1 ; Options for the language- and target-independent parts of the compiler.
3 ; Copyright (C) 2003, 2004, 2005, 2006, 2007 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 for a description of this file's format.
23 ; Please try to keep this file in ASCII collating order.
27 Display this information
31 --help=<class> Display descriptions of a specific class of options. <class> is one or more of optimizers, target, warnings, undocumented, params
35 Alias for --help=target
37 ;; The following three entries are to work around the gcc driver
38 ;; program's insatiable desire to turn options starting with a
39 ;; double dash (--) into options starting with a dash f (-f).
51 --param <param>=<value> Set parameter <param> to value. See below for a complete list of parameters
57 Common Joined Separate UInteger
58 -G<number> Put global and static data smaller than <number> bytes into a special section (on some targets)
61 Common JoinedOrMissing
62 -O<number> Set optimization level to <number>
66 Optimize for space rather than speed
70 This switch is deprecated; use -Wextra instead
73 Common Var(warn_aggregate_return) Warning
74 Warn about returning structures, unions or arrays
77 Common Var(warn_array_bounds) Warning
78 Warn if an array is accessed out of bounds
81 Common Var(warn_attributes) Init(1) Warning
82 Warn about inappropriate attribute usage
85 Common Var(warn_cast_align) Warning
86 Warn about pointer casts which increase alignment
88 Wdeprecated-declarations
89 Common Var(warn_deprecated_decl) Init(1) Warning
90 Warn about uses of __attribute__((deprecated)) declarations
92 Wdisabled-optimization
93 Common Var(warn_disabled_optimization) Warning
94 Warn when an optimization pass is disabled
97 Common Var(warnings_are_errors)
98 Treat all warnings as errors
102 Treat specified warning as error
106 Print extra (possibly unwanted) warnings
109 Common Var(flag_fatal_errors)
110 Exit on the first error occurred
113 Common Var(warn_inline) Warning
114 Warn when an inlined function cannot be inlined
117 Common RejectNegative Joined UInteger Warning
118 -Wlarger-than-<number> Warn if an object is larger than <number> bytes
121 Common Warning Var(warn_logical_op)
122 Warn when a logical operator is suspicously always evaluating to true or false
124 Wunsafe-loop-optimizations
125 Common Var(warn_unsafe_loop_optimizations) Warning
126 Warn if the loop cannot be optimized due to nontrivial assumptions.
129 Common Var(warn_missing_noreturn) Warning
130 Warn about functions which might be candidates for __attribute__((noreturn))
133 Common Var(warn_overflow) Init(1) Warning
134 Warn about overflow in arithmetic expressions
137 Common Var(warn_packed) Warning
138 Warn when the packed attribute has no effect on struct layout
141 Common Var(warn_padded) Warning
142 Warn when padding is required to align structure members
145 Common Var(warn_shadow) Warning
146 Warn when one local variable shadows another
149 Common Var(warn_stack_protect) Warning
150 Warn when not issuing stack smashing protection for some reason
154 Warn about code which might break strict aliasing rules
157 Common Joined UInteger Warning
158 Warn about code which might break strict aliasing rules
162 Warn about optimizations that assume that signed overflow is undefined
165 Common Joined UInteger Warning
166 Warn about optimizations that assume that signed overflow is undefined
169 Common Var(warn_switch) Warning
170 Warn about enumerated switches, with no default, missing a case
173 Common Var(warn_switch_default) Warning
174 Warn about enumerated switches missing a \"default:\" statement
177 Common Var(warn_switch_enum) Warning
178 Warn about all enumerated switches missing a specific case
181 Common Var(warn_system_headers) Warning
182 Do not suppress warnings from system headers
185 Common Var(warn_uninitialized) Warning
186 Warn about uninitialized automatic variables
189 Common Var(warn_notreached) Warning
190 Warn about code that will never be executed
194 Enable all -Wunused- warnings
197 Common Var(warn_unused_function) Warning
198 Warn when a function is unused
201 Common Var(warn_unused_label) Warning
202 Warn when a label is unused
205 Common Var(warn_unused_parameter) Warning
206 Warn when a function parameter is unused
209 Common Var(warn_unused_value) Warning
210 Warn when an expression value is unused
213 Common Var(warn_unused_variable) Warning
214 Warn when a variable is unused
216 Wvolatile-register-var
217 Common Var(warn_register_var) Warning
218 Warn when a register variable is declared volatile
221 Common RejectNegative Var(warn_coverage_mismatch) Warning
222 Warn instead of error in case profiles in -fprofile-use do not match
226 -aux-info <file> Emit declaration information into <file>
239 -d<letters> Enable dumps from specific passes of the compiler
243 -dumpbase <file> Set the file basename to be used for dumps
245 ; The version of the C++ ABI in use. The following values are allowed:
247 ; 0: The version of the ABI believed most conformant with the C++ ABI
248 ; specification. This ABI may change as bugs are discovered and fixed.
