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)
359 Driver Separate Alias(B)
362 Driver JoinedOrMissing Alias(B)
368 Driver Separate Alias(print-file-name=)
371 Driver JoinedOrMissing Alias(print-file-name=)
373 -print-libgcc-file-name
374 Driver Alias(print-libgcc-file-name)
376 -print-multi-directory
377 Driver Alias(print-multi-directory)
380 Driver Alias(print-multi-lib)
382 -print-multi-os-directory
383 Driver Alias(print-multi-os-directory)
386 Driver Alias(print-multiarch)
389 Driver Separate Alias(print-prog-name=)
392 Driver JoinedOrMissing Alias(print-prog-name=)
395 Driver Alias(print-search-dirs)
398 Driver Alias(print-sysroot)
400 -print-sysroot-headers-suffix
401 Driver Alias(print-sysroot-headers-suffix)
407 Driver Alias(save-temps)
413 Driver Separate Alias(specs=)
416 Driver Joined Alias(specs=)
422 Driver Alias(symbolic)
426 Alias for --help=target.
434 ;; The driver used to convert options such as --help into forms such
435 ;; as -fhelp; the following four entries are for compatibility with
436 ;; any direct uses of those (undocumented) -f forms
438 Common Driver Alias(-help)
441 Common Driver Joined Alias(-help=)
444 Common Driver Alias(-target-help)
447 Common Driver Alias(-version)
451 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters.
454 Common Joined Alias(-param)
457 Driver Separate Alias(-sysroot=)
460 Driver JoinedOrMissing
466 Driver Joined Separate
472 Driver Joined Separate
478 Common JoinedOrMissing Optimization
479 -O<number> Set optimization level to <number>.
483 Optimize for space rather than speed.
487 Optimize for speed disregarding exact standards compliance.
491 Optimize for debugging experience rather than speed or size.
503 Driver Joined Separate
509 Driver Joined Separate
530 Common RejectNegative Warning Alias(Wextra)
531 This switch is deprecated; use -Wextra instead.
534 Driver JoinedOrMissing
537 Driver JoinedOrMissing
540 Driver JoinedOrMissing
543 Common Var(warn_aggregate_return) Warning
544 Warn about returning structures, unions or arrays.
546 Waggressive-loop-optimizations
547 Common Var(warn_aggressive_loop_optimizations) Init(1) Warning
548 Warn if a loop with constant number of iterations triggers undefined behavior.
551 Common Var(warn_array_bounds) Warning
552 Warn if an array is accessed out of bounds.
555 Common Joined RejectNegative UInteger Var(warn_array_bounds) Warning IntegerRange(0, 2)
556 Warn if an array is accessed out of bounds.
559 Common Var(warn_attributes) Init(1) Warning
560 Warn about inappropriate attribute usage.
563 Common Var(warn_cast_align) Warning
564 Warn about pointer casts which increase alignment.
567 Common Var(warn_cpp) Init(1) Warning
568 Warn when a #warning directive is encountered.
570 Wdeprecated-declarations
571 Common Var(warn_deprecated_decl) Init(1) Warning
572 Warn about uses of __attribute__((deprecated)) declarations.
574 Wdisabled-optimization
575 Common Var(warn_disabled_optimization) Warning
576 Warn when an optimization pass is disabled.
579 Common Var(warnings_are_errors)
580 Treat all warnings as errors.
584 Treat specified warning as error.
587 Common Var(extra_warnings) Warning
588 Print extra (possibly unwanted) warnings.
591 Common Var(flag_fatal_errors)
592 Exit on the first error occurred.
595 Common RejectNegative Joined UInteger Warning
596 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes.
599 Common Var(warn_free_nonheap_object) Init(1) Warning
600 Warn when attempting to free a non-heap object.
603 Common Var(warn_hsa) Init(1) Warning
604 Warn when a function cannot be expanded to HSAIL.
606 Wimplicit-fallthrough
607 Common Alias(Wimplicit-fallthrough=,3,0) Warning
609 Wimplicit-fallthrough=
610 Common Var(warn_implicit_fallthrough) RejectNegative Joined UInteger Warning IntegerRange(0, 5)
611 Warn when a switch case falls through.
614 Common Var(warn_inline) Warning
615 Warn when an inlined function cannot be inlined.
617 Winvalid-memory-model
618 Common Var(warn_invalid_memory_model) Init(1) Warning
619 Warn when an atomic memory model parameter is known to be outside the valid range.
622 Common RejectNegative Joined Warning Undocumented Alias(Wlarger-than=)
625 Common RejectNegative Joined UInteger Warning
626 -Wlarger-than=<number> Warn if an object is larger than <number> bytes.
629 Var(warn_nonnull_compare) Warning
630 Warn if comparing pointer parameter with nonnull attribute with NULL.
633 Common Var(warn_null_dereference) Warning
634 Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior.
636 Wunsafe-loop-optimizations
637 Common Var(warn_unsafe_loop_optimizations) Warning
638 Warn if the loop cannot be optimized due to nontrivial assumptions.
641 Common Warning Alias(Wsuggest-attribute=noreturn)
644 Common Var(warn_odr_violations) Init(1) Warning
645 Warn about some C++ One Definition Rule violations during link time optimization.
648 Common Var(warn_overflow) Init(1) Warning
649 Warn about overflow in arithmetic expressions.
652 Common Var(warn_lto_type_mismatch) Init(1) Warning
653 During link time optimization warn about mismatched types of global declarations.
656 Common Var(warn_packed) Warning
657 Warn when the packed attribute has no effect on struct layout.
660 Common Var(warn_padded) Warning
661 Warn when padding is required to align structure members.
664 Common Var(pedantic) Init(0) Warning
665 Issue warnings needed for strict compliance to the standard.
668 Common Var(warn_return_local_addr) Init(1) Warning
669 Warn about returning a pointer/reference to a local or temporary variable.
672 Common Var(warn_shadow) Warning
673 Warn when one variable shadows another. Same as -Wshadow=global.
676 Common Warning Alias(Wshadow)
677 Warn when one variable shadows another (globally).
680 Common Var(warn_shadow_local) Warning EnabledBy(Wshadow)
681 Warn when one local variable shadows another local variable or parameter.
684 Common Warning Undocumented Alias(Wshadow=local)
686 Wshadow=compatible-local
687 Common Var(warn_shadow_compatible_local) Warning EnabledBy(Wshadow=local)
688 Warn when one local variable shadows another local variable or parameter of compatible type.
690 Wshadow-compatible-local
691 Common Warning Undocumented Alias(Wshadow=compatible-local)
694 Common Var(warn_stack_protect) Warning
695 Warn when not issuing stack smashing protection for some reason.
698 Common Joined RejectNegative UInteger Var(warn_stack_usage) Warning
699 -Wstack-usage=<number> Warn if stack usage might be larger than specified amount.
703 Warn about code which might break strict aliasing rules.
706 Common Joined RejectNegative UInteger Var(warn_strict_aliasing) Warning
707 Warn about code which might break strict aliasing rules.
711 Warn about optimizations that assume that signed overflow is undefined.
714 Common Joined RejectNegative UInteger Var(warn_strict_overflow) Warning
715 Warn about optimizations that assume that signed overflow is undefined.
717 Wsuggest-attribute=const
718 Common Var(warn_suggest_attribute_const) Warning
719 Warn about functions which might be candidates for __attribute__((const)).
721 Wsuggest-attribute=pure
722 Common Var(warn_suggest_attribute_pure) Warning
723 Warn about functions which might be candidates for __attribute__((pure)).
725 Wsuggest-attribute=noreturn
726 Common Var(warn_suggest_attribute_noreturn) Warning
727 Warn about functions which might be candidates for __attribute__((noreturn)).
730 Common Var(warn_suggest_final_types) Warning
731 Warn about C++ polymorphic types where adding final keyword would improve code quality.
733 Wsuggest-final-methods
734 Common Var(warn_suggest_final_methods) Warning
735 Warn about C++ virtual methods where adding final keyword would improve code quality.
738 Common Var(warn_switch_unreachable) Warning Init(1)
739 Warn about statements between switch's controlling expression and the first
743 Common Var(warn_system_headers) Warning
744 Do not suppress warnings from system headers.
747 Common Var(warn_trampolines) Warning
748 Warn whenever a trampoline is generated.
751 Common Var(warn_type_limits) Warning EnabledBy(Wextra)
752 Warn if a comparison is always true or always false due to the limited range of the data type.
755 Common Var(warn_uninitialized) Warning EnabledBy(Wextra)
756 Warn about uninitialized automatic variables.
759 Common Var(warn_maybe_uninitialized) Warning EnabledBy(Wuninitialized)
760 Warn about maybe uninitialized automatic variables.
763 Common Ignore Warning
764 Does nothing. Preserved for backward compatibility.
767 Common Var(warn_unused) Init(0) Warning
768 Enable all -Wunused- warnings.
770 Wunused-but-set-parameter
771 Common Var(warn_unused_but_set_parameter) Warning EnabledBy(Wunused && Wextra)
772 Warn when a function parameter is only set, otherwise unused.
774 Wunused-but-set-variable
775 Common Var(warn_unused_but_set_variable) Warning EnabledBy(Wunused)
776 Warn when a variable is only set, otherwise unused.
779 Common Var(warn_unused_function) Warning EnabledBy(Wunused)
780 Warn when a function is unused.
783 Common Var(warn_unused_label) Warning EnabledBy(Wunused)
784 Warn when a label is unused.
787 Common Var(warn_unused_parameter) Warning EnabledBy(Wunused && Wextra)
788 Warn when a function parameter is unused.
791 Common Var(warn_unused_value) Warning EnabledBy(Wunused)
792 Warn when an expression value is unused.
795 Common Var(warn_unused_variable) Warning EnabledBy(Wunused)
796 Warn when a variable is unused.
799 Common Var(warn_coverage_mismatch) Init(1) Warning
800 Warn in case profiles in -fprofile-use do not match.
802 Wvector-operation-performance
803 Common Var(warn_vector_operation_performance) Warning
804 Warn when a vector operation is compiled outside the SIMD.
819 Common Separate Var(aux_info_file_name)
820 -aux-info <file> Emit declaration information into <file>.
