Update cheatsheets

opt

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+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# opt
+
+> Runs optimizations and analyse LLVM source files.
+> More information: <https://llvm.org/docs/CommandGuide/opt.html>.
+
+- Run an optimization or analysis on a bitcode file:
+
+`opt -{{passname}} {{path/to/file.bc}} -S -o {{file_opt.bc}}`
+
+- Output the Control Flow Graph of a function to a `.dot` file:
+
+`opt {{-dot-cfg}} -S {{path/to/file.bc}} -disable-output`
+
+- Optimize the program at level 2 and output the result to another file:
+
+`opt -O2 {{path/to/file.bc}} -S -o {{path/to/output_file.bc}}`