Request for reviews (S): 7063674: Wrong results from basic comparisons after calls to Long.bitCount(long)

[Christian Thalinger]

Thank you, Vladimir.  -- Chris

On Jun 11, 2012, at 4:37 PM, Vladimir Kozlov wrote:

> Looks good.
> 
> Vladimir
> 
> Christian Thalinger wrote:
>> On Jun 11, 2012, at 4:14 PM, Vladimir Kozlov wrote:
>>> I looked around and ReverseBytes instructions (which use shifts in addition to bswap) also missing KILL cr.
>> Good catch.  I fixed them too and updated the webrev.
>> -- Chris
>>> Thanks,
>>> Vladimir
>>> 
>>> Christian Thalinger wrote:
>>>> http://cr.openjdk.java.net/~twisti/7063674
>>>> 7063674: Wrong results from basic comparisons after calls to Long.bitCount(long)
>>>> Reviewed-by:
>>>> We are scheduling popcnt instructions between compare and branch/conditional
>>>> move instructions because AD instructs are not defined to kill flags.
>>>> But the Intel Instruction Set Reference says for POPCNT:
>>>> Flags Affected
>>>> OF, SF, ZF, AF, CF, PF are all cleared. ZF is set if SRC = 0, otherwise ZF is cleared
>>>> The fix is to kill the flags in instructs that are using popcnt instructions.
>>>> Tested with test case of CR. src/cpu/x86/vm/x86_32.ad
>>>> src/cpu/x86/vm/x86_64.ad