1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003-2019 Free Software Foundation, Inc.
5 ; This file is part of GCC.
7 ; GCC is free software; you can redistribute it and/or modify it under
8 ; the terms of the GNU General Public License as published by the Free
9 ; Software Foundation; either version 3, or (at your option) any later
12 ; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 ; WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 ; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 ; You should have received a copy of the GNU General Public License
18 ; along with GCC; see the file COPYING3. If not see
19 ; <http://www.gnu.org/licenses/>.
21 ; See the GCC internals manual (options.texi) for a description of this file's format.
23 ; Please try to keep this file in ASCII collating order.
37 ; Not used directly to control optimizations, only to save -Ofast
38 ; setting for "optimize" attributes.
42 ; True if this is the lto front end. This is used to disable gimple
43 ; generation and lowering passes that are normally run on the output
44 ; of a front end. These passes must be bypassed for lto since they
45 ; have already been done before the gimple was written.
49 ; This variable is set to non-0 only by LTO front-end. 1 indicates that
50 ; the output produced will be used for incrmeental linking (thus weak symbols
51 ; can still be bound) and 2 indicates that the IL is going to be linked and
52 ; and output to LTO object file.
54 enum incremental_link flag_incremental_link = INCREMENTAL_LINK_NONE
56 ; 0 means straightforward implementation of complex divide acceptable.
57 ; 1 means wide ranges of inputs must work for complex divide.
58 ; 2 means C99-like requirements for complex multiply and divide.
60 int flag_complex_method = 1
62 ; Language specific warning pass for unused results.
64 bool flag_warn_unused_result = false
69 ; Nonzero if we should write GIMPLE bytecode for link-time optimization.
73 ; Nonzero if we should write GIMPLE bytecode for offload compilation.
75 int flag_generate_offload = 0
77 ; Nonzero means we should be saving declaration info into a .X file.
79 int flag_gen_aux_info = 0
81 ; Nonzero if we are compiling code for a shared library, zero for
86 ; These two are really VEC(char_p,heap) *.
89 void *flag_instrument_functions_exclude_functions
92 void *flag_instrument_functions_exclude_files
94 ; Generic structs (e.g. templates not explicitly specialized)
95 ; may not have a compilation unit associated with them, and so
96 ; may need to be treated differently from ordinary structs.
98 ; Structs only handled by reference (indirectly), will also usually
99 ; not need as much debugging information.
102 enum debug_struct_file debug_struct_ordinary[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
105 enum debug_struct_file debug_struct_generic[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
107 ; True if we should exit after parsing options.
109 bool exit_after_options
111 ; Type(s) of debugging information we are producing (if any). See
112 ; flag-types.h for the definitions of the different possible types of
113 ; debugging information.
115 enum debug_info_type write_symbols = NO_DEBUG
117 ; Level of debugging information we are producing. See flag-types.h
118 ; for the definitions of the different possible levels.
120 enum debug_info_levels debug_info_level = DINFO_LEVEL_NONE
122 ; Nonzero means use GNU-only extensions in the generated symbolic
123 ; debugging information. Currently, this only has an effect when
124 ; write_symbols is set to DBX_DEBUG or XCOFF_DEBUG.
126 bool use_gnu_debug_info_extensions
128 ; Original value of maximum field alignment in bytes, specified via
129 ; -fpack-struct=<value>.
131 unsigned int initial_max_fld_align = TARGET_DEFAULT_PACK_STRUCT
133 ; Type of stack check.
135 enum stack_check_type flag_stack_check = NO_STACK_CHECK
137 ; True if stack usage information needs to be computed.
139 bool flag_stack_usage_info = false
141 ; -dA causes debug commentary information to be produced in
142 ; the generated assembly code (to make it more readable). This option
143 ; is generally only of use to those who actually need to read the
144 ; generated assembly code (perhaps while debugging the compiler itself).
145 ; Currently, this switch is only used by dwarf2out.c; however, it is intended
146 ; to be a catchall for printing debug information in the assembler file.
150 ; How many NOP insns to place at each function entry by default
152 HOST_WIDE_INT function_entry_patch_area_size
154 ; And how far the real asm entry point is into this area
156 HOST_WIDE_INT function_entry_patch_area_start
158 ; Balance between GNAT encodings and standard DWARF to emit.
160 enum dwarf_gnat_encodings gnat_encodings = DWARF_GNAT_ENCODINGS_DEFAULT
162 ; -dP causes the rtl to be emitted as a comment in assembly.
164 int flag_dump_rtl_in_asm
166 ; Whether -da was passed (used only in handle_common_deferred_options).
168 bool flag_dump_all_passed
170 ; Other flags saying which kinds of debugging dump have been requested.
173 int rtl_dump_and_exit
176 int flag_print_asm_name
178 ; Name of top-level original source file (what was input to cpp).
179 ; This comes from the #-command at the beginning of the actual input.
180 ; If there isn't any there, then this is the cc1 input file name.
182 const char *main_input_filename
184 ; Pointer to base name in main_input_filename, with directories and a
185 ; single final extension removed, and the length of this base
189 const char *main_input_basename
192 int main_input_baselength
194 ; Which options have been printed by --help.
198 ; Which enums have been printed by --help. 0 = not printed, no
199 ; relevant options seen, 1 = relevant option seen, not yet printed, 2
202 char *help_enum_printed
204 ; The number of columns for --help output.
206 unsigned int help_columns
208 ; Whether this options structure has been through finish_options
210 bool flag_opts_finished
212 ; What the sanitizer should instrument
214 unsigned int flag_sanitize
216 ; What sanitizers should recover from errors
218 unsigned int flag_sanitize_recover = (SANITIZE_UNDEFINED | SANITIZE_UNDEFINED_NONDEFAULT | SANITIZE_KERNEL_ADDRESS) & ~(SANITIZE_UNREACHABLE | SANITIZE_RETURN)
220 ; What the coverage sanitizers should instrument
222 unsigned int flag_sanitize_coverage
224 ; Flag whether a prefix has been added to dump_base_name
226 bool dump_base_name_prefixed = false
228 ; Flag whether HSA generation has been explicitely disabled
230 bool flag_disable_hsa = false
242 Common Driver Joined Undocumented
243 Provide bash completion for options starting with provided string.
246 Driver Alias(coverage)
252 Common Separate Alias(d)
255 Common Joined Alias(d)
258 Common Separate Alias(dumpbase)
261 Common Separate Alias(dumpdir)
264 Driver Separate Alias(e)
267 Driver Joined Alias(e)
270 Common Warning Alias(Wextra)
273 Driver Separate Alias(Xassembler)
276 Driver JoinedOrMissing Alias(Xassembler)
279 Driver Separate Alias(Xlinker)
282 Driver JoinedOrMissing Alias(Xlinker)
285 Driver Separate Alias(u)
288 Driver Joined Alias(u)
291 Common Driver Var(help_flag)
292 Display this information.
295 Common Driver Report Joined
296 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params.
299 Driver Separate Alias(x)
302 Driver Joined Alias(x)
305 Driver Separate Alias(L)
308 Driver Joined Alias(L)
310 -no-canonical-prefixes
311 Driver Alias(no-canonical-prefixes)
313 -no-standard-libraries
314 Driver Alias(nostdlib)
317 Driver Var(no_sysroot_suffix)
326 Common Driver Separate Alias(o) MissingArgError(missing filename after %qs)
329 Common Driver Joined Alias(o) MissingArgError(missing filename after %qs)
332 Driver Alias(pass-exit-codes)
335 Common Alias(Wpedantic)
338 Common Alias(pedantic-errors)
344 Driver Alias(static-pie)
350 Driver Separate Alias(B)
353 Driver JoinedOrMissing Alias(B)
359 Driver Separate Alias(print-file-name=)
362 Driver JoinedOrMissing Alias(print-file-name=)
364 -print-libgcc-file-name
365 Driver Alias(print-libgcc-file-name)
367 -print-multi-directory
368 Driver Alias(print-multi-directory)
371 Driver Alias(print-multi-lib)
373 -print-multi-os-directory
374 Driver Alias(print-multi-os-directory)
377 Driver Alias(print-multiarch)
380 Driver Separate Alias(print-prog-name=)
383 Driver JoinedOrMissing Alias(print-prog-name=)
386 Driver Alias(print-search-dirs)
389 Driver Alias(print-sysroot)
391 -print-sysroot-headers-suffix
392 Driver Alias(print-sysroot-headers-suffix)
398 Driver Alias(save-temps)
404 Driver Separate Alias(specs=)
407 Driver Joined Alias(specs=)
413 Driver Alias(symbolic)
417 Alias for --help=target.
425 ;; The driver used to convert options such as --help into forms such
426 ;; as -fhelp; the following four entries are for compatibility with
427 ;; any direct uses of those (undocumented) -f forms
429 Common Driver Alias(-help)
432 Common Driver Joined Alias(-help=)
435 Common Driver Alias(-target-help)
438 Common Driver Alias(-version)
442 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters.
445 Common Joined Alias(-param)
448 Driver Separate Alias(-sysroot=)
451 Driver JoinedOrMissing
457 Driver Joined Separate
463 Driver Joined Separate
469 Common JoinedOrMissing Optimization
470 -O<number> Set optimization level to <number>.
474 Optimize for space rather than speed.
478 Optimize for speed disregarding exact standards compliance.
482 Optimize for debugging experience rather than speed or size.
494 Driver Joined Separate
500 Driver Joined Separate
521 Common RejectNegative Warning Alias(Wextra)
522 This switch is deprecated; use -Wextra instead.
525 Driver JoinedOrMissing RejectNegative
528 Driver JoinedOrMissing RejectNegative
531 Driver JoinedOrMissing RejectNegative
534 Common Var(warn_aggregate_return) Warning
535 Warn about returning structures, unions or arrays.
537 Waggressive-loop-optimizations
538 Common Var(warn_aggressive_loop_optimizations) Init(1) Warning
539 Warn if a loop with constant number of iterations triggers undefined behavior.
542 Common Var(warn_array_bounds) Warning
543 Warn if an array is accessed out of bounds.
546 Common Joined RejectNegative UInteger Var(warn_array_bounds) Warning IntegerRange(0, 2)
547 Warn if an array is accessed out of bounds.
550 Common Var(warn_attributes) Init(1) Warning
551 Warn about inappropriate attribute usage.
554 Common Alias(Wattribute_alias=, 1, 0) Warning
555 Warn about type safety and similar errors and mismatches in declarations with alias attributes.
558 Common Joined RejectNegative UInteger Var(warn_attribute_alias) Init(1) Warning IntegerRange(0, 2)
559 Warn about type safety and similar errors and mismatches in declarations with alias attributes.
562 Common Var(warn_cannot_profile) Init(1) Warning
563 Warn when profiling instrumentation was requested, but could not be applied to
567 Common Var(warn_cast_align) Warning
568 Warn about pointer casts which increase alignment.
571 Common Var(warn_cast_align,2) Warning
572 Warn about pointer casts which increase alignment.
575 Common Var(warn_cpp) Init(1) Warning
576 Warn when a #warning directive is encountered.
579 Common Var(warn_attribute_warning) Init(1) Warning
580 Warn about uses of __attribute__((warning)) declarations.
583 Common Var(warn_deprecated) Init(1) Warning
584 Warn if a deprecated compiler feature, class, method, or field is used.
586 Wdeprecated-declarations
587 Common Var(warn_deprecated_decl) Init(1) Warning
588 Warn about uses of __attribute__((deprecated)) declarations.
590 Wdisabled-optimization
591 Common Var(warn_disabled_optimization) Warning
592 Warn when an optimization pass is disabled.
595 Common Var(warnings_are_errors)
596 Treat all warnings as errors.
600 Treat specified warning as error.
603 Common Var(extra_warnings) Warning
604 Print extra (possibly unwanted) warnings.
607 Common Var(flag_fatal_errors)
608 Exit on the first error occurred.
611 Common RejectNegative Joined Host_Wide_Int ByteSize Warning Var(warn_frame_larger_than_size) Init(HOST_WIDE_INT_MAX)
612 -Wframe-larger-than=<byte-size> Warn if a function's stack frame requires in excess of <byte-size>.
615 Common Var(warn_free_nonheap_object) Init(1) Warning
616 Warn when attempting to free a non-heap object.
619 Common Var(warn_hsa) Init(1) Warning
620 Warn when a function cannot be expanded to HSAIL.
622 Wimplicit-fallthrough
623 Common Alias(Wimplicit-fallthrough=,3,0) Warning
625 Wimplicit-fallthrough=
626 Common Var(warn_implicit_fallthrough) RejectNegative Joined UInteger Warning IntegerRange(0, 5)
627 Warn when a switch case falls through.
630 Common Var(warn_inline) Warning
631 Warn when an inlined function cannot be inlined.
633 Winvalid-memory-model
634 Common Var(warn_invalid_memory_model) Init(1) Warning
635 Warn when an atomic memory model parameter is known to be outside the valid range.
638 Common RejectNegative Joined Warning Undocumented Alias(Wlarger-than=)
641 Common RejectNegative Joined Host_Wide_Int ByteSize Warning Var(warn_larger_than_size) Init(HOST_WIDE_INT_MAX)
642 -Wlarger-than=<byte-size> Warn if an object's size exceeds <byte-size>.
645 Var(warn_nonnull_compare) Warning
646 Warn if comparing pointer parameter with nonnull attribute with NULL.
649 Common Var(warn_null_dereference) Warning
650 Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior.
652 Wunsafe-loop-optimizations
653 Common Ignore Warning
654 Does nothing. Preserved for backward compatibility.
657 Common Warning Alias(Wsuggest-attribute=noreturn)
660 Common Var(warn_odr_violations) Init(1) Warning
661 Warn about some C++ One Definition Rule violations during link time optimization.
664 Common Var(warn_overflow) Init(1) Warning
665 Warn about overflow in arithmetic expressions.
668 Common Var(warn_lto_type_mismatch) Init(1) Warning
669 During link time optimization warn about mismatched types of global declarations.
672 Common Var(warn_packed) Warning
673 Warn when the packed attribute has no effect on struct layout.
676 Common Var(warn_padded) Warning
677 Warn when padding is required to align structure members.
680 Common Var(pedantic) Init(0) Warning
681 Issue warnings needed for strict compliance to the standard.
684 Common Var(warn_return_local_addr) Init(1) Warning
685 Warn about returning a pointer/reference to a local or temporary variable.
688 Common Var(warn_shadow) Warning
689 Warn when one variable shadows another. Same as -Wshadow=global.
692 Common Warning Alias(Wshadow)
693 Warn when one variable shadows another (globally).
696 Common Var(warn_shadow_local) Warning EnabledBy(Wshadow)
697 Warn when one local variable shadows another local variable or parameter.
700 Common Warning Undocumented Alias(Wshadow=local)
702 Wshadow=compatible-local
703 Common Var(warn_shadow_compatible_local) Warning EnabledBy(Wshadow=local)
704 Warn when one local variable shadows another local variable or parameter of compatible type.
706 Wshadow-compatible-local
707 Common Warning Undocumented Alias(Wshadow=compatible-local)
710 Common Var(warn_stack_protect) Warning
711 Warn when not issuing stack smashing protection for some reason.
714 Common Joined RejectNegative Host_Wide_Int ByteSize Var(warn_stack_usage) Warning Init(HOST_WIDE_INT_MAX)
715 -Wstack-usage=<byte-size> Warn if stack usage might exceed <byte-size>.
719 Warn about code which might break strict aliasing rules.
722 Common Joined RejectNegative UInteger Var(warn_strict_aliasing) Warning
723 Warn about code which might break strict aliasing rules.
727 Warn about optimizations that assume that signed overflow is undefined.
730 Common Joined RejectNegative UInteger Var(warn_strict_overflow) Warning
731 Warn about optimizations that assume that signed overflow is undefined.
733 Wsuggest-attribute=cold
734 Common Var(warn_suggest_attribute_cold) Warning
735 Warn about functions which might be candidates for __attribute__((cold)).
737 Wsuggest-attribute=const
738 Common Var(warn_suggest_attribute_const) Warning
739 Warn about functions which might be candidates for __attribute__((const)).
741 Wsuggest-attribute=pure
742 Common Var(warn_suggest_attribute_pure) Warning
743 Warn about functions which might be candidates for __attribute__((pure)).
745 Wsuggest-attribute=noreturn
746 Common Var(warn_suggest_attribute_noreturn) Warning
747 Warn about functions which might be candidates for __attribute__((noreturn)).
749 Wsuggest-attribute=malloc
750 Common Var(warn_suggest_attribute_malloc) Warning
751 Warn about functions which might be candidates for __attribute__((malloc)).
754 Common Var(warn_suggest_final_types) Warning
755 Warn about C++ polymorphic types where adding final keyword would improve code quality.
757 Wsuggest-final-methods
758 Common Var(warn_suggest_final_methods) Warning
759 Warn about C++ virtual methods where adding final keyword would improve code quality.
762 Common Var(warn_switch_unreachable) Warning Init(1)
763 Warn about statements between switch's controlling expression and the first
767 Common Var(warn_system_headers) Warning
768 Do not suppress warnings from system headers.
771 Common Var(warn_trampolines) Warning
772 Warn whenever a trampoline is generated.
775 Common Var(warn_type_limits) Warning EnabledBy(Wextra)
776 Warn if a comparison is always true or always false due to the limited range of the data type.
779 Common Var(warn_uninitialized) Warning EnabledBy(Wextra)
780 Warn about uninitialized automatic variables.
783 Common Var(warn_maybe_uninitialized) Warning EnabledBy(Wuninitialized)
784 Warn about maybe uninitialized automatic variables.
787 Common Ignore Warning
788 Does nothing. Preserved for backward compatibility.
791 Common Var(warn_unused) Init(0) Warning
792 Enable all -Wunused- warnings.
794 Wunused-but-set-parameter
795 Common Var(warn_unused_but_set_parameter) Warning EnabledBy(Wunused && Wextra)
796 Warn when a function parameter is only set, otherwise unused.
798 Wunused-but-set-variable
799 Common Var(warn_unused_but_set_variable) Warning EnabledBy(Wunused)
800 Warn when a variable is only set, otherwise unused.
803 Common Var(warn_unused_function) Warning EnabledBy(Wunused)
804 Warn when a function is unused.
807 Common Var(warn_unused_label) Warning EnabledBy(Wunused)
808 Warn when a label is unused.
811 Common Var(warn_unused_parameter) Warning EnabledBy(Wunused && Wextra)
812 Warn when a function parameter is unused.
815 Common Var(warn_unused_value) Warning EnabledBy(Wunused)
816 Warn when an expression value is unused.
819 Common Var(warn_unused_variable) Warning EnabledBy(Wunused)
820 Warn when a variable is unused.
823 Common Var(warn_coverage_mismatch) Init(1) Warning
824 Warn in case profiles in -fprofile-use do not match.
827 Common Var(warn_missing_profile) Init(1) Warning
828 Warn in case profiles in -fprofile-use do not exist.
830 Wvector-operation-performance
831 Common Var(warn_vector_operation_performance) Warning
832 Warn when a vector operation is compiled outside the SIMD.
847 Common Separate Var(aux_info_file_name)
848 -aux-info <file> Emit declaration information into <file>.
851 Common Joined Alias(aux-info)
854 Common Separate RejectDriver Var(aux_base_name)
857 Common Separate RejectDriver
867 -d<letters> Enable dumps from specific passes of the compiler.
870 Common Separate Var(dump_base_name)
871 -dumpbase <file> Set the file basename to be used for dumps.
874 Common Separate Var(dump_dir_name)
875 -dumpdir <dir> Set the directory name to be used for dumps.
890 Driver Joined Separate
892 ; This option has historically been passed down to the linker by an
893 ; accident of a %{e*} spec, so ensure it continues to be passed down
894 ; as a single option. The supported option for this purpose is
895 ; -rdynamic. See PR 47390.
899 ; The version of the C++ ABI in use. The following values are allowed:
901 ; 0: The version of the ABI believed most conformant with the C++ ABI
902 ; specification. This ABI may change as bugs are discovered and fixed.
903 ; Therefore, 0 will not necessarily indicate the same ABI in different
906 ; 1: The version of the ABI first used in G++ 3.2. No longer selectable.
908 ; 2: The version of the ABI first used in G++ 3.4, and the default
911 ; 3: The version of the ABI that fixes the missing underscore
912 ; in template non-type arguments of pointer type.
914 ; 4: The version of the ABI that introduces unambiguous mangling of
915 ; vector types. First selectable in G++ 4.5.
917 ; 5: The version of the ABI that ignores attribute const/noreturn
918 ; in function pointer mangling, and corrects mangling of decltype and
919 ; function parameters used in other parameters and the return type.
920 ; First selectable in G++ 4.6.
922 ; 6: The version of the ABI that doesn't promote scoped enums to int and
923 ; changes the mangling of template argument packs, const/static_cast,
924 ; prefix ++ and --, and a class scope function used as a template
926 ; First selectable in G++ 4.7.
928 ; 7: The version of the ABI that treats nullptr_t as a builtin type and
929 ; corrects the mangling of lambdas in default argument scope.
930 ; First selectable in G++ 4.8.
932 ; 8: The version of the ABI that corrects the substitution behavior of
933 ; function types with function-cv-qualifiers.
934 ; First selectable in G++ 4.9 and default in G++ 5.
936 ; 9: The version of the ABI that corrects the alignment of nullptr_t.
937 ; First selectable and default in G++ 5.2.
939 ; 10: The version of the ABI that mangles attributes that affect type
940 ; identity, such as ia32 calling convention attributes (stdcall, etc.)
941 ; Default in G++ 6 (set in c_common_post_options).
943 ; 11: The version of the ABI that corrects mangling of sizeof... expressions
944 ; and introduces new inheriting constructor handling.
947 ; 12: Corrects the calling convention for classes with only deleted copy/move
948 ; constructors and changes passing/returning of empty records.
949 ; Default in G++ 8.1.
951 ; 13: Fixes the accidental change in 12 to the calling convention for classes
952 ; with deleted copy constructor and trivial move constructor.
953 ; Default in G++ 8.2.
955 ; Additional positive integers will be assigned as new versions of
956 ; the ABI become the default version of the ABI.
958 Common Joined RejectNegative UInteger Var(flag_abi_version) Init(0)
959 The version of the C++ ABI in use.
961 faggressive-loop-optimizations
962 Common Report Var(flag_aggressive_loop_optimizations) Optimization Init(1)
963 Aggressively optimize loops using language constraints.
966 Common Report Var(flag_align_functions) Optimization
967 Align the start of functions.
970 Common RejectNegative Joined Var(str_align_functions) Optimization
972 flimit-function-alignment
973 Common Report Var(flag_limit_function_alignment) Optimization Init(0)
976 Common Report Var(flag_align_jumps) Optimization
977 Align labels which are only reached by jumping.
980 Common RejectNegative Joined Var(str_align_jumps) Optimization
983 Common Report Var(flag_align_labels) Optimization
987 Common RejectNegative Joined Var(str_align_labels) Optimization
990 Common Report Var(flag_align_loops) Optimization
991 Align the start of loops.
994 Common RejectNegative Joined Var(str_align_loops) Optimization
996 fallow-store-data-races
997 Common Report Var(flag_store_data_races) Optimization
998 Allow the compiler to introduce new data races on stores.
1002 Does nothing. Preserved for backward compatibility.
1006 Does nothing. Preserved for backward compatibility.
1008 fargument-noalias-global
1010 Does nothing. Preserved for backward compatibility.
1012 fargument-noalias-anything
1014 Does nothing. Preserved for backward compatibility.
1017 Common Driver Report Joined
1018 Select what to sanitize.
1021 Common Report Joined
1022 Select type of coverage sanitization.
1024 fasan-shadow-offset=
1025 Common Joined RejectNegative Var(common_deferred_options) Defer
1026 -fasan-shadow-offset=<number> Use custom shadow memory offset.
1029 Common Joined RejectNegative Var(common_deferred_options) Defer
1030 -fsanitize-sections=<sec1,sec2,...> Sanitize global variables
1031 in user-defined sections.
1034 Common Report Joined
1035 After diagnosing undefined behavior attempt to continue execution.
1039 This switch is deprecated; use -fsanitize-recover= instead.
1041 fsanitize-address-use-after-scope
1042 Common Driver Report Var(flag_sanitize_address_use_after_scope) Init(0)
1044 fsanitize-undefined-trap-on-error
1045 Common Driver Report Var(flag_sanitize_undefined_trap_on_error) Init(0)
1046 Use trap instead of a library function for undefined behavior sanitization.
1048 fasynchronous-unwind-tables
1049 Common Report Var(flag_asynchronous_unwind_tables) Optimization
1050 Generate unwind tables that are exact at each instruction boundary.
1053 Common Report Var(flag_auto_inc_dec) Init(1) Optimization
1054 Generate auto-inc/dec instructions.
1057 Common Report Var(flag_auto_profile)
1058 Use sample profile information for call graph node weights. The default
1059 profile file is fbdata.afdo in 'pwd'.
1062 Common Joined RejectNegative Var(auto_profile_file)
1063 Use sample profile information for call graph node weights. The profile
1064 file is specified in the argument.
1066 ; -fcheck-bounds causes gcc to generate array bounds checks.
1067 ; For C, C++ and ObjC: defaults off.
1068 ; For Java: defaults to on.
1069 ; For Fortran: defaults to off.
1071 Common Report Var(flag_bounds_check)
1072 Generate code to check bounds before indexing arrays.
1075 Common Report Var(flag_branch_on_count_reg) Optimization
1076 Replace add, compare, branch with branch on count register.
1078 fbranch-probabilities
1079 Common Report Var(flag_branch_probabilities) Optimization
1080 Use profiling information for branch probabilities.
1082 fbranch-target-load-optimize
1084 Does nothing. Preserved for backward compatibility.
1086 fbranch-target-load-optimize2
1088 Does nothing. Preserved for backward compatibility.
1092 Does nothing. Preserved for backward compatibility.
1095 Common Joined RejectNegative Var(common_deferred_options) Defer
1096 -fcall-saved-<register> Mark <register> as being preserved across functions.
1099 Common Joined RejectNegative Var(common_deferred_options) Defer
1100 -fcall-used-<register> Mark <register> as being corrupted by function calls.
1102 ; Nonzero for -fcaller-saves: allocate values in regs that need to
1103 ; be saved across function calls, if that produces overall better code.
1104 ; Optional now, so people can test it.
1106 Common Report Var(flag_caller_saves) Optimization
1107 Save registers around function calls.
1111 This switch is deprecated; do not use.
1114 Common Var(flag_check_new)
1115 Check the return value of new in C++.
1118 Common Var(flag_checking) Init(CHECKING_P ? ENABLE_EXTRA_CHECKING ? 2 : 1 : 0)
1119 Perform internal consistency checkings.
1122 Common Joined RejectNegative UInteger Var(flag_checking)
1123 Perform internal consistency checkings.
1126 Common Report Var(flag_code_hoisting) Optimization
1127 Enable code hoisting.
1129 fcombine-stack-adjustments
1130 Common Report Var(flag_combine_stack_adjustments) Optimization
1131 Looks for opportunities to reduce stack adjustments and stack references.
1134 Common Report Var(flag_no_common,0)
1135 Do not put uninitialized globals in the common section.
1139 ; Converted by the driver to -fcompare-debug= options.
1142 Common Driver JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
1143 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump.
1145 fcompare-debug-second
1146 Common Driver RejectNegative Var(flag_compare_debug)
1147 Run only the second compilation of -fcompare-debug.
1150 Common Report Var(flag_compare_elim_after_reload) Optimization
1151 Perform comparison elimination after register allocation has finished.
1154 Common Var(flag_conserve_stack) Optimization
1155 Do not perform optimizations increasing noticeably stack usage.
1158 Common Report Var(flag_cprop_registers) Optimization
1159 Perform a register copy-propagation optimization pass.
1162 Common Report Var(flag_crossjumping) Optimization
1163 Perform cross-jumping optimization.
1166 Common Report Var(flag_cse_follow_jumps) Optimization
1167 When running CSE, follow jumps to their targets.
1171 Does nothing. Preserved for backward compatibility.
1174 Common Report Var(flag_cx_limited_range) Optimization SetByCombined
1175 Omit range reduction step when performing complex division.
1178 Common Report Var(flag_cx_fortran_rules) Optimization
1179 Complex multiplication and division follow Fortran rules.
1182 Common Report Var(flag_data_sections)
1183 Place data items into their own section.
1186 Common Report Var(common_deferred_options) Defer
1187 List all available debugging counters with their limits and counts.
1190 Common RejectNegative Joined Var(common_deferred_options) Defer
1191 -fdbg-cnt=<counter>[:<lower_limit>]:<upper_limit>[,<counter>:...] Set the debug counter limit.
1194 Common Joined RejectNegative Var(common_deferred_options) Defer
1195 -fdebug-prefix-map=<old>=<new> Map one directory name to another in debug information.
1198 Common Joined RejectNegative Var(common_deferred_options) Defer
1199 -ffile-prefix-map=<old>=<new> Map one directory name to another in compilation result.
1201 fdebug-types-section
1202 Common Report Var(flag_debug_types_section) Init(0)
1203 Output .debug_types section when using DWARF v4 debuginfo.
1205 ; Nonzero for -fdefer-pop: don't pop args after each function call
1206 ; instead save them up to pop many calls' args with one insns.
1208 Common Report Var(flag_defer_pop) Optimization
1209 Defer popping functions args from stack until later.
1212 Common Report Var(flag_delayed_branch) Optimization
1213 Attempt to fill delay slots of branch instructions.
1215 fdelete-dead-exceptions
1216 Common Report Var(flag_delete_dead_exceptions) Init(0) Optimization
1217 Delete dead instructions that may throw exceptions.
1219 fdelete-null-pointer-checks
1220 Common Report Var(flag_delete_null_pointer_checks) Init(-1) Optimization
1221 Delete useless null pointer checks.
1223 fdevirtualize-at-ltrans
1224 Common Report Var(flag_ltrans_devirtualize)
1225 Stream extra data to support more aggressive devirtualization in LTO local transformation mode.
1227 fdevirtualize-speculatively
1228 Common Report Var(flag_devirtualize_speculatively) Optimization
1229 Perform speculative devirtualization.
1232 Common Report Var(flag_devirtualize) Optimization
1233 Try to convert virtual calls to direct ones.
1235 fdiagnostics-show-location=
1236 Common Joined RejectNegative Enum(diagnostic_prefixing_rule)
1237 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics.
1239 ; Required for these enum values.
1244 Name(diagnostic_prefixing_rule) Type(int)
1247 Enum(diagnostic_prefixing_rule) String(once) Value(DIAGNOSTICS_SHOW_PREFIX_ONCE)
1250 Enum(diagnostic_prefixing_rule) String(every-line) Value(DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE)
1252 fdiagnostics-show-caret
1253 Common Var(flag_diagnostics_show_caret) Init(1)
1254 Show the source line with a caret indicating the column.
1256 fdiagnostics-show-labels
1257 Common Var(flag_diagnostics_show_labels) Init(1)
1258 Show labels annotating ranges of source code when showing source.
1260 fdiagnostics-show-line-numbers
1261 Common Var(flag_diagnostics_show_line_numbers) Init(1)
1262 Show line numbers in the left margin when showing source.
1265 Common Alias(fdiagnostics-color=,always,never)
1269 Driver Common Joined RejectNegative Var(flag_diagnostics_show_color) Enum(diagnostic_color_rule) Init(DIAGNOSTICS_COLOR_NO)
1270 -fdiagnostics-color=[never|always|auto] Colorize diagnostics.
1272 ; Required for these enum values.
1277 Name(diagnostic_color_rule) Type(int)
1280 Enum(diagnostic_color_rule) String(never) Value(DIAGNOSTICS_COLOR_NO)
1283 Enum(diagnostic_color_rule) String(always) Value(DIAGNOSTICS_COLOR_YES)
1286 Enum(diagnostic_color_rule) String(auto) Value(DIAGNOSTICS_COLOR_AUTO)
1289 Driver Common Joined RejectNegative Var(flag_diagnostics_show_urls) Enum(diagnostic_url_rule) Init(DIAGNOSTICS_URL_AUTO)
1290 -fdiagnostics-urls=[never|always|auto] Embed URLs in diagnostics.
1292 ; Required for these enum values.
1297 Name(diagnostic_url_rule) Type(int)
1300 Enum(diagnostic_url_rule) String(never) Value(DIAGNOSTICS_URL_NO)
1303 Enum(diagnostic_url_rule) String(always) Value(DIAGNOSTICS_URL_YES)
1306 Enum(diagnostic_url_rule) String(auto) Value(DIAGNOSTICS_URL_AUTO)
1308 fdiagnostics-format=
1309 Common Joined RejectNegative Enum(diagnostics_output_format)
1310 -fdiagnostics-format=[text|json] Select output format.
1312 ; Required for these enum values.
1317 Name(diagnostics_output_format) Type(int)
1320 Enum(diagnostics_output_format) String(text) Value(DIAGNOSTICS_OUTPUT_FORMAT_TEXT)
1323 Enum(diagnostics_output_format) String(json) Value(DIAGNOSTICS_OUTPUT_FORMAT_JSON)
1325 fdiagnostics-parseable-fixits
1326 Common Var(flag_diagnostics_parseable_fixits)
1327 Print fix-it hints in machine-readable form.
1329 fdiagnostics-generate-patch
1330 Common Var(flag_diagnostics_generate_patch)
1331 Print fix-it hints to stderr in unified diff format.
1333 fdiagnostics-show-option
1334 Common Var(flag_diagnostics_show_option) Init(1)
1335 Amend appropriate diagnostic messages with the command line option that controls them.
1337 fdiagnostics-minimum-margin-width=
1338 Common Joined UInteger Var(diagnostics_minimum_margin_width) Init(6)
1339 Set minimum width of left margin of source code when showing source.
1342 Common Joined RejectNegative Var(common_deferred_options) Defer
1343 -fdisable-[tree|rtl|ipa]-<pass>=range1+range2 disables an optimization pass.
1346 Common Joined RejectNegative Var(common_deferred_options) Defer
1347 -fenable-[tree|rtl|ipa]-<pass>=range1+range2 enables an optimization pass.
1350 Common Joined RejectNegative Var(common_deferred_options) Defer
1351 -fdump-<type> Dump various compiler internals to a file.
1354 Driver RejectNegative
1357 Common RejectNegative Joined Var(flag_dump_final_insns)
1358 -fdump-final-insns=filename Dump to filename the insns at the end of translation.
1361 Common RejectNegative Joined Var(flag_dump_go_spec)
1362 -fdump-go-spec=filename Write all declarations to file as Go code.
1365 Common Report Var(flag_dump_noaddr)
1366 Suppress output of addresses in debugging dumps.
1369 Common Driver Var(flag_report_bug)
1370 Collect and dump debug information into temporary file if ICE in C/C++
1373 fdump-internal-locations
1374 Common Var(flag_dump_locations) Init(0)
1375 Dump detailed information on GCC's internal representation of source code locations.
1378 Common Var(flag_dump_passes) Init(0)
1379 Dump optimization passes.
1382 Common Report Var(flag_dump_unnumbered)
1383 Suppress output of instruction numbers, line number notes and addresses in debugging dumps.
1385 fdump-unnumbered-links
1386 Common Report Var(flag_dump_unnumbered_links)
1387 Suppress output of previous and next insn numbers in debugging dumps.
1390 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
1391 Enable CFI tables via GAS assembler directives.
1394 Common Report Var(flag_early_inlining) Init(1) Optimization
1395 Perform early inlining.
1397 feliminate-dwarf2-dups
1399 Does nothing. Preserved for backward compatibility.
1402 Common Report Var(flag_ipa_sra) Init(0) Optimization
1403 Perform interprocedural reduction of aggregates.
1405 feliminate-unused-debug-symbols
1406 Common Report Var(flag_debug_only_used_symbols) Init(1)
1407 Perform unused symbol elimination in debug info.
1409 feliminate-unused-debug-types
1410 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
1411 Perform unused type elimination in debug info.
1413 femit-class-debug-always
1414 Common Report Var(flag_emit_class_debug_always) Init(0)
1415 Do not suppress C++ class debug information.
1418 Common Report Var(flag_exceptions) Optimization
1419 Enable exception handling.
1421 fexpensive-optimizations
1422 Common Report Var(flag_expensive_optimizations) Optimization
1423 Perform a number of minor, expensive optimizations.
1426 Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision) Init(EXCESS_PRECISION_DEFAULT) Optimization SetByCombined
1427 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision.
1430 Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess precision style %qs)
1433 Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)
1436 Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
1438 ; Whether we permit the extended set of values for FLT_EVAL_METHOD
1439 ; introduced in ISO/IEC TS 18661-3, or limit ourselves to those in C99/C11.
1440 fpermitted-flt-eval-methods=
1441 Common Joined RejectNegative Enum(permitted_flt_eval_methods) Var(flag_permitted_flt_eval_methods) Init(PERMITTED_FLT_EVAL_METHODS_DEFAULT)
1442 -fpermitted-flt-eval-methods=[c11|ts-18661] Specify which values of FLT_EVAL_METHOD are permitted.
1445 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)
1448 Enum(permitted_flt_eval_methods) String(c11) Value(PERMITTED_FLT_EVAL_METHODS_C11)
1451 Enum(permitted_flt_eval_methods) String(ts-18661-3) Value(PERMITTED_FLT_EVAL_METHODS_TS_18661)
1457 Common Var(flag_fat_lto_objects)
1458 Output lto objects containing both the intermediate language and binary output.
1461 Common Report Var(flag_finite_math_only) Optimization SetByCombined
1462 Assume no NaNs or infinities are generated.
1465 Common Report Var(flag_finite_loops) Optimization
1466 Assume that loops with an exit will terminate and not loop indefinitely.
1469 Common Joined RejectNegative Var(common_deferred_options) Defer
1470 -ffixed-<register> Mark <register> as being unavailable to the compiler.
1473 Common Report Var(flag_float_store) Optimization
1474 Don't allocate floats and doubles in extended-precision registers.
1478 Does nothing. Preserved for backward compatibility.
1481 Common Report Var(flag_forward_propagate) Optimization
1482 Perform a forward propagation pass on RTL.
1485 Common Joined RejectNegative Enum(fp_contract_mode) Var(flag_fp_contract_mode) Init(FP_CONTRACT_FAST) Optimization
1486 -ffp-contract=[off|on|fast] Perform floating-point expression contraction.
1489 Name(fp_contract_mode) Type(enum fp_contract_mode) UnknownError(unknown floating point contraction style %qs)
1492 Enum(fp_contract_mode) String(off) Value(FP_CONTRACT_OFF)
1494 ; Not implemented, fall back to conservative FP_CONTRACT_OFF.
1496 Enum(fp_contract_mode) String(on) Value(FP_CONTRACT_OFF)
1499 Enum(fp_contract_mode) String(fast) Value(FP_CONTRACT_FAST)
1501 ffp-int-builtin-inexact
1502 Common Report Var(flag_fp_int_builtin_inexact) Init(1) Optimization
1503 Allow built-in functions ceil, floor, round, trunc to raise \"inexact\" exceptions.
1505 ; Nonzero means don't put addresses of constant functions in registers.
1506 ; Used for compiling the Unix kernel, where strange substitutions are
1507 ; done on the assembly output.
1509 Common Report Var(flag_no_function_cse,0) Optimization
1510 Allow function addresses to be held in registers.
1513 Common Report Var(flag_function_sections)
1514 Place each function into its own section.
1517 Common Report Var(flag_gcse) Optimization
1518 Perform global common subexpression elimination.
1521 Common Report Var(flag_gcse_lm) Init(1) Optimization
1522 Perform enhanced load motion during global common subexpression elimination.
1525 Common Report Var(flag_gcse_sm) Init(0) Optimization
1526 Perform store motion after global common subexpression elimination.
1529 Common Report Var(flag_gcse_las) Init(0) Optimization
1530 Perform redundant load after store elimination in global common subexpression
1534 Common Report Var(flag_gcse_after_reload) Optimization
1535 Perform global common subexpression elimination after register allocation has
1539 Name(dwarf_gnat_encodings) Type(int)
1542 Enum(dwarf_gnat_encodings) String(all) Value(DWARF_GNAT_ENCODINGS_ALL)
1545 Enum(dwarf_gnat_encodings) String(gdb) Value(DWARF_GNAT_ENCODINGS_GDB)
1548 Enum(dwarf_gnat_encodings) String(minimal) Value(DWARF_GNAT_ENCODINGS_MINIMAL)
1551 Common Enum(dwarf_gnat_encodings) Joined RejectNegative Report Undocumented Var(gnat_encodings)
1552 -fgnat-encodings=[all|gdb|minimal] Select the balance between GNAT encodings and standard DWARF emitted in the debug information.
1554 ; This option is not documented yet as its semantics will change.
1556 Common Report Var(flag_graphite) Optimization
1557 Enable in and out of Graphite representation.
1560 Common Report Var(flag_graphite_identity) Optimization
1561 Enable Graphite Identity transformation.
1563 fhoist-adjacent-loads
1564 Common Report Var(flag_hoist_adjacent_loads) Optimization
1565 Enable hoisting adjacent loads to encourage generating conditional move
1569 Common Undocumented Report Var(flag_keep_gc_roots_live) Optimization
1570 ; Always keep a pointer to a live memory block
1572 floop-parallelize-all
1573 Common Report Var(flag_loop_parallelize_all) Optimization
1574 Mark all loops as parallel.
1577 Common Alias(floop-nest-optimize)
1578 Enable loop nest transforms. Same as -floop-nest-optimize.
1581 Common Report Var(flag_loop_interchange) Optimization
1582 Enable loop interchange on trees.
1585 Common Alias(floop-nest-optimize)
1586 Enable loop nest transforms. Same as -floop-nest-optimize.
1588 floop-unroll-and-jam
1589 Common Report Var(flag_unroll_jam) Optimization
1590 Perform unroll-and-jam on loops.
1593 Common Report Var(flag_tm)
1594 Enable support for GNU transactional memory.
1597 Common Report Var(flag_gnu_unique) Init(1)
1598 Use STB_GNU_UNIQUE if supported by the assembler.
1602 Does nothing. Preserved for backward compatibility.
1605 Common Report Var(flag_loop_nest_optimize) Optimization
1606 Enable the loop nest optimizer.
1608 fstrict-volatile-bitfields
1609 Common Report Var(flag_strict_volatile_bitfields) Init(-1) Optimization
1610 Force bitfield accesses to match their type width.
1613 Common Report Var(flag_store_merging) Optimization
1614 Merge adjacent stores.
1616 fguess-branch-probability
1617 Common Report Var(flag_guess_branch_prob) Optimization
1618 Enable guessing of branch probabilities.
1620 ; Nonzero means ignore `#ident' directives. 0 means handle them.
1621 ; Generate position-independent code for executables if possible
1622 ; On SVR4 targets, it also controls whether or not to emit a
1623 ; string identifying the compiler.
1625 Common Report Var(flag_no_ident,0)
1626 Process #ident directives.
1629 Common Report Var(flag_if_conversion) Optimization
1630 Perform conversion of conditional jumps to branchless equivalents.
1633 Common Report Var(flag_if_conversion2) Optimization
1634 Perform conversion of conditional jumps to conditional execution.
1637 Common Joined RejectNegative Enum(stack_reuse_level) Var(flag_stack_reuse) Init(SR_ALL) Optimization
1638 -fstack-reuse=[all|named_vars|none] Set stack reuse level for local variables.
1641 Name(stack_reuse_level) Type(enum stack_reuse_level) UnknownError(unknown Stack Reuse Level %qs)
1644 Enum(stack_reuse_level) String(all) Value(SR_ALL)
1647 Enum(stack_reuse_level) String(named_vars) Value(SR_NAMED_VARS)
1650 Enum(stack_reuse_level) String(none) Value(SR_NONE)
1652 ftree-loop-if-convert
1653 Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
1654 Convert conditional jumps in innermost loops to branchless equivalents.
1656 ftree-loop-if-convert-stores
1658 Does nothing. Preserved for backward compatibility.
1660 ; -finhibit-size-directive inhibits output of .size for ELF.
1661 ; This is used only for compiling crtstuff.c,
1662 ; and it may be extended to other effects
1663 ; needed for crtstuff.c on other systems.
1664 finhibit-size-directive
1665 Common Report Var(flag_inhibit_size_directive)
1666 Do not generate .size directives.
1669 Common Report Var(flag_indirect_inlining) Optimization
1670 Perform indirect inlining.
1672 ; General flag to enable inlining. Specifying -fno-inline will disable
1673 ; all inlining apart from always-inline functions.
1675 Common Report Var(flag_no_inline,0) Init(0) Optimization
1676 Enable inlining of function declared \"inline\", disabling disables all inlining.
1678 finline-small-functions
1679 Common Report Var(flag_inline_small_functions) Optimization
1680 Integrate functions into their callers when code size is known not to grow.
1683 Common Report Var(flag_inline_functions) Optimization
1684 Integrate functions not declared \"inline\" into their callers when profitable.
1686 finline-functions-called-once
1687 Common Report Var(flag_inline_functions_called_once) Optimization
1688 Integrate functions only required by their single caller.
1691 Common RejectNegative Joined Alias(finline-limit=)
1694 Common RejectNegative Joined UInteger
1695 -finline-limit=<number> Limit the size of inlined functions to <number>.
1698 Common Report Var(flag_inline_atomics) Init(1) Optimization
1699 Inline __atomic operations when a lock free instruction sequence is available.
1702 Common RejectNegative Alias(fcf-protection=,full)
1705 Common Report Joined RejectNegative Enum(cf_protection_level) Var(flag_cf_protection) Init(CF_NONE)
1706 -fcf-protection=[full|branch|return|none] Instrument functions with checks to verify jump/call/return control-flow transfer
1707 instructions have valid targets.
1710 Name(cf_protection_level) Type(enum cf_protection_level) UnknownError(unknown Control-Flow Protection Level %qs)
1713 Enum(cf_protection_level) String(full) Value(CF_FULL)
1716 Enum(cf_protection_level) String(branch) Value(CF_BRANCH)
1719 Enum(cf_protection_level) String(return) Value(CF_RETURN)
1722 Enum(cf_protection_level) String(none) Value(CF_NONE)
1724 finstrument-functions
1725 Common Report Var(flag_instrument_function_entry_exit)
1726 Instrument function entry and exit with profiling calls.
1728 finstrument-functions-exclude-function-list=
1729 Common RejectNegative Joined
1730 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions.
1732 finstrument-functions-exclude-file-list=
1733 Common RejectNegative Joined
1734 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files.
1737 Common Report Var(flag_ipa_cp) Optimization
1738 Perform interprocedural constant propagation.
1741 Common Report Var(flag_ipa_cp_clone) Optimization
1742 Perform cloning to make Interprocedural constant propagation stronger.
1746 Does nothing. Preserved for backward compatibility.
1749 Common Report Var(flag_ipa_bit_cp) Optimization
1750 Perform interprocedural bitwise constant propagation.
1753 Common Report Var(flag_ipa_profile) Init(0) Optimization
1754 Perform interprocedural profile propagation.
1757 Common Report Var(flag_ipa_pta) Init(0) Optimization
1758 Perform interprocedural points-to analysis.
1761 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
1762 Discover pure and const functions.
1765 Common Report Var(flag_ipa_icf) Optimization
1766 Perform Identical Code Folding for functions and read-only variables.
1769 Common Report Var(flag_ipa_icf_functions) Optimization
1770 Perform Identical Code Folding for functions.
1773 Common Report Var(flag_ipa_icf_variables) Optimization
1774 Perform Identical Code Folding for variables.
1777 Common Report Var(flag_ipa_reference) Init(0) Optimization
1778 Discover read-only and non addressable static variables.
1780 fipa-reference-addressable
1781 Common Report Var(flag_ipa_reference_addressable) Init(0) Optimization
1782 Discover read-only, write-only and non-addressable static variables.
1784 fipa-stack-alignment
1785 Common Report Var(flag_ipa_stack_alignment) Init(1) Optimization
1786 Reduce stack alignment on call sites if possible.
1790 Does nothing. Preserved for backward compatibility.
1794 Does nothing. Preserved for backward compatibility.
1797 Common Report Var(flag_ipa_vrp) Optimization
1798 Perform IPA Value Range Propagation.
1801 Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization
1802 -fira-algorithm=[CB|priority] Set the used IRA algorithm.
1805 Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)
1808 Enum(ira_algorithm) String(CB) Value(IRA_ALGORITHM_CB)
1811 Enum(ira_algorithm) String(priority) Value(IRA_ALGORITHM_PRIORITY)
1814 Common Joined RejectNegative Enum(ira_region) Var(flag_ira_region) Init(IRA_REGION_AUTODETECT) Optimization
1815 -fira-region=[one|all|mixed] Set regions for IRA.
1818 Name(ira_region) Type(enum ira_region) UnknownError(unknown IRA region %qs)
1821 Enum(ira_region) String(one) Value(IRA_REGION_ONE)
1824 Enum(ira_region) String(all) Value(IRA_REGION_ALL)
1827 Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)
1830 Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
1831 Use IRA based register pressure calculation
1832 in RTL hoist optimizations.
1835 Common Report Var(flag_ira_loop_pressure) Optimization
1836 Use IRA based register pressure calculation
1837 in RTL loop optimizations.
1839 fira-share-save-slots
1840 Common Report Var(flag_ira_share_save_slots) Init(1) Optimization
1841 Share slots for saving different hard registers.
1843 fira-share-spill-slots
1844 Common Report Var(flag_ira_share_spill_slots) Init(1) Optimization
1845 Share stack slots for spilled pseudo-registers.
1848 Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
1849 -fira-verbose=<number> Control IRA's level of diagnostic messages.
1852 Common Report Var(flag_ivopts) Init(1) Optimization
1853 Optimize induction variables on trees.
1856 Common Var(flag_jump_tables) Init(1) Optimization
1857 Use jump tables for sufficiently large switch statements.
1859 fkeep-inline-functions
1860 Common Report Var(flag_keep_inline_functions)
1861 Generate code for functions even if they are fully inlined.
1863 fkeep-static-functions
1864 Common Report Var(flag_keep_static_functions)
1865 Generate code for static functions even if they are never called.
1868 Common Report Var(flag_keep_static_consts) Init(1)
1869 Emit static const variables even if they are not used.
1872 Common Report Var(flag_leading_underscore) Init(-1)
1873 Give external symbols a leading underscore.
1877 Does nothing. Preserved for backward compatibility.
1880 Common Report Var(flag_lra_remat) Optimization
1881 Do CFG-sensitive rematerialization in LRA.
1885 Enable link-time optimization.
1888 Common RejectNegative Joined Var(flag_lto)
1889 Link-time optimization with number of parallel jobs or jobserver.
1892 Name(lto_partition_model) Type(enum lto_partition_model) UnknownError(unknown LTO partitioning model %qs)
1895 Enum(lto_partition_model) String(none) Value(LTO_PARTITION_NONE)
1898 Enum(lto_partition_model) String(one) Value(LTO_PARTITION_ONE)
1901 Enum(lto_partition_model) String(balanced) Value(LTO_PARTITION_BALANCED)
1904 Enum(lto_partition_model) String(1to1) Value(LTO_PARTITION_1TO1)
1907 Enum(lto_partition_model) String(max) Value(LTO_PARTITION_MAX)
1910 Common Joined RejectNegative Enum(lto_partition_model) Var(flag_lto_partition) Init(LTO_PARTITION_BALANCED)
1911 Specify the algorithm to partition symbols and vars at linktime.
1913 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
1914 flto-compression-level=
1915 Common Joined RejectNegative UInteger Var(flag_lto_compression_level) Init(-1) IntegerRange(0, 19)
1916 -flto-compression-level=<number> Use zlib/zstd compression level <number> for IL.
1918 flto-odr-type-merging
1920 Does nothing. Preserved for backward compatibility.
1923 Common Report Var(flag_lto_report) Init(0)
1924 Report various link-time optimization statistics.
1927 Common Report Var(flag_lto_report_wpa) Init(0)
1928 Report various link-time optimization statistics for WPA only.
1931 Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
1932 Set errno after built-in math functions.
1935 Common Joined RejectNegative UInteger Var(flag_max_errors)
1936 -fmax-errors=<number> Maximum number of errors to report.
1939 Common Report Var(mem_report)
1940 Report on permanent memory allocation.
1943 Common Report Var(mem_report_wpa)
1944 Report on permanent memory allocation in WPA only.
1946 ; This will attempt to merge constant section constants, if 1 only
1947 ; string constants and constants from constant pool, if 2 also constant
1949 fmerge-all-constants
1950 Common Report Var(flag_merge_constants,2) Init(1)
1951 Attempt to merge identical constants and constant variables.
1954 Common Report Var(flag_merge_constants,1)
1955 Attempt to merge identical constants across compilation units.
1957 fmerge-debug-strings
1958 Common Report Var(flag_merge_debug_strings) Init(1)
1959 Attempt to merge identical debug strings across compilation units.
1962 Common RejectNegative Joined UInteger
1963 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping.
1966 Common Report Var(flag_modulo_sched) Optimization
1967 Perform SMS based modulo scheduling before the first scheduling pass.
1969 fmodulo-sched-allow-regmoves
1970 Common Report Var(flag_modulo_sched_allow_regmoves) Optimization
1971 Perform SMS based modulo scheduling with register moves allowed.
1973 fmove-loop-invariants
1974 Common Report Var(flag_move_loop_invariants) Optimization
1975 Move loop invariant computations out of loops.
1978 Common Var(flag_dce) Init(1) Optimization
1979 Use the RTL dead code elimination pass.
1982 Common Var(flag_dse) Init(0) Optimization
1983 Use the RTL dead store elimination pass.
1985 freschedule-modulo-scheduled-loops
1986 Common Report Var(flag_resched_modulo_sched) Optimization
1987 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling.
1989 fnon-call-exceptions
1990 Common Report Var(flag_non_call_exceptions) Optimization
1991 Support synchronous non-call exceptions.
1994 Common Driver Joined MissingArgError(options or targets missing after %qs)
1995 -foffload=<targets>=<options> Specify offloading targets and options for them.
1998 Common Joined RejectNegative Enum(offload_abi) Var(flag_offload_abi) Init(OFFLOAD_ABI_UNSET)
1999 -foffload-abi=[lp64|ilp32] Set the ABI to use in an offload compiler.
2002 Name(offload_abi) Type(enum offload_abi) UnknownError(unknown offload ABI %qs)
2005 Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
2008 Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
2011 Common Report Var(flag_omit_frame_pointer) Optimization
2012 When possible do not generate stack frames.
2015 Common Report Var(flag_opt_info) Optimization
2016 Enable all optimization info dumps on stderr.
2019 Common Joined RejectNegative Var(common_deferred_options) Defer
2020 -fopt-info[-<type>=filename] Dump compiler optimization details.
2022 fsave-optimization-record
2023 Common Report Var(flag_save_optimization_record) Optimization
2024 Write a SRCFILE.opt-record.json file detailing what optimizations were performed.
2026 foptimize-register-move
2028 Does nothing. Preserved for backward compatibility.
2030 foptimize-sibling-calls
2031 Common Report Var(flag_optimize_sibling_calls) Optimization
2032 Optimize sibling and tail recursive calls.
2035 Common Report Var(flag_partial_inlining) Optimization
2036 Perform partial inlining.
2039 Common Report Var(pre_ipa_mem_report)
2040 Report on memory allocation before interprocedural optimization.
2042 fpost-ipa-mem-report
2043 Common Report Var(post_ipa_mem_report)
2044 Report on memory allocation before interprocedural optimization.
2047 Common Report Var(flag_pack_struct) Optimization
2048 Pack structure members together without holes.
2051 Common RejectNegative Joined UInteger Optimization
2052 -fpack-struct=<number> Set initial maximum structure member alignment.
2055 Common Report Var(flag_pcc_struct_return,1) Init(DEFAULT_PCC_STRUCT_RETURN)
2056 Return small aggregates in memory, not registers.
2059 Common Report Var(flag_peel_loops) Optimization
2060 Perform loop peeling.
2063 Common Report Var(flag_no_peephole,0) Optimization
2064 Enable machine specific peephole optimizations.
2067 Common Report Var(flag_peephole2) Optimization
2068 Enable an RTL peephole pass before sched2.
2071 Common Report Var(flag_pic,2) Negative(fPIE) Init(-1)
2072 Generate position-independent code if possible (large mode).
2075 Common Report Var(flag_pie,2) Negative(fpic) Init(-1)
2076 Generate position-independent code for executables if possible (large mode).
2079 Common Report Var(flag_pic,1) Negative(fpie) Init(-1)
2080 Generate position-independent code if possible (small mode).
2083 Common Report Var(flag_pie,1) Negative(fPIC) Init(-1)
2084 Generate position-independent code for executables if possible (small mode).
2087 Common Report Var(flag_plt) Init(1) Optimization
2088 Use PLT for PIC calls (-fno-plt: load the address from GOT at call site).
2091 Common Joined RejectNegative Var(common_deferred_options) Defer
2092 Specify a plugin to load.
2095 Common Joined RejectNegative Var(common_deferred_options) Defer
2096 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>.
2098 fpredictive-commoning
2099 Common Report Var(flag_predictive_commoning) Optimization
2100 Run predictive commoning optimization.
2102 fprefetch-loop-arrays
2103 Common Report Var(flag_prefetch_loop_arrays) Init(-1) Optimization
2104 Generate prefetch instructions, if available, for arrays in loops.
2107 Common Report Var(profile_flag)
2108 Enable basic program profiling code.
2111 Common Report Var(profile_abs_path_flag)
2112 Generate absolute source path names for gcov.
2115 Common Report Var(profile_arc_flag)
2116 Insert arc-based program profiling code.
2119 Common Joined RejectNegative Var(profile_data_prefix)
2120 Set the top-level directory for storing the profile data.
2121 The default is 'pwd'.
2124 Common Joined RejectNegative Var(profile_note_location)
2125 Select the name for storing the profile note file.
2128 Common Report Var(flag_profile_correction)
2129 Enable correction of flow inconsistent profile data input.
2132 Common Joined RejectNegative Enum(profile_update) Var(flag_profile_update) Init(PROFILE_UPDATE_SINGLE)
2133 -fprofile-update=[single|atomic|prefer-atomic] Set the profile update method.
2135 fprofile-filter-files=
2136 Common Joined RejectNegative Var(flag_profile_filter_files)
2137 Instrument only functions from files where names match any regular expression (separated by a semi-colon).
2139 fprofile-exclude-files=
2140 Common Joined RejectNegative Var(flag_profile_exclude_files)
2141 Instrument only functions from files where names do not match all the regular expressions (separated by a semi-colon).
2144 Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
2147 Enum(profile_update) String(single) Value(PROFILE_UPDATE_SINGLE)
2150 Enum(profile_update) String(atomic) Value(PROFILE_UPDATE_ATOMIC)
2153 Enum(profile_update) String(prefer-atomic) Value(PROFILE_UPDATE_PREFER_ATOMIC)
2157 Enable common options for generating profile info for profile feedback directed optimizations.
2160 Common Joined RejectNegative
2161 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=.
2164 Common Var(flag_profile_use)
2165 Enable common options for performing profile feedback directed optimizations.
2168 Common Joined RejectNegative
2169 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=.
2172 Common Report Var(flag_profile_values)
2173 Insert code to profile values of expressions.
2176 Common Report Var(profile_report)
2177 Report on consistency of profile.
2179 fprofile-reorder-functions
2180 Common Report Var(flag_profile_reorder_functions)
2181 Enable function reordering that improves code placement.
2183 fpatchable-function-entry=
2184 Common Joined Optimization
2185 Insert NOP instructions at each function entry.
2188 Common Var(common_deferred_options) Defer
2191 Common Joined RejectNegative Var(common_deferred_options) Defer
2192 -frandom-seed=<string> Make compile reproducible using <string>.
2194 ; This switch causes the command line that was used to create an
2195 ; object file to be recorded into the object file. The exact format
2196 ; of this recording is target and binary file format dependent.
2197 ; It is related to the -fverbose-asm switch, but that switch only
2198 ; records information in the assembler output file as comments, so
2199 ; they never reach the object file.
2200 frecord-gcc-switches
2201 Common Report Var(flag_record_gcc_switches)
2202 Record gcc command line switches in the object file.
2205 Common Report Var(flag_pcc_struct_return,0) Optimization
2206 Return small aggregates in registers.
2210 Does nothing. Preserved for backward compatibility.
2213 Common Report Var(flag_lifetime_dse,2) Init(2) Optimization
2214 Tell DSE that the storage for a C++ object is dead when the constructor
2215 starts and when the destructor finishes.
2218 Common Joined RejectNegative UInteger Var(flag_lifetime_dse) Optimization IntegerRange(0, 2)
2221 Common RejectNegative Alias(flive-patching=,inline-clone) Optimization
2224 Common Report Joined RejectNegative Enum(live_patching_level) Var(flag_live_patching) Init(LIVE_PATCHING_NONE) Optimization
2225 -flive-patching=[inline-only-static|inline-clone] Control IPA
2226 optimizations to provide a safe compilation for live-patching. At the same
2227 time, provides multiple-level control on the enabled IPA optimizations.
2230 Name(live_patching_level) Type(enum live_patching_level) UnknownError(unknown Live-Patching Level %qs)
2233 Enum(live_patching_level) String(inline-only-static) Value(LIVE_PATCHING_INLINE_ONLY_STATIC)
2236 Enum(live_patching_level) String(inline-clone) Value(LIVE_PATCHING_INLINE_CLONE)
2239 Common Report Var(flag_allocation_dce) Init(1) Optimization
2240 Tell DCE to remove unused C++ allocations.
2242 flive-range-shrinkage
2243 Common Report Var(flag_live_range_shrinkage) Init(0) Optimization
2244 Relief of register pressure through live range shrinkage.
2247 Common Report Var(flag_rename_registers) Init(2) Optimization
2248 Perform a register renaming optimization pass.
2251 Common Report Var(flag_schedule_fusion) Init(2) Optimization
2252 Perform a target dependent instruction fusion optimization pass.
2255 Common Report Var(flag_reorder_blocks) Optimization
2256 Reorder basic blocks to improve code placement.
2258 freorder-blocks-algorithm=
2259 Common Joined RejectNegative Enum(reorder_blocks_algorithm) Var(flag_reorder_blocks_algorithm) Init(REORDER_BLOCKS_ALGORITHM_SIMPLE) Optimization
2260 -freorder-blocks-algorithm=[simple|stc] Set the used basic block reordering algorithm.
2263 Name(reorder_blocks_algorithm) Type(enum reorder_blocks_algorithm) UnknownError(unknown basic block reordering algorithm %qs)
2266 Enum(reorder_blocks_algorithm) String(simple) Value(REORDER_BLOCKS_ALGORITHM_SIMPLE)
2269 Enum(reorder_blocks_algorithm) String(stc) Value(REORDER_BLOCKS_ALGORITHM_STC)
2271 freorder-blocks-and-partition
2272 Common Report Var(flag_reorder_blocks_and_partition) Optimization
2273 Reorder basic blocks and partition into hot and cold sections.
2276 Common Report Var(flag_reorder_functions) Optimization
2277 Reorder functions to improve code placement.
2279 frerun-cse-after-loop
2280 Common Report Var(flag_rerun_cse_after_loop) Optimization
2281 Add a common subexpression elimination pass after loop optimizations.
2285 Does nothing. Preserved for backward compatibility.
2288 Common Report Var(flag_rounding_math) Optimization SetByCombined
2289 Disable optimizations that assume default FP rounding behavior.
2292 Common Report Var(flag_schedule_interblock) Init(1) Optimization
2293 Enable scheduling across basic blocks.
2296 Common Report Var(flag_sched_pressure) Init(0) Optimization
2297 Enable register pressure sensitive insn scheduling.
2300 Common Report Var(flag_schedule_speculative) Init(1) Optimization
2301 Allow speculative motion of non-loads.
2304 Common Report Var(flag_schedule_speculative_load) Optimization
2305 Allow speculative motion of some loads.
2307 fsched-spec-load-dangerous
2308 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
2309 Allow speculative motion of more loads.
2312 Common RejectNegative Joined UInteger Var(sched_verbose_param) Init(1)
2313 -fsched-verbose=<number> Set the verbosity level of the scheduler.
2315 fsched2-use-superblocks
2316 Common Report Var(flag_sched2_use_superblocks) Optimization
2317 If scheduling post reload, do superblock scheduling.
2321 Does nothing. Preserved for backward compatibility.
2324 Common Report Var(flag_schedule_insns) Optimization
2325 Reschedule instructions before register allocation.
2328 Common Report Var(flag_schedule_insns_after_reload) Optimization
2329 Reschedule instructions after register allocation.
2331 ; This flag should be on when a target implements non-trivial
2332 ; scheduling hooks, maybe saving some information for its own sake.
2333 ; On IA64, for example, this is used for correct bundling.
2334 fselective-scheduling
2335 Common Report Var(flag_selective_scheduling) Optimization
2336 Schedule instructions using selective scheduling algorithm.
2338 fselective-scheduling2
2339 Common Report Var(flag_selective_scheduling2) Optimization
2340 Run selective scheduling after reload.
2343 Common Undocumented Joined Var(flag_self_test)
2344 Run self-tests, using the given path to locate test files.
2346 fsel-sched-pipelining
2347 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
2348 Perform software pipelining of inner loops during selective scheduling.
2350 fsel-sched-pipelining-outer-loops
2351 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
2352 Perform software pipelining of outer loops during selective scheduling.
2354 fsel-sched-reschedule-pipelined
2355 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
2356 Reschedule pipelined regions without pipelining.
2358 fsemantic-interposition
2359 Common Report Var(flag_semantic_interposition) Init(1)
2360 Allow interposing function (or variables) by ones with different semantics (or initializer) respectively by dynamic linker.
2362 ; sched_stalled_insns means that insns can be moved prematurely from the queue
2363 ; of stalled insns into the ready list.
2364 fsched-stalled-insns
2365 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
2366 Allow premature scheduling of queued insns.
2368 fsched-stalled-insns=
2369 Common RejectNegative Joined UInteger Optimization
2370 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled.
2372 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
2373 ; be examined for a dependency on a stalled insn that is candidate for
2374 ; premature removal from the queue of stalled insns into the ready list (has
2375 ; an effect only if the flag 'sched_stalled_insns' is set).
2376 fsched-stalled-insns-dep
2377 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
2378 Set dependence distance checking in premature scheduling of queued insns.
2380 fsched-stalled-insns-dep=
2381 Common RejectNegative Joined UInteger Optimization
2382 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns.
2384 fsched-group-heuristic
2385 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
2386 Enable the group heuristic in the scheduler.
2388 fsched-critical-path-heuristic
2389 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
2390 Enable the critical path heuristic in the scheduler.
2392 fsched-spec-insn-heuristic
2393 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
2394 Enable the speculative instruction heuristic in the scheduler.
2396 fsched-rank-heuristic
2397 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
2398 Enable the rank heuristic in the scheduler.
2400 fsched-last-insn-heuristic
2401 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
2402 Enable the last instruction heuristic in the scheduler.
2404 fsched-dep-count-heuristic
2405 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
2406 Enable the dependent count heuristic in the scheduler.
2409 Common Report Var(flag_section_anchors) Optimization
2410 Access data in the same section from shared anchor points.
2414 Does nothing. Preserved for backward compatibility.
2418 Does nothing. Preserved for backward compatibility.
2421 Common Report Var(flag_ree) Init(0)
2422 Turn on Redundant Extensions Elimination pass.
2425 Common Report Var(flag_show_column) Init(1)
2426 Show column numbers in diagnostics, when available. Default on.
2429 Common Report Var(flag_shrink_wrap) Optimization
2430 Emit function prologues only before parts of the function that need it,
2431 rather than at the top of the function.
2433 fshrink-wrap-separate
2434 Common Report Var(flag_shrink_wrap_separate) Init(1) Optimization
2435 Shrink-wrap parts of the prologue and epilogue separately.
2438 Common Report Var(flag_signaling_nans) Optimization SetByCombined
2439 Disable optimizations observable by IEEE signaling NaNs.
2442 Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
2443 Disable floating point optimizations that ignore the IEEE signedness of zero.
2445 fsingle-precision-constant
2446 Common Report Var(flag_single_precision_constant) Optimization
2447 Convert floating point constants to single precision constants.
2449 fsplit-ivs-in-unroller
2450 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
2451 Split lifetimes of induction variables when loops are unrolled.
2454 Common Report Var(flag_split_stack) Init(-1)
2455 Generate discontiguous stack frames.
2458 Common Report Var(flag_split_wide_types) Optimization
2459 Split wide types into independent registers.
2461 fsplit-wide-types-early
2462 Common Report Var(flag_split_wide_types_early) Optimization
2463 Split wide types into independent registers earlier.
2466 Common Report Var(flag_ssa_backprop) Init(1) Optimization
2467 Enable backward propagation of use properties at the SSA level.
2470 Common Report Var(flag_ssa_phiopt) Optimization
2471 Optimize conditional patterns using SSA PHI nodes.
2474 Common Report Var(flag_stdarg_opt) Init(1) Optimization
2475 Optimize amount of stdarg registers saved to stack at start of function.
2477 fvariable-expansion-in-unroller
2478 Common Report Var(flag_variable_expansion_in_unroller) Optimization
2479 Apply variable expansion when loops are unrolled.
2482 Common Report RejectNegative Joined Optimization
2483 -fstack-check=[no|generic|specific] Insert stack checking code into the program.
2486 Common Alias(fstack-check=, specific, no)
2487 Insert stack checking code into the program. Same as -fstack-check=specific.
2489 fstack-clash-protection
2490 Common Report Var(flag_stack_clash_protection) Optimization
2491 Insert code to probe each page of stack space as it is allocated to protect
2492 from stack-clash style attacks.
2495 Common Var(common_deferred_options) Defer
2497 fstack-limit-register=
2498 Common RejectNegative Joined Var(common_deferred_options) Defer
2499 -fstack-limit-register=<register> Trap if the stack goes past <register>.
2501 fstack-limit-symbol=
2502 Common RejectNegative Joined Var(common_deferred_options) Defer
2503 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>.
2506 Common Report Var(flag_stack_protect, 1) Init(-1) Optimization
2507 Use propolice as a stack protection method.
2509 fstack-protector-all
2510 Common Report RejectNegative Var(flag_stack_protect, 2) Init(-1) Optimization
2511 Use a stack protection method for every function.
2513 fstack-protector-strong
2514 Common Report RejectNegative Var(flag_stack_protect, 3) Init(-1) Optimization
2515 Use a smart stack protection method for certain functions.
2517 fstack-protector-explicit
2518 Common Report RejectNegative Var(flag_stack_protect, 4) Optimization
2519 Use stack protection method only for functions with the stack_protect attribute.
2522 Common RejectNegative Var(flag_stack_usage)
2523 Output stack usage information on a per-function basis.
2527 Does nothing. Preserved for backward compatibility.
2529 ; Nonzero if we should do (language-dependent) alias analysis.
2530 ; Typically, this analysis will assume that expressions of certain
2531 ; types do not alias expressions of certain other types. Only used
2532 ; if alias analysis (in general) is enabled.
2534 Common Report Var(flag_strict_aliasing) Optimization
2535 Assume strict aliasing rules apply.
2539 Treat signed overflow as undefined. Negated as -fwrapv -fwrapv-pointer.
2542 Common Report Var(flag_sync_libcalls) Init(1)
2543 Implement __atomic operations via libcalls to legacy __sync functions.
2546 Common Report Var(flag_syntax_only)
2547 Check for syntax errors, then stop.
2550 Common Report Var(flag_test_coverage)
2551 Create data files needed by \"gcov\".
2554 Common Report Var(flag_thread_jumps) Optimization
2555 Perform jump threading optimizations.
2558 Common Report Var(time_report)
2559 Report the time taken by each compiler pass.
2561 ftime-report-details
2562 Common Report Var(time_report_details)
2563 Record times taken by sub-phases separately.
2566 Common Joined RejectNegative Enum(tls_model) Var(flag_tls_default) Init(TLS_MODEL_GLOBAL_DYNAMIC)
2567 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model.
2570 Name(tls_model) Type(enum tls_model) UnknownError(unknown TLS model %qs)
2573 Enum(tls_model) String(global-dynamic) Value(TLS_MODEL_GLOBAL_DYNAMIC)
2576 Enum(tls_model) String(local-dynamic) Value(TLS_MODEL_LOCAL_DYNAMIC)
2579 Enum(tls_model) String(initial-exec) Value(TLS_MODEL_INITIAL_EXEC)
2582 Enum(tls_model) String(local-exec) Value(TLS_MODEL_LOCAL_EXEC)
2585 Common Report Var(flag_toplevel_reorder) Init(2)
2586 Reorder top level functions, variables, and asms.
2589 Common Report Var(flag_tracer) Optimization
2590 Perform superblock formation via tail duplication.
2593 Common Report Var(flag_trampolines) Init(0)
2594 For targets that normally need trampolines for nested functions, always
2595 generate them instead of using descriptors.
2597 ; Zero means that floating-point math operations cannot generate a
2598 ; (user-visible) trap. This is the case, for example, in nonstop
2599 ; IEEE 754 arithmetic.
2601 Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
2602 Assume floating-point operations can trap.
2605 Common Report Var(flag_trapv) Optimization
2606 Trap for signed overflow in addition, subtraction and multiplication.
2609 Common Report Var(flag_tree_ccp) Optimization
2610 Enable SSA-CCP optimization on trees.
2613 Common Report Var(flag_tree_bit_ccp) Optimization
2614 Enable SSA-BIT-CCP optimization on trees.
2618 Does nothing. Preserved for backward compatibility.
2621 Common Report Var(flag_tree_ch) Optimization
2622 Enable loop header copying on trees.
2624 ftree-coalesce-inlined-vars
2625 Common Ignore RejectNegative
2626 Does nothing. Preserved for backward compatibility.
2629 Common Report Var(flag_tree_coalesce_vars) Optimization
2630 Enable SSA coalescing of user variables.
2634 Does nothing. Preserved for backward compatibility.
2637 Common Report Var(flag_tree_copy_prop) Optimization
2638 Enable copy propagation on trees.
2640 ftree-store-copy-prop
2642 Does nothing. Preserved for backward compatibility.
2645 Common Report Var(flag_tree_cselim) Init(2) Optimization
2646 Transform condition stores into unconditional ones.
2648 ftree-switch-conversion
2649 Common Report Var(flag_tree_switch_conversion) Optimization
2650 Perform conversions of switch initializations.
2653 Common Report Var(flag_tree_dce) Optimization
2654 Enable SSA dead code elimination optimization on trees.
2656 ftree-dominator-opts
2657 Common Report Var(flag_tree_dom) Optimization
2658 Enable dominator optimizations.
2661 Common Report Var(flag_tree_tail_merge) Optimization
2662 Enable tail merging on trees.
2665 Common Report Var(flag_tree_dse) Optimization
2666 Enable dead store elimination.
2669 Common Report Var(flag_tree_forwprop) Init(1) Optimization
2670 Enable forward propagation on trees.
2673 Common Report Var(flag_tree_fre) Optimization
2674 Enable Full Redundancy Elimination (FRE) on trees.
2677 Common Report Var(flag_optimize_strlen) Optimization
2678 Enable string length optimizations on trees.
2680 fisolate-erroneous-paths-dereference
2681 Common Report Var(flag_isolate_erroneous_paths_dereference) Optimization
2682 Detect paths that trigger erroneous or undefined behavior due to
2683 dereferencing a null pointer. Isolate those paths from the main control
2684 flow and turn the statement with erroneous or undefined behavior into a trap.
2686 fisolate-erroneous-paths-attribute
2687 Common Report Var(flag_isolate_erroneous_paths_attribute) Optimization
2688 Detect paths that trigger erroneous or undefined behavior due to a null value
2689 being used in a way forbidden by a returns_nonnull or nonnull
2690 attribute. Isolate those paths from the main control flow and turn the
2691 statement with erroneous or undefined behavior into a trap.
2693 ftree-loop-distribution
2694 Common Report Var(flag_tree_loop_distribution) Optimization
2695 Enable loop distribution on trees.
2697 ftree-loop-distribute-patterns
2698 Common Report Var(flag_tree_loop_distribute_patterns) Optimization
2699 Enable loop distribution for patterns transformed into a library call.
2702 Common Report Var(flag_tree_loop_im) Init(1) Optimization
2703 Enable loop invariant motion on trees.
2706 Common Alias(floop-nest-optimize)
2707 Enable loop nest transforms. Same as -floop-nest-optimize.
2710 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
2711 Create canonical induction variables in loops.
2714 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
2715 Enable loop optimizations on tree level.
2717 ftree-parallelize-loops=
2718 Common Report Joined RejectNegative UInteger Var(flag_tree_parallelize_loops) Init(1) Optimization
2719 -ftree-parallelize-loops=<number> Enable automatic parallelization of loops.
2722 Common Report Var(flag_tree_phiprop) Init(1) Optimization
2723 Enable hoisting loads from conditional pointers.
2726 Common Report Var(flag_tree_pre) Optimization
2727 Enable SSA-PRE optimization on trees.
2730 Common Report Var(flag_tree_partial_pre) Optimization
2731 In SSA-PRE optimization on trees, enable partial-partial redundancy elimination.
2734 Common Report Var(flag_tree_pta) Optimization
2735 Perform function-local points-to analysis on trees.
2738 Common Report Var(flag_tree_reassoc) Init(1) Optimization
2739 Enable reassociation on tree level.
2743 Does nothing. Preserved for backward compatibility.
2746 Common Report Var(flag_tree_sink) Optimization
2747 Enable SSA code sinking on trees.
2750 Common Report Var(flag_tree_slsr) Optimization
2751 Perform straight-line strength reduction.
2754 Common Report Var(flag_tree_sra) Optimization
2755 Perform scalar replacement of aggregates.
2758 Common Report Var(flag_tree_ter) Optimization
2759 Replace temporary expressions in the SSA->normal pass.
2762 Common Report Var(flag_tree_live_range_split) Optimization
2763 Perform live range splitting during the SSA->normal pass.
2766 Common Report Var(flag_tree_vrp) Init(0) Optimization
2767 Perform Value Range Propagation on trees.
2770 Common Report Var(flag_split_paths) Init(0) Optimization
2771 Split paths leading to loop backedges.
2773 funconstrained-commons
2774 Common Var(flag_unconstrained_commons) Optimization
2775 Assume common declarations may be overridden with ones with a larger
2779 Common Report Var(flag_unit_at_a_time) Init(1)
2780 Compile whole compilation unit at a time.
2783 Common Report Var(flag_unroll_loops) Optimization
2784 Perform loop unrolling when iteration count is known.
2787 Common Report Var(flag_unroll_all_loops) Optimization
2788 Perform loop unrolling for all loops.
2790 ; Nonzero means that loop optimizer may assume that the induction variables
2791 ; that control loops do not overflow and that the loops with nontrivial
2792 ; exit condition are not infinite
2793 funsafe-loop-optimizations
2795 Does nothing. Preserved for backward compatibility.
2798 Common Report Var(flag_associative_math) SetByCombined Optimization
2799 Allow optimization for floating-point arithmetic which may change the
2800 result of the operation due to rounding.
2803 Common Report Var(flag_reciprocal_math) SetByCombined Optimization
2804 Same as -fassociative-math for expressions which include division.
2806 ; Nonzero means that unsafe floating-point math optimizations are allowed
2807 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
2808 ; are allowed to assume that their arguments and results are "normal"
2809 ; (e.g., nonnegative for SQRT).
2810 funsafe-math-optimizations
2811 Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
2812 Allow math optimizations that may violate IEEE or ISO standards.
2815 Common Report Var(flag_unswitch_loops) Optimization
2816 Perform loop unswitching.
2819 Common Report Var(flag_split_loops) Optimization
2820 Perform loop splitting.
2822 fversion-loops-for-strides
2823 Common Report Var(flag_version_loops_for_strides) Optimization
2824 Version loops based on whether indices have a stride of one.
2827 Common Report Var(flag_unwind_tables) Optimization
2828 Just generate unwind tables for exception handling.
2831 Common Driver Negative(fuse-ld=gold)
2832 Use the bfd linker instead of the default linker.
2835 Common Driver Negative(fuse-ld=bfd)
2836 Use the gold linker instead of the default linker.
2839 Common Driver Negative(fuse-ld=lld)
2840 Use the lld LLVM linker instead of the default linker.
2843 Common Undocumented Var(flag_use_linker_plugin)
2845 ; Positive if we should track variables, negative if we should run
2846 ; the var-tracking pass only to discard debug annotations, zero if
2847 ; we're not to run it. When flag_var_tracking == 2 (AUTODETECT_VALUE) it
2848 ; will be set according to optimize, debug_info_level and debug_hooks
2849 ; in process_options ().
2851 Common Report Var(flag_var_tracking) Init(2) PerFunction
2852 Perform variable tracking.
2854 ; Positive if we should track variables at assignments, negative if
2855 ; we should run the var-tracking pass only to discard debug
2856 ; annotations. When flag_var_tracking_assignments ==
2857 ; AUTODETECT_VALUE it will be set according to flag_var_tracking.
2858 fvar-tracking-assignments
2859 Common Report Var(flag_var_tracking_assignments) Init(2) PerFunction
2860 Perform variable tracking by annotating assignments.
2862 ; Nonzero if we should toggle flag_var_tracking_assignments after
2863 ; processing options and computing its default. */
2864 fvar-tracking-assignments-toggle
2865 Common Report Var(flag_var_tracking_assignments_toggle) PerFunction
2866 Toggle -fvar-tracking-assignments.
2868 ; Positive if we should track uninitialized variables, negative if
2869 ; we should run the var-tracking pass only to discard debug
2870 ; annotations. When flag_var_tracking_uninit == AUTODETECT_VALUE it
2871 ; will be set according to flag_var_tracking.
2872 fvar-tracking-uninit
2873 Common Report Var(flag_var_tracking_uninit) PerFunction
2874 Perform variable tracking and also tag variables that are uninitialized.
2876 ; Alias to enable both -ftree-loop-vectorize and -ftree-slp-vectorize.
2878 Common Report Optimization
2879 Enable vectorization on trees.
2881 ftree-vectorizer-verbose=
2882 Common Joined RejectNegative Ignore
2883 Does nothing. Preserved for backward compatibility.
2885 ftree-loop-vectorize
2886 Common Report Var(flag_tree_loop_vectorize) Optimization EnabledBy(ftree-vectorize)
2887 Enable loop vectorization on trees.
2890 Common Report Var(flag_tree_slp_vectorize) Optimization EnabledBy(ftree-vectorize)
2891 Enable basic block vectorization (SLP) on trees.
2894 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_vect_cost_model) Init(VECT_COST_MODEL_DEFAULT) Optimization
2895 -fvect-cost-model=[unlimited|dynamic|cheap] Specifies the cost model for vectorization.
2898 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_simd_cost_model) Init(VECT_COST_MODEL_UNLIMITED) Optimization
2899 -fsimd-cost-model=[unlimited|dynamic|cheap] Specifies the vectorization cost model for code marked with a simd directive.
2902 Name(vect_cost_model) Type(enum vect_cost_model) UnknownError(unknown vectorizer cost model %qs)
2905 Enum(vect_cost_model) String(unlimited) Value(VECT_COST_MODEL_UNLIMITED)
2908 Enum(vect_cost_model) String(dynamic) Value(VECT_COST_MODEL_DYNAMIC)
2911 Enum(vect_cost_model) String(cheap) Value(VECT_COST_MODEL_CHEAP)
2914 Common Alias(fvect-cost-model=,dynamic,unlimited)
2915 Enables the dynamic vectorizer cost model. Preserved for backward compatibility.
2917 ftree-vect-loop-version
2919 Does nothing. Preserved for backward compatibility.
2922 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
2923 Enable copy propagation of scalar-evolution information.
2925 ; -fverbose-asm causes extra commentary information to be produced in
2926 ; the generated assembly code (to make it more readable). This option
2927 ; is generally only of use to those who actually need to read the
2928 ; generated assembly code (perhaps while debugging the compiler itself).
2929 ; -fno-verbose-asm, the default, causes the extra information
2930 ; to not be added and is useful when comparing two assembler files.
2932 Common Report Var(flag_verbose_asm)
2933 Add extra commentary to assembler output.
2936 Common Joined RejectNegative Enum(symbol_visibility) Var(default_visibility) Init(VISIBILITY_DEFAULT)
2937 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility.
2940 Name(symbol_visibility) Type(enum symbol_visibility) UnknownError(unrecognized visibility value %qs)
2943 Enum(symbol_visibility) String(default) Value(VISIBILITY_DEFAULT)
2946 Enum(symbol_visibility) String(internal) Value(VISIBILITY_INTERNAL)
2949 Enum(symbol_visibility) String(hidden) Value(VISIBILITY_HIDDEN)
2952 Enum(symbol_visibility) String(protected) Value(VISIBILITY_PROTECTED)
2955 Common Joined RejectNegative Enum(vtv_priority) Var(flag_vtable_verify) Init(VTV_NO_PRIORITY)
2956 Validate vtable pointers before using them.
2959 Name(vtv_priority) Type(enum vtv_priority) UnknownError(unknown vtable verify initialization priority %qs)
2962 Enum(vtv_priority) String(none) Value(VTV_NO_PRIORITY)
2965 Enum(vtv_priority) String(std) Value(VTV_STANDARD_PRIORITY)
2968 Enum(vtv_priority) String(preinit) Value(VTV_PREINIT_PRIORITY)
2971 Common Var(flag_vtv_counts)
2972 Output vtable verification counters.
2975 Common Var(flag_vtv_debug)
2976 Output vtable verification pointer sets information.
2979 Common Report Var(flag_value_profile_transformations) Optimization
2980 Use expression value profiles in optimizations.
2983 Common Report Var(flag_web) Init(2) Optimization
2984 Construct webs and split unrelated uses of single variable.
2986 ftree-builtin-call-dce
2987 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
2988 Enable conditional dead code elimination for builtin calls.
2991 Common Report Var(flag_whole_program) Init(0)
2992 Perform whole program optimizations.
2995 Common Report Var(flag_wrapv_pointer) Optimization
2996 Assume pointer overflow wraps around.
2999 Common Report Var(flag_wrapv) Optimization
3000 Assume signed arithmetic overflow wraps around.
3002 fzero-initialized-in-bss
3003 Common Report Var(flag_zero_initialized_in_bss) Init(1)
3004 Put zero initialized data in the bss section.
3007 Common Driver RejectNegative JoinedOrMissing
3008 Generate debug information in default format.
3011 Common Driver Var(dwarf2out_as_loc_support) Init(2)
3012 Assume assembler support for (DWARF2+) .loc directives.
3015 Common Driver Var(dwarf2out_as_locview_support) Init(2)
3016 Assume assembler support for view in (DWARF2+) .loc directives.
3019 Common Driver WarnRemoved
3020 Does nothing. Preserved for backward compatibility.
3023 Common Driver WarnRemoved
3024 Does nothing. Preserved for backward compatibility.
3027 Common Driver WarnRemoved
3028 Does nothing. Preserved for backward compatibility.
3031 Common Driver WarnRemoved
3032 Does nothing. Preserved for backward compatibility.
3035 Common Driver Var(debug_column_info,1) Init(1)
3036 Record DW_AT_decl_column and DW_AT_call_column in DWARF.
3039 Common Driver JoinedOrMissing Negative(gdwarf-)
3040 Generate debug information in default version of DWARF format.
3043 Common Driver Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
3044 Generate debug information in DWARF v2 (or later) format.
3047 Common Driver JoinedOrMissing
3048 Generate debug information in default extended format.
3051 Common Driver Var(debug_inline_points) Init(2)
3052 Generate extended entry point information for inlined functions.
3054 ginternal-reset-location-views
3055 Common Driver Var(debug_internal_reset_location_views) Init(2)
3056 Compute locview reset points based on insn length estimates.
3059 RejectNegative Joined Undocumented
3060 ; Catch the gno- prefix, so it doesn't backtrack to g<level>.
3063 Common Driver Negative(gpubnames) Var(debug_generate_pub_sections, 0) Init(-1)
3064 Don't generate DWARF pubnames and pubtypes sections.
3067 Common Driver Negative(ggnu-pubnames) Var(debug_generate_pub_sections, 1)
3068 Generate DWARF pubnames and pubtypes sections.
3071 Common Driver Negative(gno-pubnames) Var(debug_generate_pub_sections, 2)
3072 Generate DWARF pubnames and pubtypes sections with GNU extensions.
3074 grecord-gcc-switches
3075 Common Driver Var(dwarf_record_gcc_switches) Init(1)
3076 Record gcc command line switches in DWARF DW_AT_producer.
3079 Common Driver Var(dwarf_split_debug_info) Init(0)
3080 Generate debug information in separate .dwo files.
3083 Common Driver JoinedOrMissing Negative(gstabs+)
3084 Generate debug information in STABS format.
3087 Common Driver JoinedOrMissing Negative(gvms)
3088 Generate debug information in extended STABS format.
3090 gstatement-frontiers
3091 Common Driver Var(debug_nonbind_markers_p) Init(2)
3092 Emit progressive recommended breakpoint locations.
3095 Common Driver Report Var(dwarf_strict) Init(0)
3096 Don't emit DWARF additions beyond selected version.
3099 Common Driver Report Var(flag_describe_dies) Init(0)
3100 Add description attributes to some DWARF DIEs that have no name attribute.
3103 Common Driver Report Var(flag_gtoggle)
3104 Toggle debug information generation.
3106 gvariable-location-views
3107 Common Driver Var(debug_variable_location_views, 1) Init(2)
3108 Augment variable location lists with progressive views.
3110 gvariable-location-views=incompat5
3111 Common Driver RejectNegative Var(debug_variable_location_views, -1) Init(2)
3114 Common Driver JoinedOrMissing Negative(gxcoff)
3115 Generate debug information in VMS format.
3118 Common Driver JoinedOrMissing Negative(gxcoff+)
3119 Generate debug information in XCOFF format.
3122 Common Driver JoinedOrMissing Negative(gdwarf)
3123 Generate debug information in extended XCOFF format.
3126 Name(compressed_debug_sections) Type(int)
3128 ; Since -gz= is completely handled in specs, the values aren't used and we
3129 ; assign arbitrary constants.
3131 Enum(compressed_debug_sections) String(none) Value(0)
3134 Enum(compressed_debug_sections) String(zlib) Value(1)
3137 Enum(compressed_debug_sections) String(zlib-gnu) Value(2)
3141 Generate compressed debug sections.
3144 Common Driver RejectNegative Joined Enum(compressed_debug_sections)
3145 -gz=<format> Generate compressed debug sections in format <format>.
3148 Driver Joined Separate
3151 Common Joined Var(plugindir_string) Init(0)
3152 -iplugindir=<dir> Set <dir> to be the default plugin directory.
3155 Common Joined Separate RejectDriver Var(imultiarch) Init(0)
3156 -imultiarch <dir> Set <dir> to be the multiarch include subdirectory.
3159 Driver Joined Separate
3164 no-canonical-prefixes
3180 Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs)
3181 -o <file> Place output into <file>.
3184 Common Var(profile_flag)
3185 Enable function profiling.
3188 Driver Var(pass_exit_codes)
3191 Common Alias(Wpedantic)
3194 Common Var(flag_pedantic_errors)
3195 Like -pedantic but issue them as errors.
3201 Driver Var(use_pipes)
3204 Driver JoinedOrMissing Var(print_file_name)
3206 print-libgcc-file-name
3209 print-multi-directory
3210 Driver Var(print_multi_directory)
3213 Driver Var(print_multi_lib)
3215 print-multi-os-directory
3216 Driver Var(print_multi_os_directory)
3219 Driver Var(print_multiarch)
3222 Driver JoinedOrMissing Var(print_prog_name)
3225 Driver Var(print_search_dirs)
3228 Driver Var(print_sysroot)
3230 print-sysroot-headers-suffix
3231 Driver Var(print_sysroot_headers_suffix)
3234 Common Var(quiet_flag) RejectDriver
3235 Do not display functions compiled or elapsed time.
3253 Driver Var(report_times)
3256 Driver JoinedOrMissing
3259 Driver Joined Separate
3263 ; C option, but driver must not handle as "-u ndef".
3266 Common Driver Var(verbose_flag)
3267 Enable verbose output.
3270 Common Var(version_flag) RejectDriver
3271 Display the compiler's version.
3274 Common Var(inhibit_warnings)
3278 Driver Separate Var(wrapper_string)
3281 Driver Joined Separate
3284 Driver RejectNegative Negative(static-pie)
3285 Create a shared library.
3291 Driver Separate Alias(specs=)
3304 ; Documented for Fortran, but always accepted by driver.
3311 ; Documented for Go, but always accepted by driver.
3329 Driver RejectNegative Negative(shared)
3330 Don't create a dynamically linked position independent executable.
3333 Driver RejectNegative Negative(no-pie)
3334 Create a dynamically linked position independent executable.
3337 Driver RejectNegative Negative(pie)
3338 Create a static position independent executable.
3341 Driver Joined Separate
3344 Common Report Var(flag_ipa_ra) Optimization
3345 Use caller save register across calls if possible.
3347 ; This comment is to ensure we retain the blank line above.