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
540 Driver JoinedOrMissing
543 Driver JoinedOrMissing
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_cast_align) Warning
567 Warn about pointer casts which increase alignment.
570 Common Var(warn_cast_align,2) Warning
571 Warn about pointer casts which increase alignment.
574 Common Var(warn_cpp) Init(1) Warning
575 Warn when a #warning directive is encountered.
577 Wdeprecated-declarations
578 Common Var(warn_deprecated_decl) Init(1) Warning
579 Warn about uses of __attribute__((deprecated)) declarations.
581 Wdisabled-optimization
582 Common Var(warn_disabled_optimization) Warning
583 Warn when an optimization pass is disabled.
586 Common Var(warnings_are_errors)
587 Treat all warnings as errors.
591 Treat specified warning as error.
594 Common Var(extra_warnings) Warning
595 Print extra (possibly unwanted) warnings.
598 Common Var(flag_fatal_errors)
599 Exit on the first error occurred.
602 Common RejectNegative Joined UInteger Warning
603 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes.
606 Common Var(warn_free_nonheap_object) Init(1) Warning
607 Warn when attempting to free a non-heap object.
610 Common Var(warn_hsa) Init(1) Warning
611 Warn when a function cannot be expanded to HSAIL.
613 Wimplicit-fallthrough
614 Common Alias(Wimplicit-fallthrough=,3,0) Warning
616 Wimplicit-fallthrough=
617 Common Var(warn_implicit_fallthrough) RejectNegative Joined UInteger Warning IntegerRange(0, 5)
618 Warn when a switch case falls through.
621 Common Var(warn_inline) Warning
622 Warn when an inlined function cannot be inlined.
624 Winvalid-memory-model
625 Common Var(warn_invalid_memory_model) Init(1) Warning
626 Warn when an atomic memory model parameter is known to be outside the valid range.
629 Common RejectNegative Joined Warning Undocumented Alias(Wlarger-than=)
632 Common RejectNegative Joined UInteger Warning
633 -Wlarger-than=<number> Warn if an object is larger than <number> bytes.
636 Var(warn_nonnull_compare) Warning
637 Warn if comparing pointer parameter with nonnull attribute with NULL.
640 Common Var(warn_null_dereference) Warning
641 Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior.
643 Wunsafe-loop-optimizations
644 Common Var(warn_unsafe_loop_optimizations) Warning
645 Warn if the loop cannot be optimized due to nontrivial assumptions.
648 Common Warning Alias(Wsuggest-attribute=noreturn)
651 Common Var(warn_odr_violations) Init(1) Warning
652 Warn about some C++ One Definition Rule violations during link time optimization.
655 Common Var(warn_overflow) Init(1) Warning
656 Warn about overflow in arithmetic expressions.
659 Common Var(warn_lto_type_mismatch) Init(1) Warning
660 During link time optimization warn about mismatched types of global declarations.
663 Common Var(warn_packed) Warning
664 Warn when the packed attribute has no effect on struct layout.
667 Common Var(warn_padded) Warning
668 Warn when padding is required to align structure members.
671 Common Var(pedantic) Init(0) Warning
672 Issue warnings needed for strict compliance to the standard.
675 Common Var(warn_return_local_addr) Init(1) Warning
676 Warn about returning a pointer/reference to a local or temporary variable.
679 Common Var(warn_shadow) Warning
680 Warn when one variable shadows another. Same as -Wshadow=global.
683 Common Warning Alias(Wshadow)
684 Warn when one variable shadows another (globally).
687 Common Var(warn_shadow_local) Warning EnabledBy(Wshadow)
688 Warn when one local variable shadows another local variable or parameter.
691 Common Warning Undocumented Alias(Wshadow=local)
693 Wshadow=compatible-local
694 Common Var(warn_shadow_compatible_local) Warning EnabledBy(Wshadow=local)
695 Warn when one local variable shadows another local variable or parameter of compatible type.
697 Wshadow-compatible-local
698 Common Warning Undocumented Alias(Wshadow=compatible-local)
701 Common Var(warn_stack_protect) Warning
702 Warn when not issuing stack smashing protection for some reason.
705 Common Joined RejectNegative UInteger Var(warn_stack_usage) Warning
706 -Wstack-usage=<number> Warn if stack usage might be larger than specified amount.
710 Warn about code which might break strict aliasing rules.
713 Common Joined RejectNegative UInteger Var(warn_strict_aliasing) Warning
714 Warn about code which might break strict aliasing rules.
718 Warn about optimizations that assume that signed overflow is undefined.
721 Common Joined RejectNegative UInteger Var(warn_strict_overflow) Warning
722 Warn about optimizations that assume that signed overflow is undefined.
724 Wsuggest-attribute=const
725 Common Var(warn_suggest_attribute_const) Warning
726 Warn about functions which might be candidates for __attribute__((const)).
728 Wsuggest-attribute=pure
729 Common Var(warn_suggest_attribute_pure) Warning
730 Warn about functions which might be candidates for __attribute__((pure)).
732 Wsuggest-attribute=noreturn
733 Common Var(warn_suggest_attribute_noreturn) Warning
734 Warn about functions which might be candidates for __attribute__((noreturn)).
737 Common Var(warn_suggest_final_types) Warning
738 Warn about C++ polymorphic types where adding final keyword would improve code quality.
740 Wsuggest-final-methods
741 Common Var(warn_suggest_final_methods) Warning
742 Warn about C++ virtual methods where adding final keyword would improve code quality.
745 Common Var(warn_switch_unreachable) Warning Init(1)
746 Warn about statements between switch's controlling expression and the first
750 Common Var(warn_system_headers) Warning
751 Do not suppress warnings from system headers.
754 Common Var(warn_trampolines) Warning
755 Warn whenever a trampoline is generated.
758 Common Var(warn_type_limits) Warning EnabledBy(Wextra)
759 Warn if a comparison is always true or always false due to the limited range of the data type.
762 Common Var(warn_uninitialized) Warning EnabledBy(Wextra)
763 Warn about uninitialized automatic variables.
766 Common Var(warn_maybe_uninitialized) Warning EnabledBy(Wuninitialized)
767 Warn about maybe uninitialized automatic variables.
770 Common Ignore Warning
771 Does nothing. Preserved for backward compatibility.
774 Common Var(warn_unused) Init(0) Warning
775 Enable all -Wunused- warnings.
777 Wunused-but-set-parameter
778 Common Var(warn_unused_but_set_parameter) Warning EnabledBy(Wunused && Wextra)
779 Warn when a function parameter is only set, otherwise unused.
781 Wunused-but-set-variable
782 Common Var(warn_unused_but_set_variable) Warning EnabledBy(Wunused)
783 Warn when a variable is only set, otherwise unused.
786 Common Var(warn_unused_function) Warning EnabledBy(Wunused)
787 Warn when a function is unused.
790 Common Var(warn_unused_label) Warning EnabledBy(Wunused)
791 Warn when a label is unused.
794 Common Var(warn_unused_parameter) Warning EnabledBy(Wunused && Wextra)
795 Warn when a function parameter is unused.
798 Common Var(warn_unused_value) Warning EnabledBy(Wunused)
799 Warn when an expression value is unused.
802 Common Var(warn_unused_variable) Warning EnabledBy(Wunused)
803 Warn when a variable is unused.
806 Common Var(warn_coverage_mismatch) Init(1) Warning
807 Warn in case profiles in -fprofile-use do not match.
809 Wvector-operation-performance
810 Common Var(warn_vector_operation_performance) Warning
811 Warn when a vector operation is compiled outside the SIMD.
826 Common Separate Var(aux_info_file_name)
827 -aux-info <file> Emit declaration information into <file>.
830 Common Joined Alias(aux-info)
833 Common Separate RejectDriver Var(aux_base_name)
836 Common Separate RejectDriver
846 -d<letters> Enable dumps from specific passes of the compiler.
849 Common Separate Var(dump_base_name)
850 -dumpbase <file> Set the file basename to be used for dumps.
853 Common Separate Var(dump_dir_name)
854 -dumpdir <dir> Set the directory name to be used for dumps.
869 Driver Joined Separate
871 ; This option has historically been passed down to the linker by an
872 ; accident of a %{e*} spec, so ensure it continues to be passed down
873 ; as a single option. The supported option for this purpose is
874 ; -rdynamic. See PR 47390.
878 ; The version of the C++ ABI in use. The following values are allowed:
880 ; 0: The version of the ABI believed most conformant with the C++ ABI
881 ; specification. This ABI may change as bugs are discovered and fixed.
882 ; Therefore, 0 will not necessarily indicate the same ABI in different
885 ; 1: The version of the ABI first used in G++ 3.2. No longer selectable.
887 ; 2: The version of the ABI first used in G++ 3.4, and the default
890 ; 3: The version of the ABI that fixes the missing underscore
891 ; in template non-type arguments of pointer type.
893 ; 4: The version of the ABI that introduces unambiguous mangling of
894 ; vector types. First selectable in G++ 4.5.
896 ; 5: The version of the ABI that ignores attribute const/noreturn
897 ; in function pointer mangling, and corrects mangling of decltype and
898 ; function parameters used in other parameters and the return type.
899 ; First selectable in G++ 4.6.
901 ; 6: The version of the ABI that doesn't promote scoped enums to int and
902 ; changes the mangling of template argument packs, const/static_cast,
903 ; prefix ++ and --, and a class scope function used as a template
905 ; First selectable in G++ 4.7.
907 ; 7: The version of the ABI that treats nullptr_t as a builtin type and
908 ; corrects the mangling of lambdas in default argument scope.
909 ; First selectable in G++ 4.8.
