docs/CommandGuide/opt.md

# opt - LLVM optimizer

:::{program} opt
:::

## SYNOPSIS

{program}`opt` \[*options*\] \[*filename*\]

## DESCRIPTION

The {program}`opt` command is the modular LLVM optimizer and analyzer. It takes
LLVM source files as input, runs the specified optimizations or analyses on it,
and then outputs the optimized file. The optimizations available via
{program}`opt` depend upon what libraries were linked into it as well as any
additional libraries that have been loaded with the {option}`-load` option. Use
the {option}`-help` option to determine what optimizations you can use.

If `filename` is omitted from the command line or is "`-`", {program}`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 {option}`-o` option,
{program}`opt` writes its output to the standard output.

## OPTIONS

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

:::{option} -help
Print a summary of command line options.
:::

:::{option} -o <filename>
Specify the output filename.
:::

:::{option} -S
Write output in LLVM intermediate language (instead of bitcode).
:::

:::{option} -passes=<string>
A textual (comma-separated) description of the pass pipeline,
e.g., `-passes="sroa,instcombine"`. See
[invoking opt](../NewPassManager.md#invoking-opt) for more details on the
pass pipeline syntax.
:::

:::{option} -mtriple=<target triple>
Override the target triple specified in the input file with the specified
string.
:::

:::{option} -mtune=<cpuname>
Specify a specific chip microarchitecture in the current architecture
to tune code for. By default this is inferred from the target triple and
autodetected to the current architecture. For a list of available tuning
CPUs, use:

```none
llvm-as < /dev/null | opt -march=xyz -mtune=help
```
:::

:::{option} -strip-debug
This option causes opt to strip debug information from the module before
applying other optimizations. It is essentially the same as `-strip`
but it ensures that stripping of debug information is done first.
:::

:::{option} -verify-each
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.
:::

:::{option} -stats
Print statistics.
:::

:::{option} --save-stats, --save-stats=cwd, --save-stats=obj
Save LLVM statistics to a file in the current directory
({option}`--save-stats`/"--save-stats=cwd") or the directory
of the output file ("--save-stats=obj") in JSON format.
:::

:::{option} -time-passes
Record the amount of time needed for each pass and print it to standard
error.
:::

:::{option} -debug
If this is a debug build, this option will enable debug printouts from passes
which use the `LLVM_DEBUG()` macro. See {ref}`the LDBG and LLVM_DEBUG() macros
and -debug option <debug>` for more
information.
:::

:::{option} -load=<plugin>
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 {option}`-help` and {option}`-load`
options together. For example:

```sh
opt -load=plugin.so -help
```
:::

:::{option} -print-passes
Print all available passes and exit.
:::

## EXIT STATUS

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