RFR: 8357982: Fix several failing BMI tests with -XX:+UseAPX [v4]

[Sandhya Viswanathan]

On Tue, 3 Jun 2025 18:07:34 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> A) Patch extends the following tests with hard-coded encoding checks for various BMI instructions to cover REX2 or extended EVEX encodings supported by APX. 
>> 
>> 
>>      compiler/intrinsics/bmi/verifycode/AndnTestI.java
>>      compiler/intrinsics/bmi/verifycode/AndnTestL.java
>>      compiler/intrinsics/bmi/verifycode/BzhiTestI2L.java
>>      compiler/intrinsics/bmi/verifycode/LZcntTestL.java
>>      compiler/intrinsics/bmi/verifycode/TZcntTestL.java
>> 
>> 
>> B) After integration of JDK-8349582, which added APX NDD support, AndN instruction selection patterns that expect (Xor SRC, -1) as one of its operands were not getting selected because of a lower-cost generic immediate pattern match; patch fixes this issue through strict predicate checks.
>> 
>> Above tests are now passing, validations were carried out using Intel Software Development emulator.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review comments resolutions

src/hotspot/cpu/x86/x86_64.ad line 11341:

> 11339: %{
> 11340:   // Strict predicate check to make selection of xorL_rReg_im1_ndd cost agnostic if immL32 src2 is -1.
> 11341:   predicate(UseAPX && n->in(2)->bottom_type()->is_long()->get_con() != -1L);

We need a check here for isa_long() before accessing is_long() otherwise is_long() may assert.

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PR Review Comment: https://git.openjdk.org/jdk/pull/25501#discussion_r2125105798