Fix Cycles CUDA performance on CUDA 8.0.

Mostly this is making inlining match CUDA 7.5 in a few performance critical
places. The end result is that performance is now better than before, possibly
due to less register spilling or other CUDA 8.0 compiler improvements.

On benchmarks scenes, there are 3% to 35% render time reductions. Stack memory
usage is reduced a little too.

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D2269

intern/cycles/kernel/kernel_path.h

@@ -69,7 +69,7 @@ ccl_device void kernel_path_indirect(KernelGlobals *kg,
 		Intersection isect;
 		uint visibility = path_state_ray_visibility(kg, state);
 		bool hit = scene_intersect(kg,
-		                           ray,
+		                           *ray,
 		                           visibility,
 		                           &isect,
 		                           NULL,
@@ -655,9 +655,9 @@ ccl_device_inline float4 kernel_path_integrate(KernelGlobals *kg,
 			lcg_state = lcg_state_init(rng, &state, 0x51633e2d);
 		}
 
-		bool hit = scene_intersect(kg, &ray, visibility, &isect, &lcg_state, difl, extmax);
+		bool hit = scene_intersect(kg, ray, visibility, &isect, &lcg_state, difl, extmax);
 #else
-		bool hit = scene_intersect(kg, &ray, visibility, &isect, NULL, 0.0f, 0.0f);
+		bool hit = scene_intersect(kg, ray, visibility, &isect, NULL, 0.0f, 0.0f);
 #endif
 
 #ifdef __KERNEL_DEBUG__