Compiler Explorer Assembly Output for C, C++ and D (dlang)

[Tariq Siddiqui via Digitalmars-d-learn]

When using Compiler Explorer (https://godbolt.org/) to compare 
assembly output of simple programs, why D language assembly 
output is so long compared to C or C++ output. The simple square 
function output is the same for C, C++, and D, but the D output 
has additional lines that are not highlighted when hovering over 
the square function in the source code.

 - What are these additional lines?
 - How can I remove these lines from being generated?