[Bug rtl-optimization/116325] [lra] error: unable to generate reloads for:

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116325

--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Created attachment 58945
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58945&action=edit
C++ test case from libstdc++v3

This is a test case from libstdc++v3.  Compile with

$ avr-g++ pr116389.cpp -S -dumpbase "" -O2 -mmcu=avrtiny -dp
-fdump-rtl-ira-details -fdump-rtl-reload-details -mlra

error: unable to generate reloads for:
(call_insn/j 43 42 44 8 (parallel [
            (set (reg:HI 24 r24)
                (call (mem:HI (reg/f:HI 45 [ _8 ]) [0
*OBJ_TYPE_REF(_8;this_1(D)->7B) S2 A8])
                    (const_int 2 [0x2])))
            (use (const_int 1 [0x1]))
        ])
"/ssd1/build/avr/gcc-bug/avr/avrtiny/libstdc++-v3/include/bits/locale_facets.h":917:23
774 {call_value_insn}
     (expr_list:REG_DEAD (reg/f:HI 45 [ _8 ])
        (expr_list:REG_DEAD (reg:QI 35 argH)
            (expr_list:REG_DEAD (reg:HI 22 r22)
                (expr_list:REG_DEAD (reg:HI 20 r20)
                    (expr_list:REG_UNUSED (reg:HI 24 r24)
                        (expr_list:REG_CALL_DECL (nil)
                            (nil)))))))
    (expr_list:HI (use (reg:HI 24 r24))
        (expr_list:HI (use (reg:HI 22 r22))
            (expr_list:HI (use (reg:HI 20 r20))
                (expr_list:HI (use (mem/f:HI (reg/f:HI 34 argL) [0  S2 A8]))
                    (nil))))))
during RTL pass: reload
dump file: pr116389.cpp.317r.reload
/ssd1/build/avr/gcc-bug/avr/avrtiny/libstdc++-v3/include/bits/locale_facets.h:918:7:
internal compiler error: in curr_insn_transform, at lra-constraints.cc:4283