Re: [PATCH V2] RISC-V: Ensure vector args and return use function stack to pass [PR110119]

[Jeff Law <jeffreyalaw@gmail.com>]

On 6/14/23 05:56, Lehua Ding wrote:
> The V2 patch address comments from Juzhe, thanks.
> 
> Hi,
>   
> The reason for this bug is that in the case where the vector register is set
> to a fixed length (with `--param=riscv-autovec-preference=fixed-vlmax` option),
> TARGET_PASS_BY_REFERENCE thinks that variables of type vint32m1 can be passed
> through two scalar registers, but when GCC calls FUNCTION_VALUE (call function
> riscv_get_arg_info inside) it returns NULL_RTX. These two functions are not
> unified. The current treatment is to pass all vector arguments and returns
> through the function stack, and a new calling convention for vector registers
> will be added in the future.
>   
> Best,
> Lehua
> 
>          PR target/110119
> 
> gcc/ChangeLog:
> 
>          * config/riscv/riscv.cc (riscv_get_arg_info): Return NULL_RTX for vector mode
>          (riscv_pass_by_reference): Return true for vector mode
> 
> gcc/testsuite/ChangeLog:
> 
>          * gcc.target/riscv/rvv/base/pr110119-1.c: New test.
>          * gcc.target/riscv/rvv/base/pr110119-2.c: New test.
And just to be clear, I've asked for a minor comment update.  The usual 
procedure is to go ahead and post a V3.  In this case I'll also give 
that V3 pre-approval.  So no need to wait for additional acks.  Post it 
and it can be committed immediately.

jeff