Excessive nop instructions when branching and after calls in optimized release builds

[Draugr-official]

After looking through the CIL of some test applications I build, I noticed that Roslyn produces some extra nop instructions instead of just directly branching to the given code block.

I used the latest version of Visual Studio 2026 Community alongside .NET 10.0.201.

The code used to produce this CIL:

namespace TEST_CS_NET_10
{
    internal class Program
    {
        static void Main(string[] args)
        {
            for(int i = 0; i <= 10; i++)
            {
                Console.WriteLine(i);
            }
        }
    }
}

Is this just lazy compiler design, intentional or overseen? I dont see the debug use for these instructions, especially since its a release build.

Would this cause excess file size / performance issues in large, intense projects or has this been ignored simply because its too trivial?

[hamarb123]

especially since its a release build

Pretty sure that's compiled in debug mode: Debug IL (has nops), Release IL (no nops).

[Draugr-official]

@hamarb123 Please read the entire issue:

#83081 (comment)
"Is this just lazy compiler design, intentional or overseen? I dont see the debug use for these instructions, especially since its a release build."

[hamarb123]

"Is this just lazy compiler design, intentional or overseen? I dont see the debug use for these instructions, especially since its a release build."

It's not a release build. That's literally what the entirety of my first response is addressing.

If you want to know why it exists in debug builds, it's to help with debugging so you can step on lines like { and }.

[Draugr-official]

Since you are still in so much doubt over the trustworthiness of my issue, I highly suggest you open Visual Studio, compile the stub and inspect the produced CIL yourself.

[hamarb123]

Sure

[333fred]

@Draugr-official I am also unable to reproduce this. If you are observing this in a release build, then it would be helpful if you were to include a complete repro, including csproj and any Directory.Build.props/targets that may be in the current directory or located in containing directories that you are building from. More than likely, you are either accidentally not building for release, or you've set <Optimize>false</Optimize> in your csproj/Dir.Build.props somewhere.