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diff --git a/third_party/jpeg-xl/lib/jxl/base/cache_aligned.h b/third_party/jpeg-xl/lib/jxl/base/cache_aligned.h
new file mode 100644
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--- /dev/null
+++ b/third_party/jpeg-xl/lib/jxl/base/cache_aligned.h
@@ -0,0 +1,74 @@
+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#ifndef LIB_JXL_BASE_CACHE_ALIGNED_H_
+#define LIB_JXL_BASE_CACHE_ALIGNED_H_
+
+// Memory allocator with support for alignment + misalignment.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <memory>
+
+#include "lib/jxl/base/compiler_specific.h"
+
+namespace jxl {
+
+// Functions that depend on the cache line size.
+class CacheAligned {
+ public:
+  static void PrintStats();
+
+  static constexpr size_t kPointerSize = sizeof(void*);
+  static constexpr size_t kCacheLineSize = 64;
+  // To avoid RFOs, match L2 fill size (pairs of lines).
+  static constexpr size_t kAlignment = 2 * kCacheLineSize;
+  // Minimum multiple for which cache set conflicts and/or loads blocked by
+  // preceding stores can occur.
+  static constexpr size_t kAlias = 2048;
+
+  // Returns a 'random' (cyclical) offset suitable for Allocate.
+  static size_t NextOffset();
+
+  // Returns null or memory whose address is congruent to `offset` (mod kAlias).
+  // This reduces cache conflicts and load/store stalls, especially with large
+  // allocations that would otherwise have similar alignments. At least
+  // `payload_size` (which can be zero) bytes will be accessible.
+  static void* Allocate(size_t payload_size, size_t offset);
+
+  static void* Allocate(const size_t payload_size) {
+    return Allocate(payload_size, NextOffset());
+  }
+
+  static void Free(const void* aligned_pointer);
+};
+
+// Avoids the need for a function pointer (deleter) in CacheAlignedUniquePtr.
+struct CacheAlignedDeleter {
+  void operator()(uint8_t* aligned_pointer) const {
+    return CacheAligned::Free(aligned_pointer);
+  }
+};
+
+using CacheAlignedUniquePtr = std::unique_ptr<uint8_t[], CacheAlignedDeleter>;
+
+// Does not invoke constructors.
+static inline CacheAlignedUniquePtr AllocateArray(const size_t bytes) {
+  return CacheAlignedUniquePtr(
+      static_cast<uint8_t*>(CacheAligned::Allocate(bytes)),
+      CacheAlignedDeleter());
+}
+
+static inline CacheAlignedUniquePtr AllocateArray(const size_t bytes,
+                                                  const size_t offset) {
+  return CacheAlignedUniquePtr(
+      static_cast<uint8_t*>(CacheAligned::Allocate(bytes, offset)),
+      CacheAlignedDeleter());
+}
+
+}  // namespace jxl
+
+#endif  // LIB_JXL_BASE_CACHE_ALIGNED_H_