Tesseract goes down from 402 to 385fps. (Using nir,sisched)
I saw other games too with a performance regression. But the impact is smaller.

Extended renderer info (GLX_MESA_query_renderer):
    Vendor: X.Org (0x1002)
    Device: AMD Radeon HD 7900 Series (TAHITI, DRM 3.27.0,
4.19.0-2-amd-staging-drm-next-git, LLVM 8.0.0) (0x6798)
    Version: 18.3.0
    Accelerated: yes
    Video memory: 3072MB
    Unified memory: no
    Preferred profile: core (0x1)
    Max core profile version: 4.5
    Max compat profile version: 4.5
    Max GLES1 profile version: 1.1
    Max GLES[23] profile version: 3.2
Memory info (GL_ATI_meminfo):
    VBO free memory - total: 2876 MB, largest block: 2876 MB
    VBO free aux. memory - total: 2966 MB, largest block: 2966 MB
    Texture free memory - total: 2876 MB, largest block: 2876 MB
    Texture free aux. memory - total: 2966 MB, largest block: 2966 MB
    Renderbuffer free memory - total: 2876 MB, largest block: 2876 MB
    Renderbuffer free aux. memory - total: 2966 MB, largest block: 2966 MB
Memory info (GL_NVX_gpu_memory_info):
    Dedicated video memory: 3072 MB
    Total available memory: 6144 MB
    Currently available dedicated video memory: 2876 MB
OpenGL vendor string: X.Org
OpenGL renderer string: AMD Radeon HD 7900 Series (TAHITI, DRM 3.27.0,
4.19.0-2-amd-staging-drm-next-git, LLVM 8.0.0)
OpenGL core profile version string: 4.5 (Core Profile) Mesa 18.3.0-devel
(git-4052624398)
OpenGL core profile shading language version string: 4.50
OpenGL core profile context flags: (none)
OpenGL core profile profile mask: core profile

OpenGL version string: 4.5 (Compatibility Profile) Mesa 18.3.0-devel
(git-4052624398)
OpenGL shading language version string: 4.50
OpenGL context flags: (none)
OpenGL profile mask: compatibility profile

OpenGL ES profile version string: OpenGL ES 3.2 Mesa 18.3.0-devel
(git-4052624398)
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20


f243980f2c1e8005dab0cbadf52eb4392feb2ecc is the first bad commit
commit f243980f2c1e8005dab0cbadf52eb4392feb2ecc
Author: Sonny Jiang <sonny.jiang@amd.com>
Date:   Wed Oct 3 11:53:11 2018 -0400

    radeonsi:optimizing SET_CONTEXT_REG for shaders VS

    Signed-off-by: Sonny Jiang <sonny.jiang@amd.com>
    Signed-off-by: Marek Olšák <marek.olsak@amd.com>

:040000 040000 e32a7539bb1a32c3c9d700651aa50f8dada31b5e
0e04f0305e4e893fdee0b394b5aa2c9c0bf0edaf M      src