911 ; 8: The version of the ABI that corrects the substitution behavior of
912 ; function types with function-cv-qualifiers.
913 ; First selectable in G++ 4.9 and default in G++ 5.
915 ; 9: The version of the ABI that corrects the alignment of nullptr_t.
916 ; First selectable and default in G++ 5.2.
918 ; 10: The version of the ABI that mangles attributes that affect type
919 ; identity, such as ia32 calling convention attributes (stdcall, etc.)
920 ; Default in G++ 6 (set in c_common_post_options).
922 ; 11: The version of the ABI that corrects mangling of sizeof... expressions
923 ; and introduces new inheriting constructor handling.
926 ; 12: Corrects the calling convention for classes with only deleted copy/move
930 ; Additional positive integers will be assigned as new versions of
931 ; the ABI become the default version of the ABI.
933 Common Joined RejectNegative UInteger Var(flag_abi_version) Init(0)
934 The version of the C++ ABI in use.
936 faggressive-loop-optimizations
937 Common Report Var(flag_aggressive_loop_optimizations) Optimization Init(1)
938 Aggressively optimize loops using language constraints.
941 Common Report Var(align_functions,0) Optimization UInteger
942 Align the start of functions.
945 Common RejectNegative Joined UInteger Var(align_functions)
947 flimit-function-alignment
948 Common Report Var(flag_limit_function_alignment) Optimization Init(0)
951 Common Report Var(align_jumps,0) Optimization UInteger
952 Align labels which are only reached by jumping.
955 Common RejectNegative Joined UInteger Var(align_jumps)
958 Common Report Var(align_labels,0) Optimization UInteger
962 Common RejectNegative Joined UInteger Var(align_labels)
965 Common Report Var(align_loops,0) Optimization UInteger
966 Align the start of loops.
969 Common RejectNegative Joined UInteger Var(align_loops)
973 Does nothing. Preserved for backward compatibility.
977 Does nothing. Preserved for backward compatibility.
979 fargument-noalias-global
981 Does nothing. Preserved for backward compatibility.
983 fargument-noalias-anything
985 Does nothing. Preserved for backward compatibility.
988 Common Driver Report Joined
989 Select what to sanitize.
993 Select what to coverage sanitize.
996 Common Joined RejectNegative Var(common_deferred_options) Defer
997 -fasan-shadow-offset=<number> Use custom shadow memory offset.
1000 Common Joined RejectNegative Var(common_deferred_options) Defer
1001 -fsanitize-sections=<sec1,sec2,...> Sanitize global variables
1002 in user-defined sections.
1005 Common Report Joined
1006 After diagnosing undefined behavior attempt to continue execution.
1010 This switch is deprecated; use -fsanitize-recover= instead.
1012 fsanitize-address-use-after-scope
1013 Common Driver Report Var(flag_sanitize_address_use_after_scope) Init(0)
1015 fsanitize-undefined-trap-on-error
1016 Common Driver Report Var(flag_sanitize_undefined_trap_on_error) Init(0)
1017 Use trap instead of a library function for undefined behavior sanitization.
1019 fasynchronous-unwind-tables
1020 Common Report Var(flag_asynchronous_unwind_tables) Optimization
1021 Generate unwind tables that are exact at each instruction boundary.
1024 Common Report Var(flag_auto_inc_dec) Init(1) Optimization
1025 Generate auto-inc/dec instructions.
1028 Common Report Var(flag_auto_profile)
1029 Use sample profile information for call graph node weights. The default
1030 profile file is fbdata.afdo in 'pwd'.
1033 Common Joined RejectNegative Var(auto_profile_file)
1034 Use sample profile information for call graph node weights. The profile
1035 file is specified in the argument.
1037 ; -fcheck-bounds causes gcc to generate array bounds checks.
1038 ; For C, C++ and ObjC: defaults off.
1039 ; For Java: defaults to on.
1040 ; For Fortran: defaults to off.
1042 Common Report Var(flag_bounds_check)
1043 Generate code to check bounds before indexing arrays.
1046 Common Report Var(flag_branch_on_count_reg) Optimization
1047 Replace add, compare, branch with branch on count register.
1049 fbranch-probabilities
1050 Common Report Var(flag_branch_probabilities) Optimization
1051 Use profiling information for branch probabilities.
1053 fbranch-target-load-optimize
1054 Common Report Var(flag_branch_target_load_optimize) Optimization
1055 Perform branch target load optimization before prologue / epilogue threading.
1057 fbranch-target-load-optimize2
1058 Common Report Var(flag_branch_target_load_optimize2) Optimization
1059 Perform branch target load optimization after prologue / epilogue threading.
1062 Common Report Var(flag_btr_bb_exclusive) Optimization
1063 Restrict target load migration not to re-use registers in any basic block.
1066 Common Joined RejectNegative Var(common_deferred_options) Defer
1067 -fcall-saved-<register> Mark <register> as being preserved across functions.
1070 Common Joined RejectNegative Var(common_deferred_options) Defer
1071 -fcall-used-<register> Mark <register> as being corrupted by function calls.
1073 ; Nonzero for -fcaller-saves: allocate values in regs that need to
1074 ; be saved across function calls, if that produces overall better code.
1075 ; Optional now, so people can test it.
1077 Common Report Var(flag_caller_saves) Optimization
1078 Save registers around function calls.
1081 Common Report Var(flag_check_data_deps)
1082 This switch is deprecated; do not use.
1085 Common Var(flag_check_new)
1086 Check the return value of new in C++.
1089 Common Var(flag_checking) Init(CHECKING_P ? ENABLE_EXTRA_CHECKING ? 2 : 1 : 0)
1090 Perform internal consistency checkings.
1093 Common Joined RejectNegative UInteger Var(flag_checking)
1094 Perform internal consistency checkings.
1097 Common Report Var(flag_code_hoisting) Optimization
1098 Enable code hoisting.
1100 fcombine-stack-adjustments
1101 Common Report Var(flag_combine_stack_adjustments) Optimization
1102 Looks for opportunities to reduce stack adjustments and stack references.
1105 Common Report Var(flag_no_common,0)
1106 Do not put uninitialized globals in the common section.
1110 ; Converted by the driver to -fcompare-debug= options.
1113 Common Driver JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
1114 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump.
1116 fcompare-debug-second
1117 Common Driver RejectNegative Var(flag_compare_debug)
1118 Run only the second compilation of -fcompare-debug.
1121 Common Report Var(flag_compare_elim_after_reload) Optimization
1122 Perform comparison elimination after register allocation has finished.
1125 Common Var(flag_conserve_stack) Optimization
1126 Do not perform optimizations increasing noticeably stack usage.
1129 Common Report Var(flag_cprop_registers) Optimization
1130 Perform a register copy-propagation optimization pass.
1133 Common Report Var(flag_crossjumping) Optimization
1134 Perform cross-jumping optimization.
1137 Common Report Var(flag_cse_follow_jumps) Optimization
1138 When running CSE, follow jumps to their targets.
1142 Does nothing. Preserved for backward compatibility.
1145 Common Report Var(flag_cx_limited_range) Optimization SetByCombined
1146 Omit range reduction step when performing complex division.
1149 Common Report Var(flag_cx_fortran_rules) Optimization
1150 Complex multiplication and division follow Fortran rules.
1153 Common Report Var(flag_data_sections)
1154 Place data items into their own section.
1157 Common Report Var(common_deferred_options) Defer
1158 List all available debugging counters with their limits and counts.
1161 Common RejectNegative Joined Var(common_deferred_options) Defer
1162 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
1165 Common Joined RejectNegative Var(common_deferred_options) Defer
1166 Map one directory name to another in debug information.
1168 fdebug-types-section
1169 Common Report Var(flag_debug_types_section) Init(0)
1170 Output .debug_types section when using DWARF v4 debuginfo.
1172 ; Nonzero for -fdefer-pop: don't pop args after each function call
1173 ; instead save them up to pop many calls' args with one insns.
1175 Common Report Var(flag_defer_pop) Optimization
1176 Defer popping functions args from stack until later.
1179 Common Report Var(flag_delayed_branch) Optimization
1180 Attempt to fill delay slots of branch instructions.
1182 fdelete-dead-exceptions
1183 Common Report Var(flag_delete_dead_exceptions) Init(0) Optimization
1184 Delete dead instructions that may throw exceptions.
1186 fdelete-null-pointer-checks
1187 Common Report Var(flag_delete_null_pointer_checks) Init(-1) Optimization
1188 Delete useless null pointer checks.
1190 fdevirtualize-at-ltrans
1191 Common Report Var(flag_ltrans_devirtualize)
1192 Stream extra data to support more aggressive devirtualization in LTO local transformation mode.
1194 fdevirtualize-speculatively
1195 Common Report Var(flag_devirtualize_speculatively) Optimization
1196 Perform speculative devirtualization.
1199 Common Report Var(flag_devirtualize) Optimization
1200 Try to convert virtual calls to direct ones.
1202 fdiagnostics-show-location=
1203 Common Joined RejectNegative Enum(diagnostic_prefixing_rule)
1204 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics.
1206 ; Required for these enum values.
1211 Name(diagnostic_prefixing_rule) Type(int)
1214 Enum(diagnostic_prefixing_rule) String(once) Value(DIAGNOSTICS_SHOW_PREFIX_ONCE)
1217 Enum(diagnostic_prefixing_rule) String(every-line) Value(DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE)
1219 fdiagnostics-show-caret
1220 Common Var(flag_diagnostics_show_caret) Init(1)
1221 Show the source line with a caret indicating the column.
1224 Common Alias(fdiagnostics-color=,always,never)
1228 Driver Common Joined RejectNegative Var(flag_diagnostics_show_color) Enum(diagnostic_color_rule) Init(DIAGNOSTICS_COLOR_NO)
1229 -fdiagnostics-color=[never|always|auto] Colorize diagnostics.
