[OpenMPOpt] ICV tracking for calls

Authored by sstefan1 on Aug 12 2020, 3:20 AM.


[OpenMPOpt] ICV tracking for calls

Introduce two new AAs. AAICVTrackerFunctionReturned which checks if a
function can have a unique ICV value after it is finished, and
AAICVCallSiteReturned which checks AAICVTrackerFunctionReturned for a
call site. This enables us to check the value of a call and if it
changes the ICV. This also changes the approach in
getReplacementValues() to a worklist-based approach so we can explore
all relevant BBs.

Differential Revision: https://reviews.llvm.org/D85544