Request for reviews (S): 6910484: incorrect integer optimization (loosing and op-r in a given example)

[Vladimir Kozlov]

Thanks, Tom

Vladimir

Tom Rodriguez wrote:
> I get it now.  Looks good.
> 
> tom
> 
> On Jan 7, 2010, at 7:10 PM, Vladimir Kozlov wrote:
> 
>> On 1/7/10 7:00 PM, Tom Rodriguez wrote:
>>> Why does the new test only guard the dividend->in(i) line and not the needs_rounding line?  Shouldn't it guard both?
>> Previous outer check has it: (-andconi) >= d
>>
>> Rounding is not needed if mask cleans up more or equal number of bits then shift.
>>
>> Vladimir
>>
>>> tom
>>>
>>> On Jan 7, 2010, at 5:48 PM, Vladimir Kozlov wrote:
>>>
>>>> http://cr.openjdk.java.net/~kvn/6910484/webrev
>>>>
>>>> Fixed 6910484: incorrect integer optimization (loosing and op-r in a given example)
>>>>
>>>> Problem:
>>>> After 6667595 changes Div node ideal optimization incorrectly
>>>> removes AND operation if mask is larger then shift:
>>>>
>>>> (x&  -32)/2 incorrectly transformed to x/2
>>>>
>>>> Solution:
>>>> Remove AND operation only if mask is equal to shift.
>>>> Add regression test.
>>>>
>>>> Reviewed by:
>>>>
>>>> Fix verified (y/n): y, test
>>>>
>>>> Other testing:
>>>> JPRT
>>>>
>