CodeGen: Move an initialization away from an unrelated comment

An initialization somehow found its way in between a comment and the
block of code the comment is about. Moving the initialization makes
this less confusing.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193993 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen: Use EmitBranchOnBool when generating For and CXXForRange

A while ago EmitForStmt was changed to explicitly evaluate the
condition expression and create a branch instead of using
EmitBranchOnBool, so that the condition expression could be used for
some cleanup logic. The cleanup stuff has since been reorganized, and
this is no longer necessary.

In EmitCXXForRange, the evaluated condition was never used for
anything else. The logic was presumably modeled on EmitForStmt.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193994 91177308-0d34-0410-b5e6-96231b3b80d8
CodeGen: Test that simple expressions are simplified at -O0

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193995 91177308-0d34-0410-b5e6-96231b3b80d8