rustc from trixie-backports crashes compiling compiler-builtins

I'm trying to build https://github.com/microsoft/edit using the bpo
version of cargo & rustc, and running into a compiler crash:

Repro:
1. Install rustc, rust-src, and cargo from trixie-backports
(1.90.0+dfsg1-1~bpo13+2)
2. Clone https://github.com/microsoft/edit
3. Build with: RUSTC_BOOTSTRAP=1 cargo build --config
.cargo/release.toml --release
4. rustc crashes with SIGSEGV

The top of the backtrace is:
error: rustc interrupted by SIGSEGV, printing backtrace

/lib/x86_64-linux-gnu/librustc_driver-1986f22fdc122ac9.so(+0x960ba5)
[0x7fe9f0960ba5]
/lib/x86_64-linux-gnu/libc.so.6(+0x3fdf0) [0x7fe9efe4adf0]
/lib/x86_64-linux-gnu/libLLVM.so.19.1(+0x23b294a) [0x7fe9ea3b294a]
/lib/x86_64-linux-gnu/libLLVM.so.19.1(_ZN4llvm16ConstantFoldCallEPKNS_8CallBaseEPNS_8FunctionENS_8ArrayRefIPNS_8ConstantEEEPKNS_17TargetLibraryInfoEb+0x13c)
[0x7fe9ea3af6ec]

The full crash output is here:
https://gist.github.com/fastcat/b41a69b0c171e9a8dacec9b6b5a48837

If I use the rust:1.90.0-trixie docker image to do the build, it
doesn't crash. Similarly if I use rustc 1.90.1 from a forky docker
container, it also doesn't crash. This seems to point to it being
something haywire with the BPO build, or perhaps with its
dependencies?

If there's a way to get symbols for rustc & llvm to get a better
backtrace, or other things I can do to get more/better diagnostics,
I'm all ears.

Please CC me on replies.

Thanks,
  -- Matt