Obviously some not human generated code: I used Csmith "a tool that can generate random C programs" (https://embed.cs.utah.edu/csmith/) and ran SDCC (3.6.9 #10174) over that.
The code e.g. generated with --seed 105 throws an error.
~/csmith/src/csmith --version csmith 2.2.0 Git version: 704fdc4 ~/csmith/src/csmith --seed 105 --no-safe-math --no-longlong --no-math64 > test.c sdcc --model-large -I ~/csmith/runtime test.c "test.c:56: error 9: FATAL Compiler Internal Error in file 'gen.c' line number '1835' : need pointerCode"
This specific seed generates an Internal Error with a relatively small file (test.c, 4174 byte, appended) so I picked that. (There is more)