a small C (naive) program faster with clang than with gcc

Hello all, Consider the naive program (GPLv3+) to solve the cryptaddition `NEUF` + `DEUX` = `ONZE` onhttps://github.com/bstarynk/misc-basile/blob/master/CryptArithm/neuf%2Bdeux%3Donze/naive0.c (commit0d1bd0e

Why spill_failure() aborts the compiler when hard-registers cannot find to spill pseudo-registers?

I am curious why spill_failure() in gcc/reload1.cc aborts the compiler. static void spill_failure (rtx_insn *insn, enum reg_class rclass) { if (asm_noperands (PATTERN (insn)) >= 0) error_for_asm (insn, "cannot find a register in class %qs while " "reloading %", reg_class_names[rclass])