249 ; Therefore, 0 will not necessarily indicate the same ABI in different
252 ; 1: The version of the ABI first used in G++ 3.2.
254 ; 2: The version of the ABI first used in G++ 3.4.
256 ; Additional positive integers will be assigned as new versions of
257 ; the ABI become the default version of the ABI.
259 Common Joined UInteger Var(flag_abi_version) Init(2)
262 Common Report Var(align_functions,0)
263 Align the start of functions
266 Common RejectNegative Joined UInteger
269 Common Report Var(align_jumps,0) Optimization
270 Align labels which are only reached by jumping
273 Common RejectNegative Joined UInteger
276 Common Report Var(align_labels,0) Optimization
280 Common RejectNegative Joined UInteger
283 Common Report Var(align_loops) Optimization
284 Align the start of loops
287 Common RejectNegative Joined UInteger
289 ; This flag is only tested if alias checking is enabled.
290 ; 0 if pointer arguments may alias each other. True in C.
291 ; 1 if pointer arguments may not alias each other but may alias
293 ; 2 if pointer arguments may not alias each other and may not
294 ; alias global variables.
295 ; 3 if pointer arguments may not alias anything. True in Fortran.
296 ; Set by the front end.
298 Common Report Var(flag_argument_noalias,0) Optimization
299 Specify that arguments may alias each other and globals
302 Common Report Var(flag_argument_noalias,1) VarExists Optimization
303 Assume arguments may alias globals but not each other
305 fargument-noalias-global
306 Common Report Var(flag_argument_noalias,2) VarExists Optimization
307 Assume arguments alias neither each other nor globals
309 fargument-noalias-anything
310 Common Report Var(flag_argument_noalias,3) VarExists Optimization
311 Assume arguments alias no other storage
313 fasynchronous-unwind-tables
314 Common Report Var(flag_asynchronous_unwind_tables) Optimization
315 Generate unwind tables that are exact at each instruction boundary
318 Common Report Var(flag_auto_inc_dec) Init(1)
319 Generate auto-inc/dec instructions
321 ; -fcheck-bounds causes gcc to generate array bounds checks.
322 ; For C, C++ and ObjC: defaults off.
323 ; For Java: defaults to on.
324 ; For Fortran: defaults to off.
326 Common Report Var(flag_bounds_check)
327 Generate code to check bounds before indexing arrays
330 Common Report Var(flag_branch_on_count_reg) Init(1) Optimization
331 Replace add, compare, branch with branch on count register
333 fbranch-probabilities
334 Common Report Var(flag_branch_probabilities) Optimization
335 Use profiling information for branch probabilities
337 fbranch-target-load-optimize
338 Common Report Var(flag_branch_target_load_optimize) Optimization
339 Perform branch target load optimization before prologue / epilogue threading
341 fbranch-target-load-optimize2
342 Common Report Var(flag_branch_target_load_optimize2) Optimization
343 Perform branch target load optimization after prologue / epilogue threading
346 Common Report Var(flag_btr_bb_exclusive) Optimization
347 Restrict target load migration not to re-use registers in any basic block
350 Common Joined RejectNegative
351 -fcall-saved-<register> Mark <register> as being preserved across functions
354 Common Joined RejectNegative
355 -fcall-used-<register> Mark <register> as being corrupted by function calls
357 ; Nonzero for -fcaller-saves: allocate values in regs that need to
358 ; be saved across function calls, if that produces overall better code.
359 ; Optional now, so people can test it.
361 Common Report Var(flag_caller_saves) Optimization
362 Save registers around function calls
365 Common Report Var(flag_check_data_deps)
366 Compare the results of several data dependence analyzers.
369 Common Report Var(flag_no_common,0) Optimization
370 Do not put uninitialized globals in the common section
373 Common Report Var(flag_cprop_registers) Optimization
374 Perform a register copy-propagation optimization pass
377 Common Report Var(flag_crossjumping) Optimization
378 Perform cross-jumping optimization
381 Common Report Var(flag_cse_follow_jumps) Optimization
382 When running CSE, follow jumps to their targets
385 Common Report Var(flag_cse_skip_blocks) Optimization
386 When running CSE, follow conditional jumps
389 Common Report Var(flag_cx_limited_range) Optimization
390 Omit range reduction step when performing complex division
393 Common Report Var(flag_data_sections) Optimization
394 Place data items into their own section
398 List all available debugging counters with their limits and counts.
401 Common RejectNegative Joined
402 -fdbg-cnt=<counter>:<limit>[,<counter>:<limit>,...] Set the debug counter limit.
