-C target-cpu=native

[jhpratt]

By using RUSTFLAGS="-C target-cpu=native", the resulting binary will be far less portable, but it can reduce the binary size a fair amount.

[tesuji]

But beware of codegen bug which occasionally happened.
Please report issue if that happens.

[tesuji]

Also can you measure it?

[jhpratt]

I haven't heard of any issues with codegen, but I may just not be aware.

I'm not sure where this would be inserted, which would obviously affect the measurement. It's relatively trivial to do so, however.

[tesuji]

Like this: rust-lang/rust#63791

[jhpratt]

That's closed as fixed. Bugs happen in the compiler, that's not terribly surprising.

[tesuji]

• Possible miscompilation of alacritty with -C target-cpu=native rust-lang/rust#48464 I don't know current status of it
• Miscompilation with target-cpu=znver1 (AMD Ryzen 1000/2000 series) on Windows + LLVM 9. rust-lang/rust#63959

I just want to add a small note to raise awareness for using target-cpu=native.

[tesuji]

And this one may seems serious: rust-lang/rust#64609