[libc-commits] [libc] [libc][regex] Switch ExprPool to 32-bit ExprId and 16B Expr (PR #230687)

[Jeff Bailey via libc-commits]

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@@ -27,89 +30,113 @@ namespace regex {
 /// This class manages the allocation and hash-consing of Expr nodes. All
 /// nodes created through this pool are owned by it and will be freed when
 /// the pool is destroyed. Hash-consing ensures that identical expressions
-/// are represented by the same pointer, enabling fast comparison and
+/// are represented by the same ExprId, enabling fast comparison and
 /// derivative normalization.
 class ExprPool {
   /// Internal storage block for AST nodes.
   ///
-  /// Blocks are allocated on demand to avoid large contiguous allocations
-  /// and are linked together in a list for cleanup.
-  /// TODO: Consider adopting cpp::forward_list for block management once
-  /// it is available in LLVM-libc.
+  /// Blocks are allocated on demand to avoid large contiguous allocations.
   struct Block {
-    /// Number of Expr nodes stored in each block.
-    static constexpr size_t BLOCK_SIZE = 256;
+    /// 32 nodes * 16B = 512B per block (8 cache lines).
+    static constexpr size_t BLOCK_SIZE = 32;
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kaladron wrote:

Sorry, nodes per block.  Fixed.

https://github.com/llvm/llvm-project/pull/230687