823 Common Joined Alias(aux-info)
826 Common Separate RejectDriver Var(aux_base_name)
829 Common Separate RejectDriver
839 -d<letters> Enable dumps from specific passes of the compiler.
842 Common Separate Var(dump_base_name)
843 -dumpbase <file> Set the file basename to be used for dumps.
846 Common Separate Var(dump_dir_name)
847 -dumpdir <dir> Set the directory name to be used for dumps.
862 Driver Joined Separate
864 ; This option has historically been passed down to the linker by an
865 ; accident of a %{e*} spec, so ensure it continues to be passed down
866 ; as a single option. The supported option for this purpose is
867 ; -rdynamic. See PR 47390.
871 ; The version of the C++ ABI in use. The following values are allowed:
873 ; 0: The version of the ABI believed most conformant with the C++ ABI
874 ; specification. This ABI may change as bugs are discovered and fixed.
875 ; Therefore, 0 will not necessarily indicate the same ABI in different
878 ; 1: The version of the ABI first used in G++ 3.2. No longer selectable.
880 ; 2: The version of the ABI first used in G++ 3.4, and the default
883 ; 3: The version of the ABI that fixes the missing underscore
884 ; in template non-type arguments of pointer type.
886 ; 4: The version of the ABI that introduces unambiguous mangling of
887 ; vector types. First selectable in G++ 4.5.
889 ; 5: The version of the ABI that ignores attribute const/noreturn
890 ; in function pointer mangling, and corrects mangling of decltype and
891 ; function parameters used in other parameters and the return type.
892 ; First selectable in G++ 4.6.
894 ; 6: The version of the ABI that doesn't promote scoped enums to int and
895 ; changes the mangling of template argument packs, const/static_cast,
896 ; prefix ++ and --, and a class scope function used as a template
898 ; First selectable in G++ 4.7.
900 ; 7: The version of the ABI that treats nullptr_t as a builtin type and
901 ; corrects the mangling of lambdas in default argument scope.
902 ; First selectable in G++ 4.8.
904 ; 8: The version of the ABI that corrects the substitution behavior of
905 ; function types with function-cv-qualifiers.
906 ; First selectable in G++ 4.9 and default in G++ 5.
908 ; 9: The version of the ABI that corrects the alignment of nullptr_t.
909 ; First selectable and default in G++ 5.2.
911 ; 10: The version of the ABI that mangles attributes that affect type
912 ; identity, such as ia32 calling convention attributes (stdcall, etc.)
913 ; Default in G++ 6 (set in c_common_post_options).
915 ; 11: The version of the ABI that corrects mangling of sizeof... expressions
916 ; and introduces new inheriting constructor handling.
919 ; 12: Corrects the calling convention for classes with only deleted copy/move
923 ; Additional positive integers will be assigned as new versions of
924 ; the ABI become the default version of the ABI.
926 Common Joined RejectNegative UInteger Var(flag_abi_version) Init(0)
927 The version of the C++ ABI in use.
929 faggressive-loop-optimizations
930 Common Report Var(flag_aggressive_loop_optimizations) Optimization Init(1)
931 Aggressively optimize loops using language constraints.
934 Common Report Var(align_functions,0) Optimization UInteger
935 Align the start of functions.
938 Common RejectNegative Joined UInteger Var(align_functions)
940 flimit-function-alignment
941 Common Report Var(flag_limit_function_alignment) Optimization Init(0)
944 Common Report Var(align_jumps,0) Optimization UInteger
945 Align labels which are only reached by jumping.
948 Common RejectNegative Joined UInteger Var(align_jumps)
951 Common Report Var(align_labels,0) Optimization UInteger
955 Common RejectNegative Joined UInteger Var(align_labels)
958 Common Report Var(align_loops,0) Optimization UInteger
959 Align the start of loops.
962 Common RejectNegative Joined UInteger Var(align_loops)
966 Does nothing. Preserved for backward compatibility.
970 Does nothing. Preserved for backward compatibility.
972 fargument-noalias-global
974 Does nothing. Preserved for backward compatibility.
976 fargument-noalias-anything
978 Does nothing. Preserved for backward compatibility.
981 Common Driver Report Joined
982 Select what to sanitize.
986 Select what to coverage sanitize.
989 Common Joined RejectNegative Var(common_deferred_options) Defer
990 -fasan-shadow-offset=<number> Use custom shadow memory offset.
993 Common Joined RejectNegative Var(common_deferred_options) Defer
994 -fsanitize-sections=<sec1,sec2,...> Sanitize global variables
995 in user-defined sections.
999 After diagnosing undefined behavior attempt to continue execution.
1003 This switch is deprecated; use -fsanitize-recover= instead.
1005 fsanitize-address-use-after-scope
1006 Common Driver Report Var(flag_sanitize_address_use_after_scope) Init(0)
1008 fsanitize-undefined-trap-on-error
1009 Common Driver Report Var(flag_sanitize_undefined_trap_on_error) Init(0)
1010 Use trap instead of a library function for undefined behavior sanitization.
1012 fasynchronous-unwind-tables
1013 Common Report Var(flag_asynchronous_unwind_tables) Optimization
1014 Generate unwind tables that are exact at each instruction boundary.
1017 Common Report Var(flag_auto_inc_dec) Init(1) Optimization
1018 Generate auto-inc/dec instructions.
1021 Common Report Var(flag_auto_profile)
1022 Use sample profile information for call graph node weights. The default
1023 profile file is fbdata.afdo in 'pwd'.
1026 Common Joined RejectNegative Var(auto_profile_file)
1027 Use sample profile information for call graph node weights. The profile
1028 file is specified in the argument.
1030 ; -fcheck-bounds causes gcc to generate array bounds checks.
1031 ; For C, C++ and ObjC: defaults off.
1032 ; For Java: defaults to on.
1033 ; For Fortran: defaults to off.
1035 Common Report Var(flag_bounds_check)
1036 Generate code to check bounds before indexing arrays.
1039 Common Report Var(flag_branch_on_count_reg) Optimization
1040 Replace add, compare, branch with branch on count register.
1042 fbranch-probabilities
1043 Common Report Var(flag_branch_probabilities) Optimization
1044 Use profiling information for branch probabilities.
1046 fbranch-target-load-optimize
1047 Common Report Var(flag_branch_target_load_optimize) Optimization
1048 Perform branch target load optimization before prologue / epilogue threading.
1050 fbranch-target-load-optimize2
1051 Common Report Var(flag_branch_target_load_optimize2) Optimization
1052 Perform branch target load optimization after prologue / epilogue threading.
1055 Common Report Var(flag_btr_bb_exclusive) Optimization
1056 Restrict target load migration not to re-use registers in any basic block.
1059 Common Joined RejectNegative Var(common_deferred_options) Defer
1060 -fcall-saved-<register> Mark <register> as being preserved across functions.
1063 Common Joined RejectNegative Var(common_deferred_options) Defer
1064 -fcall-used-<register> Mark <register> as being corrupted by function calls.
1066 ; Nonzero for -fcaller-saves: allocate values in regs that need to
1067 ; be saved across function calls, if that produces overall better code.
1068 ; Optional now, so people can test it.
1070 Common Report Var(flag_caller_saves) Optimization
1071 Save registers around function calls.
1074 Common Report Var(flag_check_data_deps)
1075 This switch is deprecated; do not use.
1078 Common Var(flag_check_new)
1079 Check the return value of new in C++.
1082 Common Var(flag_checking) Init(CHECKING_P ? ENABLE_EXTRA_CHECKING ? 2 : 1 : 0)
1083 Perform internal consistency checkings.
1086 Common Joined RejectNegative UInteger Var(flag_checking)
1087 Perform internal consistency checkings.
1090 Common Report Var(flag_code_hoisting) Optimization
1091 Enable code hoisting.
1093 fcombine-stack-adjustments
1094 Common Report Var(flag_combine_stack_adjustments) Optimization
1095 Looks for opportunities to reduce stack adjustments and stack references.
1098 Common Report Var(flag_no_common,0)
1099 Do not put uninitialized globals in the common section.
1103 ; Converted by the driver to -fcompare-debug= options.
1106 Common Driver JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
1107 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump.
1109 fcompare-debug-second
1110 Common Driver RejectNegative Var(flag_compare_debug)
1111 Run only the second compilation of -fcompare-debug.
1114 Common Report Var(flag_compare_elim_after_reload) Optimization
1115 Perform comparison elimination after register allocation has finished.
1118 Common Var(flag_conserve_stack) Optimization
1119 Do not perform optimizations increasing noticeably stack usage.
1122 Common Report Var(flag_cprop_registers) Optimization
1123 Perform a register copy-propagation optimization pass.
1126 Common Report Var(flag_crossjumping) Optimization
1127 Perform cross-jumping optimization.
1130 Common Report Var(flag_cse_follow_jumps) Optimization
1131 When running CSE, follow jumps to their targets.
1135 Does nothing. Preserved for backward compatibility.
1138 Common Report Var(flag_cx_limited_range) Optimization SetByCombined
1139 Omit range reduction step when performing complex division.
1142 Common Report Var(flag_cx_fortran_rules) Optimization
1143 Complex multiplication and division follow Fortran rules.
1146 Common Report Var(flag_data_sections)
1147 Place data items into their own section.
1150 Common Report Var(common_deferred_options) Defer
1151 List all available debugging counters with their limits and counts.
1154 Common RejectNegative Joined Var(common_deferred_options) Defer
1155 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
1158 Common Joined RejectNegative Var(common_deferred_options) Defer
1159 Map one directory name to another in debug information.
1161 fdebug-types-section
1162 Common Report Var(flag_debug_types_section) Init(0)
1163 Output .debug_types section when using DWARF v4 debuginfo.
1165 ; Nonzero for -fdefer-pop: don't pop args after each function call
1166 ; instead save them up to pop many calls' args with one insns.
