From a71127dfd803ad79dc69e0a9acc50735ea25c13a Mon Sep 17 00:00:00 2001
From: Masashi Yoshimura <yoshimura.masashi.frbs@gmail.com>
Date: Fri, 9 Jan 2026 01:36:42 +0900
Subject: [PATCH] ggml-webgpu: Fix GGML_MEM_ALIGN to 8 for emscripten.
 (llama/18628)

* Fix GGML_MEM_ALIGN to 8 for emscripten.

* Add a comment explaining the need for GGML_MEM_ALIGN == 8 in 64-bit wasm with emscripten
---
 ggml/include/ggml.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/ggml/include/ggml.h b/ggml/include/ggml.h
index 20c912d0..b69583dd 100644
--- a/ggml/include/ggml.h
+++ b/ggml/include/ggml.h
@@ -234,6 +234,11 @@
 
 #if UINTPTR_MAX == 0xFFFFFFFF
     #define GGML_MEM_ALIGN 4
+#elif defined(__EMSCRIPTEN__)
+// emscripten uses max_align_t == 8, so we need GGML_MEM_ALIGN == 8 for 64-bit wasm.
+// (for 32-bit wasm, the first conditional is true and GGML_MEM_ALIGN stays 4.)
+// ref: https://github.com/ggml-org/llama.cpp/pull/18628
+    #define GGML_MEM_ALIGN 8
 #else
     #define GGML_MEM_ALIGN 16
 #endif