1opt - LLVM optimizer
2====================
3
4SYNOPSIS
5--------
6
7:program:`opt` [*options*] [*filename*]
8
9DESCRIPTION
10-----------
11
12The :program:`opt` command is the modular LLVM optimizer and analyzer.  It
13takes LLVM source files as input, runs the specified optimizations or analyses
14on it, and then outputs the optimized file or the analysis results.  The
15function of :program:`opt` depends on whether the :option:`-analyze` option is
16given.
17
18When :option:`-analyze` is specified, :program:`opt` performs various analyses
19of the input source.  It will usually print the results on standard output, but
20in a few cases, it will print output to standard error or generate a file with
21the analysis output, which is usually done when the output is meant for another
22program.
23
24While :option:`-analyze` is *not* given, :program:`opt` attempts to produce an
25optimized output file.  The optimizations available via :program:`opt` depend
26upon what libraries were linked into it as well as any additional libraries
27that have been loaded with the :option:`-load` option.  Use the :option:`-help`
28option to determine what optimizations you can use.
29
30If ``filename`` is omitted from the command line or is "``-``", :program:`opt`
31reads its input from standard input.  Inputs can be in either the LLVM assembly
32language format (``.ll``) or the LLVM bitcode format (``.bc``).
33
34If an output filename is not specified with the :option:`-o` option,
35:program:`opt` writes its output to the standard output.
36
37OPTIONS
38-------
39
40.. option:: -f
41
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.
45
46.. option:: -help
47
48 Print a summary of command line options.
49
50.. option:: -o <filename>
51
52 Specify the output filename.
53
54.. option:: -S
55
56 Write output in LLVM intermediate language (instead of bitcode).
57
58.. option:: -{passname}
59
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).
64
65.. option:: -disable-inlining
66
67 This option simply removes the inlining pass from the standard list.
68
69.. option:: -disable-opt
70
71 This option is only meaningful when :option:`-std-link-opts` is given.  It
72 disables most passes.
73
74.. option:: -strip-debug
75
76 This option causes opt to strip debug information from the module before
77 applying other optimizations.  It is essentially the same as :option:`-strip`
78 but it ensures that stripping of debug information is done first.
79
80.. option:: -verify-each
81
82 This option causes opt to add a verify pass after every pass otherwise
83 specified on the command line (including :option:`-verify`).  This is useful
84 for cases where it is suspected that a pass is creating an invalid module but
85 it is not clear which pass is doing it.
86
87.. option:: -stats
88
89 Print statistics.
90
91.. option:: -time-passes
92
93 Record the amount of time needed for each pass and print it to standard
94 error.
95
96.. option:: -debug
97
98 If this is a debug build, this option will enable debug printouts from passes
99 which use the ``DEBUG()`` macro.  See the `LLVM Programmer's Manual
100 <../ProgrammersManual.html>`_, section ``#DEBUG`` for more information.
101
102.. option:: -load=<plugin>
103
104 Load the dynamic object ``plugin``.  This object should register new
105 optimization or analysis passes.  Once loaded, the object will add new command
106 line options to enable various optimizations or analyses.  To see the new
107 complete list of optimizations, use the :option:`-help` and :option:`-load`
108 options together.  For example:
109
110 .. code-block:: sh
111
112     opt -load=plugin.so -help
113
114.. option:: -p
115
116 Print module after each transformation.
117
118EXIT STATUS
119-----------
120
121If :program:`opt` succeeds, it will exit with 0.  Otherwise, if an error
122occurs, it will exit with a non-zero value.
123
124