Cycles: Enable MNEE on Metal (macOS >= 13)

This patch enables MNEE on macOS >= 13. There was an inefficiency in the calculation of spill requirements, fixed as of macOS 13. This patch also adds a temporary inlining workaround for a Metal compiler bug which causes `mnee_compute_constraint_derivatives` to behave incorrectly.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D16235

intern/cycles/device/metal/device_impl.mm

@@ -254,6 +254,10 @@ void MetalDevice::make_source(MetalPipelineType pso_type, const uint kernel_feat
       break;
   }
 
+  NSProcessInfo *processInfo = [NSProcessInfo processInfo];
+  NSOperatingSystemVersion macos_ver = [processInfo operatingSystemVersion];
+  global_defines += "#define __KERNEL_METAL_MACOS__ " + to_string(macos_ver.majorVersion) + "\n";
+
   string &source = this->source[pso_type];
   source = "\n#include \"kernel/device/metal/kernel.metal\"\n";
   source = path_source_replace_includes(source, path_get("source"));

intern/cycles/kernel/integrator/mnee.h

@@ -279,7 +279,15 @@ ccl_device_forceinline void mnee_setup_manifold_vertex(KernelGlobals kg,
 }
 
 /* Compute constraint derivatives. */
-ccl_device_forceinline bool mnee_compute_constraint_derivatives(
+
+#  if defined(__KERNEL_METAL__)
+/* Temporary workaround for front-end compilation bug (incorrect MNEE rendering when this is
+ * inlined). */
+__attribute__((noinline))
+#  else
+ccl_device_forceinline
+#  endif
+bool mnee_compute_constraint_derivatives(
     int vertex_count,
     ccl_private ManifoldVertex *vertices,
     ccl_private const float3 &surface_sample_pos,

intern/cycles/kernel/types.h

@@ -85,9 +85,9 @@ CCL_NAMESPACE_BEGIN
 #  define __VOLUME_RECORD_ALL__
 #endif /* !__KERNEL_GPU__ */
 
-/* MNEE currently causes "Compute function exceeds available temporary registers"
- * on Metal, disabled for now. */
-#ifndef __KERNEL_METAL__
+/* MNEE caused "Compute function exceeds available temporary registers" in macOS < 13 due to a bug
+ * in spill buffer allocation sizing. */
+#if !defined(__KERNEL_METAL__) || (__KERNEL_METAL_MACOS__ >= 13)
 #  define __MNEE__
 #endif
 

tests/python/cycles_render_tests.py

@@ -33,7 +33,7 @@ BLACKLIST_OPTIX = [
 ]
 
 BLACKLIST_METAL = [
-    # No MNEE for Metal currently
+    # MNEE only works on Metal with macOS >= 13
     "underwater_caustics.blend",
 ]