在 2024/1/4 下午12:05, Xi Ruoyao 写道:
> On Thu, 2024-01-04 at 11:58 +0800, chenglulu wrote:
>> 在 2024/1/4 上午11:51, Xi Ruoyao 写道:
>>> On Wed, 2023-12-27 at 16:46 +0800, Lulu Cheng wrote:
>>>> +(define_insn "movdi_pcrel64"
>>>> + [(set (match_operand:DI 0 "register_operand" "=&r")
>>>> +       (match_operand:DI 1 "symbolic_pcrel64_operand"))
>>>> +  (unspec:DI [(const_int 0)]
>>>> +    UNSPEC_MOV_PCREL64)
>>>> +  (use (reg:DI T3_REGNUM))
>>>> +  (clobber (reg:DI T3_REGNUM))]
>>> It's better not to hard code $t3 here.  We can write
>>>
>>> [(set (match_operand:DI 0 "register_operand" "=r")
>>>          (match_operand:DI 1 "symbolic_pcrel64_operand"))
>>>     (clobber (match_operand:DI 2 "register_operand "=&r"))]
>>>
>>> And use
>>>
>>>      gen_movdi_pcrel64 (operands[0], operands[1], gen_reg_rtx(DImode))
>>>
>>> in expand.
>>>
>> I tried using (clobber (match_scratch)) when implementing it, but it
>> didn't work.
> I tried match_scratch a few times as well in my previous hacks but never
> succeeded :(.
>
In the function loongarch_output_mi_thunk, the address of the symbol 
.LTHUNK0

will be obtained, but at this time it is no longer possible to apply for 
temporary variables.

So there will be ICE here

See attachment for test cases.

The compilation command is as follows:

$ ./gcc/cc1plus -fpreprocessed example.ii -quiet -dumpbase example.cc 
-dumpbase-ext .cc -mexplicit-relocs=none -mno-relax -mabi=lp64d 
-march=loongarch64 -mfpu=64 -msimd=lasx -mcmodel=extreme 
-mtune=loongarch64 -g3 -O2 -Wno-int-conversion -Wno-implicit-int 
-Wno-implicit-function-declaration -Wno-incompatible-pointer-types 
-std=c++98 -version -o example.s