gcc (page 4)

   Options for Debugging Your Program or GCC
       GCC has various special options that are used for debugging either your
       program or GCC:

       -g  Produce debugging information in the operating system's native
           format (stabs, COFF, XCOFF, or DWARF 2).  GDB can work with this
           debugging information.

           On most systems that use stabs format, -g enables use of extra
           debugging information that only GDB can use; this extra information
           makes debugging work better in GDB but will probably make other
           debuggers crash or refuse to read the program.  If you want to
           control for certain whether to generate the extra information, use
           -gstabs+, -gstabs, -gxcoff+, -gxcoff, or -gvms (see below).

           GCC allows you to use -g with -O.  The shortcuts taken by optimized
           code may occasionally produce surprising results: some variables
           you declared may not exist at all; flow of control may briefly move
           where you did not expect it; some statements may not be executed
           because they compute constant results or their values were already
           at hand; some statements may execute in different places because
           they were moved out of loops.

           Nevertheless it proves possible to debug optimized output.  This
           makes it reasonable to use the optimizer for programs that might
           have bugs.

           The following options are useful when GCC is generated with the
           capability for more than one debugging format.

       -ggdb
           Produce debugging information for use by GDB.  This means to use
           the most expressive format available (DWARF 2, stabs, or the native
           format if neither of those are supported), including GDB extensions
           if at all possible.

       -gstabs
           Produce debugging information in stabs format (if that is
           supported), without GDB extensions.  This is the format used by DBX
           on most BSD systems.  On MIPS, Alpha and System V Release 4 systems
           this option produces stabs debugging output which is not understood
           by DBX or SDB.  On System V Release 4 systems this option requires
           the GNU assembler.

       -feliminate-unused-debug-symbols
           Produce debugging information in stabs format (if that is
           supported), for only symbols that are actually used.

       -femit-class-debug-always
           Instead of emitting debugging information for a C++ class in only
           one object file, emit it in all object files using the class.  This
           option should be used only with debuggers that are unable to handle
           the way GCC normally emits debugging information for classes
           because using this option will increase the size of debugging
           information by as much as a factor of two.

       -gstabs+
           Produce debugging information in stabs format (if that is
           supported), using GNU extensions understood only by the GNU
           debugger (GDB).  The use of these extensions is likely to make
           other debuggers crash or refuse to read the program.

       -gcoff
           Produce debugging information in COFF format (if that is
           supported).  This is the format used by SDB on most System V
           systems prior to System V Release 4.

       -gxcoff
           Produce debugging information in XCOFF format (if that is
           supported).  This is the format used by the DBX debugger on IBM
           RS/6000 systems.

       -gxcoff+
           Produce debugging information in XCOFF format (if that is
           supported), using GNU extensions understood only by the GNU
           debugger (GDB).  The use of these extensions is likely to make
           other debuggers crash or refuse to read the program, and may cause
           assemblers other than the GNU assembler (GAS) to fail with an
           error.

       -gdwarf-2
           Produce debugging information in DWARF version 2 format (if that is
           supported).  This is the format used by DBX on IRIX 6.  With this
           option, GCC uses features of DWARF version 3 when they are useful;
           version 3 is upward compatible with version 2, but may still cause
           problems for older debuggers.

       -gvms
           Produce debugging information in VMS debug format (if that is
           supported).  This is the format used by DEBUG on VMS systems.

       -glevel
       -ggdblevel
       -gstabslevel
       -gcofflevel
       -gxcofflevel
       -gvmslevel
           Request debugging information and also use level to specify how
           much information.  The default level is 2.

           Level 0 produces no debug information at all.  Thus, -g0 negates
           -g.

           Level 1 produces minimal information, enough for making backtraces
           in parts of the program that you don't plan to debug.  This
           includes descriptions of functions and external variables, but no
           information about local variables and no line numbers.

           Level 3 includes extra information, such as all the macro
           definitions present in the program.  Some debuggers support macro
           expansion when you use -g3.

