Created attachment 133745 [details]
TGSI and byte code of the buggy shader

When running UE4Editor (4.17) on BARTS with -opengl3 and mesa (1e696b9) is
compiled in debug mode I get the following assertion failure on one shader
(attached), that then leads to UE4Editor shutting down: 

  error at : MUL_IEEE     R17.x.5F@R124.x,    R14.x.5F@R124.x, R90.x.22||F@R2.w
   : expected operand value R90.x.22||F@R2.w, gpr contains t39||FP@R2.w
  sb/sb_ra_checker.cpp:46:run: Assertion `sh.errors.empty()' failed.

Sometimes it happens right away, when loading the assets, sometimes I have to
load a specific level. I guess it depends on what assets are actually
displayed.  

If I disable the assertion then I can use UE4Editor (I still need to add a
patch to work around to a problem introduced by another shader that for some
bug in UE4 exceeds the limits of the GPRs, but this has nothing to do which
this assertion failure).

Best, 
Gert