From 3831352fa46fe363b4c0f952f71bb0daa47f9eec Mon Sep 17 00:00:00 2001
From: Stanislaw Halik <sthalik@misaki.pl>
Date: Sat, 26 Sep 2026 12:34:24 +0200
Subject: [PATCH] Misc: fixed strict aliasing violation in ImHashData().
 (#9557)

The SSE4.2 path read the input through an `ImU32` pointer but callers
hash floats, pointers and structs. With clang 23 and LTO (such as
`-O2 -msse4.2 -flto -fuse-ld=lld`) the float stores in
`ImFontAtlasBakedGetId()` were optimized away, so every size of a font
got the same `BakedId`.
---
 imgui.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/imgui.cpp b/imgui.cpp
index 57ed579af..a988ce6e0 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -2493,7 +2493,7 @@ ImGuiID ImHashData(const void* data_p, size_t data_size, ImGuiID seed)
 #else
     while (data + 4 <= data_end)
     {
-        crc = _mm_crc32_u32(crc, *(ImU32*)data);
+        ImU32 v; memcpy(&v, data, sizeof(v)); crc = _mm_crc32_u32(crc, v);
         data += 4;
     }
     while (data < data_end)