           -gdwarf-2 does not accept a concatenated debug level, because GCC
           used to support an option -gdwarf that meant to generate debug
           information in version 1 of the DWARF format (which is very
           different from version 2), and it would have been too confusing.
           That debug format is long obsolete, but the option cannot be
           changed now.  Instead use an additional -glevel option to change
           the debug level for DWARF2.

       -feliminate-dwarf2-dups
           Compress DWARF2 debugging information by eliminating duplicated
           information about each symbol.  This option only makes sense when
           generating DWARF2 debugging information with -gdwarf-2.

       -femit-struct-debug-baseonly
           Emit debug information for struct-like types only when the base
           name of the compilation source file matches the base name of file
           in which the struct was defined.

           This option substantially reduces the size of debugging
           information, but at significant potential loss in type information
           to the debugger.  See -femit-struct-debug-reduced for a less
           aggressive option.  See -femit-struct-debug-detailed for more
           detailed control.

           This option works only with DWARF 2.

       -femit-struct-debug-reduced
           Emit debug information for struct-like types only when the base
           name of the compilation source file matches the base name of file
           in which the type was defined, unless the struct is a template or
           defined in a system header.

           This option significantly reduces the size of debugging
           information, with some potential loss in type information to the
           debugger.  See -femit-struct-debug-baseonly for a more aggressive
           option.  See -femit-struct-debug-detailed for more detailed
           control.

           This option works only with DWARF 2.

       -femit-struct-debug-detailed[=spec-list]
           Specify the struct-like types for which the compiler will generate
           debug information.  The intent is to reduce duplicate struct debug
           information between different object files within the same program.

           This option is a detailed version of -femit-struct-debug-reduced
           and -femit-struct-debug-baseonly, which will serve for most needs.

           A specification has the syntax
           [dir:|ind:][ord:|gen:](any|sys|base|none)

           The optional first word limits the specification to structs that
           are used directly (dir:) or used indirectly (ind:).  A struct type
           is used directly when it is the type of a variable, member.
           Indirect uses arise through pointers to structs.  That is, when use
           of an incomplete struct would be legal, the use is indirect.  An
           example is struct one direct; struct two * indirect;.

           The optional second word limits the specification to ordinary
           structs (ord:) or generic structs (gen:).  Generic structs are a
           bit complicated to explain.  For C++, these are non-explicit
           specializations of template classes, or non-template classes within
           the above.  Other programming languages have generics, but
           -femit-struct-debug-detailed does not yet implement them.

           The third word specifies the source files for those structs for
           which the compiler will emit debug information.  The values none
           and any have the normal meaning.  The value base means that the
           base of name of the file in which the type declaration appears must
           match the base of the name of the main compilation file.  In
           practice, this means that types declared in foo.c and foo.h will
           have debug information, but types declared in other header will
           not.  The value sys means those types satisfying base or declared
           in system or compiler headers.

           You may need to experiment to determine the best settings for your
           application.

           The default is -femit-struct-debug-detailed=all.

           This option works only with DWARF 2.

       -fno-merge-debug-strings
           Direct the linker to not merge together strings in the debugging
           information which are identical in different object files.  Merging
           is not supported by all assemblers or linkers.  Merging decreases
           the size of the debug information in the output file at the cost of
           increasing link processing time.  Merging is enabled by default.

       -fdebug-prefix-map=old=new
           When compiling files in directory old, record debugging information
           describing them as in new instead.

       -fno-dwarf2-cfi-asm
           Emit DWARF 2 unwind info as compiler generated ".eh_frame" section
           instead of using GAS ".cfi_*" directives.

       -p  Generate extra code to write profile information suitable for the
           analysis program prof.  You must use this option when compiling the
           source files you want data about, and you must also use it when
           linking.

       -pg Generate extra code to write profile information suitable for the
           analysis program gprof.  You must use this option when compiling
           the source files you want data about, and you must also use it when
           linking.

