[llvm] r245169 - [X86] Widen the 'AND' mask if doing so shrinks the encoding size

[Tobias Grosser via llvm-commits]

On 08/18/2015 01:13 PM, Tobias Grosser wrote:
> On 08/16/2015 06:52 AM, David Majnemer via llvm-commits wrote:
>> Author: majnemer
>> Date: Sat Aug 15 23:52:11 2015
>> New Revision: 245169
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=245169&view=rev
>> Log:
>> [X86] Widen the 'AND' mask if doing so shrinks the encoding size
>>
>> We can set additional bits in a mask given that we know the other
>> operand of an AND already has some bits set to zero.  This can be more
>> efficient if doing so allows us to use an instruction which implicitly
>> sign extends the immediate.
>>
>> This fixes PR24085.
>>
>
> This change seems to have broken an LNT builder:
>
> http://lab.llvm.org:8011/builders/perf-x86_64-penryn-O3/builds/6117
>
> FAIL: siod.execution_time

I reverted this commit for now in 245432 to get our LNT correctness bots
green. Please let me know if you need more information about this bug.

Best,
Tobias