Failed to compile shader brush_blend

[nical]

There is a crash report with this in the critical error log:

|[0][GFX1-]: Failed to compile shader: brush_blend
 (t=25.798) |[16][GFX1-]: Compositors might be mixed (5,2) (t=26.0736) |[17][GFX1]: Shader compilation failure, cfg: features: 0x100 multiplier: 1 op: CompositionOp::OP_OVER (t=54.2463) |[3][GFX1-]: wr_renderer_render: Shader(Compilation("brush_blend", "")) (t=25.8461) |[4][GFX1-]: Failed to compile shader: brush_blend
 (t=25.8627) |[5][GFX1-]: wr_renderer_render: Shader(Compilation("brush_blend", "")) (t=25.863) |[6][GFX1-]: Failed to compile shader: brush_blend
 (t=25.8812) |[7][GFX1-]: wr_renderer_render: Shader(Compilation("brush_blend", "")) (t=25.8814) |[8][GFX1-]: Failed to compile shader: brush_blend
 (t=25.8961) |[9][GFX1-]: wr_renderer_render: Shader(Compilation("brush_blend", "")) (t=25.8965) |[10][GFX1-]: Failed to compile shader: brush_blend
 (t=25.9085) |[11][GFX1-]: wr_renderer_render: Shader(Compilation("brush_blend", "")) (t=25.9089) |[12][GFX1-]: Failed to compile shader: brush_blend
 (t=25.9124) |[13][GFX1-]: wr_renderer_render: Shader(Compilation("brush_blend", "")) (t=25.9204) |[14][GFX1-]: Failed to compile shader: brush_blend
 (t=25.9305) |[15][GFX1-]: wr_renderer_render: Shader(Compilation("brush_blend", "")) (t=25.9308) 

[kvark]

whoa, not much useful info in the log ^

Mesa DRI Intel(R) Ivybridge Mobile -- 3.0 Mesa 18.0.5

Would be great to repro it in lab conditions. Ivybridge is a popular piece of HW.

[staktrace]

https://bugzilla.mozilla.org/show_bug.cgi?id=1462777 has investigation that might be relevant