but never used.

Fix a bug in LiveVariables where uses on the LHS of self-assign
operators (e.g +=, *=, etc) would not be properly recorded in the
liveness state of the variable.

llvm-svn: 41757

that contained no declarations, or when a variable is declared but never used.

llvm-svn: 41756

to variables that are no longer live.  This analysis is built on top
of CFGs and the LiveVariables analysis.

changes to driver:
 added driver option "-check-dead-stores" to run the analysis

llvm-svn: 41754

 - Finished 99% of analysis logic.  Probably a few bugs.
 - Added querying functions to query liveness.
 - Added better pretty printing of liveness.
 - Added better bookkeeping of per-variable liveness information.
 - Added LiveVariablesAuditor interface, which allows "lazy" querying
   of intra-basic block liveness information.

Driver:
 - Minor cleanups involved in dumping liveness information.

llvm-svn: 41753

source-level CFGs.  This code may change significantly in the near
future as we explore different means to implement dataflow analyses.

Added a driver option, -dump-live-variables, to view the output of
live variable analysis.  This output is very ALPHA; it will be improved shortly.

llvm-svn: 41737