https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103271
--- Comment #17 from qinzhao at gcc dot gnu.org ---
(In reply to Richard Biener from comment #12)
> diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c
> index 6ac3460d538..08f94b7a17a 100644
> --- a/gcc/internal-fn.c
> +++ b/gcc/internal-fn.c
> @@ -3050,6 +3050,23 @@ expand_DEFERRED_INIT (internal_fn, gcall *stmt)
> lhs_base = TREE_OPERAND (lhs_base, 0);
> reg_lhs = (mem_ref_refers_to_non_mem_p (lhs_base)
> || non_mem_decl_p (lhs_base));
> + /* If this expands to a register and the underlying decl is wrapped in
> + a MEM_REF that just serves as an access type change expose the decl
> + if it is of correct size. This avoids a situation as in PR103271
> + if the target does not support a direct move to the registers mode.
> */
> + if (reg_lhs
> + && TREE_CODE (lhs_base) == MEM_REF
> + && TREE_CODE (TREE_OPERAND (lhs_base, 0)) == ADDR_EXPR
> + && DECL_P (TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0))
> + && integer_zerop (TREE_OPERAND (lhs_base, 1))
> + && tree_fits_uhwi_p (var_size)
> + && tree_int_cst_equal
> + (var_size,
> + DECL_SIZE_UNIT (TREE_OPERAND (TREE_OPERAND (lhs_base, 0),
> 0))))
> + {
> + lhs = TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0);
> + var_type = TREE_TYPE (lhs);
> + }
> }
>
> if (!reg_lhs)
>
> solves the issue. There might be a situation where that's not enough though,
> I'm giving the above some testing.
this patch is so specific to target this specific case, I am wondering whether
this is needed if Tim will provide a patch to support MOVTI in riscv backend?
