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package/opencv4: respect LoongArch SIMD selection

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OpenCV probes the host compiler for LSX/LASX by trying to compile a
small test program with '-mlsx' / '-mlasx'. With Buildroot's toolchain
this probe succeeds even when the target CPU lacks the matching ISA
extension, and the resulting libraries then contain LSX/LASX
instructions. This causes SIGILL at runtime on, e.g., the LA264.

Map Buildroot's BR2_LOONGARCH_SIMD_* selection to OpenCV's
CPU_BASELINE / CPU_DISPATCH knobs:

  BR2_LOONGARCH_SIMD_NONE  -> no baseline, no dispatch
  BR2_LOONGARCH_SIMD_LSX   -> baseline = LSX,  no dispatch
  BR2_LOONGARCH_SIMD_LASX  -> baseline = LSX,  dispatch = LASX

The block is gated on BR2_loongarch64, so the existing auto detection
remains in effect for every other architecture.

Signed-off-by: Pengji Li <wjjsn@qq.com>
Reviewed-by: Woodrow Douglass <wdouglass@carnegierobotics.com>
Signed-off-by: Arnout Vandecappelle <arnout@rnout.be>
This commit is contained in:
Pengji Li
2026-06-01 18:55:49 +08:00
committed by Arnout Vandecappelle
parent ccf15ef72b
commit b9d10eed1f
1 changed files with 35 additions and 0 deletions
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35
package/opencv4/opencv4.mk
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@@ -120,6 +120,41 @@ OPENCV4_CONF_OPTS += \
-DENABLE_NEON=$(if $(BR2_ARM_CPU_HAS_NEON),ON,OFF) \ -DENABLE_NEON=$(if $(BR2_ARM_CPU_HAS_NEON),ON,OFF) \
-DENABLE_VFPV3=OFF -DENABLE_VFPV3=OFF
# LoongArch: OpenCV probes the host compiler for LSX/LASX by trying to
# compile a small test program with '-mlsx' / '-mlasx'. With Buildroot's
# toolchain this check succeeds even when the target CPU does not have
# the matching ISA extension, and the resulting OpenCV libraries end up
# containing LSX/LASX instructions, causing SIGILL at runtime on CPUs
# such as the LA264.
#
# Trust Buildroot's own LoongArch SIMD selection (BR2_LOONGARCH_SIMD_*)
# as the source of truth and translate it to OpenCV's CPU_BASELINE /
# CPU_DISPATCH knobs (OpenCV knows LSX and LASX on LoongArch):
#
# BR2_LOONGARCH_SIMD_NONE -> no baseline, no dispatch
# BR2_LOONGARCH_SIMD_LSX -> baseline = LSX, no dispatch
# BR2_LOONGARCH_SIMD_LASX -> baseline = LSX, dispatch = LASX
# (LASX implies LSX; OpenCV's own upstream
# combination matches BR2's choice above.)
#
# We only enter this block on LoongArch, so the existing OpenCV auto
# detection still applies for all other architectures.
ifeq ($(BR2_loongarch64),y)
ifeq ($(BR2_LOONGARCH_SIMD_NONE),y)
OPENCV4_CONF_OPTS += \
-DCPU_BASELINE= \
-DCPU_DISPATCH=
else ifeq ($(BR2_LOONGARCH_SIMD_LSX),y)
OPENCV4_CONF_OPTS += \
-DCPU_BASELINE=LSX \
-DCPU_DISPATCH=
else ifeq ($(BR2_LOONGARCH_SIMD_LASX),y)
OPENCV4_CONF_OPTS += \
-DCPU_BASELINE=LSX \
-DCPU_DISPATCH=LASX
endif
endif
# Cuda stuff # Cuda stuff
OPENCV4_CONF_OPTS += \ OPENCV4_CONF_OPTS += \
-DBUILD_CUDA_STUBS=OFF \ -DBUILD_CUDA_STUBS=OFF \