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diff --git a/third_party/jpeg-xl/lib/jxl/convolve.h b/third_party/jpeg-xl/lib/jxl/convolve.h
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+++ b/third_party/jpeg-xl/lib/jxl/convolve.h
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+// 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_CONVOLVE_H_
+#define LIB_JXL_CONVOLVE_H_
+
+// 2D convolution.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "lib/jxl/base/data_parallel.h"
+#include "lib/jxl/image.h"
+
+namespace jxl {
+
+// No valid values outside [0, xsize), but the strategy may still safely load
+// the preceding vector, and/or round xsize up to the vector lane count. This
+// avoids needing PadImage.
+// Requires xsize >= kConvolveLanes + kConvolveMaxRadius.
+static constexpr size_t kConvolveMaxRadius = 3;
+
+// Weights must already be normalized.
+
+struct WeightsSymmetric3 {
+  // d r d (each replicated 4x)
+  // r c r
+  // d r d
+  float c[4];
+  float r[4];
+  float d[4];
+};
+
+struct WeightsSymmetric5 {
+  // The lower-right quadrant is: c r R  (each replicated 4x)
+  //                              r d L
+  //                              R L D
+  float c[4];
+  float r[4];
+  float R[4];
+  float d[4];
+  float D[4];
+  float L[4];
+};
+
+// Weights for separable 5x5 filters (typically but not necessarily the same
+// values for horizontal and vertical directions). The kernel must already be
+// normalized, but note that values for negative offsets are omitted, so the
+// given values do not sum to 1.
+struct WeightsSeparable5 {
+  // Horizontal 1D, distances 0..2 (each replicated 4x)
+  float horz[3 * 4];
+  float vert[3 * 4];
+};
+
+// Weights for separable 7x7 filters (typically but not necessarily the same
+// values for horizontal and vertical directions). The kernel must already be
+// normalized, but note that values for negative offsets are omitted, so the
+// given values do not sum to 1.
+//
+// NOTE: for >= 7x7 Gaussian kernels, it is faster to use FastGaussian instead,
+// at least when images exceed the L1 cache size.
+struct WeightsSeparable7 {
+  // Horizontal 1D, distances 0..3 (each replicated 4x)
+  float horz[4 * 4];
+  float vert[4 * 4];
+};
+
+const WeightsSymmetric3& WeightsSymmetric3Lowpass();
+const WeightsSeparable5& WeightsSeparable5Lowpass();
+const WeightsSymmetric5& WeightsSymmetric5Lowpass();
+
+void SlowSymmetric3(const ImageF& in, const Rect& rect,
+                    const WeightsSymmetric3& weights, ThreadPool* pool,
+                    ImageF* JXL_RESTRICT out);
+
+void SlowSeparable5(const ImageF& in, const Rect& rect,
+                    const WeightsSeparable5& weights, ThreadPool* pool,
+                    ImageF* out);
+
+void SlowSeparable7(const ImageF& in, const Rect& rect,
+                    const WeightsSeparable7& weights, ThreadPool* pool,
+                    ImageF* out);
+
+void Symmetric3(const ImageF& in, const Rect& rect,
+                const WeightsSymmetric3& weights, ThreadPool* pool,
+                ImageF* out);
+
+void Symmetric5(const ImageF& in, const Rect& rect,
+                const WeightsSymmetric5& weights, ThreadPool* pool,
+                ImageF* JXL_RESTRICT out);
+
+void Separable5(const ImageF& in, const Rect& rect,
+                const WeightsSeparable5& weights, ThreadPool* pool,
+                ImageF* out);
+
+void Separable7(const ImageF& in, const Rect& rect,
+                const WeightsSeparable7& weights, ThreadPool* pool,
+                ImageF* out);
+
+}  // namespace jxl
+
+#endif  // LIB_JXL_CONVOLVE_H_