1231 ; Required for these enum values.
1236 Name(diagnostic_color_rule) Type(int)
1239 Enum(diagnostic_color_rule) String(never) Value(DIAGNOSTICS_COLOR_NO)
1242 Enum(diagnostic_color_rule) String(always) Value(DIAGNOSTICS_COLOR_YES)
1245 Enum(diagnostic_color_rule) String(auto) Value(DIAGNOSTICS_COLOR_AUTO)
1247 fdiagnostics-parseable-fixits
1248 Common Var(flag_diagnostics_parseable_fixits)
1249 Print fix-it hints in machine-readable form.
1251 fdiagnostics-generate-patch
1252 Common Var(flag_diagnostics_generate_patch)
1253 Print fix-it hints to stderr in unified diff format.
1255 fdiagnostics-show-option
1256 Common Var(flag_diagnostics_show_option) Init(1)
1257 Amend appropriate diagnostic messages with the command line option that controls them.
1260 Common Joined RejectNegative Var(common_deferred_options) Defer
1261 -fdisable-[tree|rtl|ipa]-<pass>=range1+range2 disables an optimization pass.
1264 Common Joined RejectNegative Var(common_deferred_options) Defer
1265 -fenable-[tree|rtl|ipa]-<pass>=range1+range2 enables an optimization pass.
1268 Common Joined RejectNegative Var(common_deferred_options) Defer
1269 -fdump-<type> Dump various compiler internals to a file.
1272 Driver RejectNegative
1275 Common RejectNegative Joined Var(flag_dump_final_insns)
1276 -fdump-final-insns=filename Dump to filename the insns at the end of translation.
1279 Common RejectNegative Joined Var(flag_dump_go_spec)
1280 -fdump-go-spec=filename Write all declarations to file as Go code.
1283 Common Report Var(flag_dump_noaddr)
1284 Suppress output of addresses in debugging dumps.
1287 Common Driver Var(flag_report_bug)
1288 Collect and dump debug information into temporary file if ICE in C/C++
1291 fdump-internal-locations
1292 Common Var(flag_dump_locations) Init(0)
1293 Dump detailed information on GCC's internal representation of source code locations.
1296 Common Var(flag_dump_passes) Init(0)
1297 Dump optimization passes.
1300 Common Report Var(flag_dump_unnumbered)
1301 Suppress output of instruction numbers, line number notes and addresses in debugging dumps.
1303 fdump-unnumbered-links
1304 Common Report Var(flag_dump_unnumbered_links)
1305 Suppress output of previous and next insn numbers in debugging dumps.
1308 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
1309 Enable CFI tables via GAS assembler directives.
1312 Common Report Var(flag_early_inlining) Init(1) Optimization
1313 Perform early inlining.
1315 feliminate-dwarf2-dups
1317 Does nothing. Preserved for backward compatibility.
1320 Common Report Var(flag_ipa_sra) Init(0) Optimization
1321 Perform interprocedural reduction of aggregates.
1323 feliminate-unused-debug-symbols
1324 Common Report Var(flag_debug_only_used_symbols)
1325 Perform unused symbol elimination in debug info.
1327 feliminate-unused-debug-types
1328 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
1329 Perform unused type elimination in debug info.
1331 femit-class-debug-always
1332 Common Report Var(flag_emit_class_debug_always) Init(0)
1333 Do not suppress C++ class debug information.
1336 Common Report Var(flag_exceptions) Optimization
1337 Enable exception handling.
1339 fexpensive-optimizations
1340 Common Report Var(flag_expensive_optimizations) Optimization
1341 Perform a number of minor, expensive optimizations.
1344 Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision_cmdline) Init(EXCESS_PRECISION_DEFAULT) SetByCombined
1345 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision.
1348 Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess precision style %qs)
1351 Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)
1354 Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
1356 ; Whether we permit the extended set of values for FLT_EVAL_METHOD
1357 ; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C99/C11.
1358 fpermitted-flt-eval-methods=
1359 Common Joined RejectNegative Enum(permitted_flt_eval_methods) Var(flag_permitted_flt_eval_methods) Init(PERMITTED_FLT_EVAL_METHODS_DEFAULT)
1360 -fpermitted-flt-eval-methods=[c11|ts-18661] Specify which values of FLT_EVAL_METHOD are permitted.
1363 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)
1366 Enum(permitted_flt_eval_methods) String(c11) Value(PERMITTED_FLT_EVAL_METHODS_C11)
1369 Enum(permitted_flt_eval_methods) String(ts-18661-3) Value(PERMITTED_FLT_EVAL_METHODS_TS_18661)
1375 Common Var(flag_fat_lto_objects)
1376 Output lto objects containing both the intermediate language and binary output.
1379 Common Report Var(flag_finite_math_only) Optimization SetByCombined
1380 Assume no NaNs or infinities are generated.
1383 Common Joined RejectNegative Var(common_deferred_options) Defer
1384 -ffixed-<register> Mark <register> as being unavailable to the compiler.
1387 Common Report Var(flag_float_store) Optimization
1388 Don't allocate floats and doubles in extended-precision registers.
1392 Does nothing. Preserved for backward compatibility.
1395 Common Report Var(flag_forward_propagate) Optimization
1396 Perform a forward propagation pass on RTL.
1399 Common Joined RejectNegative Enum(fp_contract_mode) Var(flag_fp_contract_mode) Init(FP_CONTRACT_FAST) Optimization
1400 -ffp-contract=[off|on|fast] Perform floating-point expression contraction.
1403 Name(fp_contract_mode) Type(enum fp_contract_mode) UnknownError(unknown floating point contraction style %qs)
1406 Enum(fp_contract_mode) String(off) Value(FP_CONTRACT_OFF)
1408 ; Not implemented, fall back to conservative FP_CONTRACT_OFF.
1410 Enum(fp_contract_mode) String(on) Value(FP_CONTRACT_OFF)
1413 Enum(fp_contract_mode) String(fast) Value(FP_CONTRACT_FAST)
1415 ffp-int-builtin-inexact
1416 Common Report Var(flag_fp_int_builtin_inexact) Init(1) Optimization
1417 Allow built-in functions ceil, floor, round, trunc to raise \"inexact\" exceptions.
1419 ; Nonzero means don't put addresses of constant functions in registers.
1420 ; Used for compiling the Unix kernel, where strange substitutions are
1421 ; done on the assembly output.
1423 Common Report Var(flag_no_function_cse,0) Optimization
1424 Allow function addresses to be held in registers.
1427 Common Report Var(flag_function_sections)
1428 Place each function into its own section.
1431 Common Report Var(flag_gcse) Optimization
1432 Perform global common subexpression elimination.
1435 Common Report Var(flag_gcse_lm) Init(1) Optimization
1436 Perform enhanced load motion during global common subexpression elimination.
1439 Common Report Var(flag_gcse_sm) Init(0) Optimization
1440 Perform store motion after global common subexpression elimination.
1443 Common Report Var(flag_gcse_las) Init(0) Optimization
1444 Perform redundant load after store elimination in global common subexpression
1448 Common Report Var(flag_gcse_after_reload) Optimization
1449 Perform global common subexpression elimination after register allocation has
1453 Name(dwarf_gnat_encodings) Type(int)
1456 Enum(dwarf_gnat_encodings) String(all) Value(DWARF_GNAT_ENCODINGS_ALL)
1459 Enum(dwarf_gnat_encodings) String(gdb) Value(DWARF_GNAT_ENCODINGS_GDB)
1462 Enum(dwarf_gnat_encodings) String(minimal) Value(DWARF_GNAT_ENCODINGS_MINIMAL)
1465 Common Enum(dwarf_gnat_encodings) Joined RejectNegative Report Undocumented Var(gnat_encodings)
1466 -fgnat-encodings=[all|gdb|minimal] Select the balance between GNAT encodings and standard DWARF emitted in the debug information
1468 ; This option is not documented yet as its semantics will change.
1470 Common Report Var(flag_graphite) Optimization
1471 Enable in and out of Graphite representation.
1474 Common Report Var(flag_graphite_identity) Optimization
1475 Enable Graphite Identity transformation.
1477 fhoist-adjacent-loads
1478 Common Report Var(flag_hoist_adjacent_loads) Optimization
1479 Enable hoisting adjacent loads to encourage generating conditional move
1483 Common Undocumented Report Var(flag_keep_gc_roots_live) Optimization
1484 ; Always keep a pointer to a live memory block
1486 floop-parallelize-all
1487 Common Report Var(flag_loop_parallelize_all) Optimization
1488 Mark all loops as parallel.
1491 Common Alias(floop-nest-optimize)
1492 Enable loop nest transforms. Same as -floop-nest-optimize.
1495 Common Alias(floop-nest-optimize)
1496 Enable loop nest transforms. Same as -floop-nest-optimize.
1499 Common Alias(floop-nest-optimize)
1500 Enable loop nest transforms. Same as -floop-nest-optimize.
1502 floop-unroll-and-jam
1503 Common Alias(floop-nest-optimize)
1504 Enable loop nest transforms. Same as -floop-nest-optimize.
1507 Common Report Var(flag_tm)
1508 Enable support for GNU transactional memory.
1511 Common Report Var(flag_gnu_unique) Init(1)
1512 Use STB_GNU_UNIQUE if supported by the assembler.
1516 Does nothing. Preserved for backward compatibility.
1519 Common Report Var(flag_loop_nest_optimize) Optimization
1520 Enable the loop nest optimizer.
1522 fstrict-volatile-bitfields
1523 Common Report Var(flag_strict_volatile_bitfields) Init(-1) Optimization
1524 Force bitfield accesses to match their type width.
1527 Common Report Var(flag_store_merging) Optimization
1528 Merge adjacent stores.
1530 fguess-branch-probability
1531 Common Report Var(flag_guess_branch_prob) Optimization
1532 Enable guessing of branch probabilities.
1534 ; Nonzero means ignore `#ident' directives. 0 means handle them.