1168 Common Report Var(flag_defer_pop) Optimization
1169 Defer popping functions args from stack until later.
1172 Common Report Var(flag_delayed_branch) Optimization
1173 Attempt to fill delay slots of branch instructions.
1175 fdelete-dead-exceptions
1176 Common Report Var(flag_delete_dead_exceptions) Init(0) Optimization
1177 Delete dead instructions that may throw exceptions.
1179 fdelete-null-pointer-checks
1180 Common Report Var(flag_delete_null_pointer_checks) Init(-1) Optimization
1181 Delete useless null pointer checks.
1183 fdevirtualize-at-ltrans
1184 Common Report Var(flag_ltrans_devirtualize)
1185 Stream extra data to support more aggressive devirtualization in LTO local transformation mode.
1187 fdevirtualize-speculatively
1188 Common Report Var(flag_devirtualize_speculatively) Optimization
1189 Perform speculative devirtualization.
1192 Common Report Var(flag_devirtualize) Optimization
1193 Try to convert virtual calls to direct ones.
1195 fdiagnostics-show-location=
1196 Common Joined RejectNegative Enum(diagnostic_prefixing_rule)
1197 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics.
1199 ; Required for these enum values.
1204 Name(diagnostic_prefixing_rule) Type(int)
1207 Enum(diagnostic_prefixing_rule) String(once) Value(DIAGNOSTICS_SHOW_PREFIX_ONCE)
1210 Enum(diagnostic_prefixing_rule) String(every-line) Value(DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE)
1212 fdiagnostics-show-caret
1213 Common Var(flag_diagnostics_show_caret) Init(1)
1214 Show the source line with a caret indicating the column.
1217 Common Alias(fdiagnostics-color=,always,never)
1221 Driver Common Joined RejectNegative Var(flag_diagnostics_show_color) Enum(diagnostic_color_rule) Init(DIAGNOSTICS_COLOR_NO)
1222 -fdiagnostics-color=[never|always|auto] Colorize diagnostics.
1224 ; Required for these enum values.
1229 Name(diagnostic_color_rule) Type(int)
1232 Enum(diagnostic_color_rule) String(never) Value(DIAGNOSTICS_COLOR_NO)
1235 Enum(diagnostic_color_rule) String(always) Value(DIAGNOSTICS_COLOR_YES)
1238 Enum(diagnostic_color_rule) String(auto) Value(DIAGNOSTICS_COLOR_AUTO)
1240 fdiagnostics-parseable-fixits
1241 Common Var(flag_diagnostics_parseable_fixits)
1242 Print fix-it hints in machine-readable form.
1244 fdiagnostics-generate-patch
1245 Common Var(flag_diagnostics_generate_patch)
1246 Print fix-it hints to stderr in unified diff format.
1248 fdiagnostics-show-option
1249 Common Var(flag_diagnostics_show_option) Init(1)
1250 Amend appropriate diagnostic messages with the command line option that controls them.
1253 Common Joined RejectNegative Var(common_deferred_options) Defer
1254 -fdisable-[tree|rtl|ipa]-<pass>=range1+range2 disables an optimization pass.
1257 Common Joined RejectNegative Var(common_deferred_options) Defer
1258 -fenable-[tree|rtl|ipa]-<pass>=range1+range2 enables an optimization pass.
1261 Common Joined RejectNegative Var(common_deferred_options) Defer
1262 -fdump-<type> Dump various compiler internals to a file.
1265 Driver RejectNegative
1268 Common RejectNegative Joined Var(flag_dump_final_insns)
1269 -fdump-final-insns=filename Dump to filename the insns at the end of translation.
1272 Common RejectNegative Joined Var(flag_dump_go_spec)
1273 -fdump-go-spec=filename Write all declarations to file as Go code.
1276 Common Report Var(flag_dump_noaddr)
1277 Suppress output of addresses in debugging dumps.
1280 Common Driver Var(flag_report_bug)
1281 Collect and dump debug information into temporary file if ICE in C/C++
1284 fdump-internal-locations
1285 Common Var(flag_dump_locations) Init(0)
1286 Dump detailed information on GCC's internal representation of source code locations.
1289 Common Var(flag_dump_passes) Init(0)
1290 Dump optimization passes.
1293 Common Report Var(flag_dump_unnumbered)
1294 Suppress output of instruction numbers, line number notes and addresses in debugging dumps.
1296 fdump-unnumbered-links
1297 Common Report Var(flag_dump_unnumbered_links)
1298 Suppress output of previous and next insn numbers in debugging dumps.
1301 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
1302 Enable CFI tables via GAS assembler directives.
1305 Common Report Var(flag_early_inlining) Init(1) Optimization
1306 Perform early inlining.
1308 feliminate-dwarf2-dups
1310 Does nothing. Preserved for backward compatibility.
1313 Common Report Var(flag_ipa_sra) Init(0) Optimization
1314 Perform interprocedural reduction of aggregates.
1316 feliminate-unused-debug-symbols
1317 Common Report Var(flag_debug_only_used_symbols)
1318 Perform unused symbol elimination in debug info.
1320 feliminate-unused-debug-types
1321 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
1322 Perform unused type elimination in debug info.
1324 femit-class-debug-always
1325 Common Report Var(flag_emit_class_debug_always) Init(0)
1326 Do not suppress C++ class debug information.
1329 Common Report Var(flag_exceptions) Optimization
1330 Enable exception handling.
1332 fexpensive-optimizations
1333 Common Report Var(flag_expensive_optimizations) Optimization
1334 Perform a number of minor, expensive optimizations.
1337 Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision_cmdline) Init(EXCESS_PRECISION_DEFAULT) SetByCombined
1338 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision.
1341 Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess precision style %qs)
1344 Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)
1347 Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
1349 ; Whether we permit the extended set of values for FLT_EVAL_METHOD
1350 ; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C99/C11.
1351 fpermitted-flt-eval-methods=
1352 Common Joined RejectNegative Enum(permitted_flt_eval_methods) Var(flag_permitted_flt_eval_methods) Init(PERMITTED_FLT_EVAL_METHODS_DEFAULT)
1353 -fpermitted-flt-eval-methods=[c11|ts-18661] Specify which values of FLT_EVAL_METHOD are permitted.
1356 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)
1359 Enum(permitted_flt_eval_methods) String(c11) Value(PERMITTED_FLT_EVAL_METHODS_C11)
1362 Enum(permitted_flt_eval_methods) String(ts-18661-3) Value(PERMITTED_FLT_EVAL_METHODS_TS_18661)
1368 Common Var(flag_fat_lto_objects)
1369 Output lto objects containing both the intermediate language and binary output.
1372 Common Report Var(flag_finite_math_only) Optimization SetByCombined
1373 Assume no NaNs or infinities are generated.
1376 Common Joined RejectNegative Var(common_deferred_options) Defer
1377 -ffixed-<register> Mark <register> as being unavailable to the compiler.
1380 Common Report Var(flag_float_store) Optimization
1381 Don't allocate floats and doubles in extended-precision registers.
1385 Does nothing. Preserved for backward compatibility.
1388 Common Report Var(flag_forward_propagate) Optimization
1389 Perform a forward propagation pass on RTL.
1392 Common Joined RejectNegative Enum(fp_contract_mode) Var(flag_fp_contract_mode) Init(FP_CONTRACT_FAST) Optimization
1393 -ffp-contract=[off|on|fast] Perform floating-point expression contraction.
1396 Name(fp_contract_mode) Type(enum fp_contract_mode) UnknownError(unknown floating point contraction style %qs)
1399 Enum(fp_contract_mode) String(off) Value(FP_CONTRACT_OFF)
1401 ; Not implemented, fall back to conservative FP_CONTRACT_OFF.
1403 Enum(fp_contract_mode) String(on) Value(FP_CONTRACT_OFF)
1406 Enum(fp_contract_mode) String(fast) Value(FP_CONTRACT_FAST)
1408 ffp-int-builtin-inexact
1409 Common Report Var(flag_fp_int_builtin_inexact) Init(1) Optimization
1410 Allow built-in functions ceil, floor, round, trunc to raise \"inexact\" exceptions.
1412 ; Nonzero means don't put addresses of constant functions in registers.
1413 ; Used for compiling the Unix kernel, where strange substitutions are
1414 ; done on the assembly output.
1416 Common Report Var(flag_no_function_cse,0) Optimization
1417 Allow function addresses to be held in registers.
1420 Common Report Var(flag_function_sections)
1421 Place each function into its own section.
1424 Common Report Var(flag_gcse) Optimization
1425 Perform global common subexpression elimination.
1428 Common Report Var(flag_gcse_lm) Init(1) Optimization
1429 Perform enhanced load motion during global common subexpression elimination.
1432 Common Report Var(flag_gcse_sm) Init(0) Optimization
1433 Perform store motion after global common subexpression elimination.
1436 Common Report Var(flag_gcse_las) Init(0) Optimization
1437 Perform redundant load after store elimination in global common subexpression
1441 Common Report Var(flag_gcse_after_reload) Optimization
1442 Perform global common subexpression elimination after register allocation has
1446 Name(dwarf_gnat_encodings) Type(int)
1449 Enum(dwarf_gnat_encodings) String(all) Value(DWARF_GNAT_ENCODINGS_ALL)
1452 Enum(dwarf_gnat_encodings) String(gdb) Value(DWARF_GNAT_ENCODINGS_GDB)
1455 Enum(dwarf_gnat_encodings) String(minimal) Value(DWARF_GNAT_ENCODINGS_MINIMAL)
1458 Common Enum(dwarf_gnat_encodings) Joined RejectNegative Report Undocumented Var(gnat_encodings)
1459 -fgnat-encodings=[all|gdb|minimal] Select the balance between GNAT encodings and standard DWARF emitted in the debug information
1461 ; This option is not documented yet as its semantics will change.