       -Q  Makes the compiler print out each function name as it is compiled,
           and print some statistics about each pass when it finishes.

       -ftime-report
           Makes the compiler print some statistics about the time consumed by
           each pass when it finishes.

       -fmem-report
           Makes the compiler print some statistics about permanent memory
           allocation when it finishes.

       -fpre-ipa-mem-report
       -fpost-ipa-mem-report
           Makes the compiler print some statistics about permanent memory
           allocation before or after interprocedural optimization.

       -fprofile-arcs
           Add code so that program flow arcs are instrumented.  During
           execution the program records how many times each branch and call
           is executed and how many times it is taken or returns.  When the
           compiled program exits it saves this data to a file called
           auxname.gcda for each source file.  The data may be used for
           profile-directed optimizations (-fbranch-probabilities), or for
           test coverage analysis (-ftest-coverage).  Each object file's
           auxname is generated from the name of the output file, if
           explicitly specified and it is not the final executable, otherwise
           it is the basename of the source file.  In both cases any suffix is
           removed (e.g. foo.gcda for input file dir/foo.c, or dir/foo.gcda
           for output file specified as -o dir/foo.o).

       --coverage
           This option is used to compile and link code instrumented for
           coverage analysis.  The option is a synonym for -fprofile-arcs
           -ftest-coverage (when compiling) and -lgcov (when linking).  See
           the documentation for those options for more details.

           ·   Compile the source files with -fprofile-arcs plus optimization
               and code generation options.  For test coverage analysis, use
               the additional -ftest-coverage option.  You do not need to
               profile every source file in a program.

           ·   Link your object files with -lgcov or -fprofile-arcs (the
               latter implies the former).

           ·   Run the program on a representative workload to generate the
               arc profile information.  This may be repeated any number of
               times.  You can run concurrent instances of your program, and
               provided that the file system supports locking, the data files
               will be correctly updated.  Also "fork" calls are detected and
               correctly handled (double counting will not happen).

           ·   For profile-directed optimizations, compile the source files
               again with the same optimization and code generation options
               plus -fbranch-probabilities.

           ·   For test coverage analysis, use gcov to produce human readable
               information from the .gcno and .gcda files.  Refer to the gcov
               documentation for further information.

           With -fprofile-arcs, for each function of your program GCC creates
           a program flow graph, then finds a spanning tree for the graph.
           Only arcs that are not on the spanning tree have to be
           instrumented: the compiler adds code to count the number of times
           that these arcs are executed.  When an arc is the only exit or only
           entrance to a block, the instrumentation code can be added to the
           block; otherwise, a new basic block must be created to hold the
           instrumentation code.

       -ftest-coverage
           Produce a notes file that the gcov code-coverage utility can use to
           show program coverage.  Each source file's note file is called
           auxname.gcno.  Refer to the -fprofile-arcs option above for a
           description of auxname and instructions on how to generate test
           coverage data.  Coverage data will match the source files more
           closely, if you do not optimize.

       -fdbg-cnt-list
           Print the name and the counter upperbound for all debug counters.

       -fdbg-cnt=counter-value-list
           Set the internal debug counter upperbound. counter-value-list is a
           comma-separated list of name:value pairs which sets the upperbound
           of each debug counter name to value.  All debug counters have the
           initial upperbound of UINT_MAX, thus dbg_cnt() returns true always
           unless the upperbound is set by this option.  e.g. With
           -fdbg-cnt=dce:10,tail_call:0 dbg_cnt(dce) will return true only for
           first 10 invocations and dbg_cnt(tail_call) will return false
           always.

       -dletters
       -fdump-rtl-pass
           Says to make debugging dumps during compilation at times specified
           by letters.    This is used for debugging the RTL-based passes of
           the compiler.  The file names for most of the dumps are made by
           appending a pass number and a word to the dumpname.  dumpname is
           generated from the name of the output file, if explicitly specified
           and it is not an executable, otherwise it is the basename of the
           source file. These switches may have different effects when -E is
           used for preprocessing.

