RFR: 8352620: C2: rename MemNode::memory_type() to MemNode::value_basic_type()

[Roberto Castañeda Lozano]

On Thu, 3 Apr 2025 21:06:17 GMT, Saranya Natarajan <duke at openjdk.org> wrote:

> Description: The current name MemNode::memory_type() is misleading because the returned type is a property of the value that is loaded/stored, not the memory that is accessed. Usually, the two of them match, but for mismatched memory accesses (arising e.g. from using Unsafe or memory segments) they might differ, e.g. one might store a value of type 'short' into an array of elements of type 'long'. The proposal was to rename MemNode::memory_type() to MemNode::value_basic_type() to clarify these cases.
> 
> Solution: Replaced all occurrence of MemNode::memory_type() with MemNode::value_basic_type()

src/hotspot/share/opto/escape.cpp line 2822:

> 2820:         Node* value = nullptr;
> 2821:         if (ini != nullptr) {
> 2822:           // StoreP::memory_type() == T_ADDRESS

The value of this comment is debatable, but I think it is best to not remove it in this RFE (just rename `memory_type` to `value_basic_type`), to preserve the original scope of the RFE.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24427#discussion_r2039560349