7 :program:`opt` [*options*] [*filename*]
12 The :program:`opt` command is the modular LLVM optimizer and analyzer. It
13 takes LLVM source files as input, runs the specified optimizations or analyses
14 on it, and then outputs the optimized file or the analysis results. The
15 function of :program:`opt` depends on whether the :option:`-analyze` option is
18 When :option:`-analyze` is specified, :program:`opt` performs various analyses
19 of the input source. It will usually print the results on standard output, but
20 in a few cases, it will print output to standard error or generate a file with
21 the analysis output, which is usually done when the output is meant for another
24 While :option:`-analyze` is *not* given, :program:`opt` attempts to produce an
25 optimized output file. The optimizations available via :program:`opt` depend
26 upon what libraries were linked into it as well as any additional libraries
27 that have been loaded with the :option:`-load` option. Use the :option:`-help`
28 option to determine what optimizations you can use.
30 If ``filename`` is omitted from the command line or is "``-``", :program:`opt`
31 reads its input from standard input. Inputs can be in either the LLVM assembly
32 language format (``.ll``) or the LLVM bitcode format (``.bc``).
34 If an output filename is not specified with the :option:`-o` option,
35 :program:`opt` writes its output to the standard output.
42 Enable binary output on terminals. Normally, :program:`opt` will refuse to
43 write raw bitcode output if the output stream is a terminal. With this option,
44 :program:`opt` will write raw bitcode regardless of the output device.
48 Print a summary of command line options.
50 .. option:: -o <filename>
52 Specify the output filename.
56 Write output in LLVM intermediate language (instead of bitcode).
58 .. option:: -{passname}
60 :program:`opt` provides the ability to run any of LLVM's optimization or
61 analysis passes in any order. The :option:`-help` option lists all the passes
62 available. The order in which the options occur on the command line are the
63 order in which they are executed (within pass constraints).
65 .. option:: -std-compile-opts
67 This is short hand for a standard list of *compile time optimization* passes.
68 It might be useful for other front end compilers as well. To discover the
69 full set of options available, use the following command:
73 llvm-as < /dev/null | opt -std-compile-opts -disable-output -debug-pass=Arguments
75 .. option:: -disable-inlining
77 This option is only meaningful when :option:`-std-compile-opts` is given. It
78 simply removes the inlining pass from the standard list.
80 .. option:: -disable-opt
82 This option is only meaningful when :option:`-std-compile-opts` is given. It
83 disables most, but not all, of the :option:`-std-compile-opts`. The ones that
84 remain are :option:`-verify`, :option:`-lower-setjmp`, and
85 :option:`-funcresolve`.
87 .. option:: -strip-debug
89 This option causes opt to strip debug information from the module before
90 applying other optimizations. It is essentially the same as :option:`-strip`
91 but it ensures that stripping of debug information is done first.
93 .. option:: -verify-each
95 This option causes opt to add a verify pass after every pass otherwise
96 specified on the command line (including :option:`-verify`). This is useful
97 for cases where it is suspected that a pass is creating an invalid module but
98 it is not clear which pass is doing it. The combination of
99 :option:`-std-compile-opts` and :option:`-verify-each` can quickly track down
100 this kind of problem.
106 .. option:: -time-passes
108 Record the amount of time needed for each pass and print it to standard
113 If this is a debug build, this option will enable debug printouts from passes
114 which use the ``DEBUG()`` macro. See the `LLVM Programmer's Manual
115 <../ProgrammersManual.html>`_, section ``#DEBUG`` for more information.
117 .. option:: -load=<plugin>
119 Load the dynamic object ``plugin``. This object should register new
120 optimization or analysis passes. Once loaded, the object will add new command
121 line options to enable various optimizations or analyses. To see the new
122 complete list of optimizations, use the :option:`-help` and :option:`-load`
123 options together. For example:
127 opt -load=plugin.so -help
131 Print module after each transformation.
136 If :program:`opt` succeeds, it will exit with 0. Otherwise, if an error
137 occurs, it will exit with a non-zero value.