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Diffstat (limited to 'src/doc/rustc-dev-guide')
| -rw-r--r-- | src/doc/rustc-dev-guide/src/mir/index.md | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/doc/rustc-dev-guide/src/mir/index.md b/src/doc/rustc-dev-guide/src/mir/index.md index dc0be167b01..b90c5ad83b7 100644 --- a/src/doc/rustc-dev-guide/src/mir/index.md +++ b/src/doc/rustc-dev-guide/src/mir/index.md @@ -62,6 +62,12 @@ show you the MIR for your program. Try putting this program into play button on the top: [sample-play]: https://play.rust-lang.org/?gist=30074856e62e74e91f06abd19bd72ece&version=stable +MIR shown by above link is optimized. +Some statements like `StorageLive` are removed in optimization. +This happens because compiler notices the value is never acessed in the code. +We can use `rustc [filename].rs -Z mir-opt-level=0 --emit mir` to view unoptimized MIR. +This requires the nightly toolchain. + ```rust fn main() { |