           Debug dumps can be enabled with a -fdump-rtl switch or some -d
           option letters.  Here are the possible letters for use in pass and
           letters, and their meanings:

           -fdump-rtl-alignments
               Dump after branch alignments have been computed.

           -fdump-rtl-asmcons
               Dump after fixing rtl statements that have unsatisfied in/out
               constraints.

           -fdump-rtl-auto_inc_dec
               Dump after auto-inc-dec discovery.  This pass is only run on
               architectures that have auto inc or auto dec instructions.

           -fdump-rtl-barriers
               Dump after cleaning up the barrier instructions.

           -fdump-rtl-bbpart
               Dump after partitioning hot and cold basic blocks.

           -fdump-rtl-bbro
               Dump after block reordering.

           -fdump-rtl-btl1
           -fdump-rtl-btl2
               -fdump-rtl-btl1 and -fdump-rtl-btl2 enable dumping after the
               two branch target load optimization passes.

           -fdump-rtl-bypass
               Dump after jump bypassing and control flow optimizations.

           -fdump-rtl-combine
               Dump after the RTL instruction combination pass.

           -fdump-rtl-compgotos
               Dump after duplicating the computed gotos.

           -fdump-rtl-ce1
           -fdump-rtl-ce2
           -fdump-rtl-ce3
               -fdump-rtl-ce1, -fdump-rtl-ce2, and -fdump-rtl-ce3 enable
               dumping after the three if conversion passes.

           -fdump-rtl-cprop_hardreg
               Dump after hard register copy propagation.

           -fdump-rtl-csa
               Dump after combining stack adjustments.

           -fdump-rtl-cse1
           -fdump-rtl-cse2
               -fdump-rtl-cse1 and -fdump-rtl-cse2 enable dumping after the
               two common sub-expression elimination passes.

           -fdump-rtl-dce
               Dump after the standalone dead code elimination passes.

           -fdump-rtl-dbr
               Dump after delayed branch scheduling.

           -fdump-rtl-dce1
           -fdump-rtl-dce2
               -fdump-rtl-dce1 and -fdump-rtl-dce2 enable dumping after the
               two dead store elimination passes.

           -fdump-rtl-eh
               Dump after finalization of EH handling code.

           -fdump-rtl-eh_ranges
               Dump after conversion of EH handling range regions.

           -fdump-rtl-expand
               Dump after RTL generation.

           -fdump-rtl-fwprop1
           -fdump-rtl-fwprop2
               -fdump-rtl-fwprop1 and -fdump-rtl-fwprop2 enable dumping after
               the two forward propagation passes.

           -fdump-rtl-gcse1
           -fdump-rtl-gcse2
               -fdump-rtl-gcse1 and -fdump-rtl-gcse2 enable dumping after
               global common subexpression elimination.

           -fdump-rtl-init-regs
               Dump after the initialization of the registers.

           -fdump-rtl-initvals
               Dump after the computation of the initial value sets.

           -fdump-rtl-into_cfglayout
               Dump after converting to cfglayout mode.

           -fdump-rtl-ira
               Dump after iterated register allocation.

           -fdump-rtl-jump
               Dump after the second jump optimization.

           -fdump-rtl-loop2
               -fdump-rtl-loop2 enables dumping after the rtl loop
               optimization passes.

           -fdump-rtl-mach
               Dump after performing the machine dependent reorganization
               pass, if that pass exists.

           -fdump-rtl-mode_sw
               Dump after removing redundant mode switches.

           -fdump-rtl-rnreg
               Dump after register renumbering.

           -fdump-rtl-outof_cfglayout
               Dump after converting from cfglayout mode.

           -fdump-rtl-peephole2
               Dump after the peephole pass.

           -fdump-rtl-postreload
               Dump after post-reload optimizations.

           -fdump-rtl-pro_and_epilogue
               Dump after generating the function pro and epilogues.

           -fdump-rtl-regmove
               Dump after the register move pass.

           -fdump-rtl-sched1
           -fdump-rtl-sched2
               -fdump-rtl-sched1 and -fdump-rtl-sched2 enable dumping after
               the basic block scheduling passes.

           -fdump-rtl-see
               Dump after sign extension elimination.

           -fdump-rtl-seqabstr
               Dump after common sequence discovery.

           -fdump-rtl-shorten
               Dump after shortening branches.

           -fdump-rtl-sibling
               Dump after sibling call optimizations.

           -fdump-rtl-split1
           -fdump-rtl-split2
           -fdump-rtl-split3
           -fdump-rtl-split4
           -fdump-rtl-split5
               -fdump-rtl-split1, -fdump-rtl-split2, -fdump-rtl-split3,
               -fdump-rtl-split4 and -fdump-rtl-split5 enable dumping after
               five rounds of instruction splitting.

           -fdump-rtl-sms
               Dump after modulo scheduling.  This pass is only run on some
               architectures.

           -fdump-rtl-stack
               Dump after conversion from GCC's "flat register file" registers
               to the x87's stack-like registers.  This pass is only run on
               x86 variants.

           -fdump-rtl-subreg1
           -fdump-rtl-subreg2
               -fdump-rtl-subreg1 and -fdump-rtl-subreg2 enable dumping after
               the two subreg expansion passes.

           -fdump-rtl-unshare
               Dump after all rtl has been unshared.

           -fdump-rtl-vartrack
               Dump after variable tracking.

           -fdump-rtl-vregs
               Dump after converting virtual registers to hard registers.

           -fdump-rtl-web
               Dump after live range splitting.

           -fdump-rtl-regclass
           -fdump-rtl-subregs_of_mode_init
           -fdump-rtl-subregs_of_mode_finish
           -fdump-rtl-dfinit
           -fdump-rtl-dfinish
               These dumps are defined but always produce empty files.

           -fdump-rtl-all
               Produce all the dumps listed above.

           -dA Annotate the assembler output with miscellaneous debugging
               information.

           -dD Dump all macro definitions, at the end of preprocessing, in
               addition to normal output.

           -dH Produce a core dump whenever an error occurs.

           -dm Print statistics on memory usage, at the end of the run, to
               standard error.

           -dp Annotate the assembler output with a comment indicating which
               pattern and alternative was used.  The length of each
               instruction is also printed.

           -dP Dump the RTL in the assembler output as a comment before each
               instruction.  Also turns on -dp annotation.

           -dv For each of the other indicated dump files (-fdump-rtl-pass),
               dump a representation of the control flow graph suitable for
               viewing with VCG to file.pass.vcg.

           -dx Just generate RTL for a function instead of compiling it.
               Usually used with -fdump-rtl-expand.

           -dy Dump debugging information during parsing, to standard error.

       -fdump-noaddr
           When doing debugging dumps, suppress address output.  This makes it
           more feasible to use diff on debugging dumps for compiler
           invocations with different compiler binaries and/or different text
           / bss / data / heap / stack / dso start locations.

       -fdump-unnumbered
           When doing debugging dumps, suppress instruction numbers and
           address output.  This makes it more feasible to use diff on
           debugging dumps for compiler invocations with different options, in
           particular with and without -g.

       -fdump-translation-unit (C++ only)
       -fdump-translation-unit-options (C++ only)
           Dump a representation of the tree structure for the entire
           translation unit to a file.  The file name is made by appending .tu
           to the source file name.  If the -options form is used, options
           controls the details of the dump as described for the -fdump-tree
           options.

       -fdump-class-hierarchy (C++ only)
       -fdump-class-hierarchy-options (C++ only)
           Dump a representation of each class's hierarchy and virtual
           function table layout to a file.  The file name is made by
           appending .class to the source file name.  If the -options form is
           used, options controls the details of the dump as described for the
           -fdump-tree options.

       -fdump-ipa-switch
           Control the dumping at various stages of inter-procedural analysis
           language tree to a file.  The file name is generated by appending a
           switch specific suffix to the source file name.  The following
           dumps are possible:

           all Enables all inter-procedural analysis dumps.

           cgraph
               Dumps information about call-graph optimization, unused
               function removal, and inlining decisions.

           inline
               Dump after function inlining.

       -fdump-statistics-option
           Enable and control dumping of pass statistics in a separate file.
           The file name is generated by appending a suffix ending in
           .statistics to the source file name.  If the -option form is used,
           -stats will cause counters to be summed over the whole compilation
           unit while -details will dump every event as the passes generate
           them.  The default with no option is to sum counters for each
           function compiled.

       -fdump-tree-switch
       -fdump-tree-switch-options
           Control the dumping at various stages of processing the
           intermediate language tree to a file.  The file name is generated
           by appending a switch specific suffix to the source file name.  If
           the -options form is used, options is a list of - separated options
           that control the details of the dump.  Not all options are
           applicable to all dumps, those which are not meaningful will be
           ignored.  The following options are available

           address
               Print the address of each node.  Usually this is not meaningful
               as it changes according to the environment and source file.
               Its primary use is for tying up a dump file with a debug
               environment.

           slim
               Inhibit dumping of members of a scope or body of a function
               merely because that scope has been reached.  Only dump such
               items when they are directly reachable by some other path.
               When dumping pretty-printed trees, this option inhibits dumping
               the bodies of control structures.

           raw Print a raw representation of the tree.  By default, trees are
               pretty-printed into a C-like representation.

           details
               Enable more detailed dumps (not honored by every dump option).

           stats
               Enable dumping various statistics about the pass (not honored
               by every dump option).

           blocks
               Enable showing basic block boundaries (disabled in raw dumps).

           vops
               Enable showing virtual operands for every statement.

           lineno
               Enable showing line numbers for statements.

           uid Enable showing the unique ID ("DECL_UID") for each variable.

           verbose
               Enable showing the tree dump for each statement.

           all Turn on all options, except raw, slim, verbose and lineno.

           The following tree dumps are possible:

           original
               Dump before any tree based optimization, to file.original.

           optimized
               Dump after all tree based optimization, to file.optimized.

           gimple
               Dump each function before and after the gimplification pass to
               a file.  The file name is made by appending .gimple to the
               source file name.

           cfg Dump the control flow graph of each function to a file.  The
               file name is made by appending .cfg to the source file name.

           vcg Dump the control flow graph of each function to a file in VCG
               format.  The file name is made by appending .vcg to the source
               file name.  Note that if the file contains more than one
               function, the generated file cannot be used directly by VCG.
               You will need to cut and paste each function's graph into its
               own separate file first.

           ch  Dump each function after copying loop headers.  The file name
               is made by appending .ch to the source file name.

           ssa Dump SSA related information to a file.  The file name is made
               by appending .ssa to the source file name.

           alias
               Dump aliasing information for each function.  The file name is
               made by appending .alias to the source file name.

           ccp Dump each function after CCP.  The file name is made by
               appending .ccp to the source file name.

           storeccp
               Dump each function after STORE-CCP.  The file name is made by
               appending .storeccp to the source file name.

           pre Dump trees after partial redundancy elimination.  The file name
               is made by appending .pre to the source file name.

           fre Dump trees after full redundancy elimination.  The file name is
               made by appending .fre to the source file name.

           copyprop
               Dump trees after copy propagation.  The file name is made by
               appending .copyprop to the source file name.

           store_copyprop
               Dump trees after store copy-propagation.  The file name is made
               by appending .store_copyprop to the source file name.

           dce Dump each function after dead code elimination.  The file name
               is made by appending .dce to the source file name.

