OPT(1)                               LLVM                               OPT(1)

       opt - LLVM optimizer

       opt [options] [filename]

       The  opt  command is the modular LLVM optimizer and analyzer.  It takes
       LLVM source files as input, runs the specified optimizations or  analy-
       ses on it, and then outputs the optimized file or the analysis results.
       The function of opt depends on whether the -analyze option is given.

       When -analyze is specified, opt performs various analyses of the  input
       source.  It will usually print the results on standard output, but in a
       few cases, it will print output to standard error or  generate  a  file
       with  the  analysis  output,  which  is usually done when the output is
       meant for another program.

       While -analyze is not given, opt attempts to produce an optimized  out-
       put  file.   The  optimizations  available  via  opt  depend  upon what
       libraries were linked into it as well as any additional libraries  that
       have been loaded with the -load option.  Use the -help option to deter-
       mine what optimizations you can use.

       If filename is omitted from the command line or is "-", opt  reads  its
       input  from  standard input.  Inputs can be in either the LLVM assembly
       language format (.ll) or the LLVM bitcode format (.bc).

       If an output filename is not specified with the -o option,  opt  writes
       its output to the standard output.

       -f     Enable binary output on terminals.  Normally, opt will refuse to
              write raw bitcode output if the output  stream  is  a  terminal.
              With  this  option, opt will write raw bitcode regardless of the
              output device.

       -help  Print a summary of command line options.

       -o <filename>
              Specify the output filename.

       -S     Write output in LLVM intermediate language (instead of bitcode).

              opt provides the ability to run any of  LLVM's  optimization  or
              analysis  passes  in  any order.  The -help option lists all the
              passes available.  The order in which the options occur  on  the
              command  line  are  the order in which they are executed (within
              pass constraints).

              This is short hand for a standard list of compile time optimiza-
              tion  passes.   It might be useful for other front end compilers
              as well.  To discover the full set of options available, use the
              following command:

                 llvm-as < /dev/null | opt -std-compile-opts -disable-output -debug-pass=Arguments

              This  option is only meaningful when -std-compile-opts is given.
              It simply removes the inlining pass from the standard list.

              This option is only meaningful when -std-compile-opts is  given.
              It  disables  most,  but not all, of the -std-compile-opts.  The
              ones that remain are -verify, -lower-setjmp, and -funcresolve.

              This option causes opt to strip debug information from the  mod-
              ule  before applying other optimizations.  It is essentially the
              same as -strip but it ensures that stripping of  debug  informa-
              tion is done first.

              This  option  causes  opt  to add a verify pass after every pass
              otherwise specified on the  command  line  (including  -verify).
              This  is  useful  for cases where it is suspected that a pass is
              creating an invalid module but it is not  clear  which  pass  is
              doing it.  The combination of -std-compile-opts and -verify-each
              can quickly track down this kind of problem.

       -stats Print statistics.

              Record the amount of time needed for each pass and print  it  to
              standard error.

       -debug If  this  is a debug build, this option will enable debug print-
              outs from passes which use the DEBUG() macro.  See the LLVM Pro-
              grammer's Manual, section #DEBUG for more information.

              Load the dynamic object plugin.  This object should register new
              optimization or analysis passes.  Once loaded, the  object  will
              add  new command line options to enable various optimizations or
              analyses.  To see the new complete list  of  optimizations,  use
              the -help and -load options together.  For example:

                 opt -load=plugin.so -help

       -p     Print module after each transformation.

       If  opt  succeeds, it will exit with 0.  Otherwise, if an error occurs,
       it will exit with a non-zero value.

       Maintained by The LLVM Team (http://llvm.org/).

       2003-2016, LLVM Project

3.5                               2016-10-07                            OPT(1)

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