Matt Godbolt and I have added Swift support to his compiler explorer project
It let's you interactively explore assembly emitted by the Swift compiler.
Right now, if you want the compiler to emit Intel syntax instructions, pass
"-emit-assembly -Xllvm --x86-asm-syntax=intel" to the compiler as a command
line argument in the text field in the top right corner.
Note that right now it's might still be kinda rough around the edges.
You can contribute to the project here