[CodeGen]: BlockPlacement: Skip extraneous logging.

Move a check for blocks that are not candidates for tail duplication up before
the logging. Reduces logging noise. No non-logging changes intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294086 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed