RFR: 8261671: X86 I2L conversion can be skipped for certain masked positive values [v2]

[Marcus G K Williams]

On Tue, 16 Feb 2021 17:08:13 GMT, Florian Weimer <fweimer at openjdk.org> wrote:

>> Marcus G K Williams has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Update convI2LAndI_reg_immIbitmask w/ is_Intel
>>   
>>   Signed-off-by: Marcus G K Williams <marcus.williams at intel.com>
>
> src/hotspot/cpu/x86/x86_64.ad line 9172:
> 
>> 9170: instruct convI2LAndI_reg_immIbitmask(rRegL dst, rRegI src, immI_bitmask mask, rRegI tmp, rFlagsReg cr)
>> 9171: %{
>> 9172:   predicate(VM_Version::supports_bmi2());
> 
> Agner's optimization guide says that BZHI uses microcode on Zen 2 and earlier, so perhaps the predicate should reflect that?

Added `predicate(VM_Version::supports_bmi2() && VM_Version::is_intel());`

-------------

PR: https://git.openjdk.java.net/jdk/pull/2590