This looks to be the culprit
commit 45912fb908f7a1d2efbce0f1dbe81e5bc975fbe1
Author: Jason Ekstrand <jason.ekstrand@intel.com>
Date:   Fri Dec 9 22:32:08 2016 -0800

    i965/compiler: Use the new nir_opt_copy_prop_vars pass
    
    We run this after nir_lower_vars_to_ssa so that as many load/store_var
    intrinsics as possible before copy_prop_vars executes.  This is because the
    pass isn't particularly efficient (it does a lot of linear walks of a
    linked list) so we'd like as much of the work as possible to be done before
    copy_prop_vars runs.
    
    Shader DB results on Sky Lake:
    
       total instructions in shared programs: 12020290 -> 12013627 (-0.06%)
       instructions in affected programs: 26033 -> 19370 (-25.59%)
       helped: 16
       HURT: 13
    
       total cycles in shared programs: 137772848 -> 137549012 (-0.16%)
       cycles in affected programs: 6955660 -> 6731824 (-3.22%)
       helped: 217
       HURT: 237
    
       total loops in shared programs: 3208 -> 3208 (0.00%)
       loops in affected programs: 0 -> 0
       helped: 0
       HURT: 0
    
       total spills in shared programs: 4112 -> 4057 (-1.34%)
       spills in affected programs: 483 -> 428 (-11.39%)
       helped: 2
       HURT: 0
    
       total fills in shared programs: 5519 -> 5102 (-7.56%)
       fills in affected programs: 993 -> 576 (-41.99%)
       helped: 2
       HURT: 0
    
       LOST:   0
       GAINED: 0
    
    Broadwell had similar results.  On older hardware, the impact isn't as
    large because they don't advertise GL 4.5.  Of the hurt programs, all but
    one are hurt by a single instruction and the one is hurt by 3 instructions.
    All of the helped programs, on the other hand, are helped by at least 3
    instructions and one kerbal space program shader is helped by 44.59%.
    
    The real star of the show, however, is the Gl43CSDof synmark2 benchmark
    which has two shaders which are cut by 28% and 40% and the over-all runtime
    performance of the benchmark on my Sky Lake laptop is improved by around
    25-30% (it's a bit hard to be exact due to thermal throttling).
    
    Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>

diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
index 46eeb17..3645f48 100644
--- a/src/mesa/drivers/dri/i965/brw_nir.c
+++ b/src/mesa/drivers/dri/i965/brw_nir.c
@@ -477,6 +477,7 @@ nir_optimize(nir_shader *nir, const struct brw_compiler *compiler,
    do {
       progress = false;
       OPT_V(nir_lower_vars_to_ssa);
+      OPT(nir_opt_copy_prop_vars);
 
       if (is_scalar) {
          OPT(nir_lower_alu_to_scalar);

this one seems to have dropped around 15fps from 563 to 548
commit fc707f570f918ab0defd33405c8c82f307196d17
Author: Timothy Arceri <timothy.arceri@collabora.com>
Date:   Sun Nov 20 23:05:42 2016 +1100

    mesa/glsl: set {clip,cull}_distance_array_size directly in gl_program
    
    There are some line wrapping violations here but those lines will get
    deleted in the following patch.
    
    Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>