[CodeGen] Print executed statement instances at runtime.
Add the options -polly-codegen-trace-stmts and
-polly-codegen-trace-scalars. When enabled, adds a call to the
beginning of every generated statement that prints the executed
statement instance. With -polly-codegen-trace-scalars, it also prints
the value of all scalars that are used in the statement, and PHIs
defined in the beginning of the statement.
Differential Revision: https://reviews.llvm.org/D45743
git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@330864 91177308-0d34-0410-b5e6-96231b3b80d8