1463 Common Report Var(flag_graphite) Optimization
1464 Enable in and out of Graphite representation.
1467 Common Report Var(flag_graphite_identity) Optimization
1468 Enable Graphite Identity transformation.
1470 fhoist-adjacent-loads
1471 Common Report Var(flag_hoist_adjacent_loads) Optimization
1472 Enable hoisting adjacent loads to encourage generating conditional move
1476 Common Undocumented Report Var(flag_keep_gc_roots_live) Optimization
1477 ; Always keep a pointer to a live memory block
1479 floop-parallelize-all
1480 Common Report Var(flag_loop_parallelize_all) Optimization
1481 Mark all loops as parallel.
1484 Common Alias(floop-nest-optimize)
1485 Enable loop nest transforms. Same as -floop-nest-optimize.
1488 Common Alias(floop-nest-optimize)
1489 Enable loop nest transforms. Same as -floop-nest-optimize.
1492 Common Alias(floop-nest-optimize)
1493 Enable loop nest transforms. Same as -floop-nest-optimize.
1495 floop-unroll-and-jam
1496 Common Alias(floop-nest-optimize)
1497 Enable loop nest transforms. Same as -floop-nest-optimize.
1500 Common Report Var(flag_tm)
1501 Enable support for GNU transactional memory.
1504 Common Report Var(flag_gnu_unique) Init(1)
1505 Use STB_GNU_UNIQUE if supported by the assembler.
1509 Does nothing. Preserved for backward compatibility.
1512 Common Report Var(flag_loop_nest_optimize) Optimization
1513 Enable the loop nest optimizer.
1515 fstrict-volatile-bitfields
1516 Common Report Var(flag_strict_volatile_bitfields) Init(-1) Optimization
1517 Force bitfield accesses to match their type width.
1520 Common Report Var(flag_store_merging) Optimization
1521 Merge adjacent stores.
1523 fguess-branch-probability
1524 Common Report Var(flag_guess_branch_prob) Optimization
1525 Enable guessing of branch probabilities.
1527 ; Nonzero means ignore `#ident' directives. 0 means handle them.
1528 ; Generate position-independent code for executables if possible
1529 ; On SVR4 targets, it also controls whether or not to emit a
1530 ; string identifying the compiler.
1532 Common Report Var(flag_no_ident,0)
1533 Process #ident directives.
1536 Common Report Var(flag_if_conversion) Optimization
1537 Perform conversion of conditional jumps to branchless equivalents.
1540 Common Report Var(flag_if_conversion2) Optimization
1541 Perform conversion of conditional jumps to conditional execution.
1544 Common Joined RejectNegative Enum(stack_reuse_level) Var(flag_stack_reuse) Init(SR_ALL) Optimization
1545 -fstack-reuse=[all|named_vars|none] Set stack reuse level for local variables.
1548 Name(stack_reuse_level) Type(enum stack_reuse_level) UnknownError(unknown Stack Reuse Level %qs)
1551 Enum(stack_reuse_level) String(all) Value(SR_ALL)
1554 Enum(stack_reuse_level) String(named_vars) Value(SR_NAMED_VARS)
1557 Enum(stack_reuse_level) String(none) Value(SR_NONE)
1559 ftree-loop-if-convert
1560 Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
1561 Convert conditional jumps in innermost loops to branchless equivalents.
1563 ftree-loop-if-convert-stores
1565 Does nothing. Preserved for backward compatibility.
1567 ; -finhibit-size-directive inhibits output of .size for ELF.
1568 ; This is used only for compiling crtstuff.c,
1569 ; and it may be extended to other effects
1570 ; needed for crtstuff.c on other systems.
1571 finhibit-size-directive
1572 Common Report Var(flag_inhibit_size_directive)
1573 Do not generate .size directives.
1576 Common Report Var(flag_indirect_inlining) Optimization
1577 Perform indirect inlining.
1579 ; General flag to enable inlining. Specifying -fno-inline will disable
1580 ; all inlining apart from always-inline functions.
1582 Common Report Var(flag_no_inline,0) Init(0) Optimization
1583 Enable inlining of function declared \"inline\", disabling disables all inlining.
1585 finline-small-functions
1586 Common Report Var(flag_inline_small_functions) Optimization
1587 Integrate functions into their callers when code size is known not to grow.
1590 Common Report Var(flag_inline_functions) Optimization
1591 Integrate functions not declared \"inline\" into their callers when profitable.
1593 finline-functions-called-once
1594 Common Report Var(flag_inline_functions_called_once) Optimization
1595 Integrate functions only required by their single caller.
1598 Common RejectNegative Joined Alias(finline-limit=)
1601 Common RejectNegative Joined UInteger
1602 -finline-limit=<number> Limit the size of inlined functions to <number>.
1605 Common Report Var(flag_inline_atomics) Init(1) Optimization
1606 Inline __atomic operations when a lock free instruction sequence is available.
1608 finstrument-functions
1609 Common Report Var(flag_instrument_function_entry_exit)
1610 Instrument function entry and exit with profiling calls.
1612 finstrument-functions-exclude-function-list=
1613 Common RejectNegative Joined
1614 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions.
1616 finstrument-functions-exclude-file-list=
1617 Common RejectNegative Joined
1618 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files.
1621 Common Report Var(flag_ipa_cp) Optimization
1622 Perform interprocedural constant propagation.
1625 Common Report Var(flag_ipa_cp_clone) Optimization
1626 Perform cloning to make Interprocedural constant propagation stronger.
1630 Does nothing. Preserved for backward compatibility.
1633 Common Report Var(flag_ipa_bit_cp) Optimization
1634 Perform interprocedural bitwise constant propagation.
1637 Common Report Var(flag_ipa_profile) Init(0) Optimization
1638 Perform interprocedural profile propagation.
1641 Common Report Var(flag_ipa_pta) Init(0) Optimization
1642 Perform interprocedural points-to analysis.
1645 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
1646 Discover pure and const functions.
1649 Common Report Var(flag_ipa_icf) Optimization
1650 Perform Identical Code Folding for functions and read-only variables.
1653 Common Report Var(flag_ipa_icf_functions) Optimization
1654 Perform Identical Code Folding for functions.
1657 Common Report Var(flag_ipa_icf_variables) Optimization
1658 Perform Identical Code Folding for variables.
1661 Common Report Var(flag_ipa_reference) Init(0) Optimization
1662 Discover readonly and non addressable static variables.
1666 Does nothing. Preserved for backward compatibility.
1670 Does nothing. Preserved for backward compatibility.
1673 Common Report Var(flag_ipa_vrp) Optimization
1674 Perform IPA Value Range Propagation.
1677 Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization
1678 -fira-algorithm=[CB|priority] Set the used IRA algorithm.
1681 Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)
1684 Enum(ira_algorithm) String(CB) Value(IRA_ALGORITHM_CB)
1687 Enum(ira_algorithm) String(priority) Value(IRA_ALGORITHM_PRIORITY)
1690 Common Joined RejectNegative Enum(ira_region) Var(flag_ira_region) Init(IRA_REGION_AUTODETECT) Optimization
1691 -fira-region=[one|all|mixed] Set regions for IRA.
1694 Name(ira_region) Type(enum ira_region) UnknownError(unknown IRA region %qs)
1697 Enum(ira_region) String(one) Value(IRA_REGION_ONE)
1700 Enum(ira_region) String(all) Value(IRA_REGION_ALL)
1703 Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)
1706 Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
1707 Use IRA based register pressure calculation
1708 in RTL hoist optimizations.
1711 Common Report Var(flag_ira_loop_pressure) Optimization
1712 Use IRA based register pressure calculation
1713 in RTL loop optimizations.
1715 fira-share-save-slots
1716 Common Report Var(flag_ira_share_save_slots) Init(1) Optimization
1717 Share slots for saving different hard registers.
1719 fira-share-spill-slots
1720 Common Report Var(flag_ira_share_spill_slots) Init(1) Optimization
1721 Share stack slots for spilled pseudo-registers.
1724 Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
1725 -fira-verbose=<number> Control IRA's level of diagnostic messages.
1728 Common Report Var(flag_ivopts) Init(1) Optimization
1729 Optimize induction variables on trees.
1732 Common Var(flag_jump_tables) Init(1) Optimization
1733 Use jump tables for sufficiently large switch statements.
1735 fkeep-inline-functions
1736 Common Report Var(flag_keep_inline_functions)
1737 Generate code for functions even if they are fully inlined.
1739 fkeep-static-functions
1740 Common Report Var(flag_keep_static_functions)
1741 Generate code for static functions even if they are never called.
1744 Common Report Var(flag_keep_static_consts) Init(1)
1745 Emit static const variables even if they are not used.
1748 Common Report Var(flag_leading_underscore) Init(-1)
1749 Give external symbols a leading underscore.
1753 Does nothing. Preserved for backward compatibility.
1756 Common Report Var(flag_lra_remat) Optimization
1757 Do CFG-sensitive rematerialization in LRA.
1761 Enable link-time optimization.
1764 Common RejectNegative Joined Var(flag_lto)
1765 Link-time optimization with number of parallel jobs or jobserver.
1768 Name(lto_partition_model) Type(enum lto_partition_model) UnknownError(unknown LTO partitioning model %qs)
1771 Enum(lto_partition_model) String(none) Value(LTO_PARTITION_NONE)
1774 Enum(lto_partition_model) String(one) Value(LTO_PARTITION_ONE)
1777 Enum(lto_partition_model) String(balanced) Value(LTO_PARTITION_BALANCED)
1780 Enum(lto_partition_model) String(1to1) Value(LTO_PARTITION_1TO1)
1783 Enum(lto_partition_model) String(max) Value(LTO_PARTITION_MAX)
1786 Common Joined RejectNegative Enum(lto_partition_model) Var(flag_lto_partition) Init(LTO_PARTITION_BALANCED)
1787 Specify the algorithm to partition symbols and vars at linktime.
1789 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
1790 flto-compression-level=
1791 Common Joined RejectNegative UInteger Var(flag_lto_compression_level) Init(-1) IntegerRange(0, 9)
1792 -flto-compression-level=<number> Use zlib compression level <number> for IL.
