[Bug target/97715] [11 Regression] ICE in insn_default_length, at config/i386/i386.md:15325 since r11-4578-gd10f3e900b0377b4

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97715

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
;; Floating-point register constraints.
(define_register_constraint "f"
 "TARGET_80387 || TARGET_FLOAT_RETURNS_IN_80387 ? FLOAT_REGS : NO_REGS"
 "Any 80387 floating-point (stack) register.")

So, zero_all_st_registers really should just
  if (!TARGET_80387 && !TARGET_FLOAT_RETURNS_IN_80387)
    return false;
somewhere early.