Re: [PATCH] vect: Check that vector factor is a compile-time constant

[Michael Collison <collison@rivosinc.com>]

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Juzhe,

I disagree with this comment. There are many stakeholders for 
autovectorization and waiting until GCC 14 is not a viable solution for 
us as well as other stakeholders ready to begin work on autovectorization.

As we discussed I have been moving forward with patches for 
autovectorization and am preparing to send them to gcc-patches. This 
assert is preventing code from compiling and needs to be addressed.

If you have a solution in either the RISCV backend or in this file can 
you please present it?

On 2/22/23 10:27, juzhe.zhong@rivai.ai wrote:
> >/gcc/ />//>/* tree-vect-loop-manip.cc (vect_do_peeling): Verify />/that vectorization factor is a compile-time constant. />//>/--- />/gcc/tree-vect-loop-manip.cc | 2 +- />/1 file changed, 1 insertion(+), 1 deletion(-) />//>/diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc />/index 6aa3d2ed0bf..1ad1961c788 100644 />/--- a/gcc/tree-vect-loop-manip.cc />/+++ b/gcc/tree-vect-loop-manip.cc />/@@ -2930,7 +2930,7 @@ vect_do_peeling (loop_vec_info loop_vinfo, tree />/niters, tree nitersm1, />/niters = vect_build_loop_niters (loop_vinfo, &new_var_p); />//* It's guaranteed that vector loop bound before vectorization is at />/least VF, so set range information for newly generated var. */ />/- if (new_var_p) />/+ if (new_var_p && vf.is_constant ()) />/{ />/value_range vr (type, />/wi::to_wide (build_int_cst (type, vf)),/
>
> I don't think we need to apply this limit in case of RVV 
> auto-vectorization.
> I have talked with Kito and I have a full solution of supporting RVV 
> solution.
>
> We are going to support RVV auto-vectorization in 3 configuration 
> according to RVV ISA spec:
> 1. -march=zve32* support QI and HI auto-vectorization by VNx4QImode 
> and VNx2HImode
> 2. -march=zve64* support QI and HI and SI auto-vectorization by 
> VNx8QImode and VNx4HImode and VNx2SImode
> 3.-march=v* support QI and HI and SI and DI auto-vectorization by 
> VNx16QImode and VNx8HImode and VNx4SImode and VNx2DImode
>
> I will support them in GCC 14. Current loop vectorizer works well for 
> us no need to fix it.
> Thanks.
> ------------------------------------------------------------------------
> juzhe.zhong@rivai.ai