Reading up on SSA stuff again because it's been a few years since I last poked at this...
"A Gentle Introduction to LLVM IR"
https://mcyoung.xyz/2023/08/01/llvm-ir/
Reminded me that LLVM initially leaves locals in stack allocated slots and then "promotes" them in the mem2reg pass.
"A catalog of ways to generate SSA"
https://bernsteinbear.com/blog/ssa/
New since I last looked, links to a selection of papers.
"SSA-based Register Allocation"
https://compilers.cs.uni-saarland.de/projects/ssara/
Leaning toward at least starting with write "Single-Pass Generation of Static Single-Assignment Form for Structured Languages", Brandis and Mössenböck, 1994, which is where I started last time around.
https://bernsteinbear.com/assets/img/brandis-single-pass.pdf
"Simple and Efficient Construction of Static Single Assignment Form", Braun et al, 2013, seems interesting too from a more flexible but maybe not all that much more complicated standpoint.
https://bernsteinbear.com/assets/img/braun13cc.pdf
Brian Swetland
Alex Rosenberg