diff --git a/docs/troubleshooting.md b/docs/troubleshooting.md
index 35ea611..8bcdbc1 100644
--- a/docs/troubleshooting.md
+++ b/docs/troubleshooting.md
@@ -217,6 +217,26 @@ dns=default
 
 Adjust `-j4` based on your available RAM (roughly 2-3GB per job). With 24GB RAM, `-j6` to `-j8` is usually safe.
 
+### LLVM/Clang GCC 15 ICE (Steam 32-bit)
+
+When building LLVM with `abi_x86_32` for Steam, GCC 15 may crash with an internal compiler error (ICE):
+
+```
+internal compiler error: Segmentation fault
+```
+
+This typically occurs in `AMDGPURewriteAGPRCopyMFMA.cpp` and is triggered by `-march=znver3` optimizations.
+
+**Fix:** Have LLVM compile itself with clang instead of GCC:
+
+```bash
+# Add to /etc/portage/package.use/steam
+llvm-core/llvm clang
+llvm-core/clang clang
+```
+
+This is already included in the provided `package.use/steam` file.
+
 ### Circular Dependency (freetype/harfbuzz)
 
 During initial install, use `-harfbuzz` flag temporarily:
diff --git a/portage/package.use/steam b/portage/package.use/steam
index 3bba9d2..dcad598 100644
--- a/portage/package.use/steam
+++ b/portage/package.use/steam
@@ -37,8 +37,9 @@ dev-util/spirv-tools            abi_x86_32
 dev-util/sysprof-capture        abi_x86_32
 gnome-base/librsvg              abi_x86_32
 gui-libs/libdecor               abi_x86_32
-llvm-core/clang                 abi_x86_32
-llvm-core/llvm                  abi_x86_32
+# Use clang to build LLVM/clang - workaround for GCC 15 ICE on AMDGPURewriteAGPRCopyMFMA.cpp
+llvm-core/clang                 abi_x86_32 clang
+llvm-core/llvm                  abi_x86_32 clang
 media-gfx/graphite2             abi_x86_32
 media-libs/alsa-lib             abi_x86_32
 media-libs/flac                 abi_x86_32