1794 flto-odr-type-merging
1795 Common Report Var(flag_lto_odr_type_mering) Init(1)
1796 Merge C++ types using One Definition Rule.
1799 Common Report Var(flag_lto_report) Init(0)
1800 Report various link-time optimization statistics.
1803 Common Report Var(flag_lto_report_wpa) Init(0)
1804 Report various link-time optimization statistics for WPA only.
1807 Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
1808 Set errno after built-in math functions.
1811 Common Joined RejectNegative UInteger Var(flag_max_errors)
1812 -fmax-errors=<number> Maximum number of errors to report.
1815 Common Report Var(mem_report)
1816 Report on permanent memory allocation.
1819 Common Report Var(mem_report_wpa)
1820 Report on permanent memory allocation in WPA only.
1822 ; This will attempt to merge constant section constants, if 1 only
1823 ; string constants and constants from constant pool, if 2 also constant
1825 fmerge-all-constants
1826 Common Report Var(flag_merge_constants,2) Init(1)
1827 Attempt to merge identical constants and constant variables.
1830 Common Report Var(flag_merge_constants,1)
1831 Attempt to merge identical constants across compilation units.
1833 fmerge-debug-strings
1834 Common Report Var(flag_merge_debug_strings) Init(1)
1835 Attempt to merge identical debug strings across compilation units.
1838 Common RejectNegative Joined UInteger
1839 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping.
1842 Common Report Var(flag_modulo_sched) Optimization
1843 Perform SMS based modulo scheduling before the first scheduling pass.
1845 fmodulo-sched-allow-regmoves
1846 Common Report Var(flag_modulo_sched_allow_regmoves) Optimization
1847 Perform SMS based modulo scheduling with register moves allowed.
1849 fmove-loop-invariants
1850 Common Report Var(flag_move_loop_invariants) Optimization
1851 Move loop invariant computations out of loops.
1854 Common Var(flag_dce) Init(1) Optimization
1855 Use the RTL dead code elimination pass.
1858 Common Var(flag_dse) Init(1) Optimization
1859 Use the RTL dead store elimination pass.
1861 freschedule-modulo-scheduled-loops
1862 Common Report Var(flag_resched_modulo_sched) Optimization
1863 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling.
1865 fnon-call-exceptions
1866 Common Report Var(flag_non_call_exceptions) Optimization
1867 Support synchronous non-call exceptions.
1870 Common Driver Joined MissingArgError(options or targets missing after %qs)
1871 -foffload=<targets>=<options> Specify offloading targets and options for them.
1874 Common Joined RejectNegative Enum(offload_abi) Var(flag_offload_abi) Init(OFFLOAD_ABI_UNSET)
1875 -foffload-abi=[lp64|ilp32] Set the ABI to use in an offload compiler.
1878 Name(offload_abi) Type(enum offload_abi) UnknownError(unknown offload ABI %qs)
1881 Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
1884 Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
1887 Common Report Var(flag_omit_frame_pointer) Optimization
1888 When possible do not generate stack frames.
1891 Common Report Var(flag_opt_info) Optimization
1892 Enable all optimization info dumps on stderr.
1895 Common Joined RejectNegative Var(common_deferred_options) Defer
1896 -fopt-info[-<type>=filename] Dump compiler optimization details.
1898 foptimize-register-move
1900 Does nothing. Preserved for backward compatibility.
1902 foptimize-sibling-calls
1903 Common Report Var(flag_optimize_sibling_calls) Optimization
1904 Optimize sibling and tail recursive calls.
1907 Common Report Var(flag_partial_inlining) Optimization
1908 Perform partial inlining.
1911 Common Report Var(pre_ipa_mem_report)
1912 Report on memory allocation before interprocedural optimization.
1914 fpost-ipa-mem-report
1915 Common Report Var(post_ipa_mem_report)
1916 Report on memory allocation before interprocedural optimization.
1919 Common Report Var(flag_pack_struct) Optimization
1920 Pack structure members together without holes.
1923 Common RejectNegative Joined UInteger Optimization
1924 -fpack-struct=<number> Set initial maximum structure member alignment.
1927 Common Report Var(flag_pcc_struct_return,1) Init(DEFAULT_PCC_STRUCT_RETURN)
1928 Return small aggregates in memory, not registers.
1931 Common Report Var(flag_peel_loops) Optimization
1932 Perform loop peeling.
1935 Common Report Var(flag_no_peephole,0) Optimization
1936 Enable machine specific peephole optimizations.
1939 Common Report Var(flag_peephole2) Optimization
1940 Enable an RTL peephole pass before sched2.
1943 Common Report Var(flag_pic,2) Negative(fPIE) Init(-1)
1944 Generate position-independent code if possible (large mode).
1947 Common Report Var(flag_pie,2) Negative(fpic) Init(-1)
1948 Generate position-independent code for executables if possible (large mode).
1951 Common Report Var(flag_pic,1) Negative(fpie) Init(-1)
1952 Generate position-independent code if possible (small mode).
1955 Common Report Var(flag_pie,1) Negative(fPIC) Init(-1)
1956 Generate position-independent code for executables if possible (small mode).
1959 Common Report Var(flag_plt) Init(1) Optimization
1960 Use PLT for PIC calls (-fno-plt: load the address from GOT at call site).
1963 Common Joined RejectNegative Var(common_deferred_options) Defer
1964 Specify a plugin to load.
1967 Common Joined RejectNegative Var(common_deferred_options) Defer
1968 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>.
1970 fpredictive-commoning
1971 Common Report Var(flag_predictive_commoning) Optimization
1972 Run predictive commoning optimization.
1974 fprefetch-loop-arrays
1975 Common Report Var(flag_prefetch_loop_arrays) Init(-1) Optimization
1976 Generate prefetch instructions, if available, for arrays in loops.
1979 Common Report Var(profile_flag)
1980 Enable basic program profiling code.
1983 Common Report Var(profile_abs_path_flag)
1984 Generate absolute source path names for gcov.
1987 Common Report Var(profile_arc_flag)
1988 Insert arc-based program profiling code.
1991 Common Joined RejectNegative Var(profile_data_prefix)
1992 Set the top-level directory for storing the profile data.
1993 The default is 'pwd'.
1996 Common Report Var(flag_profile_correction)
1997 Enable correction of flow inconsistent profile data input.
2000 Common Joined RejectNegative Enum(profile_update) Var(flag_profile_update) Init(PROFILE_UPDATE_SINGLE)
2001 -fprofile-update=[single|atomic|prefer-atomic] Set the profile update method.
2004 Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
2007 Enum(profile_update) String(single) Value(PROFILE_UPDATE_SINGLE)
2010 Enum(profile_update) String(atomic) Value(PROFILE_UPDATE_ATOMIC)
2013 Enum(profile_update) String(prefer-atomic) Value(PROFILE_UPDATE_PREFER_ATOMIC)
2017 Enable common options for generating profile info for profile feedback directed optimizations.
2020 Common Joined RejectNegative
2021 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=.
2024 Common Var(flag_profile_use)
2025 Enable common options for performing profile feedback directed optimizations.
2028 Common Joined RejectNegative
2029 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=.
2032 Common Report Var(flag_profile_values)
2033 Insert code to profile values of expressions.
2036 Common Report Var(profile_report)
2037 Report on consistency of profile.
2039 fprofile-reorder-functions
2040 Common Report Var(flag_profile_reorder_functions)
2041 Enable function reordering that improves code placement.
2043 fpatchable-function-entry=
2044 Common Joined Optimization
2045 Insert NOP instructions at each function entry.
2048 Common Var(common_deferred_options) Defer
2051 Common Joined RejectNegative Var(common_deferred_options) Defer
2052 -frandom-seed=<string> Make compile reproducible using <string>.
2054 ; This switch causes the command line that was used to create an
2055 ; object file to be recorded into the object file. The exact format
2056 ; of this recording is target and binary file format dependent.
2057 ; It is related to the -fverbose-asm switch, but that switch only
2058 ; records information in the assembler output file as comments, so
2059 ; they never reach the object file.
2060 frecord-gcc-switches
2061 Common Report Var(flag_record_gcc_switches)
2062 Record gcc command line switches in the object file.
2065 Common Report Var(flag_pcc_struct_return,0) Optimization
2066 Return small aggregates in registers.
2070 Does nothing. Preserved for backward compatibility.
2073 Common Report Var(flag_lifetime_dse,2) Init(2) Optimization
2074 Tell DSE that the storage for a C++ object is dead when the constructor
2075 starts and when the destructor finishes.
2078 Common Joined RejectNegative UInteger Var(flag_lifetime_dse) Optimization IntegerRange(0, 2)
2080 flive-range-shrinkage
2081 Common Report Var(flag_live_range_shrinkage) Init(0) Optimization
2082 Relief of register pressure through live range shrinkage.
2085 Common Report Var(flag_rename_registers) Init(2) Optimization
2086 Perform a register renaming optimization pass.
2089 Common Report Var(flag_schedule_fusion) Init(2) Optimization
2090 Perform a target dependent instruction fusion optimization pass.
2093 Common Report Var(flag_reorder_blocks) Optimization
2094 Reorder basic blocks to improve code placement.
2096 freorder-blocks-algorithm=
2097 Common Joined RejectNegative Enum(reorder_blocks_algorithm) Var(flag_reorder_blocks_algorithm) Init(REORDER_BLOCKS_ALGORITHM_SIMPLE) Optimization
2098 -freorder-blocks-algorithm=[simple|stc] Set the used basic block reordering algorithm.
2101 Name(reorder_blocks_algorithm) Type(enum reorder_blocks_algorithm) UnknownError(unknown basic block reordering algorithm %qs)
2104 Enum(reorder_blocks_algorithm) String(simple) Value(REORDER_BLOCKS_ALGORITHM_SIMPLE)
2107 Enum(reorder_blocks_algorithm) String(stc) Value(REORDER_BLOCKS_ALGORITHM_STC)
2109 freorder-blocks-and-partition
2110 Common Report Var(flag_reorder_blocks_and_partition) Optimization
2111 Reorder basic blocks and partition into hot and cold sections.
2114 Common Report Var(flag_reorder_functions) Optimization
2115 Reorder functions to improve code placement.
2117 frerun-cse-after-loop
2118 Common Report Var(flag_rerun_cse_after_loop) Optimization
2119 Add a common subexpression elimination pass after loop optimizations.
2123 Does nothing. Preserved for backward compatibility.
2126 Common Report Var(flag_rounding_math) Optimization SetByCombined
2127 Disable optimizations that assume default FP rounding behavior.
2130 Common Report Var(flag_schedule_interblock) Init(1) Optimization
2131 Enable scheduling across basic blocks.
2134 Common Report Var(flag_sched_pressure) Init(0) Optimization
2135 Enable register pressure sensitive insn scheduling.
2138 Common Report Var(flag_schedule_speculative) Init(1) Optimization
2139 Allow speculative motion of non-loads.
2142 Common Report Var(flag_schedule_speculative_load) Optimization
2143 Allow speculative motion of some loads.
2145 fsched-spec-load-dangerous
2146 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
2147 Allow speculative motion of more loads.
2150 Common RejectNegative Joined UInteger Var(sched_verbose_param) Init(1)
2151 -fsched-verbose=<number> Set the verbosity level of the scheduler.
2153 fsched2-use-superblocks
2154 Common Report Var(flag_sched2_use_superblocks) Optimization
2155 If scheduling post reload, do superblock scheduling.
2159 Does nothing. Preserved for backward compatibility.
2162 Common Report Var(flag_schedule_insns) Optimization
2163 Reschedule instructions before register allocation.
2166 Common Report Var(flag_schedule_insns_after_reload) Optimization
2167 Reschedule instructions after register allocation.
2169 ; This flag should be on when a target implements non-trivial
2170 ; scheduling hooks, maybe saving some information for its own sake.
2171 ; On IA64, for example, this is used for correct bundling.
2172 fselective-scheduling
2173 Common Report Var(flag_selective_scheduling) Optimization
2174 Schedule instructions using selective scheduling algorithm.
2176 fselective-scheduling2
2177 Common Report Var(flag_selective_scheduling2) Optimization
2178 Run selective scheduling after reload.
2181 Common Undocumented Joined Var(flag_self_test)
2182 Run self-tests, using the given path to locate test files.
2184 fsel-sched-pipelining
2185 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
2186 Perform software pipelining of inner loops during selective scheduling.
2188 fsel-sched-pipelining-outer-loops
2189 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
2190 Perform software pipelining of outer loops during selective scheduling.
2192 fsel-sched-reschedule-pipelined
2193 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
2194 Reschedule pipelined regions without pipelining.
2196 fsemantic-interposition
2197 Common Report Var(flag_semantic_interposition) Init(1)
2198 Allow interposing function (or variables) by ones with different semantics (or initializer) respectively by dynamic linker.
2200 ; sched_stalled_insns means that insns can be moved prematurely from the queue
2201 ; of stalled insns into the ready list.
2202 fsched-stalled-insns
2203 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
2204 Allow premature scheduling of queued insns.
2206 fsched-stalled-insns=
2207 Common RejectNegative Joined UInteger Optimization
2208 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled.
2210 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
2211 ; be examined for a dependency on a stalled insn that is candidate for
2212 ; premature removal from the queue of stalled insns into the ready list (has
2213 ; an effect only if the flag 'sched_stalled_insns' is set).
2214 fsched-stalled-insns-dep
2215 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
2216 Set dependence distance checking in premature scheduling of queued insns.
2218 fsched-stalled-insns-dep=
2219 Common RejectNegative Joined UInteger Optimization
2220 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns.
2222 fsched-group-heuristic
2223 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
2224 Enable the group heuristic in the scheduler.
2226 fsched-critical-path-heuristic
2227 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
2228 Enable the critical path heuristic in the scheduler.
2230 fsched-spec-insn-heuristic
2231 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
2232 Enable the speculative instruction heuristic in the scheduler.
2234 fsched-rank-heuristic
2235 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
2236 Enable the rank heuristic in the scheduler.
2238 fsched-last-insn-heuristic
2239 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
2240 Enable the last instruction heuristic in the scheduler.
2242 fsched-dep-count-heuristic
2243 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
2244 Enable the dependent count heuristic in the scheduler.
2247 Common Report Var(flag_section_anchors) Optimization
2248 Access data in the same section from shared anchor points.
2252 Does nothing. Preserved for backward compatibility.
2256 Does nothing. Preserved for backward compatibility.
2259 Common Report Var(flag_ree) Init(0)
2260 Turn on Redundant Extensions Elimination pass.
2263 Common Report Var(flag_show_column) Init(1)
2264 Show column numbers in diagnostics, when available. Default on.
2267 Common Report Var(flag_shrink_wrap) Optimization
2268 Emit function prologues only before parts of the function that need it,
2269 rather than at the top of the function.
2271 fshrink-wrap-separate
2272 Common Report Var(flag_shrink_wrap_separate) Init(1) Optimization
2273 Shrink-wrap parts of the prologue and epilogue separately.
2276 Common Report Var(flag_signaling_nans) Optimization SetByCombined
2277 Disable optimizations observable by IEEE signaling NaNs.
2280 Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
2281 Disable floating point optimizations that ignore the IEEE signedness of zero.
2283 fsingle-precision-constant
2284 Common Report Var(flag_single_precision_constant) Optimization
2285 Convert floating point constants to single precision constants.
2287 fsplit-ivs-in-unroller
2288 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
2289 Split lifetimes of induction variables when loops are unrolled.
2292 Common Report Var(flag_split_stack) Init(-1)
2293 Generate discontiguous stack frames.
2296 Common Report Var(flag_split_wide_types) Optimization
2297 Split wide types into independent registers.
2300 Common Report Var(flag_ssa_backprop) Init(1) Optimization
2301 Enable backward propagation of use properties at the SSA level.
2304 Common Report Var(flag_ssa_phiopt) Optimization
2305 Optimize conditional patterns using SSA PHI nodes.
2308 Common Report Var(flag_stdarg_opt) Init(1) Optimization
2309 Optimize amount of stdarg registers saved to stack at start of function.
2311 fvariable-expansion-in-unroller
2312 Common Report Var(flag_variable_expansion_in_unroller) Optimization
2313 Apply variable expansion when loops are unrolled.
2316 Common Report RejectNegative Joined
2317 -fstack-check=[no|generic|specific] Insert stack checking code into the program.
2320 Common Alias(fstack-check=, specific, no)
2321 Insert stack checking code into the program. Same as -fstack-check=specific.
2324 Common Var(common_deferred_options) Defer
2326 fstack-limit-register=
2327 Common RejectNegative Joined Var(common_deferred_options) Defer
2328 -fstack-limit-register=<register> Trap if the stack goes past <register>.
2330 fstack-limit-symbol=
2331 Common RejectNegative Joined Var(common_deferred_options) Defer
2332 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>.
2335 Common Report Var(flag_stack_protect, 1) Init(-1) Optimization
2336 Use propolice as a stack protection method.
2338 fstack-protector-all
2339 Common Report RejectNegative Var(flag_stack_protect, 2) Init(-1) Optimization
2340 Use a stack protection method for every function.
2342 fstack-protector-strong
2343 Common Report RejectNegative Var(flag_stack_protect, 3) Init(-1) Optimization
2344 Use a smart stack protection method for certain functions.
2346 fstack-protector-explicit
2347 Common Report RejectNegative Var(flag_stack_protect, 4) Optimization
2348 Use stack protection method only for functions with the stack_protect attribute.
2351 Common RejectNegative Var(flag_stack_usage)
2352 Output stack usage information on a per-function basis.
2356 Does nothing. Preserved for backward compatibility.
2358 ; Nonzero if we should do (language-dependent) alias analysis.
2359 ; Typically, this analysis will assume that expressions of certain
2360 ; types do not alias expressions of certain other types. Only used
2361 ; if alias analysis (in general) is enabled.
2363 Common Report Var(flag_strict_aliasing) Optimization
2364 Assume strict aliasing rules apply.
2367 Common NegativeAlias Alias(fwrapv)
2368 Treat signed overflow as undefined. Negated as -fwrapv.
2371 Common Report Var(flag_sync_libcalls) Init(1)
2372 Implement __atomic operations via libcalls to legacy __sync functions.
2375 Common Report Var(flag_syntax_only)
2376 Check for syntax errors, then stop.
2379 Common Report Var(flag_test_coverage)
2380 Create data files needed by \"gcov\".
2383 Common Report Var(flag_thread_jumps) Optimization
2384 Perform jump threading optimizations.
2387 Common Report Var(time_report)
2388 Report the time taken by each compiler pass.
2390 ftime-report-details
2391 Common Report Var(time_report_details)
2392 Record times taken by sub-phases separately.
2395 Common Joined RejectNegative Enum(tls_model) Var(flag_tls_default) Init(TLS_MODEL_GLOBAL_DYNAMIC)
2396 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model.
2399 Name(tls_model) Type(enum tls_model) UnknownError(unknown TLS model %qs)
2402 Enum(tls_model) String(global-dynamic) Value(TLS_MODEL_GLOBAL_DYNAMIC)
2405 Enum(tls_model) String(local-dynamic) Value(TLS_MODEL_LOCAL_DYNAMIC)
2408 Enum(tls_model) String(initial-exec) Value(TLS_MODEL_INITIAL_EXEC)
2411 Enum(tls_model) String(local-exec) Value(TLS_MODEL_LOCAL_EXEC)
2414 Common Report Var(flag_toplevel_reorder) Init(2)
2415 Reorder top level functions, variables, and asms.
2418 Common Report Var(flag_tracer) Optimization
2419 Perform superblock formation via tail duplication.
2422 Common Report Var(flag_trampolines) Init(0)
2423 For targets that normally need trampolines for nested functions, always
2424 generate them instead of using descriptors.
2426 ; Zero means that floating-point math operations cannot generate a
2427 ; (user-visible) trap. This is the case, for example, in nonstop
2428 ; IEEE 754 arithmetic.
2430 Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
2431 Assume floating-point operations can trap.
2434 Common Report Var(flag_trapv) Optimization
2435 Trap for signed overflow in addition, subtraction and multiplication.
2438 Common Report Var(flag_tree_ccp) Optimization
2439 Enable SSA-CCP optimization on trees.
2442 Common Report Var(flag_tree_bit_ccp) Optimization
2443 Enable SSA-BIT-CCP optimization on trees.
2447 Does nothing. Preserved for backward compatibility.
2450 Common Report Var(flag_tree_ch) Optimization
2451 Enable loop header copying on trees.
2453 ftree-coalesce-inlined-vars
2454 Common Ignore RejectNegative
2455 Does nothing. Preserved for backward compatibility.
2458 Common Report Var(flag_tree_coalesce_vars) Optimization
2459 Enable SSA coalescing of user variables.
2463 Does nothing. Preserved for backward compatibility.
2466 Common Report Var(flag_tree_copy_prop) Optimization
2467 Enable copy propagation on trees.
2469 ftree-store-copy-prop
2471 Does nothing. Preserved for backward compatibility.
2474 Common Report Var(flag_tree_cselim) Init(2) Optimization
2475 Transform condition stores into unconditional ones.
2477 ftree-switch-conversion
2478 Common Report Var(flag_tree_switch_conversion) Optimization
2479 Perform conversions of switch initializations.
2482 Common Report Var(flag_tree_dce) Optimization
2483 Enable SSA dead code elimination optimization on trees.
2485 ftree-dominator-opts
2486 Common Report Var(flag_tree_dom) Optimization
2487 Enable dominator optimizations.
2490 Common Report Var(flag_tree_tail_merge) Optimization
2491 Enable tail merging on trees.
2494 Common Report Var(flag_tree_dse) Optimization
2495 Enable dead store elimination.
2498 Common Report Var(flag_tree_forwprop) Init(1) Optimization
2499 Enable forward propagation on trees.
2502 Common Report Var(flag_tree_fre) Optimization
2503 Enable Full Redundancy Elimination (FRE) on trees.
2506 Common Report Var(flag_optimize_strlen) Optimization
2507 Enable string length optimizations on trees.
2509 fisolate-erroneous-paths-dereference
2510 Common Report Var(flag_isolate_erroneous_paths_dereference) Optimization
2511 Detect paths that trigger erroneous or undefined behavior due to
2512 dereferencing a null pointer. Isolate those paths from the main control
2513 flow and turn the statement with erroneous or undefined behavior into a trap.
2515 fisolate-erroneous-paths-attribute
2516 Common Report Var(flag_isolate_erroneous_paths_attribute) Optimization
2517 Detect paths that trigger erroneous or undefined behavior due to a null value
2518 being used in a way forbidden by a returns_nonnull or nonnull
2519 attribute. Isolate those paths from the main control flow and turn the
2520 statement with erroneous or undefined behavior into a trap.
2522 ftree-loop-distribution
2523 Common Report Var(flag_tree_loop_distribution) Optimization
2524 Enable loop distribution on trees.
2526 ftree-loop-distribute-patterns
2527 Common Report Var(flag_tree_loop_distribute_patterns) Optimization
2528 Enable loop distribution for patterns transformed into a library call.
2531 Common Report Var(flag_tree_loop_im) Init(1) Optimization
2532 Enable loop invariant motion on trees.
2535 Common Alias(floop-nest-optimize)
2536 Enable loop nest transforms. Same as -floop-nest-optimize.
2539 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
2540 Create canonical induction variables in loops.
2543 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
2544 Enable loop optimizations on tree level.
2546 ftree-parallelize-loops=
2547 Common Report Joined RejectNegative UInteger Var(flag_tree_parallelize_loops) Init(1) Optimization
2548 -ftree-parallelize-loops=<number> Enable automatic parallelization of loops.
2551 Common Report Var(flag_tree_phiprop) Init(1) Optimization
2552 Enable hoisting loads from conditional pointers.
2555 Common Report Var(flag_tree_pre) Optimization
2556 Enable SSA-PRE optimization on trees.
2559 Common Report Var(flag_tree_partial_pre) Optimization
2560 In SSA-PRE optimization on trees, enable partial-partial redundancy elimination.
2563 Common Report Var(flag_tree_pta) Optimization
2564 Perform function-local points-to analysis on trees.
2567 Common Report Var(flag_tree_reassoc) Init(1) Optimization
2568 Enable reassociation on tree level.
2572 Does nothing. Preserved for backward compatibility.
2575 Common Report Var(flag_tree_sink) Optimization
2576 Enable SSA code sinking on trees.
2579 Common Report Var(flag_tree_slsr) Optimization
2580 Perform straight-line strength reduction.
2583 Common Report Var(flag_tree_sra) Optimization
2584 Perform scalar replacement of aggregates.
2587 Common Report Var(flag_tree_ter) Optimization
2588 Replace temporary expressions in the SSA->normal pass.
2591 Common Report Var(flag_tree_live_range_split) Optimization
2592 Perform live range splitting during the SSA->normal pass.
2595 Common Report Var(flag_tree_vrp) Init(0) Optimization
2596 Perform Value Range Propagation on trees.
2599 Common Report Var(flag_split_paths) Init(0) Optimization
2600 Split paths leading to loop backedges.
2602 funconstrained-commons
2603 Common Var(flag_unconstrained_commons) Optimization
2604 Assume common declarations may be overridden with ones with a larger
2608 Common Report Var(flag_unit_at_a_time) Init(1)
2609 Compile whole compilation unit at a time.
2612 Common Report Var(flag_unroll_loops) Optimization
2613 Perform loop unrolling when iteration count is known.
2616 Common Report Var(flag_unroll_all_loops) Optimization
2617 Perform loop unrolling for all loops.
2619 ; Nonzero means that loop optimizer may assume that the induction variables
2620 ; that control loops do not overflow and that the loops with nontrivial
2621 ; exit condition are not infinite
2622 funsafe-loop-optimizations
2624 Does nothing. Preserved for backward compatibility.
2627 Common Report Var(flag_associative_math) SetByCombined Optimization
2628 Allow optimization for floating-point arithmetic which may change the
2629 result of the operation due to rounding.
2632 Common Report Var(flag_reciprocal_math) SetByCombined Optimization
2633 Same as -fassociative-math for expressions which include division.
2635 ; Nonzero means that unsafe floating-point math optimizations are allowed
2636 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
2637 ; are allowed to assume that their arguments and results are "normal"
2638 ; (e.g., nonnegative for SQRT).
2639 funsafe-math-optimizations
2640 Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
2641 Allow math optimizations that may violate IEEE or ISO standards.
2644 Common Report Var(flag_unswitch_loops) Optimization
2645 Perform loop unswitching.
2648 Common Report Var(flag_split_loops) Optimization
2649 Perform loop splitting.
2652 Common Report Var(flag_unwind_tables) Optimization
2653 Just generate unwind tables for exception handling.
2656 Common Driver Negative(fuse-ld=gold)
2657 Use the bfd linker instead of the default linker.
2660 Common Driver Negative(fuse-ld=bfd)
2661 Use the gold linker instead of the default linker.
2664 Common Undocumented Var(flag_use_linker_plugin)
2666 ; Positive if we should track variables, negative if we should run
2667 ; the var-tracking pass only to discard debug annotations, zero if
2668 ; we're not to run it. When flag_var_tracking == 2 (AUTODETECT_VALUE) it
2669 ; will be set according to optimize, debug_info_level and debug_hooks
2670 ; in process_options ().
2672 Common Report Var(flag_var_tracking) Init(2) PerFunction
2673 Perform variable tracking.
2675 ; Positive if we should track variables at assignments, negative if
2676 ; we should run the var-tracking pass only to discard debug
2677 ; annotations. When flag_var_tracking_assignments ==
2678 ; AUTODETECT_VALUE it will be set according to flag_var_tracking.
2679 fvar-tracking-assignments
2680 Common Report Var(flag_var_tracking_assignments) Init(2) PerFunction
2681 Perform variable tracking by annotating assignments.
2683 ; Nonzero if we should toggle flag_var_tracking_assignments after
2684 ; processing options and computing its default. */
2685 fvar-tracking-assignments-toggle
2686 Common Report Var(flag_var_tracking_assignments_toggle) PerFunction
2687 Toggle -fvar-tracking-assignments.
2689 ; Positive if we should track uninitialized variables, negative if
2690 ; we should run the var-tracking pass only to discard debug
2691 ; annotations. When flag_var_tracking_uninit == AUTODETECT_VALUE it
2692 ; will be set according to flag_var_tracking.
2693 fvar-tracking-uninit
2694 Common Report Var(flag_var_tracking_uninit) PerFunction
2695 Perform variable tracking and also tag variables that are uninitialized.
2697 ; Alias to enable both -ftree-loop-vectorize and -ftree-slp-vectorize.
2699 Common Report Optimization
2700 Enable vectorization on trees.
2702 ftree-vectorizer-verbose=
2703 Common Joined RejectNegative Ignore
2704 Does nothing. Preserved for backward compatibility.
2706 ftree-loop-vectorize
2707 Common Report Var(flag_tree_loop_vectorize) Optimization EnabledBy(ftree-vectorize)
2708 Enable loop vectorization on trees.
2711 Common Report Var(flag_tree_slp_vectorize) Optimization EnabledBy(ftree-vectorize)
2712 Enable basic block vectorization (SLP) on trees.
2715 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_vect_cost_model) Init(VECT_COST_MODEL_DEFAULT) Optimization
2716 Specifies the cost model for vectorization.
2717 -fvect-cost-model=[unlimited|dynamic|cheap] Specifies the cost model for vectorization.
2720 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_simd_cost_model) Init(VECT_COST_MODEL_UNLIMITED) Optimization
2721 -fsimd-cost-model=[unlimited|dynamic|cheap] Specifies the vectorization cost model for code marked with a simd directive.
2724 Name(vect_cost_model) Type(enum vect_cost_model) UnknownError(unknown vectorizer cost model %qs)
2727 Enum(vect_cost_model) String(unlimited) Value(VECT_COST_MODEL_UNLIMITED)
2730 Enum(vect_cost_model) String(dynamic) Value(VECT_COST_MODEL_DYNAMIC)
2733 Enum(vect_cost_model) String(cheap) Value(VECT_COST_MODEL_CHEAP)
2736 Common Alias(fvect-cost-model=,dynamic,unlimited)
2737 Enables the dynamic vectorizer cost model. Preserved for backward compatibility.
2739 ftree-vect-loop-version
2741 Does nothing. Preserved for backward compatibility.
2744 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
2745 Enable copy propagation of scalar-evolution information.
2747 ; -fverbose-asm causes extra commentary information to be produced in
2748 ; the generated assembly code (to make it more readable). This option
2749 ; is generally only of use to those who actually need to read the
2750 ; generated assembly code (perhaps while debugging the compiler itself).
2751 ; -fno-verbose-asm, the default, causes the extra information
2752 ; to not be added and is useful when comparing two assembler files.
2754 Common Report Var(flag_verbose_asm)
2755 Add extra commentary to assembler output.
2758 Common Joined RejectNegative Enum(symbol_visibility) Var(default_visibility) Init(VISIBILITY_DEFAULT)
2759 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility.
2762 Name(symbol_visibility) Type(enum symbol_visibility) UnknownError(unrecognized visibility value %qs)
2765 Enum(symbol_visibility) String(default) Value(VISIBILITY_DEFAULT)
2768 Enum(symbol_visibility) String(internal) Value(VISIBILITY_INTERNAL)
2771 Enum(symbol_visibility) String(hidden) Value(VISIBILITY_HIDDEN)
2774 Enum(symbol_visibility) String(protected) Value(VISIBILITY_PROTECTED)
2777 Common Joined RejectNegative Enum(vtv_priority) Var(flag_vtable_verify) Init(VTV_NO_PRIORITY)
2778 Validate vtable pointers before using them.
2781 Name(vtv_priority) Type(enum vtv_priority) UnknownError(unknown vtable verify initialization priority %qs)
2784 Enum(vtv_priority) String(none) Value(VTV_NO_PRIORITY)
2787 Enum(vtv_priority) String(std) Value(VTV_STANDARD_PRIORITY)
2790 Enum(vtv_priority) String(preinit) Value(VTV_PREINIT_PRIORITY)
2793 Common Var(flag_vtv_counts)
2794 Output vtable verification counters.
2797 Common Var(flag_vtv_debug)
2798 Output vtable verification pointer sets information.
2801 Common Report Var(flag_value_profile_transformations) Optimization
2802 Use expression value profiles in optimizations.
2805 Common Report Var(flag_web) Init(2) Optimization
2806 Construct webs and split unrelated uses of single variable.
2808 ftree-builtin-call-dce
2809 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
2810 Enable conditional dead code elimination for builtin calls.
2813 Common Report Var(flag_whole_program) Init(0)
2814 Perform whole program optimizations.
2817 Common Report Var(flag_wrapv) Optimization
2818 Assume signed arithmetic overflow wraps around.
2820 fzero-initialized-in-bss
2821 Common Report Var(flag_zero_initialized_in_bss) Init(1)
2822 Put zero initialized data in the bss section.
2825 Common Driver JoinedOrMissing
2826 Generate debug information in default format.
2829 Common Driver JoinedOrMissing Negative(gdwarf)
2830 Generate debug information in COFF format.
2833 Common Driver RejectNegative Var(debug_column_info,0) Init(0)
2834 Don't record DW_AT_decl_column and DW_AT_call_column in DWARF.
2837 Common Driver RejectNegative Var(debug_column_info,1)
2838 Record DW_AT_decl_column and DW_AT_call_column in DWARF.
2841 Common Driver JoinedOrMissing Negative(gdwarf-)
2842 Generate debug information in default version of DWARF format.
2845 Common Driver Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
2846 Generate debug information in DWARF v2 (or later) format.
2849 Common Driver JoinedOrMissing
2850 Generate debug information in default extended format.
2853 Common Driver Negative(gpubnames) Var(debug_generate_pub_sections, 0) Init(-1)
2854 Don't generate DWARF pubnames and pubtypes sections.
2857 Common Driver Negative(ggnu-pubnames) Var(debug_generate_pub_sections, 1)
2858 Generate DWARF pubnames and pubtypes sections.
2861 Common Driver Negative(gno-pubnames) Var(debug_generate_pub_sections, 2)
2862 Generate DWARF pubnames and pubtypes sections with GNU extensions.
2864 gno-record-gcc-switches
2865 Common Driver RejectNegative Var(dwarf_record_gcc_switches,0) Init(1)
2866 Don't record gcc command line switches in DWARF DW_AT_producer.
2868 grecord-gcc-switches
2869 Common Driver RejectNegative Var(dwarf_record_gcc_switches,1)
2870 Record gcc command line switches in DWARF DW_AT_producer.
2873 Common Driver RejectNegative Var(dwarf_split_debug_info,0) Init(0)
2874 Don't generate debug information in separate .dwo files.
2877 Common Driver RejectNegative Var(dwarf_split_debug_info,1)
2878 Generate debug information in separate .dwo files.
2881 Common Driver JoinedOrMissing Negative(gstabs+)
2882 Generate debug information in STABS format.
2885 Common Driver JoinedOrMissing Negative(gvms)
2886 Generate debug information in extended STABS format.
2889 Common Driver RejectNegative Var(dwarf_strict,0) Init(0)
2890 Emit DWARF additions beyond selected version.
2893 Common Driver Report RejectNegative Var(dwarf_strict,1)
2894 Don't emit DWARF additions beyond selected version.
2897 Common Driver Report Var(flag_gtoggle)
2898 Toggle debug information generation.
2901 Common Driver JoinedOrMissing Negative(gxcoff)
2902 Generate debug information in VMS format.
2905 Common Driver JoinedOrMissing Negative(gxcoff+)
2906 Generate debug information in XCOFF format.
2909 Common Driver JoinedOrMissing Negative(gcoff)
2910 Generate debug information in extended XCOFF format.
2913 Name(compressed_debug_sections) Type(int)
2915 ; Since -gz= is completely handled in specs, the values aren't used and we
2916 ; assign arbitrary constants.
2918 Enum(compressed_debug_sections) String(none) Value(0)
2921 Enum(compressed_debug_sections) String(zlib) Value(1)
2924 Enum(compressed_debug_sections) String(zlib-gnu) Value(2)
2928 Generate compressed debug sections.
2931 Common Driver Joined Enum(compressed_debug_sections)
2932 -gz=<format> Generate compressed debug sections in format <format>.
2935 Driver Joined Separate
2938 Common Joined Var(plugindir_string) Init(0)
2939 -iplugindir=<dir> Set <dir> to be the default plugin directory.
2942 Common Joined Separate RejectDriver Var(imultiarch) Init(0)
2943 -imultiarch <dir> Set <dir> to be the multiarch include subdirectory.
2946 Driver Joined Separate
2951 no-canonical-prefixes
2964 Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs)
2965 -o <file> Place output into <file>.
2968 Common Var(profile_flag)
2969 Enable function profiling.
2972 Driver Var(pass_exit_codes)
2975 Common Alias(Wpedantic)
2978 Common Var(flag_pedantic_errors)
2979 Like -pedantic but issue them as errors.
2985 Driver Var(use_pipes)
2988 Driver JoinedOrMissing Var(print_file_name)
2990 print-libgcc-file-name
2993 print-multi-directory
2994 Driver Var(print_multi_directory)
2997 Driver Var(print_multi_lib)
2999 print-multi-os-directory
3000 Driver Var(print_multi_os_directory)
3003 Driver Var(print_multiarch)
3006 Driver JoinedOrMissing Var(print_prog_name)
3009 Driver Var(print_search_dirs)
3012 Driver Var(print_sysroot)
3014 print-sysroot-headers-suffix
3015 Driver Var(print_sysroot_headers_suffix)
3018 Common Var(quiet_flag) RejectDriver
3019 Do not display functions compiled or elapsed time.
3037 Driver Var(report_times)
3040 Driver JoinedOrMissing
3043 Driver Joined Separate
3047 ; C option, but driver must not handle as "-u ndef".
3050 Common Driver Var(verbose_flag)
3051 Enable verbose output.
3054 Common Var(version_flag) RejectDriver
3055 Display the compiler's version.
3058 Common Var(inhibit_warnings)
3062 Driver Separate Var(wrapper_string)
3065 Driver Joined Separate
3068 Driver RejectNegative Negative(pie)
3069 Create a shared library.
3075 Driver Separate Alias(specs=)
3088 ; Documented for Fortran, but always accepted by driver.
3095 ; Documented for Go, but always accepted by driver.
3113 Driver RejectNegative Negative(shared)
3114 Don't create a position independent executable.
3117 Driver RejectNegative Negative(no-pie)
3118 Create a position independent executable.
3121 Driver Joined Separate
3124 Common Report Var(flag_ipa_ra) Optimization
3125 Use caller save register across calls if possible.
3127 ; This comment is to ensure we retain the blank line above.