I was hoping to see if an SNA problem with 2.99.917 had been fixed (will raise that in a few days, after rebuilding a system with debug info), but it crapped out.

  CC       gen4_vertex.lo
gen4_vertex.c: In function ‘emit_primitive_linear__avx2’:
gen4_vertex.c:312:1: error: inlining failed in call to always_inline ‘compute_linear’: optimization level attribute mismatch
 compute_linear(const struct sna_composite_channel *channel,
 ^
gen4_vertex.c:1523:9: error: called from here
  v[5] = compute_linear(&op->src, r->src.x, r->src.y);
         ^
gen4_vertex.c:312:1: error: inlining failed in call to always_inline ‘compute_linear’: optimization level attribute mismatch
 compute_linear(const struct sna_composite_channel *channel,
 ^
gen4_vertex.c:1522:9: error: called from here
  v[3] = compute_linear(&op->src, r->src.x, r->src.y+r->height);
         ^
gen4_vertex.c:312:1: error: inlining failed in call to always_inline ‘compute_linear’: optimization level attribute mismatch
 compute_linear(const struct sna_composite_channel *channel,
 ^
gen4_vertex.c:1521:9: error: called from here
  v[1] = compute_linear(&op->src, r->src.x+r->width, r->src.y+r->height);
         ^
Makefile:647: recipe for target 'gen4_vertex.lo' failed
make[4]: *** [gen4_vertex.lo] Error 1
make[4]: Leaving directory '/scratch/ken/xf86-video-intel-git/src/sna'
Makefile:666: recipe for target 'all-recursive' failed
make[3]: *** [all-recursive] Error 1

This is with gcc-5.1.0 and a linux x86_64 system built with kernel 4.0.3 headers.
Head was at
commit e617c1941c4e5ee90b69221013aab799eace925d
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Tue May 19 12:14:24 2015 +0100

but google found a similar pastebin posting from about 7th May.