llvm dev - Nov 2014 - [LLVMdev] architecture-specific builtins and OpenCL

I'm trying to ascertain whether or not it is possible to use
architecture-specific builtins (LLVM3.4.2) in OpenCL:

This compiles cleanly for my target when it has a .c extension:

void fred(unsigned long* in, unsigned long* where)
{
    *where = __builtin_coge_reverse(*in);
}

But this variant crashes very early when it is a .cl file:
void kernel fred(unsigned long *in, unsigned long* where)
{
    *where = __builtin_coge_reverse(*in);
}



I'm not even sure how to go about determining the source of problem - it
crashes before generating any IR (-mllvm -print-after-all)

clang:
/localspace/rcgorton/svn/Compiler/trunk/LLVM3_4/llvm-3.4.2.src/lib/IR/Instructions.cpp:2352:
static llvm::CastInst* llvm::CastInst::Create(llvm::Instruction::CastOps,
llvm::Value*, llvm::Type*, const llvm::Twine&, llvm::Instruction*):
Assertion `castIsValid(op, S, Ty) && "Invalid cast!"'
failed.

Is there a document somewhere which describes how to use various
front-end-dumping switches?  Is there a better way to attack this?

Thanks in advance,

	Richard
	rcgorton at cog-e.com