1535 ; Generate position-independent code for executables if possible
1536 ; On SVR4 targets, it also controls whether or not to emit a
1537 ; string identifying the compiler.
1539 Common Report Var(flag_no_ident,0)
1540 Process #ident directives.
1543 Common Report Var(flag_if_conversion) Optimization
1544 Perform conversion of conditional jumps to branchless equivalents.
1547 Common Report Var(flag_if_conversion2) Optimization
1548 Perform conversion of conditional jumps to conditional execution.
1551 Common Joined RejectNegative Enum(stack_reuse_level) Var(flag_stack_reuse) Init(SR_ALL) Optimization
1552 -fstack-reuse=[all|named_vars|none] Set stack reuse level for local variables.
1555 Name(stack_reuse_level) Type(enum stack_reuse_level) UnknownError(unknown Stack Reuse Level %qs)
1558 Enum(stack_reuse_level) String(all) Value(SR_ALL)
1561 Enum(stack_reuse_level) String(named_vars) Value(SR_NAMED_VARS)
1564 Enum(stack_reuse_level) String(none) Value(SR_NONE)
1566 ftree-loop-if-convert
1567 Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
1568 Convert conditional jumps in innermost loops to branchless equivalents.
1570 ftree-loop-if-convert-stores
1572 Does nothing. Preserved for backward compatibility.
1574 ; -finhibit-size-directive inhibits output of .size for ELF.
1575 ; This is used only for compiling crtstuff.c,
1576 ; and it may be extended to other effects
1577 ; needed for crtstuff.c on other systems.
1578 finhibit-size-directive
1579 Common Report Var(flag_inhibit_size_directive)
1580 Do not generate .size directives.
1583 Common Report Var(flag_indirect_inlining) Optimization
1584 Perform indirect inlining.
1586 ; General flag to enable inlining. Specifying -fno-inline will disable
1587 ; all inlining apart from always-inline functions.
1589 Common Report Var(flag_no_inline,0) Init(0) Optimization
1590 Enable inlining of function declared \"inline\", disabling disables all inlining.
1592 finline-small-functions
1593 Common Report Var(flag_inline_small_functions) Optimization
1594 Integrate functions into their callers when code size is known not to grow.
1597 Common Report Var(flag_inline_functions) Optimization
1598 Integrate functions not declared \"inline\" into their callers when profitable.
1600 finline-functions-called-once
1601 Common Report Var(flag_inline_functions_called_once) Optimization
1602 Integrate functions only required by their single caller.
1605 Common RejectNegative Joined Alias(finline-limit=)
1608 Common RejectNegative Joined UInteger
1609 -finline-limit=<number> Limit the size of inlined functions to <number>.
1612 Common Report Var(flag_inline_atomics) Init(1) Optimization
1613 Inline __atomic operations when a lock free instruction sequence is available.
1615 finstrument-functions
1616 Common Report Var(flag_instrument_function_entry_exit)
1617 Instrument function entry and exit with profiling calls.
1619 finstrument-functions-exclude-function-list=
1620 Common RejectNegative Joined
1621 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions.
1623 finstrument-functions-exclude-file-list=
1624 Common RejectNegative Joined
1625 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files.
1628 Common Report Var(flag_ipa_cp) Optimization
1629 Perform interprocedural constant propagation.
1632 Common Report Var(flag_ipa_cp_clone) Optimization
1633 Perform cloning to make Interprocedural constant propagation stronger.
1637 Does nothing. Preserved for backward compatibility.
1640 Common Report Var(flag_ipa_bit_cp) Optimization
1641 Perform interprocedural bitwise constant propagation.
1644 Common Report Var(flag_ipa_profile) Init(0) Optimization
1645 Perform interprocedural profile propagation.
1648 Common Report Var(flag_ipa_pta) Init(0) Optimization
1649 Perform interprocedural points-to analysis.
1652 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
1653 Discover pure and const functions.
1656 Common Report Var(flag_ipa_icf) Optimization
1657 Perform Identical Code Folding for functions and read-only variables.
1660 Common Report Var(flag_ipa_icf_functions) Optimization
1661 Perform Identical Code Folding for functions.
1664 Common Report Var(flag_ipa_icf_variables) Optimization
1665 Perform Identical Code Folding for variables.
1668 Common Report Var(flag_ipa_reference) Init(0) Optimization
1669 Discover readonly and non addressable static variables.
1673 Does nothing. Preserved for backward compatibility.
1677 Does nothing. Preserved for backward compatibility.
1680 Common Report Var(flag_ipa_vrp) Optimization
1681 Perform IPA Value Range Propagation.
1684 Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization
1685 -fira-algorithm=[CB|priority] Set the used IRA algorithm.
1688 Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)
1691 Enum(ira_algorithm) String(CB) Value(IRA_ALGORITHM_CB)
1694 Enum(ira_algorithm) String(priority) Value(IRA_ALGORITHM_PRIORITY)
1697 Common Joined RejectNegative Enum(ira_region) Var(flag_ira_region) Init(IRA_REGION_AUTODETECT) Optimization
1698 -fira-region=[one|all|mixed] Set regions for IRA.
1701 Name(ira_region) Type(enum ira_region) UnknownError(unknown IRA region %qs)
1704 Enum(ira_region) String(one) Value(IRA_REGION_ONE)
1707 Enum(ira_region) String(all) Value(IRA_REGION_ALL)
1710 Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)
1713 Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
1714 Use IRA based register pressure calculation
1715 in RTL hoist optimizations.
1718 Common Report Var(flag_ira_loop_pressure) Optimization
1719 Use IRA based register pressure calculation
1720 in RTL loop optimizations.
1722 fira-share-save-slots
1723 Common Report Var(flag_ira_share_save_slots) Init(1) Optimization
1724 Share slots for saving different hard registers.
1726 fira-share-spill-slots
1727 Common Report Var(flag_ira_share_spill_slots) Init(1) Optimization
1728 Share stack slots for spilled pseudo-registers.
1731 Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
1732 -fira-verbose=<number> Control IRA's level of diagnostic messages.
1735 Common Report Var(flag_ivopts) Init(1) Optimization
1736 Optimize induction variables on trees.
1739 Common Var(flag_jump_tables) Init(1) Optimization
1740 Use jump tables for sufficiently large switch statements.
1742 fkeep-inline-functions
1743 Common Report Var(flag_keep_inline_functions)
1744 Generate code for functions even if they are fully inlined.
1746 fkeep-static-functions
1747 Common Report Var(flag_keep_static_functions)
1748 Generate code for static functions even if they are never called.
1751 Common Report Var(flag_keep_static_consts) Init(1)
1752 Emit static const variables even if they are not used.
1755 Common Report Var(flag_leading_underscore) Init(-1)
1756 Give external symbols a leading underscore.
1760 Does nothing. Preserved for backward compatibility.
1763 Common Report Var(flag_lra_remat) Optimization
1764 Do CFG-sensitive rematerialization in LRA.
1768 Enable link-time optimization.
1771 Common RejectNegative Joined Var(flag_lto)
1772 Link-time optimization with number of parallel jobs or jobserver.
1775 Name(lto_partition_model) Type(enum lto_partition_model) UnknownError(unknown LTO partitioning model %qs)
1778 Enum(lto_partition_model) String(none) Value(LTO_PARTITION_NONE)
1781 Enum(lto_partition_model) String(one) Value(LTO_PARTITION_ONE)
1784 Enum(lto_partition_model) String(balanced) Value(LTO_PARTITION_BALANCED)
1787 Enum(lto_partition_model) String(1to1) Value(LTO_PARTITION_1TO1)
1790 Enum(lto_partition_model) String(max) Value(LTO_PARTITION_MAX)
1793 Common Joined RejectNegative Enum(lto_partition_model) Var(flag_lto_partition) Init(LTO_PARTITION_BALANCED)
1794 Specify the algorithm to partition symbols and vars at linktime.
1796 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
1797 flto-compression-level=
1798 Common Joined RejectNegative UInteger Var(flag_lto_compression_level) Init(-1) IntegerRange(0, 9)
1799 -flto-compression-level=<number> Use zlib compression level <number> for IL.
1801 flto-odr-type-merging
1802 Common Report Var(flag_lto_odr_type_mering) Init(1)
1803 Merge C++ types using One Definition Rule.
1806 Common Report Var(flag_lto_report) Init(0)
1807 Report various link-time optimization statistics.
1810 Common Report Var(flag_lto_report_wpa) Init(0)
1811 Report various link-time optimization statistics for WPA only.
1814 Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
1815 Set errno after built-in math functions.
1818 Common Joined RejectNegative UInteger Var(flag_max_errors)
1819 -fmax-errors=<number> Maximum number of errors to report.
1822 Common Report Var(mem_report)
1823 Report on permanent memory allocation.
1826 Common Report Var(mem_report_wpa)
1827 Report on permanent memory allocation in WPA only.
1829 ; This will attempt to merge constant section constants, if 1 only
1830 ; string constants and constants from constant pool, if 2 also constant
1832 fmerge-all-constants
1833 Common Report Var(flag_merge_constants,2) Init(1)
1834 Attempt to merge identical constants and constant variables.
1837 Common Report Var(flag_merge_constants,1)
1838 Attempt to merge identical constants across compilation units.
1840 fmerge-debug-strings
1841 Common Report Var(flag_merge_debug_strings) Init(1)
1842 Attempt to merge identical debug strings across compilation units.
1845 Common RejectNegative Joined UInteger
1846 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping.
