(In reply to comment #28)
> > LLVM ERROR: ran out of registers during register allocation

I do not get this message on upstream llvm recent revisions.

But every demo segfaults. Mostly in LLVMBuildBitCast().

Running a demo looks like this:

$ DRI_PRIME=1 ./Effects
Using binned.
4.3.0-0+UE4 7038 3077 379 0
Signal 11 caught.
EngineCrashHandler: Signal=11

Exiting due to error
Starting ../../../Engine/Binaries/Linux/CrashReportClient
[1]    10932 abort (core dumped)  DRI_PRIME=1 ./Effects

This is still a problem with register spilling that just looks different,
right?
Should I compile with debug symbols and get a complete backtrace or wouldn't
that provide any new information?

(By the way, applying this small patch makes it render almost completely
correct on intel: https://bugs.freedesktop.org/show_bug.cgi?id=78716#c10)