405 Common Joined RejectNegative
406 Map one directory name to another in debug information
408 ; Nonzero for -fdefer-pop: don't pop args after each function call
409 ; instead save them up to pop many calls' args with one insns.
411 Common Report Var(flag_defer_pop) Optimization
412 Defer popping functions args from stack until later
415 Common Report Var(flag_delayed_branch) Optimization
416 Attempt to fill delay slots of branch instructions
418 fdelete-null-pointer-checks
419 Common Report Var(flag_delete_null_pointer_checks) Optimization
420 Delete useless null pointer checks
422 fdiagnostics-show-location=
423 Common Joined RejectNegative
424 -fdiagnostics-show-location=[once|every-line] How often to emit source location at the beginning of line-wrapped diagnostics
426 fdiagnostics-show-option
428 Amend appropriate diagnostic messages with the command line option that controls them
431 Common Joined RejectNegative
432 -fdump-<type> Dump various compiler internals to a file
435 Common Report Var(flag_dump_noaddr)
436 Suppress output of addresses in debugging dumps
439 Common Report Var(flag_dump_unnumbered) VarExists
440 Suppress output of instruction numbers, line number notes and addresses in debugging dumps
443 Common Report Var(flag_early_inlining) Init(1) Optimization
444 Perform early inlining
446 feliminate-dwarf2-dups
447 Common Report Var(flag_eliminate_dwarf2_dups)
448 Perform DWARF2 duplicate elimination
450 feliminate-unused-debug-symbols
451 Common Report Var(flag_debug_only_used_symbols)
452 Perform unused type elimination in debug info
454 feliminate-unused-debug-types
455 Common Report Var(flag_eliminate_unused_debug_types) Init(1)
456 Perform unused type elimination in debug info
458 femit-class-debug-always
459 Common Report Var(flag_emit_class_debug_always) Init(1)
460 Do not suppress C++ class debug information.
463 Common Report Var(flag_exceptions) Optimization
464 Enable exception handling
466 fexpensive-optimizations
467 Common Report Var(flag_expensive_optimizations) Optimization
468 Perform a number of minor, expensive optimizations
474 Common Report Var(flag_finite_math_only) Optimization
475 Assume no NaNs or infinities are generated
478 Common Joined RejectNegative
479 -ffixed-<register> Mark <register> as being unavailable to the compiler
482 Common Report Var(flag_float_store) Optimization
483 Don't allocate floats and doubles in extended-precision registers
485 ; Nonzero for -fforce-addr: load memory address into a register before
486 ; reference to memory. This makes better cse but slower compilation.
488 Common Report Var(flag_force_addr) Optimization
489 Copy memory address constants into registers before use
492 Common Report Var(flag_forward_propagate) Optimization
493 Perform a forward propagation pass on RTL
495 ; Nonzero means don't put addresses of constant functions in registers.
496 ; Used for compiling the Unix kernel, where strange substitutions are
497 ; done on the assembly output.
499 Common Report Var(flag_no_function_cse,0)
500 Allow function addresses to be held in registers
503 Common Report Var(flag_function_sections)
504 Place each function into its own section
507 Common Report Var(flag_gcse) Optimization
508 Perform global common subexpression elimination
511 Common Report Var(flag_gcse_lm) Init(1) Optimization
512 Perform enhanced load motion during global common subexpression elimination
515 Common Report Var(flag_gcse_sm) Init(0) Optimization
516 Perform store motion after global common subexpression elimination
519 Common Report Var(flag_gcse_las) Init(0) Optimization
520 Perform redundant load after store elimination in global common subexpression
524 Common Report Var(flag_gcse_after_reload) Optimization
525 Perform global common subexpression elimination after register allocation
528 fguess-branch-probability
529 Common Report Var(flag_guess_branch_prob) Optimization
530 Enable guessing of branch probabilities
532 ; Nonzero means ignore `#ident' directives. 0 means handle them.
533 ; Generate position-independent code for executables if possible
534 ; On SVR4 targets, it also controls whether or not to emit a
535 ; string identifying the compiler.
