Re: [PATCH] RISC-V: Fix vec_series expander[PR110985]

[Jeff Law <jeffreyalaw@gmail.com>]

On 8/11/23 02:45, Juzhe-Zhong wrote:
> This patch fix bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110985
> 
> 	PR target/110985
> 
> gcc/ChangeLog:
> 
> 	* config/riscv/riscv-v.cc (expand_vec_series): Refactor the expander.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* gcc.target/riscv/rvv/autovec/vls-vlmax/pr110985.c: New test.
OK.  The wording on the ChangeLog could perhaps be improved -- typically 
when one says "refactor" there's not supposed to be a functional change. 
  So perhaps "Refactor the expander and don't lose final assignment" or 
something like that.

Also it's generally useful to reviewers to explain the core problem.  I 
can guess from the BZ that we lost an assignment and I can speculate it 
was a case when the destination wasn't initially a pseudo.  The 
refactoring ensured that the sequence always stores into a pseudo and if 
that pseudo is not the same as the ultimate target, then we copy from 
the pseudo to the ultimate target when expansion is done.

jeff