I've opened a new MR: https://salsa.debian.org/pkg-llvm-team/z3/-/merge_requests/8
This MR won't add SSE2 as a requirement. Instead, it will make the compiler not to emit SSE2 instructions when building for x86_32. I've tested it on my Athlon XP and it works fine. objdump -d doesn't show up any SSE2 instructions anymore. If I compile the original source of z3, SSE2 will be emitted, even when I'm building on an Athlon XP. As a next step, I'll try the SIMDEverywhere approach.
