Cycles: Tweak inline policy for some functions

The goal is to make Experimental kernel closer in performance to the
official kernel, avoiding spills and such.

There should not be big impact on official kernel, own tests showed
few percent performance drop on laptop's GPU. CPU was always the
same speed on AVX, AVX2 and SSE4.1 CPUs i've been testing here.

This seems to be the last essential step before we can get rid of
Experimental kernel and enable SSS officially on GPU without causing
some major performance issues.

Surely some more tweaks are possibly required, but that we can do
for until cows go home anyway.

1 files changed, 11 insertions, 2 deletions

diff --git a/intern/cycles/kernel/kernel_path.h b/intern/cycles/kernel/kernel_path.h
index fc32201596f..650e3b047f0 100644
--- a/intern/cycles/kernel/kernel_path.h
+++ b/intern/cycles/kernel/kernel_path.h
@@ -391,7 +391,12 @@ ccl_device void kernel_path_indirect(KernelGlobals *kg,
 	}
 }
 
-ccl_device void kernel_path_ao(KernelGlobals *kg, ShaderData *sd, PathRadiance *L, PathState *state, RNG *rng, float3 throughput)
+ccl_device_noinline void kernel_path_ao(KernelGlobals *kg,
+                                        ShaderData *sd,
+                                        PathRadiance *L,
+                                        PathState *state,
+                                        RNG *rng,
+                                        float3 throughput)
 {
 	/* todo: solve correlation */
 	float bsdf_u, bsdf_v;
@@ -586,7 +591,11 @@ ccl_device void kernel_path_subsurface_setup_indirect(
 
 #endif  /* __SUBSURFACE__ */
 
-ccl_device float4 kernel_path_integrate(KernelGlobals *kg, RNG *rng, int sample, Ray ray, ccl_global float *buffer)
+ccl_device_inline float4 kernel_path_integrate(KernelGlobals *kg,
+                                               RNG *rng,
+                                               int sample,
+                                               Ray ray,
+                                               ccl_global float *buffer)
 {
 	/* initialize */
 	PathRadiance L;