Re: [PATCH PR69052]Check if loop inv can be propagated into mem ref with additional addr expr canonicalization

[Jeff Law <law@redhat.com>]

On 02/16/2016 11:43 AM, Bin Cheng wrote:
> ________________________________________
> From: Jeff Law <law@redhat.com>
> Sent: 11 February 2016 23:26
> To: Bin.Cheng
> Cc: Bin Cheng; gcc-patches@gcc.gnu.org; nd
> Subject: Re: [PATCH PR69052]Check if loop inv can be propagated into mem ref with additional addr expr canonicalization
>
>>> On 02/11/2016 10:59 AM, Bin.Cheng wrote:
>
>>> Hi Jeff,
>>> Thanks for detailed review.  I also think a generic canonical
>>> interface for RTL is much better.  I will give it a try.  But with
>>> high chance it's a next stage1 stuff.
>> That is, of course, fine.  However, if you do get something ready, I'd
>> support using it within LICM for gcc-6, then using it in other places
>> for gcc-7.
> Hi,
> This is the updated version patch.  It fixes the problem by introducing a generic address canonicalization interface.  This new interface canonicalizes address expression in following steps:
>       1) Rewrite ASHIFT into MULT recursively.
>       2) Divide address into sub expressions with PLUS as the separator.
>       3) Sort sub expressions according to precedence defined for communative operations.
>       4) Simplify CONST_INT_P sub expressions.
>       5) Create new canonicalized address and return.
>
> According to review comments, this interface is now restricted in LCIM, and will probably be expanded to other passes like fwprop and combine after entering GCC7.
> Bootstrap and test on x86_64 and AArch64.  Is it OK?
>
> Thanks,
> bin
>
> 2016-02-15  Bin Cheng  <bin.cheng@arm.com>
>
> 	PR tree-optimization/69052
> 	* loop-invariant.c (canonicalize_address_mult): New function.
> 	(MAX_CANON_ADDR_PARTS): New macro.
> 	(collect_address_parts): New function.
> 	(compare_address_parts, canonicalize_address): New functions.
> 	(inv_can_prop_to_addr_use): Check validity of address expression
> 	which is canonicalized by above canonicalize_address.
>
> gcc/testsuite/ChangeLog
> 2016-02-15  Bin Cheng  <bin.cheng@arm.com>
>
> 	PR tree-optimization/69052
> 	* gcc.target/i386/pr69052.c: New test.
This is exactly what I was looking for from a design standpoint.

My only question is why didn't you use FOR_EACH_SUBRTX_VRA from 
rtl-iter.h to walk the RTX expressions in collect_address_parts and 
canonicalize_address_mult?

Jeff


>
>>
>> Jeff
>