LGTM, and yeah, I agree that's a code model issue.
On Wed, Nov 15, 2023 at 3:29 PM juzhe.zh...@rivai.ai
<juzhe.zh...@rivai.ai> wrote:
>
> Yes.
> (set (reg:DI) (subreg:DI (reg:V1DI 155) 0)) become vmv.x.s
>
> So, you will see:
> vsetivli zero,1,e64,m1,ta,ma
> sb zero,%lo(c)(a2)
> vle64.v v1,0(a5)
> lbu a5,%lo(b)(a4)
> vse64.v v1,0(a3)
> beq a5,zero,.L6
> vmv.x.s a5,v1
> sw zero,0(a5)
>
> I think the codegen is not good. It should be using scalar load/store.
> I think it should be COST MODEL issue.
>
> ________________________________
> juzhe.zh...@rivai.ai
>
>
> From: Kito Cheng
> Date: 2023-11-15 15:24
> To: Juzhe-Zhong
> CC: gcc-patches; kito.cheng; jeffreyalaw; rdapp.gcc
> Subject: Re: [PATCH] RISC-V: Disallow RVV mode address for any
> load/store[PR112535]
> Curious about the code gen impact, does it make IRA/LRA insert one more move
> like (set (reg:DI) (subreg:DI (reg:V1DI 155) 0)) and then (set (mem:SI
> (reg:DI)) (const_int 0))?
>
> On Wed, Nov 15, 2023 at 3:15 PM Juzhe-Zhong <juzhe.zh...@rivai.ai> wrote:
>>
>> This patch is quite obvious patch which disallow for load/store address
>> register
>> with RVV mode.
>>
>> PR target/112535
>>
>> gcc/ChangeLog:
>>
>> * config/riscv/riscv.cc (riscv_legitimate_address_p): Disallow RVV
>> modes base address.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * gcc.target/riscv/rvv/autovec/pr112535.c: New test.
>>
>> ---
>> gcc/config/riscv/riscv.cc | 4 ++++
>> .../gcc.target/riscv/rvv/autovec/pr112535.c | 17 +++++++++++++++++
>> 2 files changed, 21 insertions(+)
>> create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112535.c
>>
>> diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
>> index ecee7eb4727..e919850fc6c 100644
>> --- a/gcc/config/riscv/riscv.cc
>> +++ b/gcc/config/riscv/riscv.cc
>> @@ -1427,6 +1427,10 @@ static bool
>> riscv_legitimate_address_p (machine_mode mode, rtx x, bool strict_p,
>> code_helper = ERROR_MARK)
>> {
>> + /* Disallow RVV modes base address.
>> + E.g. (mem:SI (subreg:DI (reg:V1DI 155) 0). */
>> + if (SUBREG_P (x) && riscv_v_ext_mode_p (GET_MODE (SUBREG_REG (x))))
>> + return false;
>> struct riscv_address_info addr;
>>
>> return riscv_classify_address (&addr, x, mode, strict_p);
>> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112535.c
>> b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112535.c
>> new file mode 100644
>> index 00000000000..95799aab8d2
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr112535.c
>> @@ -0,0 +1,17 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-march=rv64gcv -mabi=lp64d -O3" } */
>> +
>> +int *a, *f;
>> +char b, c;
>> +int ***d;
>> +static int ****e = &d;
>> +void g() {
>> + c = 3;
>> + for (; c; c--)
>> + if (c < 8) {
>> + f = 0;
>> + ***e = a;
>> + }
>> + if (b)
>> + ***d = 0;
>> +}
>> --
>> 2.36.3
>>
