[x86] Bypass the shuffle mask comment generation when not using verbose asm. This can be somewhat expensive and there is no reason to do it outside of tests or debugging sessions. I'm also likely to make it significantly more expensive to support more styles of shuffles.
[x86] Bypass the shuffle mask comment generation when not using verbose
asm. This can be somewhat expensive and there is no reason to do it
outside of tests or debugging sessions. I'm also likely to make it
significantly more expensive to support more styles of shuffles.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@218362 91177308-0d34-0410-b5e6-96231b3b80d8

dslab-epfl/asap,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,dslab-epfl/asap,llvm-mirror/llvm,dslab-epfl/asap,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,dslab-epfl/asap,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,dslab-epfl/asap