a1e59bdc17
I'm not sure if this is the best way forward or not, but we have a lot of issues with forgetting that shuffle_vectors can be scalar again and again. (There is another example from the recent known-bits code added recently). As a scalar-dst shuffle vector is just an extract, and a scalar-source shuffle vector is just a build vector, this patch makes scalar shuffle vector illegal and adjusts the irbuilder to create the correct node as required. Most targets do this already through lowering or combines. Making scalar shuffles illegal simplifies gisel as a whole, it just requires that transforms that create shuffles of new sizes to account for the scalar shuffle being illegal (mostly IRBuilder and LessElements).
This directory contains tests for the MIR file format parser and printer. It was necessary to split the tests across different targets as no single target covers all features available in machine IR. Tests for codegen passes should NOT be here but in test/CodeGen/sometarget. As a rule of thumb this directory should only contain tests using 'llc -run-pass none'.