[LLVMdev] Predication on SIMD architectures and LLVM

[David Chisnall]

On 22 Oct 2012, at 18:10, <dag at cray.com> wrote:

> None of your proposed solutions is ideal.  We really should have
> first-class predication in the IR.  It's only going to get more
> important.

Perhaps I am missing something, but isn't a predicated instruction effectively an single-instruction version of an arithmetic operation followed by a select?  As we can already represent this in the IR, and already match other predicated instructions (e.g. on ARM) to this pattern, what is gained by adding predication directly to the IR?

David