1849 Common Report Var(flag_modulo_sched) Optimization
1850 Perform SMS based modulo scheduling before the first scheduling pass.
1852 fmodulo-sched-allow-regmoves
1853 Common Report Var(flag_modulo_sched_allow_regmoves) Optimization
1854 Perform SMS based modulo scheduling with register moves allowed.
1856 fmove-loop-invariants
1857 Common Report Var(flag_move_loop_invariants) Optimization
1858 Move loop invariant computations out of loops.
1861 Common Var(flag_dce) Init(1) Optimization
1862 Use the RTL dead code elimination pass.
1865 Common Var(flag_dse) Init(1) Optimization
1866 Use the RTL dead store elimination pass.
1868 freschedule-modulo-scheduled-loops
1869 Common Report Var(flag_resched_modulo_sched) Optimization
1870 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling.
1872 fnon-call-exceptions
1873 Common Report Var(flag_non_call_exceptions) Optimization
1874 Support synchronous non-call exceptions.
1877 Common Driver Joined MissingArgError(options or targets missing after %qs)
1878 -foffload=<targets>=<options> Specify offloading targets and options for them.
1881 Common Joined RejectNegative Enum(offload_abi) Var(flag_offload_abi) Init(OFFLOAD_ABI_UNSET)
1882 -foffload-abi=[lp64|ilp32] Set the ABI to use in an offload compiler.
1885 Name(offload_abi) Type(enum offload_abi) UnknownError(unknown offload ABI %qs)
1888 Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
1891 Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
1894 Common Report Var(flag_omit_frame_pointer) Optimization
1895 When possible do not generate stack frames.
1898 Common Report Var(flag_opt_info) Optimization
1899 Enable all optimization info dumps on stderr.
1902 Common Joined RejectNegative Var(common_deferred_options) Defer
1903 -fopt-info[-<type>=filename] Dump compiler optimization details.
1905 foptimize-register-move
1907 Does nothing. Preserved for backward compatibility.
1909 foptimize-sibling-calls
1910 Common Report Var(flag_optimize_sibling_calls) Optimization
1911 Optimize sibling and tail recursive calls.
1914 Common Report Var(flag_partial_inlining) Optimization
1915 Perform partial inlining.
1918 Common Report Var(pre_ipa_mem_report)
1919 Report on memory allocation before interprocedural optimization.
1921 fpost-ipa-mem-report
1922 Common Report Var(post_ipa_mem_report)
1923 Report on memory allocation before interprocedural optimization.
1926 Common Report Var(flag_pack_struct) Optimization
1927 Pack structure members together without holes.
1930 Common RejectNegative Joined UInteger Optimization
1931 -fpack-struct=<number> Set initial maximum structure member alignment.
1934 Common Report Var(flag_pcc_struct_return,1) Init(DEFAULT_PCC_STRUCT_RETURN)
1935 Return small aggregates in memory, not registers.
1938 Common Report Var(flag_peel_loops) Optimization
1939 Perform loop peeling.
1942 Common Report Var(flag_no_peephole,0) Optimization
1943 Enable machine specific peephole optimizations.
1946 Common Report Var(flag_peephole2) Optimization
1947 Enable an RTL peephole pass before sched2.
1950 Common Report Var(flag_pic,2) Negative(fPIE) Init(-1)
1951 Generate position-independent code if possible (large mode).
1954 Common Report Var(flag_pie,2) Negative(fpic) Init(-1)
1955 Generate position-independent code for executables if possible (large mode).
1958 Common Report Var(flag_pic,1) Negative(fpie) Init(-1)
1959 Generate position-independent code if possible (small mode).
1962 Common Report Var(flag_pie,1) Negative(fPIC) Init(-1)
1963 Generate position-independent code for executables if possible (small mode).
1966 Common Report Var(flag_plt) Init(1) Optimization
1967 Use PLT for PIC calls (-fno-plt: load the address from GOT at call site).
1970 Common Joined RejectNegative Var(common_deferred_options) Defer
1971 Specify a plugin to load.
1974 Common Joined RejectNegative Var(common_deferred_options) Defer
1975 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>.
1977 fpredictive-commoning
1978 Common Report Var(flag_predictive_commoning) Optimization
1979 Run predictive commoning optimization.
1981 fprefetch-loop-arrays
1982 Common Report Var(flag_prefetch_loop_arrays) Init(-1) Optimization
1983 Generate prefetch instructions, if available, for arrays in loops.
1986 Common Report Var(profile_flag)
1987 Enable basic program profiling code.
1990 Common Report Var(profile_abs_path_flag)
1991 Generate absolute source path names for gcov.
1994 Common Report Var(profile_arc_flag)
1995 Insert arc-based program profiling code.
1998 Common Joined RejectNegative Var(profile_data_prefix)
1999 Set the top-level directory for storing the profile data.
2000 The default is 'pwd'.
2003 Common Report Var(flag_profile_correction)
2004 Enable correction of flow inconsistent profile data input.
2007 Common Joined RejectNegative Enum(profile_update) Var(flag_profile_update) Init(PROFILE_UPDATE_SINGLE)
2008 -fprofile-update=[single|atomic|prefer-atomic] Set the profile update method.
2011 Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
2014 Enum(profile_update) String(single) Value(PROFILE_UPDATE_SINGLE)
2017 Enum(profile_update) String(atomic) Value(PROFILE_UPDATE_ATOMIC)
2020 Enum(profile_update) String(prefer-atomic) Value(PROFILE_UPDATE_PREFER_ATOMIC)
2024 Enable common options for generating profile info for profile feedback directed optimizations.
2027 Common Joined RejectNegative
2028 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=.
2031 Common Var(flag_profile_use)
2032 Enable common options for performing profile feedback directed optimizations.
2035 Common Joined RejectNegative
2036 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=.
2039 Common Report Var(flag_profile_values)
2040 Insert code to profile values of expressions.
2043 Common Report Var(profile_report)
2044 Report on consistency of profile.
2046 fprofile-reorder-functions
2047 Common Report Var(flag_profile_reorder_functions)
2048 Enable function reordering that improves code placement.
2050 fpatchable-function-entry=
2051 Common Joined Optimization
2052 Insert NOP instructions at each function entry.
2055 Common Var(common_deferred_options) Defer
2058 Common Joined RejectNegative Var(common_deferred_options) Defer
2059 -frandom-seed=<string> Make compile reproducible using <string>.
2061 ; This switch causes the command line that was used to create an
2062 ; object file to be recorded into the object file. The exact format
2063 ; of this recording is target and binary file format dependent.
2064 ; It is related to the -fverbose-asm switch, but that switch only
2065 ; records information in the assembler output file as comments, so
2066 ; they never reach the object file.
2067 frecord-gcc-switches
2068 Common Report Var(flag_record_gcc_switches)
2069 Record gcc command line switches in the object file.
2072 Common Report Var(flag_pcc_struct_return,0) Optimization
2073 Return small aggregates in registers.
2077 Does nothing. Preserved for backward compatibility.
2080 Common Report Var(flag_lifetime_dse,2) Init(2) Optimization
2081 Tell DSE that the storage for a C++ object is dead when the constructor
2082 starts and when the destructor finishes.
2085 Common Joined RejectNegative UInteger Var(flag_lifetime_dse) Optimization IntegerRange(0, 2)
2087 flive-range-shrinkage
2088 Common Report Var(flag_live_range_shrinkage) Init(0) Optimization
2089 Relief of register pressure through live range shrinkage.
2092 Common Report Var(flag_rename_registers) Init(2) Optimization
2093 Perform a register renaming optimization pass.
2096 Common Report Var(flag_schedule_fusion) Init(2) Optimization
2097 Perform a target dependent instruction fusion optimization pass.
2100 Common Report Var(flag_reorder_blocks) Optimization
2101 Reorder basic blocks to improve code placement.
2103 freorder-blocks-algorithm=
2104 Common Joined RejectNegative Enum(reorder_blocks_algorithm) Var(flag_reorder_blocks_algorithm) Init(REORDER_BLOCKS_ALGORITHM_SIMPLE) Optimization
2105 -freorder-blocks-algorithm=[simple|stc] Set the used basic block reordering algorithm.
2108 Name(reorder_blocks_algorithm) Type(enum reorder_blocks_algorithm) UnknownError(unknown basic block reordering algorithm %qs)
2111 Enum(reorder_blocks_algorithm) String(simple) Value(REORDER_BLOCKS_ALGORITHM_SIMPLE)
2114 Enum(reorder_blocks_algorithm) String(stc) Value(REORDER_BLOCKS_ALGORITHM_STC)
2116 freorder-blocks-and-partition
2117 Common Report Var(flag_reorder_blocks_and_partition) Optimization
2118 Reorder basic blocks and partition into hot and cold sections.
2121 Common Report Var(flag_reorder_functions) Optimization
2122 Reorder functions to improve code placement.
2124 frerun-cse-after-loop
2125 Common Report Var(flag_rerun_cse_after_loop) Optimization
2126 Add a common subexpression elimination pass after loop optimizations.
2130 Does nothing. Preserved for backward compatibility.
2133 Common Report Var(flag_rounding_math) Optimization SetByCombined
2134 Disable optimizations that assume default FP rounding behavior.
2137 Common Report Var(flag_schedule_interblock) Init(1) Optimization
2138 Enable scheduling across basic blocks.
2141 Common Report Var(flag_sched_pressure) Init(0) Optimization
2142 Enable register pressure sensitive insn scheduling.
2145 Common Report Var(flag_schedule_speculative) Init(1) Optimization
2146 Allow speculative motion of non-loads.
2149 Common Report Var(flag_schedule_speculative_load) Optimization
2150 Allow speculative motion of some loads.
2152 fsched-spec-load-dangerous
2153 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
2154 Allow speculative motion of more loads.
2157 Common RejectNegative Joined UInteger Var(sched_verbose_param) Init(1)
2158 -fsched-verbose=<number> Set the verbosity level of the scheduler.
2160 fsched2-use-superblocks
2161 Common Report Var(flag_sched2_use_superblocks) Optimization
2162 If scheduling post reload, do superblock scheduling.
2166 Does nothing. Preserved for backward compatibility.
2169 Common Report Var(flag_schedule_insns) Optimization
2170 Reschedule instructions before register allocation.
2173 Common Report Var(flag_schedule_insns_after_reload) Optimization
2174 Reschedule instructions after register allocation.
2176 ; This flag should be on when a target implements non-trivial
2177 ; scheduling hooks, maybe saving some information for its own sake.
2178 ; On IA64, for example, this is used for correct bundling.
2179 fselective-scheduling
2180 Common Report Var(flag_selective_scheduling) Optimization
2181 Schedule instructions using selective scheduling algorithm.
2183 fselective-scheduling2
2184 Common Report Var(flag_selective_scheduling2) Optimization
2185 Run selective scheduling after reload.
2188 Common Undocumented Joined Var(flag_self_test)
2189 Run self-tests, using the given path to locate test files.
2191 fsel-sched-pipelining
2192 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
2193 Perform software pipelining of inner loops during selective scheduling.
2195 fsel-sched-pipelining-outer-loops
2196 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
2197 Perform software pipelining of outer loops during selective scheduling.
2199 fsel-sched-reschedule-pipelined
2200 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
2201 Reschedule pipelined regions without pipelining.
2203 fsemantic-interposition
2204 Common Report Var(flag_semantic_interposition) Init(1)
2205 Allow interposing function (or variables) by ones with different semantics (or initializer) respectively by dynamic linker.
2207 ; sched_stalled_insns means that insns can be moved prematurely from the queue
2208 ; of stalled insns into the ready list.
2209 fsched-stalled-insns
2210 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
2211 Allow premature scheduling of queued insns.
2213 fsched-stalled-insns=
2214 Common RejectNegative Joined UInteger Optimization
2215 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled.
2217 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
2218 ; be examined for a dependency on a stalled insn that is candidate for
2219 ; premature removal from the queue of stalled insns into the ready list (has
2220 ; an effect only if the flag 'sched_stalled_insns' is set).
2221 fsched-stalled-insns-dep
2222 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
2223 Set dependence distance checking in premature scheduling of queued insns.
2225 fsched-stalled-insns-dep=
2226 Common RejectNegative Joined UInteger Optimization
2227 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns.
2229 fsched-group-heuristic
2230 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
2231 Enable the group heuristic in the scheduler.
2233 fsched-critical-path-heuristic
2234 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
2235 Enable the critical path heuristic in the scheduler.
2237 fsched-spec-insn-heuristic
2238 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
2239 Enable the speculative instruction heuristic in the scheduler.
2241 fsched-rank-heuristic
2242 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
2243 Enable the rank heuristic in the scheduler.
2245 fsched-last-insn-heuristic
2246 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
2247 Enable the last instruction heuristic in the scheduler.
2249 fsched-dep-count-heuristic
2250 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
2251 Enable the dependent count heuristic in the scheduler.
2254 Common Report Var(flag_section_anchors) Optimization
2255 Access data in the same section from shared anchor points.
2259 Does nothing. Preserved for backward compatibility.
2263 Does nothing. Preserved for backward compatibility.
2266 Common Report Var(flag_ree) Init(0)
2267 Turn on Redundant Extensions Elimination pass.
2270 Common Report Var(flag_show_column) Init(1)
2271 Show column numbers in diagnostics, when available. Default on.
2274 Common Report Var(flag_shrink_wrap) Optimization
2275 Emit function prologues only before parts of the function that need it,
2276 rather than at the top of the function.
2278 fshrink-wrap-separate
2279 Common Report Var(flag_shrink_wrap_separate) Init(1) Optimization
2280 Shrink-wrap parts of the prologue and epilogue separately.
2283 Common Report Var(flag_signaling_nans) Optimization SetByCombined
2284 Disable optimizations observable by IEEE signaling NaNs.
2287 Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
2288 Disable floating point optimizations that ignore the IEEE signedness of zero.
2290 fsingle-precision-constant
2291 Common Report Var(flag_single_precision_constant) Optimization
2292 Convert floating point constants to single precision constants.
2294 fsplit-ivs-in-unroller
2295 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
2296 Split lifetimes of induction variables when loops are unrolled.
2299 Common Report Var(flag_split_stack) Init(-1)
2300 Generate discontiguous stack frames.
2303 Common Report Var(flag_split_wide_types) Optimization
2304 Split wide types into independent registers.
2307 Common Report Var(flag_ssa_backprop) Init(1) Optimization
2308 Enable backward propagation of use properties at the SSA level.
2311 Common Report Var(flag_ssa_phiopt) Optimization
2312 Optimize conditional patterns using SSA PHI nodes.
2315 Common Report Var(flag_stdarg_opt) Init(1) Optimization
2316 Optimize amount of stdarg registers saved to stack at start of function.
2318 fvariable-expansion-in-unroller
2319 Common Report Var(flag_variable_expansion_in_unroller) Optimization
2320 Apply variable expansion when loops are unrolled.
2323 Common Report RejectNegative Joined Optimization
2324 -fstack-check=[no|generic|specific] Insert stack checking code into the program.
2327 Common Alias(fstack-check=, specific, no)
2328 Insert stack checking code into the program. Same as -fstack-check=specific.
2330 fstack-clash-protection
2331 Common Report Var(flag_stack_clash_protection) Optimization
2332 Insert code to probe each page of stack space as it is allocated to protect
2333 from stack-clash style attacks.
2336 Common Var(common_deferred_options) Defer
2338 fstack-limit-register=
2339 Common RejectNegative Joined Var(common_deferred_options) Defer
2340 -fstack-limit-register=<register> Trap if the stack goes past <register>.
2342 fstack-limit-symbol=
2343 Common RejectNegative Joined Var(common_deferred_options) Defer
2344 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>.
2347 Common Report Var(flag_stack_protect, 1) Init(-1) Optimization
2348 Use propolice as a stack protection method.
2350 fstack-protector-all
2351 Common Report RejectNegative Var(flag_stack_protect, 2) Init(-1) Optimization
2352 Use a stack protection method for every function.
2354 fstack-protector-strong
2355 Common Report RejectNegative Var(flag_stack_protect, 3) Init(-1) Optimization
2356 Use a smart stack protection method for certain functions.
2358 fstack-protector-explicit
2359 Common Report RejectNegative Var(flag_stack_protect, 4) Optimization
2360 Use stack protection method only for functions with the stack_protect attribute.
2363 Common RejectNegative Var(flag_stack_usage)
2364 Output stack usage information on a per-function basis.
2368 Does nothing. Preserved for backward compatibility.
2370 ; Nonzero if we should do (language-dependent) alias analysis.
2371 ; Typically, this analysis will assume that expressions of certain
2372 ; types do not alias expressions of certain other types. Only used
2373 ; if alias analysis (in general) is enabled.
2375 Common Report Var(flag_strict_aliasing) Optimization
2376 Assume strict aliasing rules apply.
2379 Common NegativeAlias Alias(fwrapv)
2380 Treat signed overflow as undefined. Negated as -fwrapv.
2383 Common Report Var(flag_sync_libcalls) Init(1)
2384 Implement __atomic operations via libcalls to legacy __sync functions.
2387 Common Report Var(flag_syntax_only)
2388 Check for syntax errors, then stop.
2391 Common Report Var(flag_test_coverage)
2392 Create data files needed by \"gcov\".
2395 Common Report Var(flag_thread_jumps) Optimization
2396 Perform jump threading optimizations.
2399 Common Report Var(time_report)
2400 Report the time taken by each compiler pass.
2402 ftime-report-details
2403 Common Report Var(time_report_details)
2404 Record times taken by sub-phases separately.
2407 Common Joined RejectNegative Enum(tls_model) Var(flag_tls_default) Init(TLS_MODEL_GLOBAL_DYNAMIC)
2408 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model.
2411 Name(tls_model) Type(enum tls_model) UnknownError(unknown TLS model %qs)
2414 Enum(tls_model) String(global-dynamic) Value(TLS_MODEL_GLOBAL_DYNAMIC)
2417 Enum(tls_model) String(local-dynamic) Value(TLS_MODEL_LOCAL_DYNAMIC)
2420 Enum(tls_model) String(initial-exec) Value(TLS_MODEL_INITIAL_EXEC)
2423 Enum(tls_model) String(local-exec) Value(TLS_MODEL_LOCAL_EXEC)
2426 Common Report Var(flag_toplevel_reorder) Init(2)
2427 Reorder top level functions, variables, and asms.
2430 Common Report Var(flag_tracer) Optimization
2431 Perform superblock formation via tail duplication.
2434 Common Report Var(flag_trampolines) Init(0)
2435 For targets that normally need trampolines for nested functions, always
2436 generate them instead of using descriptors.
2438 ; Zero means that floating-point math operations cannot generate a
2439 ; (user-visible) trap. This is the case, for example, in nonstop
2440 ; IEEE 754 arithmetic.