           mudflap
               Dump each function after adding mudflap instrumentation.  The
               file name is made by appending .mudflap to the source file
               name.

           sra Dump each function after performing scalar replacement of
               aggregates.  The file name is made by appending .sra to the
               source file name.

           sink
               Dump each function after performing code sinking.  The file
               name is made by appending .sink to the source file name.

           dom Dump each function after applying dominator tree optimizations.
               The file name is made by appending .dom to the source file
               name.

           dse Dump each function after applying dead store elimination.  The
               file name is made by appending .dse to the source file name.

           phiopt
               Dump each function after optimizing PHI nodes into straightline
               code.  The file name is made by appending .phiopt to the source
               file name.

           forwprop
               Dump each function after forward propagating single use
               variables.  The file name is made by appending .forwprop to the
               source file name.

           copyrename
               Dump each function after applying the copy rename optimization.
               The file name is made by appending .copyrename to the source
               file name.

           nrv Dump each function after applying the named return value
               optimization on generic trees.  The file name is made by
               appending .nrv to the source file name.

           vect
               Dump each function after applying vectorization of loops.  The
               file name is made by appending .vect to the source file name.

           vrp Dump each function after Value Range Propagation (VRP).  The
               file name is made by appending .vrp to the source file name.

           all Enable all the available tree dumps with the flags provided in
               this option.

       -ftree-vectorizer-verbose=n
           This option controls the amount of debugging output the vectorizer
           prints.  This information is written to standard error, unless
           -fdump-tree-all or -fdump-tree-vect is specified, in which case it
           is output to the usual dump listing file, .vect.  For n=0 no
           diagnostic information is reported.  If n=1 the vectorizer reports
           each loop that got vectorized, and the total number of loops that
           got vectorized.  If n=2 the vectorizer also reports non-vectorized
           loops that passed the first analysis phase (vect_analyze_loop_form)
           - i.e. countable, inner-most, single-bb, single-entry/exit loops.
           This is the same verbosity level that -fdump-tree-vect-stats uses.
           Higher verbosity levels mean either more information dumped for
           each reported loop, or same amount of information reported for more
           loops: If n=3, alignment related information is added to the
           reports.  If n=4, data-references related information (e.g. memory
           dependences, memory access-patterns) is added to the reports.  If
           n=5, the vectorizer reports also non-vectorized inner-most loops
           that did not pass the first analysis phase (i.e., may not be
           countable, or may have complicated control-flow).  If n=6, the
           vectorizer reports also non-vectorized nested loops.  For n=7, all
           the information the vectorizer generates during its analysis and
           transformation is reported.  This is the same verbosity level that
           -fdump-tree-vect-details uses.

       -frandom-seed=string
           This option provides a seed that GCC uses when it would otherwise
           use random numbers.  It is used to generate certain symbol names
           that have to be different in every compiled file.  It is also used
           to place unique stamps in coverage data files and the object files
           that produce them.  You can use the -frandom-seed option to produce
           reproducibly identical object files.

           The string should be different for every file you compile.

       -fsched-verbose=n
           On targets that use instruction scheduling, this option controls
           the amount of debugging output the scheduler prints.  This
           information is written to standard error, unless -fdump-rtl-sched1
           or -fdump-rtl-sched2 is specified, in which case it is output to
           the usual dump listing file, .sched or .sched2 respectively.
           However for n greater than nine, the output is always printed to
           standard error.

           For n greater than zero, -fsched-verbose outputs the same
           information as -fdump-rtl-sched1 and -fdump-rtl-sched2.  For n
           greater than one, it also output basic block probabilities,
           detailed ready list information and unit/insn info.  For n greater
           than two, it includes RTL at abort point, control-flow and regions
           info.  And for n over four, -fsched-verbose also includes
           dependence info.

