This patch slightly refactors data structures internally used by the bottleneck
analysis to track data and resource dependencies.
This patch also updates methods used to print out information about dependency
edges when in debug mode.
This is the last of a sequence of commits done in preparation for an upcoming
patch that fixes PR37494. No functional change intended.
llvm-svn: 363677
The resource pressure distribution computation is now delegated by class
BottleneckAnalysis to an instance of class PressureTracker.
Class PressureTracker is also responsible for:
- tracking users of processor resource units.
- tracking the number of delay cycles caused by increases in backpressure.
BottleneckAnalysis internally initializes a dependency graph. Each nodes
represents an instruction in the input code sequence. Edges of the dependency
graph are critical register/memory/resource dependencies. Dependencies are only
added to the graph if they are seen as critical by backend pressure events.
The DependencyGraph is currently unused. It is possible to print the dependency
graph (see method DependencyGraph::dump()) for debugging purposes.
The long term goal is to use the information stored by the dependency graph in
order to do critical path computation.
llvm-svn: 362246
Andrea Di Biagio