Ever since we merged the extra texture types (half etc) and spit kernel the compile time for cycles_kernel has been going out of control.
It's currently sitting at a cool 1295.762 seconds with our standard compiler (2013/x64/release)
I'm not entirely sure why msvc gets upset with it, but the inlining of matrix near the bottom of the tri-cubic 3d interpolator is the source of the issue, this patch excludes it from being inlined.
This patch bring it back down to a manageable 186 seconds. (7x faster!!)
with the attached bzzt.blend that @sergey kindly provided i got the following results with builds with identical hashes
58:51.73 buildbot
58:04.23 Patched
it's really close, the slight speedup could be explained by the switch instead of having multiple if's (switches do generate more optimal code than a chain of if/else/if/else statements) but in all honesty it might just have been pure luck (dev box,very polluted, bad for benchmarks) regardless, this patch doesn't seem to slow down anything with my limited testing.
{F532336}
{F532337}
Reviewers: brecht, lukasstockner97, juicyfruit, dingto, sergey
Reviewed By: brecht, dingto, sergey
Subscribers: InsigMathK, sergey
Tags: #cycles
Differential Revision: https://developer.blender.org/D2595
b332fc8f23