2442 Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
2443 Assume floating-point operations can trap.
2446 Common Report Var(flag_trapv) Optimization
2447 Trap for signed overflow in addition, subtraction and multiplication.
2450 Common Report Var(flag_tree_ccp) Optimization
2451 Enable SSA-CCP optimization on trees.
2454 Common Report Var(flag_tree_bit_ccp) Optimization
2455 Enable SSA-BIT-CCP optimization on trees.
2459 Does nothing. Preserved for backward compatibility.
2462 Common Report Var(flag_tree_ch) Optimization
2463 Enable loop header copying on trees.
2465 ftree-coalesce-inlined-vars
2466 Common Ignore RejectNegative
2467 Does nothing. Preserved for backward compatibility.
2470 Common Report Var(flag_tree_coalesce_vars) Optimization
2471 Enable SSA coalescing of user variables.
2475 Does nothing. Preserved for backward compatibility.
2478 Common Report Var(flag_tree_copy_prop) Optimization
2479 Enable copy propagation on trees.
2481 ftree-store-copy-prop
2483 Does nothing. Preserved for backward compatibility.
2486 Common Report Var(flag_tree_cselim) Init(2) Optimization
2487 Transform condition stores into unconditional ones.
2489 ftree-switch-conversion
2490 Common Report Var(flag_tree_switch_conversion) Optimization
2491 Perform conversions of switch initializations.
2494 Common Report Var(flag_tree_dce) Optimization
2495 Enable SSA dead code elimination optimization on trees.
2497 ftree-dominator-opts
2498 Common Report Var(flag_tree_dom) Optimization
2499 Enable dominator optimizations.
2502 Common Report Var(flag_tree_tail_merge) Optimization
2503 Enable tail merging on trees.
2506 Common Report Var(flag_tree_dse) Optimization
2507 Enable dead store elimination.
2510 Common Report Var(flag_tree_forwprop) Init(1) Optimization
2511 Enable forward propagation on trees.
2514 Common Report Var(flag_tree_fre) Optimization
2515 Enable Full Redundancy Elimination (FRE) on trees.
2518 Common Report Var(flag_optimize_strlen) Optimization
2519 Enable string length optimizations on trees.
2521 fisolate-erroneous-paths-dereference
2522 Common Report Var(flag_isolate_erroneous_paths_dereference) Optimization
2523 Detect paths that trigger erroneous or undefined behavior due to
2524 dereferencing a null pointer. Isolate those paths from the main control
2525 flow and turn the statement with erroneous or undefined behavior into a trap.
2527 fisolate-erroneous-paths-attribute
2528 Common Report Var(flag_isolate_erroneous_paths_attribute) Optimization
2529 Detect paths that trigger erroneous or undefined behavior due to a null value
2530 being used in a way forbidden by a returns_nonnull or nonnull
2531 attribute. Isolate those paths from the main control flow and turn the
2532 statement with erroneous or undefined behavior into a trap.
2534 ftree-loop-distribution
2535 Common Report Var(flag_tree_loop_distribution) Optimization
2536 Enable loop distribution on trees.
2538 ftree-loop-distribute-patterns
2539 Common Report Var(flag_tree_loop_distribute_patterns) Optimization
2540 Enable loop distribution for patterns transformed into a library call.
2543 Common Report Var(flag_tree_loop_im) Init(1) Optimization
2544 Enable loop invariant motion on trees.
2547 Common Alias(floop-nest-optimize)
2548 Enable loop nest transforms. Same as -floop-nest-optimize.
2551 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
2552 Create canonical induction variables in loops.
2555 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
2556 Enable loop optimizations on tree level.
2558 ftree-parallelize-loops=
2559 Common Report Joined RejectNegative UInteger Var(flag_tree_parallelize_loops) Init(1) Optimization
2560 -ftree-parallelize-loops=<number> Enable automatic parallelization of loops.
2563 Common Report Var(flag_tree_phiprop) Init(1) Optimization
2564 Enable hoisting loads from conditional pointers.
2567 Common Report Var(flag_tree_pre) Optimization
2568 Enable SSA-PRE optimization on trees.
2571 Common Report Var(flag_tree_partial_pre) Optimization
2572 In SSA-PRE optimization on trees, enable partial-partial redundancy elimination.
2575 Common Report Var(flag_tree_pta) Optimization
2576 Perform function-local points-to analysis on trees.
2579 Common Report Var(flag_tree_reassoc) Init(1) Optimization
2580 Enable reassociation on tree level.
2584 Does nothing. Preserved for backward compatibility.
2587 Common Report Var(flag_tree_sink) Optimization
2588 Enable SSA code sinking on trees.
2591 Common Report Var(flag_tree_slsr) Optimization
2592 Perform straight-line strength reduction.
2595 Common Report Var(flag_tree_sra) Optimization
2596 Perform scalar replacement of aggregates.
2599 Common Report Var(flag_tree_ter) Optimization
2600 Replace temporary expressions in the SSA->normal pass.
2603 Common Report Var(flag_tree_live_range_split) Optimization
2604 Perform live range splitting during the SSA->normal pass.
2607 Common Report Var(flag_tree_vrp) Init(0) Optimization
2608 Perform Value Range Propagation on trees.
2611 Common Report Var(flag_split_paths) Init(0) Optimization
2612 Split paths leading to loop backedges.
2614 funconstrained-commons
2615 Common Var(flag_unconstrained_commons) Optimization
2616 Assume common declarations may be overridden with ones with a larger
2620 Common Report Var(flag_unit_at_a_time) Init(1)
2621 Compile whole compilation unit at a time.
2624 Common Report Var(flag_unroll_loops) Optimization
2625 Perform loop unrolling when iteration count is known.
2628 Common Report Var(flag_unroll_all_loops) Optimization
2629 Perform loop unrolling for all loops.
2631 ; Nonzero means that loop optimizer may assume that the induction variables
2632 ; that control loops do not overflow and that the loops with nontrivial
2633 ; exit condition are not infinite
2634 funsafe-loop-optimizations
2636 Does nothing. Preserved for backward compatibility.
2639 Common Report Var(flag_associative_math) SetByCombined Optimization
2640 Allow optimization for floating-point arithmetic which may change the
2641 result of the operation due to rounding.
2644 Common Report Var(flag_reciprocal_math) SetByCombined Optimization
2645 Same as -fassociative-math for expressions which include division.
2647 ; Nonzero means that unsafe floating-point math optimizations are allowed
2648 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
2649 ; are allowed to assume that their arguments and results are "normal"
2650 ; (e.g., nonnegative for SQRT).
2651 funsafe-math-optimizations
2652 Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
2653 Allow math optimizations that may violate IEEE or ISO standards.
2656 Common Report Var(flag_unswitch_loops) Optimization
2657 Perform loop unswitching.
2660 Common Report Var(flag_split_loops) Optimization
2661 Perform loop splitting.
2664 Common Report Var(flag_unwind_tables) Optimization
2665 Just generate unwind tables for exception handling.
2668 Common Driver Negative(fuse-ld=gold)
2669 Use the bfd linker instead of the default linker.
2672 Common Driver Negative(fuse-ld=bfd)
2673 Use the gold linker instead of the default linker.
2676 Common Undocumented Var(flag_use_linker_plugin)
2678 ; Positive if we should track variables, negative if we should run
2679 ; the var-tracking pass only to discard debug annotations, zero if
2680 ; we're not to run it. When flag_var_tracking == 2 (AUTODETECT_VALUE) it
2681 ; will be set according to optimize, debug_info_level and debug_hooks
2682 ; in process_options ().
2684 Common Report Var(flag_var_tracking) Init(2) PerFunction
2685 Perform variable tracking.
2687 ; Positive if we should track variables at assignments, negative if
2688 ; we should run the var-tracking pass only to discard debug
2689 ; annotations. When flag_var_tracking_assignments ==
2690 ; AUTODETECT_VALUE it will be set according to flag_var_tracking.
2691 fvar-tracking-assignments
2692 Common Report Var(flag_var_tracking_assignments) Init(2) PerFunction
2693 Perform variable tracking by annotating assignments.
2695 ; Nonzero if we should toggle flag_var_tracking_assignments after
2696 ; processing options and computing its default. */
2697 fvar-tracking-assignments-toggle
2698 Common Report Var(flag_var_tracking_assignments_toggle) PerFunction
2699 Toggle -fvar-tracking-assignments.
2701 ; Positive if we should track uninitialized variables, negative if
2702 ; we should run the var-tracking pass only to discard debug
2703 ; annotations. When flag_var_tracking_uninit == AUTODETECT_VALUE it
2704 ; will be set according to flag_var_tracking.
2705 fvar-tracking-uninit
2706 Common Report Var(flag_var_tracking_uninit) PerFunction
2707 Perform variable tracking and also tag variables that are uninitialized.
2709 ; Alias to enable both -ftree-loop-vectorize and -ftree-slp-vectorize.
2711 Common Report Optimization
2712 Enable vectorization on trees.
2714 ftree-vectorizer-verbose=
2715 Common Joined RejectNegative Ignore
2716 Does nothing. Preserved for backward compatibility.
2718 ftree-loop-vectorize
2719 Common Report Var(flag_tree_loop_vectorize) Optimization EnabledBy(ftree-vectorize)
2720 Enable loop vectorization on trees.
2723 Common Report Var(flag_tree_slp_vectorize) Optimization EnabledBy(ftree-vectorize)
2724 Enable basic block vectorization (SLP) on trees.
2727 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_vect_cost_model) Init(VECT_COST_MODEL_DEFAULT) Optimization
2728 Specifies the cost model for vectorization.
2729 -fvect-cost-model=[unlimited|dynamic|cheap] Specifies the cost model for vectorization.
