fix(sycl): stop building the ggml CPU variant matrix with icpx (#11321)

Since #11255 and #11276 every GPU image also builds ggml's CPU_ALL_VARIANTS
matrix, so a partial offload uses the host's SIMD kernels. That works
everywhere except SYCL, where the Makefile compiles the whole tree with
icpx -fsycl: icpx never finishes ggml-cpu/arch/x86/repack.cpp at
-march=sapphirerapids. In run 30765516644 both sycl_f16 and sycl_f32 stopped
at that translation unit and sat there for 5h30m with a single compile in
flight until GitHub killed the job at its 6h limit, and turboquant's f16 job
lost its runner outright. gcc compiles the same file in seconds in the vulkan
and CPU jobs of the same run, so the CPU variant matrix is only unbuildable
under icpx.

Route SYCL back to the portable fallback binary, which is what these images
shipped before #11255. run.sh already prefers *-cpu-all when present and falls
back otherwise, so nothing else has to change.


Assisted-by: Claude Code:claude-opus-5[1m] [Read] [Edit] [Bash]

Signed-off-by: Ettore Di Giacinto <mudler@localai.io>
Co-authored-by: Ettore Di Giacinto <mudler@localai.io>

.docker/llama-cpp-build-target.sh

@@ -4,6 +4,17 @@ set -euo pipefail
 arch=${1:?target architecture is required}
 build_type=${2-}
 
+# SYCL compiles the whole tree with icpx -fsycl, and icpx never finishes
+# ggml-cpu/arch/x86/repack.cpp at -march=sapphirerapids: the job sits on that one
+# translation unit until GitHub kills it at 6h. gcc builds the same file in
+# seconds, so only the SYCL images have to give up the CPU variant matrix.
+case "$build_type" in
+  sycl*)
+    echo llama-cpp-fallback
+    exit 0
+    ;;
+esac
+
 # GPU arm64 base images do not consistently provide the gcc-14 toolchain needed
 # to compile ggml's armv9.2 CPU variants. Keep their portable fallback until the
 # builder images can supply that compiler.

.docker/turboquant-build-target.sh

@@ -4,6 +4,17 @@ set -euo pipefail
 arch=${1:?target architecture is required}
 build_type=${2-}
 
+# SYCL compiles the whole tree with icpx -fsycl, and icpx never finishes
+# ggml-cpu/arch/x86/repack.cpp at -march=sapphirerapids: the job sits on that one
+# translation unit until GitHub kills it at 6h. gcc builds the same file in
+# seconds, so only the SYCL images have to give up the CPU variant matrix.
+case "$build_type" in
+  sycl*)
+    echo turboquant-fallback
+    exit 0
+    ;;
+esac
+
 # GPU arm64 base images do not consistently provide the gcc-14 toolchain needed
 # to compile ggml's armv9.2 CPU variants. Keep their portable fallback until the
 # builder images can supply that compiler.

backend/cpp/llama-cpp/run.sh

@@ -12,10 +12,11 @@ grep -e "flags" /proc/cpuinfo | head -1
 
 BINARY=llama-cpp-fallback
 
-# CPU images and x86 GPU images ship a single llama-cpp-cpu-all built with ggml
+# CPU images and most x86 GPU images ship a single llama-cpp-cpu-all built with ggml
 # CPU_ALL_VARIANTS: ggml's backend registry dlopens the best libggml-cpu-*.so for this
 # host, so no shell-side AVX probing. GPU arm64 images still ship llama-cpp-fallback
-# until their builder toolchains support ggml's complete arm variant matrix.
+# until their builder toolchains support ggml's complete arm variant matrix, and so do
+# the SYCL images, whose icpx compiler hangs on the sapphirerapids variant.
 if [ -e "$CURDIR"/llama-cpp-cpu-all ]; then
 	BINARY=llama-cpp-cpu-all
 fi

backend/cpp/turboquant/run.sh

@@ -12,11 +12,12 @@ grep -e "flags" /proc/cpuinfo | head -1
 
 BINARY=turboquant-fallback
 
-# CPU images and x86 GPU images ship a single turboquant-cpu-all built with ggml
+# CPU images and most x86 GPU images ship a single turboquant-cpu-all built with ggml
 # CPU_ALL_VARIANTS: ggml's
 # backend registry dlopens the best libggml-cpu-*.so for this host, so no shell-side
 # probing. GPU arm64 images still ship turboquant-fallback until their builder toolchains
-# support ggml's complete arm variant matrix.
+# support ggml's complete arm variant matrix, and so do the SYCL images, whose icpx
+# compiler hangs on the sapphirerapids variant.
 if [ -e "$CURDIR"/turboquant-cpu-all ]; then
 	BINARY=turboquant-cpu-all
 fi

scripts/build/llama-cpp-build-target_test.sh

@@ -23,4 +23,10 @@ assert_target amd64 "" llama-cpp-cpu-all
 assert_target arm64 cublas llama-cpp-fallback
 assert_target arm64 "" llama-cpp-cpu-all
 
+# SYCL builds the whole tree with icpx -fsycl, and icpx never finishes
+# ggml-cpu/arch/x86/repack.cpp at -march=sapphirerapids: every sycl job sat on
+# that one translation unit until GitHub killed it at its 6h limit.
+assert_target amd64 sycl_f16 llama-cpp-fallback
+assert_target amd64 sycl_f32 llama-cpp-fallback
+
 echo "PASS: llama.cpp build target preserves CPU variants where supported"

scripts/build/turboquant-build-target_test.sh

@@ -23,4 +23,10 @@ assert_target amd64 "" turboquant-cpu-all
 assert_target arm64 cublas turboquant-fallback
 assert_target arm64 "" turboquant-cpu-all
 
+# SYCL builds the whole tree with icpx -fsycl, and icpx never finishes
+# ggml-cpu/arch/x86/repack.cpp at -march=sapphirerapids: every sycl job sat on
+# that one translation unit until GitHub killed it at its 6h limit.
+assert_target amd64 sycl_f16 turboquant-fallback
+assert_target amd64 sycl_f32 turboquant-fallback
+
 echo "PASS: turboquant build target preserves CPU variants where supported"