i386 doesn't like that one,

/pobj/opencolorio-2.3.2/OpenColorIO-2.3.2/src/OpenColorIO/ops/cdl/CDLOpCPU.cpp:339:18: error: always_inline function '_mm_loadu_ps' requires target feature 'sse', but would be inlined into function 'LoadRenderParams' that is compiled without support for 'sse'
    slope      = _mm_loadu_ps(renderParams.getSlope());
                 ^
/pobj/opencolorio-2.3.2/OpenColorIO-2.3.2/src/OpenColorIO/ops/cdl/CDLOpCPU.cpp:340:18: error: always_inline function '_mm_loadu_ps' requires target feature 'sse', but would be inlined into function 'LoadRenderParams' that is compiled without support for 'sse'
    offset     = _mm_loadu_ps(renderParams.getOffset());
                 ^
/pobj/opencolorio-2.3.2/OpenColorIO-2.3.2/src/OpenColorIO/ops/cdl/CDLOpCPU.cpp:341:18: error: always_inline function '_mm_loadu_ps' requires target feature 'sse', but would be inlined into function 'LoadRenderParams' that is compiled without support for 'sse'
    power      = _mm_loadu_ps(renderParams.getPower());
                 ^
/pobj/opencolorio-2.3.2/OpenColorIO-2.3.2/src/OpenColorIO/ops/cdl/CDLOpCPU.cpp:342:18: error: always_inline function '_mm_set1_ps' requires target feature 'sse', but would be inlined into function 'LoadRenderParams' that is compiled without support for 'sse'
    saturation = _mm_set1_ps(renderParams.getSaturation());
                 ^
4 errors generated.
ninja: build stopped: subcommand failed.

There is also

CMake Warning:
  Manually-specified variables were not used by the project:
...
    OCIO_USE_SSE

I'll try this for starters..

Index: Makefile
===================================================================
RCS file: /cvs/ports/graphics/opencolorio/Makefile,v
diff -u -p -r1.32 Makefile
--- Makefile	10 Apr 2024 10:38:06 -0000	1.32
+++ Makefile	13 Apr 2024 13:27:34 -0000
@@ -40,9 +40,9 @@ CONFIGURE_ARGS +=	-DPYTHON="${MODPY_BIN}
 			-Dminizip-ng_INCLUDE_DIR="${LOCALBASE}/include/minizip"
 
 .if ${MACHINE_ARCH} == "amd64"
-CONFIGURE_ARGS +=	-DOCIO_USE_SSE=ON
+CONFIGURE_ARGS +=	-DOCIO_USE_SIMD=ON
 .else
-CONFIGURE_ARGS +=	-DOCIO_USE_SSE=OFF
+CONFIGURE_ARGS +=	-DOCIO_USE_SIMD=OFF
 .endif
 
 # everything except tests