Request for reviews (L): 6761600: Use SSE 4.2 In STTNI Intrinsics

[Changpeng Fang]

Thanks. I put the updated webrev in:
http://cr.openjdk.java.net/~cfang/6761600/webrev/

and I am testing to adjust the masm.jccb stuff.

Changpeng


Vladimir Kozlov wrote:
> Changpeng,
>
> Good work.
>
> src/cpu/x86/vm/assembler_x86.cpp:
> Remove Macro NOT_LP64() around asserts in new instructions.
> VM_Version::supports_sse4_2() should be checked on LP64 also
> since not all 64-bits CPUs support it.
>
>
> src/cpu/x86/vm/vm_version_x86_32.cpp:
> src/cpu/x86/vm/vm_version_x86_64.cpp:
> Remove UseUnalignedLoadStores check in the next code,
> it is not needed and it is wrong to have it since it depends on
> UseXMMForArrayCopy flag. The top check supports_sse4_2() && supports_ht()
> is enough for movdqu verification.
>
> +         if(FLAG_IS_DEFAULT(UseSSE42Intrinsics) &&
> +            UseUnalignedLoadStores){ //sse42 intrinsics depend on movdqu
> +             UseSSE42Intrinsics = true;
>           }
>
>
> In both x86_32.ad and x86_64.ad try to use short forward branches 
> masm.jccb()
> starting from the bottom of the assembler code. Then try to use all
> intrinsics with all flags variations and revert back to long jump 
> those branches
> VM will complain about.
>
>
> cpu/x86/vm/x86_32.ad:
> align comments:
>
> !       masm.andl(rsi, 0xfffffff8); // rsi holds the vector count
> !       masm.andl(rdi, 0x00000007);       // rdi holds the tail count
>
> In enc_String_Equals() and enc_String_IndexOf()
> use movptr() for value_offset.
>
>
> src/share/vm/adlc/formssel.cpp:
> Missing checks for AryEq.
>
> src/share/vm/classfile/vmSymbols.hpp:
> Remove empty after indexOf_name since equals() also j.l.String method:
>      do_name(     indexOf_name,       "indexOf")
>
>
> +   do_intrinsic(_equals, java_lang_String, equals_name, 
> object_boolean_signature,  F_R)
>
>
> src/share/vm/opto/library_call.cpp:
> Add that it because spec allow to specify NULL as argument:
> +   //should not do null check for argument for string_equals.
>
> Remove next line
> +   //argument = do_null_check(argument, T_OBJECT);
>
> Thanks,
> Vladimir
>
> Changpeng Fang wrote:
>> http://webrev.invokedynamic.info/cfang/6761600/index.html
>>
>> Works on 6761600 : Use SSE 4.2 in intrinsics for String.compareTo(),
>> String.equals(), String.indexOf() and Arrays.equals(), among which,
>> String.equals() and String.indexOf() are intrinsified for the first 
>> time.
>>
>> Problem: Use SSE 4.2 instructions for STTNI intrinsics for for Nehalem
>>               improvements
>>
>> Solution:
>>    Implemented both 32 and 64-bit versions for X86.  Introduced  a new
>> flag  UseSSE42Intrinsics, with the default TRUE on systems that support
>> SSE4.2 (false otherwise).
>>
>> Reviewed by:
>>
>> Fix verified (y/n): y
>>
>> Other testing:  JPRT,
>>
>>