Don't overwrite existing target-cpu attributes. I've often found the replacement behavior annoying, and this is inconsistent with how the fast math command line flags interact with the function attributes. Does not yet change target-features, since I think that should behave as a concatenation.
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'.