537 Common Report Var(flag_no_ident,0)
538 Process #ident directives
541 Common Report Var(flag_if_conversion) Optimization
542 Perform conversion of conditional jumps to branchless equivalents
545 Common Report Var(flag_if_conversion2) Optimization
546 Perform conversion of conditional jumps to conditional execution
548 ; -finhibit-size-directive inhibits output of .size for ELF.
549 ; This is used only for compiling crtstuff.c,
550 ; and it may be extended to other effects
551 ; needed for crtstuff.c on other systems.
552 finhibit-size-directive
553 Common Report Var(flag_inhibit_size_directive)
554 Do not generate .size directives
556 ; Nonzero means that functions declared `inline' will be treated
557 ; as `static'. Prevents generation of zillions of copies of unused
558 ; static inline functions; instead, `inlines' are written out
559 ; only when actually used. Used in conjunction with -g. Also
560 ; does the right thing with #pragma interface.
562 Common Report Var(flag_no_inline,0) Init(2)
563 Pay attention to the \"inline\" keyword
565 finline-small-functions
566 Common Report Var(flag_inline_small_functions) Optimization
567 Integrate simple functions into their callers when code size is known to not growth
570 Common Report Var(flag_inline_functions) Optimization
571 Integrate simple functions into their callers
573 finline-functions-called-once
574 Common Report Var(flag_inline_functions_called_once) Init(1) Optimization
575 Integrate functions called once into their callers
578 Common RejectNegative Joined UInteger
581 Common RejectNegative Joined UInteger
582 -finline-limit=<number> Limit the size of inlined functions to <number>
584 finstrument-functions
585 Common Report Var(flag_instrument_function_entry_exit)
586 Instrument function entry and exit with profiling calls
588 finstrument-functions-exclude-function-list=
589 Common RejectNegative Joined
590 -finstrument-functions-exclude-function-list=name,... Do not instrument listed functions
592 finstrument-functions-exclude-file-list=
593 Common RejectNegative Joined
594 -finstrument-functions-exclude-file-list=filename,... Do not instrument functions listed in files
597 Common Report Var(flag_ipa_cp) Optimization
598 Perform Interprocedural constant propagation
601 Common Report Var(flag_ipa_pure_const) Init(0) Optimization
602 Discover pure and const functions
605 Common Report Var(flag_ipa_pta) Init(0) Optimization
606 Perform interprocedural points-to analysis
609 Common Report Var(flag_ipa_reference) Init(0) Optimization
610 Discover readonly and non addressable static variables
613 Common Report Var(flag_ipa_type_escape) Init(0) Optimization
614 Type based escape and alias analysis
617 Common Report Var(flag_ipa_matrix_reorg) Optimization
618 Perform matrix layout flattening and transposing based
619 on profiling information.
