Re: [PATCH] PR67305, tighten neon_vector_mem_operand on eliminable registers

[Jiong Wang <jiong.wang@foss.arm.com>]

On 04/11/15 09:45, Jiong Wang wrote:
> As discussed at the bugzilla
>
>   https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67305
>
> neon_vector_mem_operand is broken.  As the comments says
> "/* Reject eliminable registers.  */", the code block at the head
> of this function which checks eliminable registers is designed to do
> early reject only, there shouldn't be any early accept.
>
> If this code hunk doesn't reject the incoming rtx, then the rtx pattern
> should still go through all default checks below. All other similar
> functions, thumb1_legitimate_address_p, arm_coproc_mem_operand,
> neon_struct_mem_operand etc are exactly follow this check flow.
>
> So as Jim Wilson commented on the bugzilla, instead of "return !strict",
> we need to only do the check if strict be true, and only does rejection
> which means return FALSE, for all other cases, we need to go through
> those normal checks below.
>
> neon_vector_mem_operand is only used by several misalign pattern, I
> guess that's why this bug is not exposed for long time.
>
> boostrap & regression OK on armv8 aarch32, ok for trunk?
>
> 2015-11-04  Jiong Wang  <jiong.wang@arm.com>
>             Jim Wilson  <wilson@gcc.gnu.org>
>
> gcc/
>   PR target/67305
>   * config/arm/arm.md (neon_vector_mem_operand): Return FALSE if strict
>   be true and eliminable registers mentioned.
>
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