RFR: 8320500: [vectorapi] RISC-V: Optimize vector math operations with SLEEF [v8]

[Fei Yang]

On Fri, 27 Sep 2024 07:06:44 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> src/jdk.incubator.vector/linux/native/libsleef/lib/vector_math_rvv.c line 51:
>> 
>>> 49: // the dynamic rounding mode is always RNE.
>>> 50: 
>>> 51: #ifdef DEBUG
>> 
>> Question: Should we check for `NDEBUG` macro (A macro specified by C/C++ standard) here instead? I see checks for this macro in the original SLEEF code.
>> 
>> 
>> #ifndef NDEBUG
>> #define CHECK_FRM   __asm__ __volatile__ (     \
>>     "    frrm   t0              \n\t"          \
>>     "    beqz   t0, 2f          \n\t"          \
>>     "    csrrw  x0, cycle, x0   \n\t"          \
>>     "2:                         \n\t"          \
>>     : : : "memory" );
>> #else
>> #define CHECK_FRM
>> #endif
>
> `NDEBUG` is only used in sleefdp.c which is the original sleef code, and we don't use that file in jdk directly, in java.base module of jdk it uses `DEBUG` but not use `NDEBUG`.
> Based on above information, I think `DEBUG` is better.

Sounds good. I suppose this `DEBUG` macro will be defined for debug builds, right?

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PR Review Comment: https://git.openjdk.org/jdk/pull/21083#discussion_r1778212230