622 Common Report Var(flag_ivopts) Init(1) Optimization
623 Optimize induction variables on trees
626 Common Var(flag_jump_tables) Init(1) Optimization
627 Use jump tables for sufficiently large switch statements
629 fkeep-inline-functions
630 Common Report Var(flag_keep_inline_functions)
631 Generate code for functions even if they are fully inlined
634 Common Report Var(flag_keep_static_consts) Init(1)
635 Emit static const variables even if they are not used
638 Common Report Var(flag_leading_underscore) Init(-1)
639 Give external symbols a leading underscore
643 Does nothing. Preserved for backward compatibility.
646 Common Report Var(flag_errno_math) Init(1)
647 Set errno after built-in math functions
650 Common Report Var(mem_report)
651 Report on permanent memory allocation
653 ; This will attempt to merge constant section constants, if 1 only
654 ; string constants and constants from constant pool, if 2 also constant
657 Common Report Var(flag_merge_constants,2) Init(1) Optimization
658 Attempt to merge identical constants and constant variables
661 Common Report Var(flag_merge_constants,1) VarExists Optimization
662 Attempt to merge identical constants across compilation units
665 Common RejectNegative Joined UInteger
666 -fmessage-length=<number> Limit diagnostics to <number> characters per line. 0 suppresses line-wrapping
669 Common Report Var(flag_modulo_sched) Optimization
670 Perform SMS based modulo scheduling before the first scheduling pass
672 fmodulo-sched-allow-regmoves
673 Common Report Var(flag_modulo_sched_allow_regmoves)
674 Perform SMS based modulo scheduling with register moves allowed
676 fmove-loop-invariants
677 Common Report Var(flag_move_loop_invariants) Init(1) Optimization
678 Move loop invariant computations out of loops
681 Common RejectNegative Report Var(flag_mudflap)
682 Add mudflap bounds-checking instrumentation for single-threaded program
685 Common RejectNegative Report VarExists Var(flag_mudflap,2)
686 Add mudflap bounds-checking instrumentation for multi-threaded program
689 Common RejectNegative Report Var(flag_mudflap_ignore_reads)
690 Ignore read operations when inserting mudflap instrumentation
693 Common Var(flag_dce) Init(1) Optimization
694 Use the RTL dead code elimination pass
697 Common Var(flag_dse) Init(1) Optimization
698 Use the RTL dead store elimination pass
700 freschedule-modulo-scheduled-loops
701 Common Report Var(flag_resched_modulo_sched) Optimization
702 Enable/Disable the traditional scheduling in loops that already passed modulo scheduling
705 Common Report Var(flag_non_call_exceptions) Optimization
706 Support synchronous non-call exceptions
709 Common Report Var(flag_omit_frame_pointer) Optimization
710 When possible do not generate stack frames
712 foptimize-register-move
713 Common Report Var(flag_regmove) Optimization
714 Do the full register move optimization pass
716 foptimize-sibling-calls
717 Common Report Var(flag_optimize_sibling_calls) Optimization
718 Optimize sibling and tail recursive calls
721 Common Report Var(pre_ipa_mem_report)
722 Report on memory allocation before interprocedural optimization
725 Common Report Var(post_ipa_mem_report)
726 Report on memory allocation before interprocedural optimization
729 Common Report Var(flag_pack_struct) Optimization
730 Pack structure members together without holes
733 Common RejectNegative Joined UInteger Optimization
734 -fpack-struct=<number> Set initial maximum structure member alignment
737 Common Report Var(flag_pcc_struct_return,1) VarExists
738 Return small aggregates in memory, not registers
741 Common Report Var(flag_peel_loops) Optimization
745 Common Report Var(flag_no_peephole,0) Optimization
746 Enable machine specific peephole optimizations
749 Common Report Var(flag_peephole2) Optimization
750 Enable an RTL peephole pass before sched2
753 Common Report Var(flag_pic,2)
754 Generate position-independent code if possible (large mode)
757 Common Report Var(flag_pie,2)
758 Generate position-independent code for executables if possible (large mode)
761 Common Report Var(flag_pic,1) VarExists
762 Generate position-independent code if possible (small mode)
765 Common Report Var(flag_pie,1) VarExists
766 Generate position-independent code for executables if possible (small mode)
768 fpredictive-commoning
769 Common Report Var(flag_predictive_commoning) Optimization
770 Run predictive commoning optimization.
772 fprefetch-loop-arrays
773 Common Report Var(flag_prefetch_loop_arrays) Optimization
774 Generate prefetch instructions, if available, for arrays in loops
777 Common Report Var(profile_flag)
778 Enable basic program profiling code
781 Common Report Var(profile_arc_flag)
782 Insert arc-based program profiling code
786 Enable common options for generating profile info for profile feedback directed optimizations
790 Enable common options for performing profile feedback directed optimizations
793 Common Report Var(flag_profile_values)
794 Insert code to profile values of expressions
800 Common Joined RejectNegative
801 -frandom-seed=<string> Make compile reproducible using <string>
803 ; This switch causes the command line that was used to create an
804 ; object file to be recorded into the object file. The exact format
805 ; of this recording is target and binary file format dependent.
806 ; It is related to the -fverbose-asm switch, but that switch only
807 ; records information in the assembler output file as comments, so
808 ; they never reach the object file.
