Add change log

Author: rodiazet

Changelog.md

@@ -3,6 +3,9 @@
 Language Features:
 * General: Add a builtin that computes the base slot of a storage namespace using the `erc7201` formula from ERC-7201.
 
+Important Bugfixes:
+* Yul Optimizer: Fix `UnusedStoreEliminator` incorrectly removing `returndatacopy` operations when the length comes from a stale `returndatasize()` call that was invalidated by subsequent call opcodes.
+
 Compiler Features:
 * Commandline Interface: Disallow selecting the deprecated assembly input mode that was only accessible via `--assemble` instead of treating it as equivalent to `--strict-assembly`.
 * Commandline Interface: Introduce `--experimental` flag required for enabling the experimental mode.
@@ -15,6 +18,7 @@ Compiler Features:
 * Standard JSON Interface: Introduce `settings.experimental` setting required for enabling the experimental mode.
 * Standard JSON Interface: Replace the top-level ``ethdebug`` output with ``ethdebug.resources`` and ``ethdebug.compilation``. Decouple ethdebug outputs from binary compilation so that global ethdebug outputs can be produced without generating bytecode.
 * Yul Optimizer: Improve performance of control flow side effects collector and function references resolver.
+* Yul Optimizer: Remove optimization that eliminated `returndatacopy` operations.
 
 Bugfixes:
 * Yul: Fix incorrect serialization of Yul object names containing double quotes and escape sequences, producing output that could not be parsed as valid Yul.