       -save-temps
           Store the usual "temporary" intermediate files permanently; place
           them in the current directory and name them based on the source
           file.  Thus, compiling foo.c with -c -save-temps would produce
           files foo.i and foo.s, as well as foo.o.  This creates a
           preprocessed foo.i output file even though the compiler now
           normally uses an integrated preprocessor.

           When used in combination with the -x command line option,
           -save-temps is sensible enough to avoid over writing an input
           source file with the same extension as an intermediate file.  The
           corresponding intermediate file may be obtained by renaming the
           source file before using -save-temps.

       -time
           Report the CPU time taken by each subprocess in the compilation
           sequence.  For C source files, this is the compiler proper and
           assembler (plus the linker if linking is done).  The output looks
           like this:

                   # cc1 0.12 0.01
                   # as 0.00 0.01

           The first number on each line is the "user time", that is time
           spent executing the program itself.  The second number is "system
           time", time spent executing operating system routines on behalf of
           the program.  Both numbers are in seconds.

       -fvar-tracking
           Run variable tracking pass.  It computes where variables are stored
           at each position in code.  Better debugging information is then
           generated (if the debugging information format supports this
           information).

           It is enabled by default when compiling with optimization (-Os, -O,
           -O2, ...), debugging information (-g) and the debug info format
           supports it.

       -print-file-name=library
           Print the full absolute name of the library file library that would
           be used when linking---and don't do anything else.  With this
           option, GCC does not compile or link anything; it just prints the
           file name.

       -print-multi-directory
           Print the directory name corresponding to the multilib selected by
           any other switches present in the command line.  This directory is
           supposed to exist in GCC_EXEC_PREFIX.

       -print-multi-lib
           Print the mapping from multilib directory names to compiler
           switches that enable them.  The directory name is separated from
           the switches by ;, and each switch starts with an @} instead of the
           @samp{-, without spaces between multiple switches.  This is
           supposed to ease shell-processing.

       -print-prog-name=program
           Like -print-file-name, but searches for a program such as cpp.

       -print-libgcc-file-name
           Same as -print-file-name=libgcc.a.

           This is useful when you use -nostdlib or -nodefaultlibs but you do
           want to link with libgcc.a.  You can do

                   gcc -nostdlib ... `gcc -print-libgcc-file-name`

       -print-search-dirs
           Print the name of the configured installation directory and a list
           of program and library directories gcc will search---and don't do
           anything else.

           This is useful when gcc prints the error message installation
           problem, cannot exec cpp0: No such file or directory.  To resolve
           this you either need to put cpp0 and the other compiler components
           where gcc expects to find them, or you can set the environment
           variable GCC_EXEC_PREFIX to the directory where you installed them.
           Don't forget the trailing /.

       -print-sysroot
           Print the target sysroot directory that will be used during
           compilation.  This is the target sysroot specified either at
           configure time or using the --sysroot option, possibly with an
           extra suffix that depends on compilation options.  If no target
           sysroot is specified, the option prints nothing.

       -print-sysroot-headers-suffix
           Print the suffix added to the target sysroot when searching for
           headers, or give an error if the compiler is not configured with
           such a suffix---and don't do anything else.

       -dumpmachine
           Print the compiler's target machine (for example,
           i686-pc-linux-gnu)---and don't do anything else.

       -dumpversion
           Print the compiler version (for example, 3.0)---and don't do
           anything else.

       -dumpspecs
           Print the compiler's built-in specs---and don't do anything else.
           (This is used when GCC itself is being built.)

       -feliminate-unused-debug-types
           Normally, when producing DWARF2 output, GCC will emit debugging
           information for all types declared in a compilation unit,
           regardless of whether or not they are actually used in that
           compilation unit.  Sometimes this is useful, such as if, in the
           debugger, you want to cast a value to a type that is not actually
           used in your program (but is declared).  More often, however, this
           results in a significant amount of wasted space.  With this option,
           GCC will avoid producing debug symbol output for types that are
           nowhere used in the source file being compiled.