CodeGenPrepare: Move ret duplication out of the instruction iteration loop.

It can delete the block, and the loop continues on free'd memory.
No change in output. Found by valgrind.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168525 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed