1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003-2016 Free Software Foundation, Inc.
5 ; This file is part of GCC.
7 ; GCC is free software; you can redistribute it and/or modify it under
8 ; the terms of the GNU General Public License as published by the Free
9 ; Software Foundation; either version 3, or (at your option) any later
12 ; GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 ; WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 ; FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 ; You should have received a copy of the GNU General Public License
18 ; along with GCC; see the file COPYING3. If not see
19 ; <http://www.gnu.org/licenses/>.
21 ; See the GCC internals manual (options.texi) for a description of this file's format.
23 ; Please try to keep this file in ASCII collating order.
37 ; Not used directly to control optimizations, only to save -Ofast
38 ; setting for "optimize" attributes.
42 ; True if this is the lto front end. This is used to disable gimple
43 ; generation and lowering passes that are normally run on the output
44 ; of a front end. These passes must be bypassed for lto since they
45 ; have already been done before the gimple was written.
49 ; This variable is set to non-0 only by LTO front-end. 1 indicates that
50 ; the output produced will be used for incrmeental linking (thus weak symbols
51 ; can still be bound).
53 int flag_incremental_link = 0
55 ; 0 means straightforward implementation of complex divide acceptable.
56 ; 1 means wide ranges of inputs must work for complex divide.
57 ; 2 means C99-like requirements for complex multiply and divide.
59 int flag_complex_method = 1
61 ; Nonzero if subexpressions must be evaluated from left-to-right.
63 int flag_evaluation_order = 0
65 ; Language specific warning pass for unused results.
67 bool flag_warn_unused_result = false
72 ; Nonzero if we should write GIMPLE bytecode for link-time optimization.
76 ; Nonzero if we should write GIMPLE bytecode for offload compilation.
78 int flag_generate_offload = 0
80 ; True to warn about any objects definitions whose size is larger
81 ; than N bytes. Also want about function definitions whose returned
82 ; values are larger than N bytes, where N is 'larger_than_size'.
87 HOST_WIDE_INT larger_than_size
89 ; True to warn about any function whose frame size is larger
92 bool warn_frame_larger_than
95 HOST_WIDE_INT frame_larger_than_size
97 ; Nonzero means we should be saving declaration info into a .X file.
99 int flag_gen_aux_info = 0
101 ; Nonzero if we are compiling code for a shared library, zero for
106 ; These two are really VEC(char_p,heap) *.
109 void *flag_instrument_functions_exclude_functions
112 void *flag_instrument_functions_exclude_files
114 ; Generic structs (e.g. templates not explicitly specialized)
115 ; may not have a compilation unit associated with them, and so
116 ; may need to be treated differently from ordinary structs.
118 ; Structs only handled by reference (indirectly), will also usually
119 ; not need as much debugging information.
122 enum debug_struct_file debug_struct_ordinary[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
125 enum debug_struct_file debug_struct_generic[DINFO_USAGE_NUM_ENUMS] = { DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY, DINFO_STRUCT_FILE_ANY }
127 ; True if we should exit after parsing options.
129 bool exit_after_options
131 ; Type(s) of debugging information we are producing (if any). See
132 ; flag-types.h for the definitions of the different possible types of
133 ; debugging information.
135 enum debug_info_type write_symbols = NO_DEBUG
137 ; Level of debugging information we are producing. See flag-types.h
138 ; for the definitions of the different possible levels.
140 enum debug_info_levels debug_info_level = DINFO_LEVEL_NONE
142 ; Nonzero means use GNU-only extensions in the generated symbolic
143 ; debugging information. Currently, this only has an effect when
144 ; write_symbols is set to DBX_DEBUG, XCOFF_DEBUG, or DWARF_DEBUG.
146 bool use_gnu_debug_info_extensions
148 ; Original value of maximum field alignment in bytes, specified via
149 ; -fpack-struct=<value>.
151 unsigned int initial_max_fld_align = TARGET_DEFAULT_PACK_STRUCT
153 ; Type of stack check.
155 enum stack_check_type flag_stack_check = NO_STACK_CHECK
157 ; True if stack usage information needs to be computed.
159 bool flag_stack_usage_info = false
161 ; -dA causes debug commentary information to be produced in
162 ; the generated assembly code (to make it more readable). This option
163 ; is generally only of use to those who actually need to read the
164 ; generated assembly code (perhaps while debugging the compiler itself).
165 ; Currently, this switch is only used by dwarf2out.c; however, it is intended
166 ; to be a catchall for printing debug information in the assembler file.
171 ; Balance between GNAT encodings and standard DWARF to emit.
173 enum dwarf_gnat_encodings gnat_encodings = DWARF_GNAT_ENCODINGS_DEFAULT
175 ; -dP causes the rtl to be emitted as a comment in assembly.
177 int flag_dump_rtl_in_asm
179 ; Whether -da was passed (used only in handle_common_deferred_options).
181 bool flag_dump_all_passed
183 ; Other flags saying which kinds of debugging dump have been requested.
186 int rtl_dump_and_exit
189 int flag_print_asm_name
191 ; Name of top-level original source file (what was input to cpp).
192 ; This comes from the #-command at the beginning of the actual input.
193 ; If there isn't any there, then this is the cc1 input file name.
195 const char *main_input_filename
197 ; Pointer to base name in main_input_filename, with directories and a
198 ; single final extension removed, and the length of this base
202 const char *main_input_basename
205 int main_input_baselength
207 ; Which options have been printed by --help.
211 ; Which enums have been printed by --help. 0 = not printed, no
212 ; relevant options seen, 1 = relevant option seen, not yet printed, 2
215 char *help_enum_printed
217 ; The number of columns for --help output.
219 unsigned int help_columns
221 ; Whether this options structure has been through finish_options
223 bool flag_opts_finished
225 ; What the sanitizer should instrument
227 unsigned int flag_sanitize
229 ; What sanitizers should recover from errors
231 unsigned int flag_sanitize_recover = (SANITIZE_UNDEFINED | SANITIZE_NONDEFAULT | SANITIZE_KERNEL_ADDRESS) & ~(SANITIZE_UNREACHABLE | SANITIZE_RETURN)
233 fsanitize-coverage=trace-pc
234 Common Report Var(flag_sanitize_coverage)
235 Enable coverage-guided fuzzing code instrumentation.
236 Inserts call to __sanitizer_cov_trace_pc into every basic block.
238 ; Flag whether a prefix has been added to dump_base_name
240 bool dump_base_name_prefixed = false
242 ; Flag whether HSA generation has been explicitely disabled
244 bool flag_disable_hsa = false
256 Driver Alias(coverage)
262 Common Separate Alias(d)
265 Common Joined Alias(d)
268 Common Separate Alias(dumpbase)
271 Common Separate Alias(dumpdir)
274 Driver Separate Alias(e)
277 Driver Joined Alias(e)
280 Common Warning Alias(Wextra)
283 Driver Separate Alias(Xassembler)
286 Driver JoinedOrMissing Alias(Xassembler)
289 Driver Separate Alias(Xlinker)
292 Driver JoinedOrMissing Alias(Xlinker)
295 Driver Separate Alias(u)
298 Driver Joined Alias(u)
301 Common Driver Var(help_flag)
302 Display this information.
305 Common Driver Report Joined
306 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params.
309 Driver Separate Alias(x)
312 Driver Joined Alias(x)
315 Driver Separate Alias(L)
318 Driver Joined Alias(L)
320 -no-canonical-prefixes
321 Driver Alias(no-canonical-prefixes)
323 -no-standard-libraries
324 Driver Alias(nostdlib)
327 Driver Var(no_sysroot_suffix)
336 Common Driver Separate Alias(o) MissingArgError(missing filename after %qs)
339 Common Driver Joined Alias(o) MissingArgError(missing filename after %qs)
342 Driver Alias(pass-exit-codes)
345 Common Alias(Wpedantic)
348 Common Alias(pedantic-errors)
357 Driver Separate Alias(B)
360 Driver JoinedOrMissing Alias(B)
366 Driver Separate Alias(print-file-name=)
369 Driver JoinedOrMissing Alias(print-file-name=)
371 -print-libgcc-file-name
372 Driver Alias(print-libgcc-file-name)
374 -print-multi-directory
375 Driver Alias(print-multi-directory)
378 Driver Alias(print-multi-lib)
380 -print-multi-os-directory
381 Driver Alias(print-multi-os-directory)
384 Driver Alias(print-multiarch)
387 Driver Separate Alias(print-prog-name=)
390 Driver JoinedOrMissing Alias(print-prog-name=)
393 Driver Alias(print-search-dirs)
396 Driver Alias(print-sysroot)
398 -print-sysroot-headers-suffix
399 Driver Alias(print-sysroot-headers-suffix)
405 Driver Alias(save-temps)
411 Driver Separate Alias(specs=)
414 Driver Joined Alias(specs=)
420 Driver Alias(symbolic)
424 Alias for --help=target.
432 ;; The driver used to convert options such as --help into forms such
433 ;; as -fhelp; the following four entries are for compatibility with
434 ;; any direct uses of those (undocumented) -f forms
436 Common Driver Alias(-help)
439 Common Driver Joined Alias(-help=)
442 Common Driver Alias(-target-help)
445 Common Driver Alias(-version)
449 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters.
452 Common Joined Alias(-param)
455 Driver Separate Alias(-sysroot=)
458 Driver JoinedOrMissing
464 Driver Joined Separate
470 Driver Joined Separate
476 Common JoinedOrMissing Optimization
477 -O<number> Set optimization level to <number>.
481 Optimize for space rather than speed.
485 Optimize for speed disregarding exact standards compliance.
489 Optimize for debugging experience rather than speed or size.
501 Driver Joined Separate
507 Driver Joined Separate
528 Common RejectNegative Warning Alias(Wextra)
529 This switch is deprecated; use -Wextra instead.
532 Driver JoinedOrMissing
535 Driver JoinedOrMissing
538 Driver JoinedOrMissing
541 Common Var(warn_aggregate_return) Warning
542 Warn about returning structures, unions or arrays.
544 Waggressive-loop-optimizations
545 Common Var(warn_aggressive_loop_optimizations) Init(1) Warning
546 Warn if a loop with constant number of iterations triggers undefined behavior.
549 Common Var(warn_array_bounds) Warning
550 Warn if an array is accessed out of bounds.
553 Common Joined RejectNegative UInteger Var(warn_array_bounds) Warning
554 Warn if an array is accessed out of bounds.
557 Common Var(warn_attributes) Init(1) Warning
558 Warn about inappropriate attribute usage.
561 Common Var(warn_cast_align) Warning
562 Warn about pointer casts which increase alignment.
565 Common Var(warn_cpp) Init(1) Warning
566 Warn when a #warning directive is encountered.
568 Wdeprecated-declarations
569 Common Var(warn_deprecated_decl) Init(1) Warning
570 Warn about uses of __attribute__((deprecated)) declarations.
572 Wdisabled-optimization
573 Common Var(warn_disabled_optimization) Warning
574 Warn when an optimization pass is disabled.
577 Common Var(warnings_are_errors)
578 Treat all warnings as errors.
582 Treat specified warning as error.
585 Common Var(extra_warnings) Warning
586 Print extra (possibly unwanted) warnings.
589 Common Var(flag_fatal_errors)
590 Exit on the first error occurred.
593 Common RejectNegative Joined UInteger Warning
594 -Wframe-larger-than=<number> Warn if a function's stack frame requires more than <number> bytes.
597 Common Var(warn_free_nonheap_object) Init(1) Warning
598 Warn when attempting to free a non-heap object.
601 Common Var(warn_hsa) Init(1) Warning
602 Warn when a function cannot be expanded to HSAIL.
604 Wimplicit-fallthrough
605 Common Alias(Wimplicit-fallthrough=,3,0) Warning
607 Wimplicit-fallthrough=
608 Common Var(warn_implicit_fallthrough) RejectNegative Joined UInteger Warning
609 Warn when a switch case falls through.
612 Common Var(warn_inline) Warning
613 Warn when an inlined function cannot be inlined.
615 Winvalid-memory-model
616 Common Var(warn_invalid_memory_model) Init(1) Warning
617 Warn when an atomic memory model parameter is known to be outside the valid range.
620 Common RejectNegative Joined Warning Undocumented Alias(Wlarger-than=)
623 Common RejectNegative Joined UInteger Warning
624 -Wlarger-than=<number> Warn if an object is larger than <number> bytes.
627 Var(warn_nonnull_compare) Warning
628 Warn if comparing pointer parameter with nonnull attribute with NULL.
631 Common Var(warn_null_dereference) Warning
632 Warn if dereferencing a NULL pointer may lead to erroneous or undefined behavior.
634 Wunsafe-loop-optimizations
635 Common Var(warn_unsafe_loop_optimizations) Warning
636 Warn if the loop cannot be optimized due to nontrivial assumptions.
639 Common Warning Alias(Wsuggest-attribute=noreturn)
642 Common Var(warn_odr_violations) Init(1) Warning
643 Warn about some C++ One Definition Rule violations during link time optimization.
646 Common Var(warn_overflow) Init(1) Warning
647 Warn about overflow in arithmetic expressions.
650 Common Var(warn_lto_type_mismatch) Init(1) Warning
651 During link time optimization warn about mismatched types of global declarations.
654 Common Var(warn_packed) Warning
655 Warn when the packed attribute has no effect on struct layout.
658 Common Var(warn_padded) Warning
659 Warn when padding is required to align structure members.
662 Common Var(pedantic) Init(0) Warning
663 Issue warnings needed for strict compliance to the standard.
666 Common Var(warn_return_local_addr) Init(1) Warning
667 Warn about returning a pointer/reference to a local or temporary variable.
670 Common Var(warn_shadow) Warning
671 Warn when one variable shadows another. Same as -Wshadow=global.
674 Common Warning Alias(Wshadow)
675 Warn when one variable shadows another (globally).
678 Common Var(warn_shadow_local) Warning EnabledBy(Wshadow)
679 Warn when one local variable shadows another local variable or parameter.
682 Common Warning Undocumented Alias(Wshadow=local)
684 Wshadow=compatible-local
685 Common Var(warn_shadow_compatible_local) Warning EnabledBy(Wshadow=local)
686 Warn when one local variable shadows another local variable or parameter of compatible type.
688 Wshadow-compatible-local
689 Common Warning Undocumented Alias(Wshadow=compatible-local)
692 Common Var(warn_stack_protect) Warning
693 Warn when not issuing stack smashing protection for some reason.
696 Common Joined RejectNegative UInteger Var(warn_stack_usage) Init(-1) Warning
697 Warn if stack usage might be larger than specified amount.
701 Warn about code which might break strict aliasing rules.
704 Common Joined RejectNegative UInteger Var(warn_strict_aliasing) Warning
705 Warn about code which might break strict aliasing rules.
709 Warn about optimizations that assume that signed overflow is undefined.
712 Common Joined RejectNegative UInteger Var(warn_strict_overflow) Warning
713 Warn about optimizations that assume that signed overflow is undefined.
715 Wsuggest-attribute=const
716 Common Var(warn_suggest_attribute_const) Warning
717 Warn about functions which might be candidates for __attribute__((const)).
719 Wsuggest-attribute=pure
720 Common Var(warn_suggest_attribute_pure) Warning
721 Warn about functions which might be candidates for __attribute__((pure)).
723 Wsuggest-attribute=noreturn
724 Common Var(warn_suggest_attribute_noreturn) Warning
725 Warn about functions which might be candidates for __attribute__((noreturn)).
728 Common Var(warn_suggest_final_types) Warning
729 Warn about C++ polymorphic types where adding final keyword would improve code quality.
731 Wsuggest-final-methods
732 Common Var(warn_suggest_final_methods) Warning
733 Warn about C++ virtual methods where adding final keyword would improve code quality.
736 Common Var(warn_switch_unreachable) Warning Init(1)
737 Warn about statements between switch's controlling expression and the first
741 Common Var(warn_system_headers) Warning
742 Do not suppress warnings from system headers.
745 Common Var(warn_trampolines) Warning
746 Warn whenever a trampoline is generated.
749 Common Var(warn_type_limits) Warning EnabledBy(Wextra)
750 Warn if a comparison is always true or always false due to the limited range of the data type.
753 Common Var(warn_uninitialized) Warning EnabledBy(Wextra)
754 Warn about uninitialized automatic variables.
757 Common Var(warn_maybe_uninitialized) Warning EnabledBy(Wuninitialized)
758 Warn about maybe uninitialized automatic variables.
761 Common Ignore Warning
762 Does nothing. Preserved for backward compatibility.
765 Common Var(warn_unused) Init(0) Warning
766 Enable all -Wunused- warnings.
768 Wunused-but-set-parameter
769 Common Var(warn_unused_but_set_parameter) Warning EnabledBy(Wunused && Wextra)
770 Warn when a function parameter is only set, otherwise unused.
772 Wunused-but-set-variable
773 Common Var(warn_unused_but_set_variable) Warning EnabledBy(Wunused)
774 Warn when a variable is only set, otherwise unused.
777 Common Var(warn_unused_function) Warning EnabledBy(Wunused)
778 Warn when a function is unused.
781 Common Var(warn_unused_label) Warning EnabledBy(Wunused)
782 Warn when a label is unused.
785 Common Var(warn_unused_parameter) Warning EnabledBy(Wunused && Wextra)
786 Warn when a function parameter is unused.
789 Common Var(warn_unused_value) Warning EnabledBy(Wunused)
790 Warn when an expression value is unused.
793 Common Var(warn_unused_variable) Warning EnabledBy(Wunused)
794 Warn when a variable is unused.
797 Common Var(warn_coverage_mismatch) Init(1) Warning
798 Warn in case profiles in -fprofile-use do not match.
800 Wvector-operation-performance
801 Common Var(warn_vector_operation_performance) Warning
802 Warn when a vector operation is compiled outside the SIMD.
817 Common Separate Var(aux_info_file_name)
818 -aux-info <file> Emit declaration information into <file>.
821 Common Joined Alias(aux-info)
824 Common Separate RejectDriver Var(aux_base_name)
827 Common Separate RejectDriver
837 -d<letters> Enable dumps from specific passes of the compiler.
840 Common Separate Var(dump_base_name)
841 -dumpbase <file> Set the file basename to be used for dumps.
844 Common Separate Var(dump_dir_name)
845 -dumpdir <dir> Set the directory name to be used for dumps.
857 Driver Joined Separate
859 ; This option has historically been passed down to the linker by an
860 ; accident of a %{e*} spec, so ensure it continues to be passed down
861 ; as a single option. The supported option for this purpose is
862 ; -rdynamic. See PR 47390.
866 ; The version of the C++ ABI in use. The following values are allowed:
868 ; 0: The version of the ABI believed most conformant with the C++ ABI
869 ; specification. This ABI may change as bugs are discovered and fixed.
870 ; Therefore, 0 will not necessarily indicate the same ABI in different
873 ; 1: The version of the ABI first used in G++ 3.2. No longer selectable.
875 ; 2: The version of the ABI first used in G++ 3.4, and the default
878 ; 3: The version of the ABI that fixes the missing underscore
879 ; in template non-type arguments of pointer type.
881 ; 4: The version of the ABI that introduces unambiguous mangling of
882 ; vector types. First selectable in G++ 4.5.
884 ; 5: The version of the ABI that ignores attribute const/noreturn
885 ; in function pointer mangling, and corrects mangling of decltype and
886 ; function parameters used in other parameters and the return type.
887 ; First selectable in G++ 4.6.
889 ; 6: The version of the ABI that doesn't promote scoped enums to int and
890 ; changes the mangling of template argument packs, const/static_cast,
891 ; prefix ++ and --, and a class scope function used as a template
893 ; First selectable in G++ 4.7.
895 ; 7: The version of the ABI that treats nullptr_t as a builtin type and
896 ; corrects the mangling of lambdas in default argument scope.
897 ; First selectable in G++ 4.8.
899 ; 8: The version of the ABI that corrects the substitution behavior of
900 ; function types with function-cv-qualifiers.
901 ; First selectable in G++ 4.9 and default in G++ 5.
903 ; 9: The version of the ABI that corrects the alignment of nullptr_t.
904 ; First selectable and default in G++ 5.2.
906 ; 10: The version of the ABI that mangles attributes that affect type
907 ; identity, such as ia32 calling convention attributes (stdcall, etc.)
908 ; Default in G++ 6 (set in c_common_post_options).
910 ; 11: The version of the ABI that corrects mangling of sizeof... expressions
911 ; and introduces new inheriting constructor handling.
914 ; Additional positive integers will be assigned as new versions of
915 ; the ABI become the default version of the ABI.
917 Common Joined RejectNegative UInteger Var(flag_abi_version) Init(0)
918 The version of the C++ ABI in use.
920 faggressive-loop-optimizations
921 Common Report Var(flag_aggressive_loop_optimizations) Optimization Init(1)
922 Aggressively optimize loops using language constraints.
925 Common Report Var(align_functions,0) Optimization UInteger
926 Align the start of functions.
929 Common RejectNegative Joined UInteger Var(align_functions)
932 Common Report Var(align_jumps,0) Optimization UInteger
933 Align labels which are only reached by jumping.
936 Common RejectNegative Joined UInteger Var(align_jumps)
939 Common Report Var(align_labels,0) Optimization UInteger
943 Common RejectNegative Joined UInteger Var(align_labels)
946 Common Report Var(align_loops,0) Optimization UInteger
947 Align the start of loops.
950 Common RejectNegative Joined UInteger Var(align_loops)
954 Does nothing. Preserved for backward compatibility.
958 Does nothing. Preserved for backward compatibility.
960 fargument-noalias-global
962 Does nothing. Preserved for backward compatibility.
964 fargument-noalias-anything
966 Does nothing. Preserved for backward compatibility.
969 Common Driver Report Joined
970 Select what to sanitize.
973 Common Joined RejectNegative Var(common_deferred_options) Defer
974 -fasan-shadow-offset=<number> Use custom shadow memory offset.
977 Common Joined RejectNegative Var(common_deferred_options) Defer
978 -fsanitize-sections=<sec1,sec2,...> Sanitize global variables
979 in user-defined sections.
983 After diagnosing undefined behavior attempt to continue execution.
987 This switch is deprecated; use -fsanitize-recover= instead.
989 fsanitize-undefined-trap-on-error
990 Common Driver Report Var(flag_sanitize_undefined_trap_on_error) Init(0)
991 Use trap instead of a library function for undefined behavior sanitization.
993 fasynchronous-unwind-tables
994 Common Report Var(flag_asynchronous_unwind_tables) Optimization
995 Generate unwind tables that are exact at each instruction boundary.
998 Common Report Var(flag_auto_inc_dec) Init(1) Optimization
999 Generate auto-inc/dec instructions.
1002 Common Report Var(flag_auto_profile)
1003 Use sample profile information for call graph node weights. The default
1004 profile file is fbdata.afdo in 'pwd'.
1007 Common Joined RejectNegative Var(auto_profile_file)
1008 Use sample profile information for call graph node weights. The profile
1009 file is specified in the argument.
1011 ; -fcheck-bounds causes gcc to generate array bounds checks.
1012 ; For C, C++ and ObjC: defaults off.
1013 ; For Java: defaults to on.
1014 ; For Fortran: defaults to off.
1016 Common Report Var(flag_bounds_check)
1017 Generate code to check bounds before indexing arrays.
1020 Common Report Var(flag_branch_on_count_reg) Optimization
1021 Replace add, compare, branch with branch on count register.
1023 fbranch-probabilities
1024 Common Report Var(flag_branch_probabilities) Optimization
1025 Use profiling information for branch probabilities.
1027 fbranch-target-load-optimize
1028 Common Report Var(flag_branch_target_load_optimize) Optimization
1029 Perform branch target load optimization before prologue / epilogue threading.
1031 fbranch-target-load-optimize2
1032 Common Report Var(flag_branch_target_load_optimize2) Optimization
1033 Perform branch target load optimization after prologue / epilogue threading.
1036 Common Report Var(flag_btr_bb_exclusive) Optimization
1037 Restrict target load migration not to re-use registers in any basic block.
1040 Common Joined RejectNegative Var(common_deferred_options) Defer
1041 -fcall-saved-<register> Mark <register> as being preserved across functions.
1044 Common Joined RejectNegative Var(common_deferred_options) Defer
1045 -fcall-used-<register> Mark <register> as being corrupted by function calls.
1047 ; Nonzero for -fcaller-saves: allocate values in regs that need to
1048 ; be saved across function calls, if that produces overall better code.
1049 ; Optional now, so people can test it.
1051 Common Report Var(flag_caller_saves) Optimization
1052 Save registers around function calls.
1055 Common Report Var(flag_check_data_deps)
1056 This switch is deprecated; do not use.
1059 Common Var(flag_check_new)
1060 Check the return value of new in C++.
1063 Common Var(flag_checking) Init(CHECKING_P ? ENABLE_EXTRA_CHECKING ? 2 : 1 : 0)
1064 Perform internal consistency checkings.
1067 Common Joined RejectNegative UInteger Var(flag_checking)
1068 Perform internal consistency checkings.
1071 Common Report Var(flag_code_hoisting) Optimization
1072 Enable code hoisting.
1074 fcombine-stack-adjustments
1075 Common Report Var(flag_combine_stack_adjustments) Optimization
1076 Looks for opportunities to reduce stack adjustments and stack references.
1079 Common Report Var(flag_no_common,0)
1080 Do not put uninitialized globals in the common section.
1084 ; Converted by the driver to -fcompare-debug= options.
1087 Common Driver JoinedOrMissing RejectNegative Var(flag_compare_debug_opt)
1088 -fcompare-debug[=<opts>] Compile with and without e.g. -gtoggle, and compare the final-insns dump.
1090 fcompare-debug-second
1091 Common Driver RejectNegative Var(flag_compare_debug)
1092 Run only the second compilation of -fcompare-debug.
1095 Common Report Var(flag_compare_elim_after_reload) Optimization
1096 Perform comparison elimination after register allocation has finished.
1099 Common Var(flag_conserve_stack) Optimization
1100 Do not perform optimizations increasing noticeably stack usage.
1103 Common Report Var(flag_cprop_registers) Optimization
1104 Perform a register copy-propagation optimization pass.
1107 Common Report Var(flag_crossjumping) Optimization
1108 Perform cross-jumping optimization.
1111 Common Report Var(flag_cse_follow_jumps) Optimization
1112 When running CSE, follow jumps to their targets.
1116 Does nothing. Preserved for backward compatibility.
1119 Common Report Var(flag_cx_limited_range) Optimization SetByCombined
1120 Omit range reduction step when performing complex division.
1123 Common Report Var(flag_cx_fortran_rules) Optimization
1124 Complex multiplication and division follow Fortran rules.
1127 Common Report Var(flag_data_sections)
1128 Place data items into their own section.
1131 Common Report Var(common_deferred_options) Defer
1132 List all available debugging counters with their limits and counts.
1135 Common RejectNegative Joined Var(common_deferred_options) Defer
1136 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
1139 Common Joined RejectNegative Var(common_deferred_options) Defer
1140 Map one directory name to another in debug information.
1142 fdebug-types-section
1143 Common Report Var(flag_debug_types_section) Init(0)
1144 Output .debug_types section when using DWARF v4 debuginfo.
1146 ; Nonzero for -fdefer-pop: don't pop args after each function call
1147 ; instead save them up to pop many calls' args with one insns.
1149 Common Report Var(flag_defer_pop) Optimization
1150 Defer popping functions args from stack until later.
1153 Common Report Var(flag_delayed_branch) Optimization
1154 Attempt to fill delay slots of branch instructions.
1156 fdelete-dead-exceptions
1157 Common Report Var(flag_delete_dead_exceptions) Init(0) Optimization
1158 Delete dead instructions that may throw exceptions.
1160 fdelete-null-pointer-checks
1161 Common Report Var(flag_delete_null_pointer_checks) Init(-1) Optimization
1162 Delete useless null pointer checks.
1164 fdevirtualize-at-ltrans
1165 Common Report Var(flag_ltrans_devirtualize)
1166 Stream extra data to support more aggressive devirtualization in LTO local transformation mode.
1168 fdevirtualize-speculatively
1169 Common Report Var(flag_devirtualize_speculatively) Optimization
1170 Perform speculative devirtualization.
1173 Common Report Var(flag_devirtualize) Optimization
1174 Try to convert virtual calls to direct ones.
1176 fdiagnostics-show-location=
1177 Common Joined RejectNegative Enum(diagnostic_prefixing_rule)
1178 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics.
1180 ; Required for these enum values.
1185 Name(diagnostic_prefixing_rule) Type(int)
1188 Enum(diagnostic_prefixing_rule) String(once) Value(DIAGNOSTICS_SHOW_PREFIX_ONCE)
1191 Enum(diagnostic_prefixing_rule) String(every-line) Value(DIAGNOSTICS_SHOW_PREFIX_EVERY_LINE)
1193 fdiagnostics-show-caret
1194 Common Var(flag_diagnostics_show_caret) Init(1)
1195 Show the source line with a caret indicating the column.
1198 Common Alias(fdiagnostics-color=,always,never)
1202 Driver Common Joined RejectNegative Var(flag_diagnostics_show_color) Enum(diagnostic_color_rule) Init(DIAGNOSTICS_COLOR_NO)
1203 -fdiagnostics-color=[never|always|auto] Colorize diagnostics.
1205 ; Required for these enum values.
1210 Name(diagnostic_color_rule) Type(int)
1213 Enum(diagnostic_color_rule) String(never) Value(DIAGNOSTICS_COLOR_NO)
1216 Enum(diagnostic_color_rule) String(always) Value(DIAGNOSTICS_COLOR_YES)
1219 Enum(diagnostic_color_rule) String(auto) Value(DIAGNOSTICS_COLOR_AUTO)
1221 fdiagnostics-parseable-fixits
1222 Common Var(flag_diagnostics_parseable_fixits)
1223 Print fixit hints in machine-readable form.
1225 fdiagnostics-generate-patch
1226 Common Var(flag_diagnostics_generate_patch)
1227 Print fix-it hints to stderr in unified diff format.
1229 fdiagnostics-show-option
1230 Common Var(flag_diagnostics_show_option) Init(1)
1231 Amend appropriate diagnostic messages with the command line option that controls them.
1234 Common Joined RejectNegative Var(common_deferred_options) Defer
1235 -fdisable-[tree|rtl|ipa]-<pass>=range1+range2 disables an optimization pass.
1238 Common Joined RejectNegative Var(common_deferred_options) Defer
1239 -fenable-[tree|rtl|ipa]-<pass>=range1+range2 enables an optimization pass.
1242 Common Joined RejectNegative Var(common_deferred_options) Defer
1243 -fdump-<type> Dump various compiler internals to a file.
1246 Driver RejectNegative
1249 Common RejectNegative Joined Var(flag_dump_final_insns)
1250 -fdump-final-insns=filename Dump to filename the insns at the end of translation.
1253 Common RejectNegative Joined Var(flag_dump_go_spec)
1254 -fdump-go-spec=filename Write all declarations to file as Go code.
1257 Common Report Var(flag_dump_noaddr)
1258 Suppress output of addresses in debugging dumps.
1261 Common Driver Var(flag_report_bug)
1262 Collect and dump debug information into temporary file if ICE in C/C++
1265 fdump-internal-locations
1266 Common Var(flag_dump_locations) Init(0)
1267 Dump detailed information on GCC's internal representation of source code locations.
1270 Common Var(flag_dump_passes) Init(0)
1271 Dump optimization passes.
1274 Common Report Var(flag_dump_unnumbered)
1275 Suppress output of instruction numbers, line number notes and addresses in debugging dumps.
1277 fdump-unnumbered-links
1278 Common Report Var(flag_dump_unnumbered_links)
1279 Suppress output of previous and next insn numbers in debugging dumps.
1282 Common Report Var(flag_dwarf2_cfi_asm) Init(HAVE_GAS_CFI_DIRECTIVE)
1283 Enable CFI tables via GAS assembler directives.
1286 Common Report Var(flag_early_inlining) Init(1) Optimization
1287 Perform early inlining.
1289 feliminate-dwarf2-dups
1290 Common Report Var(flag_eliminate_dwarf2_dups)
1291 Perform DWARF duplicate elimination.
1294 Common Report Var(flag_ipa_sra) Init(0) Optimization
1295 Perform interprocedural reduction of aggregates.
1297 feliminate-unused-debug-symbols
1298 Common Report Var(flag_debug_only_used_symbols)
1299 Perform unused symbol elimination in debug info.
1301 feliminate-unused-debug-types
1302 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
1303 Perform unused type elimination in debug info.
1305 femit-class-debug-always
1306 Common Report Var(flag_emit_class_debug_always) Init(0)
1307 Do not suppress C++ class debug information.
1310 Common Report Var(flag_exceptions) Optimization
1311 Enable exception handling.
1313 fexpensive-optimizations
1314 Common Report Var(flag_expensive_optimizations) Optimization
1315 Perform a number of minor, expensive optimizations.
1318 Common Joined RejectNegative Enum(excess_precision) Var(flag_excess_precision_cmdline) Init(EXCESS_PRECISION_DEFAULT)
1319 -fexcess-precision=[fast|standard] Specify handling of excess floating-point precision.
1322 Name(excess_precision) Type(enum excess_precision) UnknownError(unknown excess precision style %qs)
1325 Enum(excess_precision) String(fast) Value(EXCESS_PRECISION_FAST)
1328 Enum(excess_precision) String(standard) Value(EXCESS_PRECISION_STANDARD)
1334 Common Var(flag_fat_lto_objects)
1335 Output lto objects containing both the intermediate language and binary output.
1338 Common Report Var(flag_finite_math_only) Optimization SetByCombined
1339 Assume no NaNs or infinities are generated.
1342 Common Joined RejectNegative Var(common_deferred_options) Defer
1343 -ffixed-<register> Mark <register> as being unavailable to the compiler.
1346 Common Report Var(flag_float_store) Optimization
1347 Don't allocate floats and doubles in extended-precision registers.
1351 Does nothing. Preserved for backward compatibility.
1354 Common Report Var(flag_forward_propagate) Optimization
1355 Perform a forward propagation pass on RTL.
1358 Common Joined RejectNegative Enum(fp_contract_mode) Var(flag_fp_contract_mode) Init(FP_CONTRACT_FAST) Optimization
1359 -ffp-contract=[off|on|fast] Perform floating-point expression contraction.
1362 Name(fp_contract_mode) Type(enum fp_contract_mode) UnknownError(unknown floating point contraction style %qs)
1365 Enum(fp_contract_mode) String(off) Value(FP_CONTRACT_OFF)
1367 ; Not implemented, fall back to conservative FP_CONTRACT_OFF.
1369 Enum(fp_contract_mode) String(on) Value(FP_CONTRACT_OFF)
1372 Enum(fp_contract_mode) String(fast) Value(FP_CONTRACT_FAST)
1374 ffp-int-builtin-inexact
1375 Common Report Var(flag_fp_int_builtin_inexact) Init(1) Optimization
1376 Allow built-in functions ceil, floor, round, trunc to raise \"inexact\" exceptions.
1378 ; Nonzero means don't put addresses of constant functions in registers.
1379 ; Used for compiling the Unix kernel, where strange substitutions are
1380 ; done on the assembly output.
1382 Common Report Var(flag_no_function_cse,0) Optimization
1383 Allow function addresses to be held in registers.
1386 Common Report Var(flag_function_sections)
1387 Place each function into its own section.
1390 Common Report Var(flag_gcse) Optimization
1391 Perform global common subexpression elimination.
1394 Common Report Var(flag_gcse_lm) Init(1) Optimization
1395 Perform enhanced load motion during global common subexpression elimination.
1398 Common Report Var(flag_gcse_sm) Init(0) Optimization
1399 Perform store motion after global common subexpression elimination.
1402 Common Report Var(flag_gcse_las) Init(0) Optimization
1403 Perform redundant load after store elimination in global common subexpression
1407 Common Report Var(flag_gcse_after_reload) Optimization
1408 Perform global common subexpression elimination after register allocation has
1412 Name(dwarf_gnat_encodings) Type(int)
1415 Enum(dwarf_gnat_encodings) String(all) Value(DWARF_GNAT_ENCODINGS_ALL)
1418 Enum(dwarf_gnat_encodings) String(gdb) Value(DWARF_GNAT_ENCODINGS_GDB)
1421 Enum(dwarf_gnat_encodings) String(minimal) Value(DWARF_GNAT_ENCODINGS_MINIMAL)
1424 Common Enum(dwarf_gnat_encodings) Joined RejectNegative Report Undocumented Var(gnat_encodings)
1425 -fgnat-encodings=[all|gdb|minimal] Select the balance between GNAT encodings and standard DWARF emitted in the debug information
1427 ; This option is not documented yet as its semantics will change.
1429 Common Report Var(flag_graphite) Optimization
1430 Enable in and out of Graphite representation.
1433 Common Report Var(flag_graphite_identity) Optimization
1434 Enable Graphite Identity transformation.
1436 fhoist-adjacent-loads
1437 Common Report Var(flag_hoist_adjacent_loads) Optimization
1438 Enable hoisting adjacent loads to encourage generating conditional move
1442 Common Undocumented Report Var(flag_keep_gc_roots_live) Optimization
1443 ; Always keep a pointer to a live memory block
1445 floop-parallelize-all
1446 Common Report Var(flag_loop_parallelize_all) Optimization
1447 Mark all loops as parallel.
1450 Common Alias(floop-nest-optimize)
1451 Enable loop nest transforms. Same as -floop-nest-optimize.
1454 Common Alias(floop-nest-optimize)
1455 Enable loop nest transforms. Same as -floop-nest-optimize.
1458 Common Alias(floop-nest-optimize)
1459 Enable loop nest transforms. Same as -floop-nest-optimize.
1461 floop-unroll-and-jam
1462 Common Alias(floop-nest-optimize)
1463 Enable loop nest transforms. Same as -floop-nest-optimize.
1466 Common Report Var(flag_tm)
1467 Enable support for GNU transactional memory.
1470 Common Report Var(flag_gnu_unique) Init(1)
1471 Use STB_GNU_UNIQUE if supported by the assembler.
1475 Does nothing. Preserved for backward compatibility.
1478 Common Report Var(flag_loop_nest_optimize) Optimization
1479 Enable the loop nest optimizer.
1481 fstrict-volatile-bitfields
1482 Common Report Var(flag_strict_volatile_bitfields) Init(-1) Optimization
1483 Force bitfield accesses to match their type width.
1486 Common Report Var(flag_store_merging) Optimization
1487 Merge adjacent stores.
1489 fguess-branch-probability
1490 Common Report Var(flag_guess_branch_prob) Optimization
1491 Enable guessing of branch probabilities.
1493 ; Nonzero means ignore `#ident' directives. 0 means handle them.
1494 ; Generate position-independent code for executables if possible
1495 ; On SVR4 targets, it also controls whether or not to emit a
1496 ; string identifying the compiler.
1498 Common Report Var(flag_no_ident,0)
1499 Process #ident directives.
1502 Common Report Var(flag_if_conversion) Optimization
1503 Perform conversion of conditional jumps to branchless equivalents.
1506 Common Report Var(flag_if_conversion2) Optimization
1507 Perform conversion of conditional jumps to conditional execution.
1510 Common Joined RejectNegative Enum(stack_reuse_level) Var(flag_stack_reuse) Init(SR_ALL) Optimization
1511 -fstack-reuse=[all|named_vars|none] Set stack reuse level for local variables.
1514 Name(stack_reuse_level) Type(enum stack_reuse_level) UnknownError(unknown Stack Reuse Level %qs)
1517 Enum(stack_reuse_level) String(all) Value(SR_ALL)
1520 Enum(stack_reuse_level) String(named_vars) Value(SR_NAMED_VARS)
1523 Enum(stack_reuse_level) String(none) Value(SR_NONE)
1525 ftree-loop-if-convert
1526 Common Report Var(flag_tree_loop_if_convert) Init(-1) Optimization
1527 Convert conditional jumps in innermost loops to branchless equivalents.
1529 ftree-loop-if-convert-stores
1530 Common Report Var(flag_tree_loop_if_convert_stores) Optimization
1531 Also if-convert conditional jumps containing memory writes.
1533 ; -finhibit-size-directive inhibits output of .size for ELF.
1534 ; This is used only for compiling crtstuff.c,
1535 ; and it may be extended to other effects
1536 ; needed for crtstuff.c on other systems.
1537 finhibit-size-directive
1538 Common Report Var(flag_inhibit_size_directive)
1539 Do not generate .size directives.
1542 Common Report Var(flag_indirect_inlining) Optimization
1543 Perform indirect inlining.
1545 ; General flag to enable inlining. Specifying -fno-inline will disable
1546 ; all inlining apart from always-inline functions.
1548 Common Report Var(flag_no_inline,0) Init(0) Optimization
1549 Enable inlining of function declared \"inline\", disabling disables all inlining.
1551 finline-small-functions
1552 Common Report Var(flag_inline_small_functions) Optimization
1553 Integrate functions into their callers when code size is known not to grow.
1556 Common Report Var(flag_inline_functions) Optimization
1557 Integrate functions not declared \"inline\" into their callers when profitable.
1559 finline-functions-called-once
1560 Common Report Var(flag_inline_functions_called_once) Optimization
1561 Integrate functions only required by their single caller.
1564 Common RejectNegative Joined Alias(finline-limit=)
1567 Common RejectNegative Joined UInteger
1568 -finline-limit=<number> Limit the size of inlined functions to <number>.
1571 Common Report Var(flag_inline_atomics) Init(1) Optimization
1572 Inline __atomic operations when a lock free instruction sequence is available.
1574 finstrument-functions
1575 Common Report Var(flag_instrument_function_entry_exit)
1576 Instrument function entry and exit with profiling calls.
1578 finstrument-functions-exclude-function-list=
1579 Common RejectNegative Joined
1580 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions.
1582 finstrument-functions-exclude-file-list=
1583 Common RejectNegative Joined
1584 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files.
1587 Common Report Var(flag_ipa_cp) Optimization
1588 Perform interprocedural constant propagation.
1591 Common Report Var(flag_ipa_cp_clone) Optimization
1592 Perform cloning to make Interprocedural constant propagation stronger.
1595 Common Report Var(flag_ipa_cp_alignment) Optimization
1596 Perform alignment discovery and propagation to make Interprocedural constant propagation stronger.
1599 Common Report Var(flag_ipa_bit_cp) Optimization
1600 Perform interprocedural bitwise constant propagation.
1603 Common Report Var(flag_ipa_profile) Init(0) Optimization
1604 Perform interprocedural profile propagation.
1607 Common Report Var(flag_ipa_pta) Init(0) Optimization
1608 Perform interprocedural points-to analysis.
1611 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
1612 Discover pure and const functions.
1615 Common Report Var(flag_ipa_icf) Optimization
1616 Perform Identical Code Folding for functions and read-only variables.
1619 Common Report Var(flag_ipa_icf_functions) Optimization
1620 Perform Identical Code Folding for functions.
1623 Common Report Var(flag_ipa_icf_variables) Optimization
1624 Perform Identical Code Folding for variables.
1627 Common Report Var(flag_ipa_reference) Init(0) Optimization
1628 Discover readonly and non addressable static variables.
1632 Does nothing. Preserved for backward compatibility.
1636 Does nothing. Preserved for backward compatibility.
1639 Common Report Var(flag_ipa_vrp) Optimization
1640 Perform IPA Value Range Propagation.
1643 Common Joined RejectNegative Enum(ira_algorithm) Var(flag_ira_algorithm) Init(IRA_ALGORITHM_CB) Optimization
1644 -fira-algorithm=[CB|priority] Set the used IRA algorithm.
1647 Name(ira_algorithm) Type(enum ira_algorithm) UnknownError(unknown IRA algorithm %qs)
1650 Enum(ira_algorithm) String(CB) Value(IRA_ALGORITHM_CB)
1653 Enum(ira_algorithm) String(priority) Value(IRA_ALGORITHM_PRIORITY)
1656 Common Joined RejectNegative Enum(ira_region) Var(flag_ira_region) Init(IRA_REGION_AUTODETECT) Optimization
1657 -fira-region=[one|all|mixed] Set regions for IRA.
1660 Name(ira_region) Type(enum ira_region) UnknownError(unknown IRA region %qs)
1663 Enum(ira_region) String(one) Value(IRA_REGION_ONE)
1666 Enum(ira_region) String(all) Value(IRA_REGION_ALL)
1669 Enum(ira_region) String(mixed) Value(IRA_REGION_MIXED)
1672 Common Report Var(flag_ira_hoist_pressure) Init(1) Optimization
1673 Use IRA based register pressure calculation
1674 in RTL hoist optimizations.
1677 Common Report Var(flag_ira_loop_pressure) Optimization
1678 Use IRA based register pressure calculation
1679 in RTL loop optimizations.
1681 fira-share-save-slots
1682 Common Report Var(flag_ira_share_save_slots) Init(1) Optimization
1683 Share slots for saving different hard registers.
1685 fira-share-spill-slots
1686 Common Report Var(flag_ira_share_spill_slots) Init(1) Optimization
1687 Share stack slots for spilled pseudo-registers.
1690 Common RejectNegative Joined UInteger Var(flag_ira_verbose) Init(5)
1691 -fira-verbose=<number> Control IRA's level of diagnostic messages.
1694 Common Report Var(flag_ivopts) Init(1) Optimization
1695 Optimize induction variables on trees.
1698 Common Var(flag_jump_tables) Init(1) Optimization
1699 Use jump tables for sufficiently large switch statements.
1701 fkeep-inline-functions
1702 Common Report Var(flag_keep_inline_functions)
1703 Generate code for functions even if they are fully inlined.
1705 fkeep-static-functions
1706 Common Report Var(flag_keep_static_functions)
1707 Generate code for static functions even if they are never called.
1710 Common Report Var(flag_keep_static_consts) Init(1)
1711 Emit static const variables even if they are not used.
1714 Common Report Var(flag_leading_underscore) Init(-1)
1715 Give external symbols a leading underscore.
1719 Does nothing. Preserved for backward compatibility.
1722 Common Report Var(flag_lra_remat) Optimization
1723 Do CFG-sensitive rematerialization in LRA.
1727 Enable link-time optimization.
1730 Common RejectNegative Joined Var(flag_lto)
1731 Link-time optimization with number of parallel jobs or jobserver.
1734 Name(lto_partition_model) Type(enum lto_partition_model) UnknownError(unknown LTO partitioning model %qs)
1737 Enum(lto_partition_model) String(none) Value(LTO_PARTITION_NONE)
1740 Enum(lto_partition_model) String(one) Value(LTO_PARTITION_ONE)
1743 Enum(lto_partition_model) String(balanced) Value(LTO_PARTITION_BALANCED)
1746 Enum(lto_partition_model) String(1to1) Value(LTO_PARTITION_1TO1)
1749 Enum(lto_partition_model) String(max) Value(LTO_PARTITION_MAX)
1752 Common Joined RejectNegative Enum(lto_partition_model) Var(flag_lto_partition) Init(LTO_PARTITION_BALANCED)
1753 Specify the algorithm to partition symbols and vars at linktime.
1755 ; The initial value of -1 comes from Z_DEFAULT_COMPRESSION in zlib.h.
1756 flto-compression-level=
1757 Common Joined RejectNegative UInteger Var(flag_lto_compression_level) Init(-1)
1758 -flto-compression-level=<number> Use zlib compression level <number> for IL.
1760 flto-odr-type-merging
1761 Common Report Var(flag_lto_odr_type_mering) Init(1)
1762 Merge C++ types using One Definition Rule.
1765 Common Report Var(flag_lto_report) Init(0)
1766 Report various link-time optimization statistics.
1769 Common Report Var(flag_lto_report_wpa) Init(0)
1770 Report various link-time optimization statistics for WPA only.
1773 Common Report Var(flag_errno_math) Init(1) Optimization SetByCombined
1774 Set errno after built-in math functions.
1777 Common Joined RejectNegative UInteger Var(flag_max_errors)
1778 -fmax-errors=<number> Maximum number of errors to report.
1781 Common Report Var(mem_report)
1782 Report on permanent memory allocation.
1785 Common Report Var(mem_report_wpa)
1786 Report on permanent memory allocation in WPA only.
1788 ; This will attempt to merge constant section constants, if 1 only
1789 ; string constants and constants from constant pool, if 2 also constant
1791 fmerge-all-constants
1792 Common Report Var(flag_merge_constants,2) Init(1)
1793 Attempt to merge identical constants and constant variables.
1796 Common Report Var(flag_merge_constants,1)
1797 Attempt to merge identical constants across compilation units.
1799 fmerge-debug-strings
1800 Common Report Var(flag_merge_debug_strings) Init(1)
1801 Attempt to merge identical debug strings across compilation units.
1804 Common RejectNegative Joined UInteger
1805 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping.
1808 Common Report Var(flag_modulo_sched) Optimization
1809 Perform SMS based modulo scheduling before the first scheduling pass.
1811 fmodulo-sched-allow-regmoves
1812 Common Report Var(flag_modulo_sched_allow_regmoves) Optimization
1813 Perform SMS based modulo scheduling with register moves allowed.
1815 fmove-loop-invariants
1816 Common Report Var(flag_move_loop_invariants) Optimization
1817 Move loop invariant computations out of loops.
1820 Common Var(flag_dce) Init(1) Optimization
1821 Use the RTL dead code elimination pass.
1824 Common Var(flag_dse) Init(1) Optimization
1825 Use the RTL dead store elimination pass.
1827 freschedule-modulo-scheduled-loops
1828 Common Report Var(flag_resched_modulo_sched) Optimization
1829 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling.
1831 fnon-call-exceptions
1832 Common Report Var(flag_non_call_exceptions) Optimization
1833 Support synchronous non-call exceptions.
1836 Common Driver Joined MissingArgError(options or targets missing after %qs)
1837 -foffload=<targets>=<options> Specify offloading targets and options for them.
1840 Common Joined RejectNegative Enum(offload_abi) Var(flag_offload_abi) Init(OFFLOAD_ABI_UNSET)
1841 -foffload-abi=[lp64|ilp32] Set the ABI to use in an offload compiler.
1844 Name(offload_abi) Type(enum offload_abi) UnknownError(unknown offload ABI %qs)
1847 Enum(offload_abi) String(ilp32) Value(OFFLOAD_ABI_ILP32)
1850 Enum(offload_abi) String(lp64) Value(OFFLOAD_ABI_LP64)
1853 Common Report Var(flag_omit_frame_pointer) Optimization
1854 When possible do not generate stack frames.
1857 Common Report Var(flag_opt_info) Optimization
1858 Enable all optimization info dumps on stderr.
1861 Common Joined RejectNegative Var(common_deferred_options) Defer
1862 -fopt-info[-<type>=filename] Dump compiler optimization details.
1864 foptimize-register-move
1866 Does nothing. Preserved for backward compatibility.
1868 foptimize-sibling-calls
1869 Common Report Var(flag_optimize_sibling_calls) Optimization
1870 Optimize sibling and tail recursive calls.
1873 Common Report Var(flag_partial_inlining) Optimization
1874 Perform partial inlining.
1877 Common Report Var(pre_ipa_mem_report)
1878 Report on memory allocation before interprocedural optimization.
1880 fpost-ipa-mem-report
1881 Common Report Var(post_ipa_mem_report)
1882 Report on memory allocation before interprocedural optimization.
1885 Common Report Var(flag_pack_struct) Optimization
1886 Pack structure members together without holes.
1889 Common RejectNegative Joined UInteger Optimization
1890 -fpack-struct=<number> Set initial maximum structure member alignment.
1893 Common Report Var(flag_pcc_struct_return,1) Init(DEFAULT_PCC_STRUCT_RETURN)
1894 Return small aggregates in memory, not registers.
1897 Common Report Var(flag_peel_loops) Optimization
1898 Perform loop peeling.
1901 Common Report Var(flag_no_peephole,0) Optimization
1902 Enable machine specific peephole optimizations.
1905 Common Report Var(flag_peephole2) Optimization
1906 Enable an RTL peephole pass before sched2.
1909 Common Report Var(flag_pic,2) Negative(fPIE) Init(-1)
1910 Generate position-independent code if possible (large mode).
1913 Common Report Var(flag_pie,2) Negative(fpic) Init(-1)
1914 Generate position-independent code for executables if possible (large mode).
1917 Common Report Var(flag_pic,1) Negative(fpie) Init(-1)
1918 Generate position-independent code if possible (small mode).
1921 Common Report Var(flag_pie,1) Negative(fPIC) Init(-1)
1922 Generate position-independent code for executables if possible (small mode).
1925 Common Report Var(flag_plt) Init(1) Optimization
1926 Use PLT for PIC calls (-fno-plt: load the address from GOT at call site).
1929 Common Joined RejectNegative Var(common_deferred_options) Defer
1930 Specify a plugin to load.
1933 Common Joined RejectNegative Var(common_deferred_options) Defer
1934 -fplugin-arg-<name>-<key>[=<value>] Specify argument <key>=<value> for plugin <name>.
1936 fpredictive-commoning
1937 Common Report Var(flag_predictive_commoning) Optimization
1938 Run predictive commoning optimization.
1940 fprefetch-loop-arrays
1941 Common Report Var(flag_prefetch_loop_arrays) Init(-1) Optimization
1942 Generate prefetch instructions, if available, for arrays in loops.
1945 Common Report Var(profile_flag)
1946 Enable basic program profiling code.
1949 Common Report Var(profile_arc_flag)
1950 Insert arc-based program profiling code.
1953 Common Joined RejectNegative Var(profile_data_prefix)
1954 Set the top-level directory for storing the profile data.
1955 The default is 'pwd'.
1958 Common Report Var(flag_profile_correction)
1959 Enable correction of flow inconsistent profile data input.
1962 Common Joined RejectNegative Enum(profile_update) Var(flag_profile_update) Init(PROFILE_UPDATE_SINGLE)
1963 -fprofile-update=[single|atomic] Set the profile update method.
1966 Name(profile_update) Type(enum profile_update) UnknownError(unknown profile update method %qs)
1969 Enum(profile_update) String(single) Value(PROFILE_UPDATE_SINGLE)
1972 Enum(profile_update) String(atomic) Value(PROFILE_UPDATE_ATOMIC)
1976 Enable common options for generating profile info for profile feedback directed optimizations.
1979 Common Joined RejectNegative
1980 Enable common options for generating profile info for profile feedback directed optimizations, and set -fprofile-dir=.
1983 Common Var(flag_profile_use)
1984 Enable common options for performing profile feedback directed optimizations.
1987 Common Joined RejectNegative
1988 Enable common options for performing profile feedback directed optimizations, and set -fprofile-dir=.
1991 Common Report Var(flag_profile_values)
1992 Insert code to profile values of expressions.
1995 Common Report Var(profile_report)
1996 Report on consistency of profile.
1998 fprofile-reorder-functions
1999 Common Report Var(flag_profile_reorder_functions)
2000 Enable function reordering that improves code placement.
2003 Common Var(common_deferred_options) Defer
2006 Common Joined RejectNegative Var(common_deferred_options) Defer
2007 -frandom-seed=<string> Make compile reproducible using <string>.
2009 ; This switch causes the command line that was used to create an
2010 ; object file to be recorded into the object file. The exact format
2011 ; of this recording is target and binary file format dependent.
2012 ; It is related to the -fverbose-asm switch, but that switch only
2013 ; records information in the assembler output file as comments, so
2014 ; they never reach the object file.
2015 frecord-gcc-switches
2016 Common Report Var(flag_record_gcc_switches)
2017 Record gcc command line switches in the object file.
2020 Common Report Var(flag_pcc_struct_return,0) Optimization
2021 Return small aggregates in registers.
2025 Does nothing. Preserved for backward compatibility.
2028 Common Report Var(flag_lifetime_dse,2) Init(2) Optimization
2029 Tell DSE that the storage for a C++ object is dead when the constructor
2030 starts and when the destructor finishes.
2033 Common Joined RejectNegative UInteger Var(flag_lifetime_dse) Optimization
2035 flive-range-shrinkage
2036 Common Report Var(flag_live_range_shrinkage) Init(0) Optimization
2037 Relief of register pressure through live range shrinkage.
2040 Common Report Var(flag_rename_registers) Init(2) Optimization
2041 Perform a register renaming optimization pass.
2044 Common Report Var(flag_schedule_fusion) Init(2) Optimization
2045 Perform a target dependent instruction fusion optimization pass.
2048 Common Report Var(flag_reorder_blocks) Optimization
2049 Reorder basic blocks to improve code placement.
2051 freorder-blocks-algorithm=
2052 Common Joined RejectNegative Enum(reorder_blocks_algorithm) Var(flag_reorder_blocks_algorithm) Init(REORDER_BLOCKS_ALGORITHM_SIMPLE) Optimization
2053 -freorder-blocks-algorithm=[simple|stc] Set the used basic block reordering algorithm.
2056 Name(reorder_blocks_algorithm) Type(enum reorder_blocks_algorithm) UnknownError(unknown basic block reordering algorithm %qs)
2059 Enum(reorder_blocks_algorithm) String(simple) Value(REORDER_BLOCKS_ALGORITHM_SIMPLE)
2062 Enum(reorder_blocks_algorithm) String(stc) Value(REORDER_BLOCKS_ALGORITHM_STC)
2064 freorder-blocks-and-partition
2065 Common Report Var(flag_reorder_blocks_and_partition) Optimization
2066 Reorder basic blocks and partition into hot and cold sections.
2069 Common Report Var(flag_reorder_functions) Optimization
2070 Reorder functions to improve code placement.
2072 frerun-cse-after-loop
2073 Common Report Var(flag_rerun_cse_after_loop) Optimization
2074 Add a common subexpression elimination pass after loop optimizations.
2078 Does nothing. Preserved for backward compatibility.
2081 Common Report Var(flag_rounding_math) Optimization SetByCombined
2082 Disable optimizations that assume default FP rounding behavior.
2085 Common Report Var(flag_schedule_interblock) Init(1) Optimization
2086 Enable scheduling across basic blocks.
2089 Common Report Var(flag_sched_pressure) Init(0) Optimization
2090 Enable register pressure sensitive insn scheduling.
2093 Common Report Var(flag_schedule_speculative) Init(1) Optimization
2094 Allow speculative motion of non-loads.
2097 Common Report Var(flag_schedule_speculative_load) Optimization
2098 Allow speculative motion of some loads.
2100 fsched-spec-load-dangerous
2101 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
2102 Allow speculative motion of more loads.
2105 Common RejectNegative Joined UInteger Var(sched_verbose_param) Init(1)
2106 -fsched-verbose=<number> Set the verbosity level of the scheduler.
2108 fsched2-use-superblocks
2109 Common Report Var(flag_sched2_use_superblocks) Optimization
2110 If scheduling post reload, do superblock scheduling.
2114 Does nothing. Preserved for backward compatibility.
2117 Common Report Var(flag_schedule_insns) Optimization
2118 Reschedule instructions before register allocation.
2121 Common Report Var(flag_schedule_insns_after_reload) Optimization
2122 Reschedule instructions after register allocation.
2124 ; This flag should be on when a target implements non-trivial
2125 ; scheduling hooks, maybe saving some information for its own sake.
2126 ; On IA64, for example, this is used for correct bundling.
2127 fselective-scheduling
2128 Common Report Var(flag_selective_scheduling) Optimization
2129 Schedule instructions using selective scheduling algorithm.
2131 fselective-scheduling2
2132 Common Report Var(flag_selective_scheduling2) Optimization
2133 Run selective scheduling after reload.
2136 Common Undocumented Var(flag_self_test)
2139 fsel-sched-pipelining
2140 Common Report Var(flag_sel_sched_pipelining) Init(0) Optimization
2141 Perform software pipelining of inner loops during selective scheduling.
2143 fsel-sched-pipelining-outer-loops
2144 Common Report Var(flag_sel_sched_pipelining_outer_loops) Init(0) Optimization
2145 Perform software pipelining of outer loops during selective scheduling.
2147 fsel-sched-reschedule-pipelined
2148 Common Report Var(flag_sel_sched_reschedule_pipelined) Init(0) Optimization
2149 Reschedule pipelined regions without pipelining.
2151 fsemantic-interposition
2152 Common Report Var(flag_semantic_interposition) Init(1)
2153 Allow interposing function (or variables) by ones with different semantics (or initializer) respectively by dynamic linker.
2155 ; sched_stalled_insns means that insns can be moved prematurely from the queue
2156 ; of stalled insns into the ready list.
2157 fsched-stalled-insns
2158 Common Report Var(flag_sched_stalled_insns) Optimization UInteger
2159 Allow premature scheduling of queued insns.
2161 fsched-stalled-insns=
2162 Common RejectNegative Joined UInteger Optimization
2163 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled.
2165 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
2166 ; be examined for a dependency on a stalled insn that is candidate for
2167 ; premature removal from the queue of stalled insns into the ready list (has
2168 ; an effect only if the flag 'sched_stalled_insns' is set).
2169 fsched-stalled-insns-dep
2170 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization UInteger
2171 Set dependence distance checking in premature scheduling of queued insns.
2173 fsched-stalled-insns-dep=
2174 Common RejectNegative Joined UInteger Optimization
2175 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns.
2177 fsched-group-heuristic
2178 Common Report Var(flag_sched_group_heuristic) Init(1) Optimization
2179 Enable the group heuristic in the scheduler.
2181 fsched-critical-path-heuristic
2182 Common Report Var(flag_sched_critical_path_heuristic) Init(1) Optimization
2183 Enable the critical path heuristic in the scheduler.
2185 fsched-spec-insn-heuristic
2186 Common Report Var(flag_sched_spec_insn_heuristic) Init(1) Optimization
2187 Enable the speculative instruction heuristic in the scheduler.
2189 fsched-rank-heuristic
2190 Common Report Var(flag_sched_rank_heuristic) Init(1) Optimization
2191 Enable the rank heuristic in the scheduler.
2193 fsched-last-insn-heuristic
2194 Common Report Var(flag_sched_last_insn_heuristic) Init(1) Optimization
2195 Enable the last instruction heuristic in the scheduler.
2197 fsched-dep-count-heuristic
2198 Common Report Var(flag_sched_dep_count_heuristic) Init(1) Optimization
2199 Enable the dependent count heuristic in the scheduler.
2202 Common Report Var(flag_section_anchors) Optimization
2203 Access data in the same section from shared anchor points.
2207 Does nothing. Preserved for backward compatibility.
2211 Does nothing. Preserved for backward compatibility.
2214 Common Report Var(flag_ree) Init(0)
2215 Turn on Redundant Extensions Elimination pass.
2218 Common Report Var(flag_show_column) Init(1)
2219 Show column numbers in diagnostics, when available. Default on.
2222 Common Report Var(flag_shrink_wrap) Optimization
2223 Emit function prologues only before parts of the function that need it,
2224 rather than at the top of the function.
2226 fshrink-wrap-separate
2227 Common Report Var(flag_shrink_wrap_separate) Init(1) Optimization
2228 Shrink-wrap parts of the prologue and epilogue separately.
2231 Common Report Var(flag_signaling_nans) Optimization SetByCombined
2232 Disable optimizations observable by IEEE signaling NaNs.
2235 Common Report Var(flag_signed_zeros) Init(1) Optimization SetByCombined
2236 Disable floating point optimizations that ignore the IEEE signedness of zero.
2238 fsingle-precision-constant
2239 Common Report Var(flag_single_precision_constant) Optimization
2240 Convert floating point constants to single precision constants.
2242 fsplit-ivs-in-unroller
2243 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
2244 Split lifetimes of induction variables when loops are unrolled.
2247 Common Report Var(flag_split_stack) Init(-1)
2248 Generate discontiguous stack frames.
2251 Common Report Var(flag_split_wide_types) Optimization
2252 Split wide types into independent registers.
2255 Common Report Var(flag_ssa_backprop) Init(1) Optimization
2256 Enable backward propagation of use properties at the SSA level.
2259 Common Report Var(flag_ssa_phiopt) Optimization
2260 Optimize conditional patterns using SSA PHI nodes.
2263 Common Report Var(flag_stdarg_opt) Init(1) Optimization
2264 Optimize amount of stdarg registers saved to stack at start of function.
2266 fvariable-expansion-in-unroller
2267 Common Report Var(flag_variable_expansion_in_unroller) Optimization
2268 Apply variable expansion when loops are unrolled.
2271 Common Report RejectNegative Joined
2272 -fstack-check=[no|generic|specific] Insert stack checking code into the program.
2275 Common Alias(fstack-check=, specific, no)
2276 Insert stack checking code into the program. Same as -fstack-check=specific.
2279 Common Var(common_deferred_options) Defer
2281 fstack-limit-register=
2282 Common RejectNegative Joined Var(common_deferred_options) Defer
2283 -fstack-limit-register=<register> Trap if the stack goes past <register>.
2285 fstack-limit-symbol=
2286 Common RejectNegative Joined Var(common_deferred_options) Defer
2287 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>.
2290 Common Report Var(flag_stack_protect, 1) Init(-1) Optimization
2291 Use propolice as a stack protection method.
2293 fstack-protector-all
2294 Common Report RejectNegative Var(flag_stack_protect, 2) Init(-1) Optimization
2295 Use a stack protection method for every function.
2297 fstack-protector-strong
2298 Common Report RejectNegative Var(flag_stack_protect, 3) Init(-1) Optimization
2299 Use a smart stack protection method for certain functions.
2301 fstack-protector-explicit
2302 Common Report RejectNegative Var(flag_stack_protect, 4) Optimization
2303 Use stack protection method only for functions with the stack_protect attribute.
2306 Common RejectNegative Var(flag_stack_usage)
2307 Output stack usage information on a per-function basis.
2311 Does nothing. Preserved for backward compatibility.
2313 ; Nonzero if we should do (language-dependent) alias analysis.
2314 ; Typically, this analysis will assume that expressions of certain
2315 ; types do not alias expressions of certain other types. Only used
2316 ; if alias analysis (in general) is enabled.
2318 Common Report Var(flag_strict_aliasing) Optimization
2319 Assume strict aliasing rules apply.
2322 Common Report Var(flag_strict_overflow) Optimization
2323 Treat signed overflow as undefined.
2326 Common Report Var(flag_sync_libcalls) Init(1)
2327 Implement __atomic operations via libcalls to legacy __sync functions.
2330 Common Report Var(flag_syntax_only)
2331 Check for syntax errors, then stop.
2334 Common Report Var(flag_test_coverage)
2335 Create data files needed by \"gcov\".
2338 Common Report Var(flag_thread_jumps) Optimization
2339 Perform jump threading optimizations.
2342 Common Report Var(time_report)
2343 Report the time taken by each compiler pass.
2345 ftime-report-details
2346 Common Report Var(time_report_details)
2347 Record times taken by sub-phases separately.
2350 Common Joined RejectNegative Enum(tls_model) Var(flag_tls_default) Init(TLS_MODEL_GLOBAL_DYNAMIC)
2351 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model.
2354 Name(tls_model) Type(enum tls_model) UnknownError(unknown TLS model %qs)
2357 Enum(tls_model) String(global-dynamic) Value(TLS_MODEL_GLOBAL_DYNAMIC)
2360 Enum(tls_model) String(local-dynamic) Value(TLS_MODEL_LOCAL_DYNAMIC)
2363 Enum(tls_model) String(initial-exec) Value(TLS_MODEL_INITIAL_EXEC)
2366 Enum(tls_model) String(local-exec) Value(TLS_MODEL_LOCAL_EXEC)
2369 Common Report Var(flag_toplevel_reorder) Init(2)
2370 Reorder top level functions, variables, and asms.
2373 Common Report Var(flag_tracer) Optimization
2374 Perform superblock formation via tail duplication.
2377 Common Report Var(flag_trampolines) Init(0)
2378 For targets that normally need trampolines for nested functions, always
2379 generate them instead of using descriptors.
2381 ; Zero means that floating-point math operations cannot generate a
2382 ; (user-visible) trap. This is the case, for example, in nonstop
2383 ; IEEE 754 arithmetic.
2385 Common Report Var(flag_trapping_math) Init(1) Optimization SetByCombined
2386 Assume floating-point operations can trap.
2389 Common Report Var(flag_trapv) Optimization
2390 Trap for signed overflow in addition, subtraction and multiplication.
2393 Common Report Var(flag_tree_ccp) Optimization
2394 Enable SSA-CCP optimization on trees.
2397 Common Report Var(flag_tree_bit_ccp) Optimization
2398 Enable SSA-BIT-CCP optimization on trees.
2402 Does nothing. Preserved for backward compatibility.
2405 Common Report Var(flag_tree_ch) Optimization
2406 Enable loop header copying on trees.
2408 ftree-coalesce-inlined-vars
2409 Common Ignore RejectNegative
2410 Does nothing. Preserved for backward compatibility.
2413 Common Report Var(flag_tree_coalesce_vars) Optimization
2414 Enable SSA coalescing of user variables.
2418 Does nothing. Preserved for backward compatibility.
2421 Common Report Var(flag_tree_copy_prop) Optimization
2422 Enable copy propagation on trees.
2424 ftree-store-copy-prop
2426 Does nothing. Preserved for backward compatibility.
2429 Common Report Var(flag_tree_cselim) Init(2) Optimization
2430 Transform condition stores into unconditional ones.
2432 ftree-switch-conversion
2433 Common Report Var(flag_tree_switch_conversion) Optimization
2434 Perform conversions of switch initializations.
2437 Common Report Var(flag_tree_dce) Optimization
2438 Enable SSA dead code elimination optimization on trees.
2440 ftree-dominator-opts
2441 Common Report Var(flag_tree_dom) Optimization
2442 Enable dominator optimizations.
2445 Common Report Var(flag_tree_tail_merge) Optimization
2446 Enable tail merging on trees.
2449 Common Report Var(flag_tree_dse) Optimization
2450 Enable dead store elimination.
2453 Common Report Var(flag_tree_forwprop) Init(1) Optimization
2454 Enable forward propagation on trees.
2457 Common Report Var(flag_tree_fre) Optimization
2458 Enable Full Redundancy Elimination (FRE) on trees.
2461 Common Report Var(flag_optimize_strlen) Optimization
2462 Enable string length optimizations on trees.
2464 fisolate-erroneous-paths-dereference
2465 Common Report Var(flag_isolate_erroneous_paths_dereference) Optimization
2466 Detect paths that trigger erroneous or undefined behavior due to
2467 dereferencing a null pointer. Isolate those paths from the main control
2468 flow and turn the statement with erroneous or undefined behavior into a trap.
2470 fisolate-erroneous-paths-attribute
2471 Common Report Var(flag_isolate_erroneous_paths_attribute) Optimization
2472 Detect paths that trigger erroneous or undefined behavior due a null value
2473 being used in a way forbidden by a returns_nonnull or nonnull
2474 attribute. Isolate those paths from the main control flow and turn the
2475 statement with erroneous or undefined behavior into a trap.
2477 ftree-loop-distribution
2478 Common Report Var(flag_tree_loop_distribution) Optimization
2479 Enable loop distribution on trees.
2481 ftree-loop-distribute-patterns
2482 Common Report Var(flag_tree_loop_distribute_patterns) Optimization
2483 Enable loop distribution for patterns transformed into a library call.
2486 Common Report Var(flag_tree_loop_im) Init(1) Optimization
2487 Enable loop invariant motion on trees.
2490 Common Alias(floop-nest-optimize)
2491 Enable loop nest transforms. Same as -floop-nest-optimize.
2494 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
2495 Create canonical induction variables in loops.
2498 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
2499 Enable loop optimizations on tree level.
2501 ftree-parallelize-loops=
2502 Common Report Joined RejectNegative UInteger Var(flag_tree_parallelize_loops) Init(1) Optimization
2503 Enable automatic parallelization of loops.
2506 Common Report Var(flag_tree_phiprop) Init(1) Optimization
2507 Enable hoisting loads from conditional pointers.
2510 Common Report Var(flag_tree_pre) Optimization
2511 Enable SSA-PRE optimization on trees.
2514 Common Report Var(flag_tree_partial_pre) Optimization
2515 In SSA-PRE optimization on trees, enable partial-partial redundancy elimination.
2518 Common Report Var(flag_tree_pta) Optimization
2519 Perform function-local points-to analysis on trees.
2522 Common Report Var(flag_tree_reassoc) Init(1) Optimization
2523 Enable reassociation on tree level.
2527 Does nothing. Preserved for backward compatibility.
2530 Common Report Var(flag_tree_sink) Optimization
2531 Enable SSA code sinking on trees.
2534 Common Report Var(flag_tree_slsr) Optimization
2535 Perform straight-line strength reduction.
2538 Common Report Var(flag_tree_sra) Optimization
2539 Perform scalar replacement of aggregates.
2542 Common Report Var(flag_tree_ter) Optimization
2543 Replace temporary expressions in the SSA->normal pass.
2546 Common Report Var(flag_tree_live_range_split) Optimization
2547 Perform live range splitting during the SSA->normal pass.
2550 Common Report Var(flag_tree_vrp) Init(0) Optimization
2551 Perform Value Range Propagation on trees.
2554 Common Report Var(flag_split_paths) Init(0) Optimization
2555 Split paths leading to loop backedges.
2557 funconstrained-commons
2558 Common Var(flag_unconstrained_commons) Optimization
2559 Assume common declarations may be overridden with ones with a larger
2563 Common Report Var(flag_unit_at_a_time) Init(1)
2564 Compile whole compilation unit at a time.
2567 Common Report Var(flag_unroll_loops) Optimization
2568 Perform loop unrolling when iteration count is known.
2571 Common Report Var(flag_unroll_all_loops) Optimization
2572 Perform loop unrolling for all loops.
2574 ; Nonzero means that loop optimizer may assume that the induction variables
2575 ; that control loops do not overflow and that the loops with nontrivial
2576 ; exit condition are not infinite
2577 funsafe-loop-optimizations
2579 Does nothing. Preserved for backward compatibility.
2582 Common Report Var(flag_associative_math) SetByCombined Optimization
2583 Allow optimization for floating-point arithmetic which may change the
2584 result of the operation due to rounding.
2587 Common Report Var(flag_reciprocal_math) SetByCombined Optimization
2588 Same as -fassociative-math for expressions which include division.
2590 ; Nonzero means that unsafe floating-point math optimizations are allowed
2591 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
2592 ; are allowed to assume that their arguments and results are "normal"
2593 ; (e.g., nonnegative for SQRT).
2594 funsafe-math-optimizations
2595 Common Report Var(flag_unsafe_math_optimizations) Optimization SetByCombined
2596 Allow math optimizations that may violate IEEE or ISO standards.
2599 Common Report Var(flag_unswitch_loops) Optimization
2600 Perform loop unswitching.
2603 Common Report Var(flag_split_loops) Optimization
2604 Perform loop splitting.
2607 Common Report Var(flag_unwind_tables) Optimization
2608 Just generate unwind tables for exception handling.
2611 Common Driver Negative(fuse-ld=gold)
2612 Use the bfd linker instead of the default linker.
2615 Common Driver Negative(fuse-ld=bfd)
2616 Use the gold linker instead of the default linker.
2619 Common Undocumented Var(flag_use_linker_plugin)
2621 ; Positive if we should track variables, negative if we should run
2622 ; the var-tracking pass only to discard debug annotations, zero if
2623 ; we're not to run it. When flag_var_tracking == 2 (AUTODETECT_VALUE) it
2624 ; will be set according to optimize, debug_info_level and debug_hooks
2625 ; in process_options ().
2627 Common Report Var(flag_var_tracking) Init(2) Optimization
2628 Perform variable tracking.
2630 ; Positive if we should track variables at assignments, negative if
2631 ; we should run the var-tracking pass only to discard debug
2632 ; annotations. When flag_var_tracking_assignments ==
2633 ; AUTODETECT_VALUE it will be set according to flag_var_tracking.
2634 fvar-tracking-assignments
2635 Common Report Var(flag_var_tracking_assignments) Init(2) Optimization
2636 Perform variable tracking by annotating assignments.
2638 ; Nonzero if we should toggle flag_var_tracking_assignments after
2639 ; processing options and computing its default. */
2640 fvar-tracking-assignments-toggle
2641 Common Report Var(flag_var_tracking_assignments_toggle) Optimization
2642 Toggle -fvar-tracking-assignments.
2644 ; Positive if we should track uninitialized variables, negative if
2645 ; we should run the var-tracking pass only to discard debug
2646 ; annotations. When flag_var_tracking_uninit == AUTODETECT_VALUE it
2647 ; will be set according to flag_var_tracking.
2648 fvar-tracking-uninit
2649 Common Report Var(flag_var_tracking_uninit) Optimization
2650 Perform variable tracking and also tag variables that are uninitialized.
2653 Common Report Var(flag_tree_vectorize) Optimization
2654 Enable vectorization on trees.
2656 ftree-vectorizer-verbose=
2657 Common Joined RejectNegative Ignore
2658 Does nothing. Preserved for backward compatibility.
2660 ftree-loop-vectorize
2661 Common Report Var(flag_tree_loop_vectorize) Optimization
2662 Enable loop vectorization on trees.
2665 Common Report Var(flag_tree_slp_vectorize) Optimization
2666 Enable basic block vectorization (SLP) on trees.
2669 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_vect_cost_model) Init(VECT_COST_MODEL_DEFAULT) Optimization
2670 Specifies the cost model for vectorization.
2673 Common Joined RejectNegative Enum(vect_cost_model) Var(flag_simd_cost_model) Init(VECT_COST_MODEL_UNLIMITED) Optimization
2674 Specifies the vectorization cost model for code marked with a simd directive.
2677 Name(vect_cost_model) Type(enum vect_cost_model) UnknownError(unknown vectorizer cost model %qs)
2680 Enum(vect_cost_model) String(unlimited) Value(VECT_COST_MODEL_UNLIMITED)
2683 Enum(vect_cost_model) String(dynamic) Value(VECT_COST_MODEL_DYNAMIC)
2686 Enum(vect_cost_model) String(cheap) Value(VECT_COST_MODEL_CHEAP)
2689 Common RejectNegative Alias(fvect-cost-model=,dynamic)
2690 Enables the dynamic vectorizer cost model. Preserved for backward compatibility.
2693 Common RejectNegative Alias(fvect-cost-model=,unlimited)
2694 Enables the unlimited vectorizer cost model. Preserved for backward compatibility.
2696 ftree-vect-loop-version
2698 Does nothing. Preserved for backward compatibility.
2701 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
2702 Enable copy propagation of scalar-evolution information.
2704 ; -fverbose-asm causes extra commentary information to be produced in
2705 ; the generated assembly code (to make it more readable). This option
2706 ; is generally only of use to those who actually need to read the
2707 ; generated assembly code (perhaps while debugging the compiler itself).
2708 ; -fno-verbose-asm, the default, causes the extra information
2709 ; to not be added and is useful when comparing two assembler files.
2711 Common Report Var(flag_verbose_asm)
2712 Add extra commentary to assembler output.
2715 Common Joined RejectNegative Enum(symbol_visibility) Var(default_visibility) Init(VISIBILITY_DEFAULT)
2716 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility.
2719 Name(symbol_visibility) Type(enum symbol_visibility) UnknownError(unrecognized visibility value %qs)
2722 Enum(symbol_visibility) String(default) Value(VISIBILITY_DEFAULT)
2725 Enum(symbol_visibility) String(internal) Value(VISIBILITY_INTERNAL)
2728 Enum(symbol_visibility) String(hidden) Value(VISIBILITY_HIDDEN)
2731 Enum(symbol_visibility) String(protected) Value(VISIBILITY_PROTECTED)
2734 Common Joined RejectNegative Enum(vtv_priority) Var(flag_vtable_verify) Init(VTV_NO_PRIORITY)
2735 Validate vtable pointers before using them.
2738 Name(vtv_priority) Type(enum vtv_priority) UnknownError(unknown vtable verify initialization priority %qs)
2741 Enum(vtv_priority) String(none) Value(VTV_NO_PRIORITY)
2744 Enum(vtv_priority) String(std) Value(VTV_STANDARD_PRIORITY)
2747 Enum(vtv_priority) String(preinit) Value(VTV_PREINIT_PRIORITY)
2750 Common Var(flag_vtv_counts)
2751 Output vtable verification counters.
2754 Common Var(flag_vtv_debug)
2755 Output vtable verification pointer sets information.
2758 Common Report Var(flag_value_profile_transformations) Optimization
2759 Use expression value profiles in optimizations.
2762 Common Report Var(flag_web) Init(2) Optimization
2763 Construct webs and split unrelated uses of single variable.
2765 ftree-builtin-call-dce
2766 Common Report Var(flag_tree_builtin_call_dce) Init(0) Optimization
2767 Enable conditional dead code elimination for builtin calls.
2770 Common Report Var(flag_whole_program) Init(0)
2771 Perform whole program optimizations.
2774 Common Report Var(flag_wrapv) Optimization
2775 Assume signed arithmetic overflow wraps around.
2777 fzero-initialized-in-bss
2778 Common Report Var(flag_zero_initialized_in_bss) Init(1)
2779 Put zero initialized data in the bss section.
2782 Common JoinedOrMissing
2783 Generate debug information in default format.
2786 Common JoinedOrMissing Negative(gdwarf)
2787 Generate debug information in COFF format.
2790 Common JoinedOrMissing Negative(gdwarf-)
2791 Generate debug information in default version of DWARF format.
2794 Common Joined UInteger Var(dwarf_version) Init(4) Negative(gstabs)
2795 Generate debug information in DWARF v2 (or later) format.
2798 Common JoinedOrMissing
2799 Generate debug information in default extended format.
2802 Common Negative(gpubnames) Var(debug_generate_pub_sections, 0) Init(-1)
2803 Don't generate DWARF pubnames and pubtypes sections.
2806 Common Negative(ggnu-pubnames) Var(debug_generate_pub_sections, 1)
2807 Generate DWARF pubnames and pubtypes sections.
2810 Common Negative(gno-pubnames) Var(debug_generate_pub_sections, 2)
2811 Generate DWARF pubnames and pubtypes sections with GNU extensions.
2813 gno-record-gcc-switches
2814 Common RejectNegative Var(dwarf_record_gcc_switches,0) Init(1)
2815 Don't record gcc command line switches in DWARF DW_AT_producer.
2817 grecord-gcc-switches
2818 Common RejectNegative Var(dwarf_record_gcc_switches,1)
2819 Record gcc command line switches in DWARF DW_AT_producer.
2822 Common Driver RejectNegative Var(dwarf_split_debug_info,0) Init(0)
2823 Don't generate debug information in separate .dwo files.
2826 Common Driver RejectNegative Var(dwarf_split_debug_info,1)
2827 Generate debug information in separate .dwo files.
2830 Common JoinedOrMissing Negative(gstabs+)
2831 Generate debug information in STABS format.
2834 Common JoinedOrMissing Negative(gvms)
2835 Generate debug information in extended STABS format.
2838 Common RejectNegative Var(dwarf_strict,0) Init(0)
2839 Emit DWARF additions beyond selected version.
2842 Common Report RejectNegative Var(dwarf_strict,1)
2843 Don't emit DWARF additions beyond selected version.
2846 Common Report Var(flag_gtoggle)
2847 Toggle debug information generation.
2850 Common JoinedOrMissing Negative(gxcoff)
2851 Generate debug information in VMS format.
2854 Common JoinedOrMissing Negative(gxcoff+)
2855 Generate debug information in XCOFF format.
2858 Common JoinedOrMissing Negative(gcoff)
2859 Generate debug information in extended XCOFF format.
2862 Name(compressed_debug_sections) Type(int)
2864 ; Since -gz= is completely handled in specs, the values aren't used and we
2865 ; assign arbitrary constants.
2867 Enum(compressed_debug_sections) String(none) Value(0)
2870 Enum(compressed_debug_sections) String(zlib) Value(1)
2873 Enum(compressed_debug_sections) String(zlib-gnu) Value(2)
2877 Generate compressed debug sections.
2880 Common Driver Joined Enum(compressed_debug_sections)
2881 -gz=<format> Generate compressed debug sections in format <format>.
2884 Driver Joined Separate
2887 Common Joined Var(plugindir_string) Init(0)
2888 -iplugindir=<dir> Set <dir> to be the default plugin directory.
2891 Common Joined Separate RejectDriver Var(imultiarch) Init(0)
2892 -imultiarch <dir> Set <dir> to be the multiarch include subdirectory.
2895 Driver Joined Separate
2900 no-canonical-prefixes
2913 Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs)
2914 -o <file> Place output into <file>.
2917 Common Var(profile_flag)
2918 Enable function profiling.
2921 Driver Var(pass_exit_codes)
2924 Common Alias(Wpedantic)
2927 Common Var(flag_pedantic_errors)
2928 Like -pedantic but issue them as errors.
2934 Driver Var(use_pipes)
2937 Driver JoinedOrMissing Var(print_file_name)
2939 print-libgcc-file-name
2942 print-multi-directory
2943 Driver Var(print_multi_directory)
2946 Driver Var(print_multi_lib)
2948 print-multi-os-directory
2949 Driver Var(print_multi_os_directory)
2952 Driver Var(print_multiarch)
2955 Driver JoinedOrMissing Var(print_prog_name)
2958 Driver Var(print_search_dirs)
2961 Driver Var(print_sysroot)
2963 print-sysroot-headers-suffix
2964 Driver Var(print_sysroot_headers_suffix)
2967 Common Var(quiet_flag) RejectDriver
2968 Do not display functions compiled or elapsed time.
2986 Driver Var(report_times)
2989 Driver JoinedOrMissing
2992 Driver Joined Separate
2996 ; C option, but driver must not handle as "-u ndef".
2999 Common Driver Var(verbose_flag)
3000 Enable verbose output.
3003 Common Var(version_flag) RejectDriver
3004 Display the compiler's version.
3007 Common Var(inhibit_warnings)
3011 Driver Separate Var(wrapper_string)
3014 Driver Joined Separate
3017 Driver RejectNegative Negative(pie)
3018 Create a shared library.
3024 Driver Separate Alias(specs=)
3037 ; Documented for Fortran, but always accepted by driver.
3044 ; Documented for Go, but always accepted by driver.
3062 Driver RejectNegative Negative(shared)
3063 Don't create a position independent executable.
3066 Driver RejectNegative Negative(no-pie)
3067 Create a position independent executable.
3070 Driver Joined Separate
3073 Common Report Var(flag_ipa_ra) Optimization
3074 Use caller save register across calls if possible.
3076 ; This comment is to ensure we retain the blank line above.