2732 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_simd_cost_model) Init(VECT_COST_MODEL_UNLIMITED) Optimization
2733 -fsimd-cost-model=[unlimited|dynamic|cheap] Specifies the vectorization cost model for code marked with a simd directive.
2736 Name(vect_cost_model) Type(enum vect_cost_model) UnknownError(unknown vectorizer cost model %qs)
2739 Enum(vect_cost_model) String(unlimited) Value(VECT_COST_MODEL_UNLIMITED)
2742 Enum(vect_cost_model) String(dynamic) Value(VECT_COST_MODEL_DYNAMIC)
2745 Enum(vect_cost_model) String(cheap) Value(VECT_COST_MODEL_CHEAP)
2748 Common Alias(fvect-cost-model=,dynamic,unlimited)
2749 Enables the dynamic vectorizer cost model. Preserved for backward compatibility.
2751 ftree-vect-loop-version
2753 Does nothing. Preserved for backward compatibility.
2756 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
2757 Enable copy propagation of scalar-evolution information.
2759 ; -fverbose-asm causes extra commentary information to be produced in
2760 ; the generated assembly code (to make it more readable). This option
2761 ; is generally only of use to those who actually need to read the
2762 ; generated assembly code (perhaps while debugging the compiler itself).
2763 ; -fno-verbose-asm, the default, causes the extra information
2764 ; to not be added and is useful when comparing two assembler files.
2766 Common Report Var(flag_verbose_asm)
2767 Add extra commentary to assembler output.
2770 Common Joined RejectNegative Enum(symbol_visibility) Var(default_visibility) Init(VISIBILITY_DEFAULT)
2771 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility.
2774 Name(symbol_visibility) Type(enum symbol_visibility) UnknownError(unrecognized visibility value %qs)
2777 Enum(symbol_visibility) String(default) Value(VISIBILITY_DEFAULT)
2780 Enum(symbol_visibility) String(internal) Value(VISIBILITY_INTERNAL)
2783 Enum(symbol_visibility) String(hidden) Value(VISIBILITY_HIDDEN)
2786 Enum(symbol_visibility) String(protected) Value(VISIBILITY_PROTECTED)
2789 Common Joined RejectNegative Enum(vtv_priority) Var(flag_vtable_verify) Init(VTV_NO_PRIORITY)
2790 Validate vtable pointers before using them.
2793 Name(vtv_priority) Type(enum vtv_priority) UnknownError(unknown vtable verify initialization priority %qs)
2796 Enum(vtv_priority) String(none) Value(VTV_NO_PRIORITY)
2799 Enum(vtv_priority) String(std) Value(VTV_STANDARD_PRIORITY)
2802 Enum(vtv_priority) String(preinit) Value(VTV_PREINIT_PRIORITY)
2805 Common Var(flag_vtv_counts)
2806 Output vtable verification counters.
2809 Common Var(flag_vtv_debug)
2810 Output vtable verification pointer sets information.
2813 Common Report Var(flag_value_profile_transformations) Optimization
2814 Use expression value profiles in optimizations.
2817 Common Report Var(flag_web) Init(2) Optimization
2818 Construct webs and split unrelated uses of single variable.
2820 ftree-builtin-call-dce
2821 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
2822 Enable conditional dead code elimination for builtin calls.
2825 Common Report Var(flag_whole_program) Init(0)
2826 Perform whole program optimizations.
2829 Common Report Var(flag_wrapv) Optimization
2830 Assume signed arithmetic overflow wraps around.
2832 fzero-initialized-in-bss
2833 Common Report Var(flag_zero_initialized_in_bss) Init(1)
2834 Put zero initialized data in the bss section.
2837 Common Driver JoinedOrMissing
2838 Generate debug information in default format.
2841 Common Driver JoinedOrMissing Negative(gdwarf)
2842 Generate debug information in COFF format.
2845 Common Driver RejectNegative Var(debug_column_info,0) Init(0)
2846 Don't record DW_AT_decl_column and DW_AT_call_column in DWARF.
2849 Common Driver RejectNegative Var(debug_column_info,1)
2850 Record DW_AT_decl_column and DW_AT_call_column in DWARF.
2853 Common Driver JoinedOrMissing Negative(gdwarf-)
2854 Generate debug information in default version of DWARF format.
2857 Common Driver Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
2858 Generate debug information in DWARF v2 (or later) format.
2861 Common Driver JoinedOrMissing
2862 Generate debug information in default extended format.
2865 Common Driver Negative(gpubnames) Var(debug_generate_pub_sections, 0) Init(-1)
2866 Don't generate DWARF pubnames and pubtypes sections.
2869 Common Driver Negative(ggnu-pubnames) Var(debug_generate_pub_sections, 1)
2870 Generate DWARF pubnames and pubtypes sections.
2873 Common Driver Negative(gno-pubnames) Var(debug_generate_pub_sections, 2)
2874 Generate DWARF pubnames and pubtypes sections with GNU extensions.
2876 gno-record-gcc-switches
2877 Common Driver RejectNegative Var(dwarf_record_gcc_switches,0) Init(1)
2878 Don't record gcc command line switches in DWARF DW_AT_producer.
2880 grecord-gcc-switches
2881 Common Driver RejectNegative Var(dwarf_record_gcc_switches,1)
2882 Record gcc command line switches in DWARF DW_AT_producer.
2885 Common Driver RejectNegative Var(dwarf_split_debug_info,0) Init(0)
2886 Don't generate debug information in separate .dwo files.
2889 Common Driver RejectNegative Var(dwarf_split_debug_info,1)
2890 Generate debug information in separate .dwo files.
2893 Common Driver JoinedOrMissing Negative(gstabs+)
2894 Generate debug information in STABS format.
2897 Common Driver JoinedOrMissing Negative(gvms)
2898 Generate debug information in extended STABS format.
2901 Common Driver RejectNegative Var(dwarf_strict,0) Init(0)
2902 Emit DWARF additions beyond selected version.
2905 Common Driver Report RejectNegative Var(dwarf_strict,1)
2906 Don't emit DWARF additions beyond selected version.
2909 Common Driver Report Var(flag_gtoggle)
2910 Toggle debug information generation.
2913 Common Driver JoinedOrMissing Negative(gxcoff)
2914 Generate debug information in VMS format.
2917 Common Driver JoinedOrMissing Negative(gxcoff+)
2918 Generate debug information in XCOFF format.
2921 Common Driver JoinedOrMissing Negative(gcoff)
2922 Generate debug information in extended XCOFF format.
2925 Name(compressed_debug_sections) Type(int)
2927 ; Since -gz= is completely handled in specs, the values aren't used and we
2928 ; assign arbitrary constants.
2930 Enum(compressed_debug_sections) String(none) Value(0)
2933 Enum(compressed_debug_sections) String(zlib) Value(1)
2936 Enum(compressed_debug_sections) String(zlib-gnu) Value(2)
2940 Generate compressed debug sections.
2943 Common Driver Joined Enum(compressed_debug_sections)
2944 -gz=<format> Generate compressed debug sections in format <format>.
2947 Driver Joined Separate
2950 Common Joined Var(plugindir_string) Init(0)
2951 -iplugindir=<dir> Set <dir> to be the default plugin directory.
2954 Common Joined Separate RejectDriver Var(imultiarch) Init(0)
2955 -imultiarch <dir> Set <dir> to be the multiarch include subdirectory.
2958 Driver Joined Separate
2963 no-canonical-prefixes
2976 Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs)
2977 -o <file> Place output into <file>.
2980 Common Var(profile_flag)
2981 Enable function profiling.
2984 Driver Var(pass_exit_codes)
2987 Common Alias(Wpedantic)
2990 Common Var(flag_pedantic_errors)
2991 Like -pedantic but issue them as errors.
2997 Driver Var(use_pipes)
3000 Driver JoinedOrMissing Var(print_file_name)
3002 print-libgcc-file-name
3005 print-multi-directory
3006 Driver Var(print_multi_directory)
3009 Driver Var(print_multi_lib)
3011 print-multi-os-directory
3012 Driver Var(print_multi_os_directory)
3015 Driver Var(print_multiarch)
3018 Driver JoinedOrMissing Var(print_prog_name)
3021 Driver Var(print_search_dirs)
3024 Driver Var(print_sysroot)
3026 print-sysroot-headers-suffix
3027 Driver Var(print_sysroot_headers_suffix)
3030 Common Var(quiet_flag) RejectDriver
3031 Do not display functions compiled or elapsed time.
3049 Driver Var(report_times)
3052 Driver JoinedOrMissing
3055 Driver Joined Separate
3059 ; C option, but driver must not handle as "-u ndef".
3062 Common Driver Var(verbose_flag)
3063 Enable verbose output.
3066 Common Var(version_flag) RejectDriver
3067 Display the compiler's version.
3070 Common Var(inhibit_warnings)
3074 Driver Separate Var(wrapper_string)
3077 Driver Joined Separate
3080 Driver RejectNegative Negative(static-pie)
3081 Create a shared library.
3087 Driver Separate Alias(specs=)
3100 ; Documented for Fortran, but always accepted by driver.
3107 ; Documented for Go, but always accepted by driver.
3125 Driver RejectNegative Negative(shared)
3126 Don't create a dynamically linked position independent executable.
3129 Driver RejectNegative Negative(no-pie)
3130 Create a dynamically linked position independent executable.
3133 Driver RejectNegative Negative(pie)
3134 Create a static position independent executable.
3137 Driver Joined Separate
3140 Common Report Var(flag_ipa_ra) Optimization
3141 Use caller save register across calls if possible.
3143 ; This comment is to ensure we retain the blank line above.