed_debug_sections) String(zlib) Value(1)
2955 Enum(compressed_debug_sections) String(zlib-gnu) Value(2)
2959 Generate compressed debug sections.
2962 Common Driver RejectNegative Joined Enum(compressed_debug_sections)
2963 -gz=<format> Generate compressed debug sections in format <format>.
2966 Driver Joined Separate
2969 Common Joined Var(plugindir_string) Init(0)
2970 -iplugindir=<dir> Set <dir> to be the default plugin directory.
2973 Common Joined Separate RejectDriver Var(imultiarch) Init(0)
2974 -imultiarch <dir> Set <dir> to be the multiarch include subdirectory.
2977 Driver Joined Separate
2982 no-canonical-prefixes
2995 Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs)
2996 -o <file> Place output into <file>.
2999 Common Var(profile_flag)
3000 Enable function profiling.
3003 Driver Var(pass_exit_codes)
3006 Common Alias(Wpedantic)
3009 Common Var(flag_pedantic_errors)
3010 Like -pedantic but issue them as errors.
3016 Driver Var(use_pipes)
3019 Driver JoinedOrMissing Var(print_file_name)
3021 print-libgcc-file-name
3024 print-multi-directory
3025 Driver Var(print_multi_directory)
3028 Driver Var(print_multi_lib)
3030 print-multi-os-directory
3031 Driver Var(print_multi_os_directory)
3034 Driver Var(print_multiarch)
3037 Driver JoinedOrMissing Var(print_prog_name)
3040 Driver Var(print_search_dirs)
3043 Driver Var(print_sysroot)
3045 print-sysroot-headers-suffix
3046 Driver Var(print_sysroot_headers_suffix)
3049 Common Var(quiet_flag) RejectDriver
3050 Do not display functions compiled or elapsed time.
3068 Driver Var(report_times)
3071 Driver JoinedOrMissing
3074 Driver Joined Separate
3078 ; C option, but driver must not handle as "-u ndef".
3081 Common Driver Var(verbose_flag)
3082 Enable verbose output.
3085 Common Var(version_flag) RejectDriver
3086 Display the compiler's version.
3089 Common Var(inhibit_warnings)
3093 Driver Separate Var(wrapper_string)
3096 Driver Joined Separate
3099 Driver RejectNegative Negative(static-pie)
3100 Create a shared library.
3106 Driver Separate Alias(specs=)
3119 ; Documented for Fortran, but always accepted by driver.
3126 ; Documented for Go, but always accepted by driver.
3144 Driver RejectNegative Negative(shared)
3145 Don't create a dynamically linked position independent executable.
3148 Driver RejectNegative Negative(no-pie)
3149 Create a dynamically linked position independent executable.
3152 Driver RejectNegative Negative(pie)
3153 Create a static position independent executable.
3156 Driver Joined Separate
3159 Common Report Var(flag_ipa_ra) Optimization
3160 Use caller save register across calls if possible.
3162 ; This comment is to ensure we retain the blank line above.