Changes:

• Renamed a flag ("callgraph-full" -> "call-multigraph") to reflect its purpose more clearly
• Removed unnecessary if-check
• General refactoring and restructuring
• Removed useHeuristic from the code - from the structure of the code it is vivid that useHeuristic variable used in getMaxFreq functions is always set to "true" and never becomes "false".

Fixed small inaccuracies
As the patch is done, @apilipenko , can you please push it for me?

Sorry, wrong diff

Addressed @apilipenko 's comments

• Switched to one flag
• Small changes in struct and comments

ping

Replying to @davidxl
This option is useful when you are analyzing only the "hot" paths on the CFG.
Using these flags you are getting rid of all the unnecessary paths in the graph (the ones that end in deopt or are unreachable)

Resolving @apilipenko 's suggestions
As I don't have commit access, can you please commit the change for me?

ping

Addressed @davidxl and @sfertile comments.

Resolving @apilipenko suggestions.
Removed deltas from the struct.

Changed unnecessarily complicated test

ping

ping

Answering @mtrofin comments.
Refactoring, little changes:

• Separated the initial flag into two: one prints the whole info on instruction cost and threshold, the other one prints only deltas of cost and threshold
• Changed the InlineCostDetail structure - introduced CostBefore, CostAfter, CostDelta, ThresholdBefore, ThresholdAfter, ThresholdDelta
• Changed the test that I wrote to match the check of new flags
• Little comment changes

Changed pait<int, int> to struct InlineCostDetails in DenseMap and changed comment defining CostThrehsoldMap.
@mtrofin : Yes, the DenseMap stores the delta of the cost and threshold after inlining the instruction, not just a snapshot.
This is done in order to see the exact cost/change in the threshold it would take to inline the instruction.

Sorry for the delay due to the changes in structure of InlineCost.cpp in this patch: https://reviews.llvm.org/D71733 .
Structural changes mostly.
Added test to llvm/test/DebugInfo to test the new flag.

ping

Refactoring