RFR: 8327381: Refactor type-improving transformations in BoolNode::Ideal to BoolNode::Value [v8]

[Kangcheng Xu]

On Fri, 5 Apr 2024 10:01:43 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> src/hotspot/share/opto/subnode.cpp line 1816:
>> 
>>> 1814:     // Change ((x & m) u<= m) or ((m & x) u<= m) to always true
>>> 1815:     // Same with ((x & m) u< m+1) and ((m & x) u< m+1)
>>> 1816:     if (cop == Op_CmpU && cmp1->Opcode() == Op_AndI) {
>> 
>> You made this a bit more complicated than the original. Or was there a specific reason for the `is_Sub`? I'd do this:
>> Suggestion:
>> 
>>   // Change ((x & m) u<= m) or ((m & x) u<= m) to always true
>>   // Same with ((x & m) u< m+1) and ((m & x) u< m+1)
>>   Node* cmp = in(1);
>>   if (cmp != nullptr && cmp->Opcode() == Op_CmpU) {
>>     Node* cmp1 = cmp->in(1);
>>     Node* cmp2 = cmp->in(2);
>>     if (cmp1->Opcode() == Op_AndI) {
>
> You could also move the whole code to its own method, and name it something like `BoolNode::Value_cmpu_and_mask`. Maybe you find an even more descriptive name.

Cleaned up and moved to `::Value_cmpu_and_mask`

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PR Review Comment: https://git.openjdk.org/jdk/pull/18198#discussion_r1598516418