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Re: [Patch, testsuite, mips] Fix two failing MIPS tests.
- From: Richard Sandiford <rdsandiford at googlemail dot com>
- To: "Steve Ellcey " <sellcey at mips dot com>
- Cc: <gcc-patches at gcc dot gnu dot org>
- Date: Sat, 03 May 2014 07:52:07 +0100
- Subject: Re: [Patch, testsuite, mips] Fix two failing MIPS tests.
- Authentication-results: sourceware.org; auth=none
- References: <832bc707-65b6-420a-aafc-3857e5c42de4 at BAMAIL02 dot ba dot imgtec dot org>
"Steve Ellcey " <sellcey@mips.com> writes:
> Two MIPS specific tests started failing a few days ago, this patch fixes
> them. The tests are trying to check that a performance optimization is
> done and that one constant is derived from another and not simply loaded
> as a completely new constant.
>
> Post 4.9 changes have affected which constant gets loaded and which one
> gets derived (and how it is derived) from it. The new code looks as
> good as the old code:
>
> Old:
>
> li $5,305397760 # 0x12340000
> addiu $4,$5,1
> addiu $5,$5,-1
>
> New:
>
> li $5,305332224 # 0x12330000
> ori $5,$5,0xffff
> addiu $4,$5,2
This isn't as good though -- $4 now depends on two previous
instructions. Do you know which specific change was responsible?
Thanks,
Richard