RFR: 8297753: AArch64: Add optimized rules for vector compare with zero on NEON [v6]

[Andrew Haley]

On Mon, 27 Feb 2023 08:56:35 GMT, Chang Peng <duke at openjdk.org> wrote:

>> I see. That sounds like a bug, but OK.
>
> Following is the code of ccode() of cmpOpUOper:
> 
> 
> virtual int ccode() const { 
>     switch (_c0) {
>     case  BoolTest::eq : return equal();
>     case  BoolTest::gt : return greater();
>     case  BoolTest::lt : return less();
>     case  BoolTest::ne : return not_equal();
>     case  BoolTest::le : return less_equal();
>     case  BoolTest::ge : return greater_equal();
>     case  BoolTest::overflow : return overflow();
>     case  BoolTest::no_overflow: return no_overflow();
>     default : ShouldNotReachHere(); return 0;
>     }
>   };
> 
> 
> I have another patch working on enabling SVE vector unsigned comparison, if we use ```assert(cmpOpUOper(unsigned_cond).ccode() == result, "Invalid conversion");```, the code will enter 
> ```ShouldNotReachHere()```.

I see, but all you have to do then is something like


if (cond & BoolTest::unsigned_compare)
  assert( cmpOpUOper(cond & something).ccode() == result)
else
  assert( cmpOpOper(cond).ccode() == result)



surely?

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PR: https://git.openjdk.org/jdk/pull/11822