810 Common Report Var(flag_record_gcc_switches)
811 Record gcc command line switches in the object file.
814 Common Report Var(flag_pcc_struct_return,0) VarExists Optimization
815 Return small aggregates in registers
818 Common Report Var(flag_regmove) Optimization
819 Enables a register move optimization
822 Common Report Var(flag_rename_registers) Init(2) Optimization
823 Perform a register renaming optimization pass
826 Common Report Var(flag_reorder_blocks) Optimization
827 Reorder basic blocks to improve code placement
829 freorder-blocks-and-partition
830 Common Report Var(flag_reorder_blocks_and_partition) Optimization
831 Reorder basic blocks and partition into hot and cold sections
834 Common Report Var(flag_reorder_functions) Optimization
835 Reorder functions to improve code placement
837 frerun-cse-after-loop
838 Common Report Var(flag_rerun_cse_after_loop) Init(2) Optimization
839 Add a common subexpression elimination pass after loop optimizations
843 Does nothing. Preserved for backward compatibility.
846 Common Report Var(flag_rounding_math) Optimization
847 Disable optimizations that assume default FP rounding behavior
850 Common Report Var(flag_schedule_interblock) Init(1) Optimization
851 Enable scheduling across basic blocks
854 Common Report Var(flag_schedule_speculative) Init(1) Optimization
855 Allow speculative motion of non-loads
858 Common Report Var(flag_schedule_speculative_load) Optimization
859 Allow speculative motion of some loads
861 fsched-spec-load-dangerous
862 Common Report Var(flag_schedule_speculative_load_dangerous) Optimization
863 Allow speculative motion of more loads
866 Common RejectNegative Joined
867 -fsched-verbose=<number> Set the verbosity level of the scheduler
869 fsched2-use-superblocks
870 Common Report Var(flag_sched2_use_superblocks) Optimization
871 If scheduling post reload, do superblock scheduling
874 Common Report Var(flag_sched2_use_traces) Optimization
875 If scheduling post reload, do trace scheduling
878 Common Report Var(flag_schedule_insns) Optimization
879 Reschedule instructions before register allocation
882 Common Report Var(flag_schedule_insns_after_reload) Optimization
883 Reschedule instructions after register allocation
885 ; sched_stalled_insns means that insns can be moved prematurely from the queue
886 ; of stalled insns into the ready list.
888 Common Report Var(flag_sched_stalled_insns) Optimization
889 Allow premature scheduling of queued insns
891 fsched-stalled-insns=
892 Common RejectNegative Joined UInteger
893 -fsched-stalled-insns=<number> Set number of queued insns that can be prematurely scheduled
895 ; sched_stalled_insns_dep controls how many recently scheduled cycles will
896 ; be examined for a dependency on a stalled insn that is candidate for
897 ; premature removal from the queue of stalled insns into the ready list (has
898 ; an effect only if the flag 'sched_stalled_insns' is set).
899 fsched-stalled-insns-dep
900 Common Report Var(flag_sched_stalled_insns_dep,1) Init(1) Optimization
901 Set dependence distance checking in premature scheduling of queued insns
903 fsched-stalled-insns-dep=
904 Common RejectNegative Joined UInteger
905 -fsched-stalled-insns-dep=<number> Set dependence distance checking in premature scheduling of queued insns
908 Common Report Var(flag_section_anchors) Optimization
909 Access data in the same section from shared anchor points
911 frtl-abstract-sequences
912 Common Report Var(flag_rtl_seqabstr) Optimization
913 Perform sequence abstraction optimization on RTL
916 Common Report Var(flag_see) Init(0)
917 Eliminate redundant sign extensions using LCM.
920 Common C ObjC C++ ObjC++ Report Var(flag_show_column) Init(1)
921 Show column numbers in diagnostics, when available. Default on
924 Common Report Var(flag_signaling_nans) Optimization
925 Disable optimizations observable by IEEE signaling NaNs
928 Common Report Var(flag_signed_zeros) Init(1) Optimization
929 Disable floating point optimizations that ignore the IEEE signedness of zero
931 fsingle-precision-constant
932 Common Report Var(flag_single_precision_constant) Optimization
933 Convert floating point constants to single precision constants
935 fsplit-ivs-in-unroller
936 Common Report Var(flag_split_ivs_in_unroller) Init(1) Optimization
937 Split lifetimes of induction variables when loops are unrolled
940 Common Report Var(flag_split_wide_types) Optimization
941 Split wide types into independent registers
943 fvariable-expansion-in-unroller
944 Common Report Var(flag_variable_expansion_in_unroller) Optimization
945 Apply variable expansion when loops are unrolled
947 ; Emit code to probe the stack, to help detect stack overflow; also
948 ; may cause large objects to be allocated dynamically.
950 Common Report Var(flag_stack_check)
951 Insert stack checking code into the program
956 fstack-limit-register=
957 Common RejectNegative Joined
958 -fstack-limit-register=<register> Trap if the stack goes past <register>
961 Common RejectNegative Joined
962 -fstack-limit-symbol=<name> Trap if the stack goes past symbol <name>
965 Common Report Var(flag_stack_protect, 1)
966 Use propolice as a stack protection method
969 Common Report RejectNegative Var(flag_stack_protect, 2) VarExists
970 Use a stack protection method for every function
974 Does nothing. Preserved for backward compatibility.
976 ; Nonzero if we should do (language-dependent) alias analysis.
977 ; Typically, this analysis will assume that expressions of certain
978 ; types do not alias expressions of certain other types. Only used
979 ; if alias analysis (in general) is enabled.
981 Common Report Var(flag_strict_aliasing) Optimization
982 Assume strict aliasing rules apply
985 Common Report Var(flag_strict_overflow)
986 Treat signed overflow as undefined
989 Common Report Var(flag_syntax_only)
990 Check for syntax errors, then stop
993 Common Report Var(flag_test_coverage)
994 Create data files needed by \"gcov\"
997 Common Report Var(flag_thread_jumps) Optimization
998 Perform jump threading optimizations
1001 Common Report Var(time_report)
1002 Report the time taken by each compiler pass
1005 Common Joined RejectNegative
1006 -ftls-model=[global-dynamic|local-dynamic|initial-exec|local-exec] Set the default thread-local storage code generation model
1009 Common Report Var(flag_toplevel_reorder) Init(1) Optimization
1010 Reorder top level functions, variables, and asms
1013 Common Report Var(flag_tracer)
1014 Perform superblock formation via tail duplication
1016 ; Zero means that floating-point math operations cannot generate a
1017 ; (user-visible) trap. This is the case, for example, in nonstop
1018 ; IEEE 754 arithmetic.
1020 Common Report Var(flag_trapping_math) Init(1) Optimization
1021 Assume floating-point operations can trap
1024 Common Report Var(flag_trapv) Optimization
1025 Trap for signed overflow in addition, subtraction and multiplication
1028 Common Report Var(flag_tree_ccp) Optimization
1029 Enable SSA-CCP optimization on trees
1032 Common Report Var(flag_tree_store_ccp) Optimization
1033 Enable SSA-CCP optimization for stores and loads
1036 Common Report Var(flag_tree_ch) Optimization
1037 Enable loop header copying on trees
1040 Common Report Var(flag_tree_copyrename) Optimization
1041 Replace SSA temporaries with better names in copies
1044 Common Report Var(flag_tree_copy_prop) Optimization
1045 Enable copy propagation on trees
1047 ftree-store-copy-prop
1048 Common Report Var(flag_tree_store_copy_prop) Optimization
1049 Enable copy propagation for stores and loads
1052 Common Report Var(flag_tree_dce) Optimization
1053 Enable SSA dead code elimination optimization on trees
1055 ftree-dominator-opts
1056 Common Report Var(flag_tree_dom) Optimization
1057 Enable dominator optimizations
1060 Common Report Var(flag_tree_dse) Optimization
1061 Enable dead store elimination
1064 Common Report Var(flag_tree_fre) Optimization
1065 Enable Full Redundancy Elimination (FRE) on trees
1068 Common Report Var(flag_tree_loop_im) Init(1) Optimization
1069 Enable loop invariant motion on trees
1072 Common Report Var(flag_tree_loop_linear) Optimization
1073 Enable linear loop transforms on trees
1076 Common Report Var(flag_tree_loop_ivcanon) Init(1) Optimization
1077 Create canonical induction variables in loops
1080 Common Report Var(flag_tree_loop_optimize) Init(1) Optimization
1081 Enable loop optimizations on tree level
1084 Common Report Var(flag_tree_pre) Optimization
1085 Enable SSA-PRE optimization on trees
1088 Common Report Var(flag_tree_reassoc) Init(1) Optimization
1089 Enable reassociation on tree level
1092 Common Report Var(flag_tree_salias) Optimization
1093 Perform structural alias analysis
1096 Common Report Var(flag_tree_sink) Optimization
1097 Enable SSA code sinking on trees
1100 Common Report Var(flag_tree_sra) Optimization
1101 Perform scalar replacement of aggregates
1104 Common Report Var(flag_tree_ter) Optimization
1105 Replace temporary expressions in the SSA->normal pass
1108 Common Report Var(flag_tree_live_range_split) Optimization
1109 Perform live range splitting during the SSA->normal pass
1112 Common Report Var(flag_tree_vrp) Init(0) Optimization
1113 Perform Value Range Propagation on trees
1116 Common Report Var(flag_unit_at_a_time) Optimization
1117 Compile whole compilation unit at a time
1120 Common Report Var(flag_unroll_loops) Optimization
1121 Perform loop unrolling when iteration count is known
1124 Common Report Var(flag_unroll_all_loops) Optimization
1125 Perform loop unrolling for all loops
1127 ; Nonzero means that loop optimizer may assume that the induction variables
1128 ; that control loops do not overflow and that the loops with nontrivial
1129 ; exit condition are not infinite
1130 funsafe-loop-optimizations
1131 Common Report Var(flag_unsafe_loop_optimizations) Optimization
1132 Allow loop optimizations to assume that the loops behave in normal way
1135 Common Report Var(flag_associative_math)
1136 Allow optimization for floating-point arithmetic which may change the
1137 result of the operation due to rounding.
