[Bug bootstrap/63573] [5 Regression] libgo: ICE building libgo on powerpc-linux-gnu

["marxin at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63573

--- Comment #5 from Martin LiÅka <marxin at gcc dot gnu.org> ---
Issue looks very similar, ICF identifies a pair of function which are
transformed to thunk (with tail-call).

Where:
(gdb) call debug_gimple_stmt(stmt)
# .MEM_3 = VDEF <.MEM_1(D)>
encoding_json.error.pN25_encoding_json.encodeState.localalias.36 (d_2(D), err);
[tail call]

and:
#9  0x00000000102a315c in expand_expr (exp=0x3fffa79d3940,
target=0x3fffaf8d0400, mode=VOIDmode, modifier=EXPAND_NORMAL) at
../../gcc/expr.h:382
382      return expand_expr_real (exp, target, mode, modifier, NULL, false);
(gdb) call debug_tree(exp)
 <call_expr 0x3fffa79d3940
    type <void_type 0x3fffaf8b1260 asm_written VOID
        align 8 symtab 0 alias set -1 canonical type 0x3fffaf8b1260
        pointer_to_this <pointer_type 0x3fffaf8b1308>>
    side-effects addressable protected
    fn <addr_expr 0x3fffafa9bc80
        type <pointer_type 0x3fffafb60a80 type <function_type 0x3fffafb609d8>
            unsigned SI
            size <integer_cst 0x3fffaf881158 constant 32>
            unit size <integer_cst 0x3fffaf881170 constant 4>
            align 32 symtab 0 alias set -1 canonical type 0x3fffafb60a80>
        constant
        arg 0 <function_decl 0x3fffa792d728
encoding_json.error.pN25_encoding_json.encodeState.localalias.36 type
<function_type 0x3fffafb609d8>
            addressable asm_written used SI file
../../../../libgo/go/encoding/json/encode.go line 272 col 1 align 32 result
<result_decl 0x3fffb1851ab8 D.3022>
            (mem:SI (symbol_ref:SI
("encoding_json.error.pN25_encoding_json.encodeState.localalias.36") [flags
0x3] <function_decl 0x3fffa792d728
encoding_json.error.pN25_encoding_json.encodeState.localalias.36>) [0  S4
A8])>>
    arg 0 <ssa_name 0x3fffa7916078
        type <pointer_type 0x3fffaf9e03f0 type <record_type 0x3fffaf8b8f10
.encoding/json.decodeState>
            sizes-gimplified asm_written public unsigned SI size <integer_cst
0x3fffaf881158 32> unit size <integer_cst 0x3fffaf881170 4>
            align 32 symtab 16383 alias set 5 canonical type 0x3fffaf9e03f0>
        visited var <parm_decl 0x3fffafad0980 d>def_stmt GIMPLE_NOP

        version 2
        ptr-info 0x3fffa58b0c90>
    arg 1 <parm_decl 0x3fffafad0a00 err
        type <record_type 0x3fffaf8b6d98 error sizes-gimplified asm_written DI
            size <integer_cst 0x3fffaf8811b8 constant 64>
            unit size <integer_cst 0x3fffaf8811d0 constant 8>
            align 32 symtab 16383 alias set 28 canonical type 0x3fffaf8b6d98
fields <field_decl 0x3fffaf961138 __methods>
            pointer_to_this <pointer_type 0x3fffaf9a6708>>
        addressable used DI file ../../../../libgo/go/encoding/json/decode.go
line 193 col 1 size <integer_cst 0x3fffaf8811b8 64> unit size <integer_cst
0x3fffaf8811d0 8>
        align 32 context <function_decl 0x3fffaf979f78
json.error.pN25_encoding_json.decodeState>
        (reg/v:DI 157 [ err ]) arg-type <record_type 0x3fffaf8b6d98 error>
        incoming-rtl (mem:DI (reg:SI 4 4) [0  S8 A8])>>

(gdb) frame 1
(gdb) call debug_rtx(result)
(reg/v:DI 157 [ err ])

Am I right that problem comes up from TREE_ADDRESSABLE flag set on arg 1 (err)?
I would appreciate any hint how should be thunk creation fixed.

Thank you,
Martin