1140 Common Report Var(flag_reciprocal_math)
1141 Same as -fassociative-math for expressions which include division.
1143 ; Nonzero means that unsafe floating-point math optimizations are allowed
1144 ; for the sake of speed. IEEE compliance is not guaranteed, and operations
1145 ; are allowed to assume that their arguments and results are "normal"
1146 ; (e.g., nonnegative for SQRT).
1147 funsafe-math-optimizations
1148 Common Report Var(flag_unsafe_math_optimizations) Optimization
1149 Allow math optimizations that may violate IEEE or ISO standards
1152 Common Report Var(flag_unswitch_loops) Optimization
1153 Perform loop unswitching
1156 Common Report Var(flag_unwind_tables) Optimization
1157 Just generate unwind tables for exception handling
1160 Common Report Var(flag_var_tracking) VarExists Optimization
1161 Perform variable tracking
1163 fvar-tracking-uninit
1164 Common Report Var(flag_var_tracking_uninit) Optimization
1165 Perform variable tracking and also tag variables that are uninitialized
1168 Common Report Var(flag_tree_vectorize) Optimization
1169 Enable loop vectorization on trees
1172 Common Report Var(flag_vect_cost_model) Optimization
1173 Enable use of cost model in vectorization
1175 ftree-vect-loop-version
1176 Common Report Var(flag_tree_vect_loop_version) Init(1) Optimization
1177 Enable loop versioning when doing loop vectorization on trees
1179 ftree-vectorizer-verbose=
1180 Common RejectNegative Joined
1181 -ftree-vectorizer-verbose=<number> Set the verbosity level of the vectorizer
1184 Common Report Var(flag_tree_scev_cprop) Init(1) Optimization
1185 Enable copy propagation of scalar-evolution information.
1187 ; -fverbose-asm causes extra commentary information to be produced in
1188 ; the generated assembly code (to make it more readable). This option
1189 ; is generally only of use to those who actually need to read the
1190 ; generated assembly code (perhaps while debugging the compiler itself).
1191 ; -fno-verbose-asm, the default, causes the extra information
1192 ; to not be added and is useful when comparing two assembler files.
1194 Common Report Var(flag_verbose_asm)
1195 Add extra commentary to assembler output
1198 Common Joined RejectNegative
1199 -fvisibility=[default|internal|hidden|protected] Set the default symbol visibility
1203 Common Report Var(flag_value_profile_transformations) Optimization
1204 Use expression value profiles in optimizations
1207 Common Report Var(flag_web) Init(2) Optimization
1208 Construct webs and split unrelated uses of single variable
1211 Common Report Var(flag_whole_program) Init(0) Optimization
1212 Perform whole program optimizations
1215 Common Report Var(flag_wrapv) Optimization
1216 Assume signed arithmetic overflow wraps around
1218 fzero-initialized-in-bss
1219 Common Report Var(flag_zero_initialized_in_bss) Init(1)
1220 Put zero initialized data in the bss section
1223 Common JoinedOrMissing
1224 Generate debug information in default format
1227 Common JoinedOrMissing Negative(gdwarf-2)
1228 Generate debug information in COFF format
1231 Common JoinedOrMissing Negative(gstabs)
1232 Generate debug information in DWARF v2 format
1235 Common JoinedOrMissing
1236 Generate debug information in default extended format
1239 Common JoinedOrMissing Negative(gstabs+)
1240 Generate debug information in STABS format
1243 Common JoinedOrMissing Negative(gvms)
1244 Generate debug information in extended STABS format
1247 Common JoinedOrMissing Negative(gxcoff)
1248 Generate debug information in VMS format
1251 Common JoinedOrMissing Negative(gxcoff+)
1252 Generate debug information in XCOFF format
1255 Common JoinedOrMissing Negative(gcoff)
1256 Generate debug information in extended XCOFF format
1259 Common Joined Separate
1260 -o <file> Place output into <file>
1263 Common Var(profile_flag)
1264 Enable function profiling
1267 Common Var(pedantic)
1268 Issue warnings needed for strict compliance to the standard
1272 Like -pedantic but issue them as errors
1275 Common Var(quiet_flag)
1276 Do not display functions compiled or elapsed time
1279 Common Var(version_flag)
1280 Display the compiler's version
1283 Common Var(inhibit_warnings)
1286 ; This comment is to ensure we retain the blank line above.