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path: root/llvm/lib/CodeGen/MachineTraceMetrics.cpp
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* Add DataDep constructors. Explicitly check SSA form.Jakob Stoklund Olesen2012-08-011-20/+18
| | | | llvm-svn: 161115
* Compute instruction depths through the current trace.Jakob Stoklund Olesen2012-07-311-0/+232
| | | | | | | | | | | Assuming infinite issue width, compute the earliest each instruction in the trace can issue, when considering the latency of data dependencies. The issue cycle is record as a 'depth' from the beginning of the trace. This is half the computation required to find the length of the critical path through the trace. Heights are next. llvm-svn: 161074
* Rename CT -> MTM. MachineTraceMetrics is abbreviated MTM.Jakob Stoklund Olesen2012-07-311-12/+12
| | | | llvm-svn: 161072
* Avoid looking at stale data in verifyAnalysis().Jakob Stoklund Olesen2012-07-301-1/+4
| | | | llvm-svn: 161004
* Allow traces to enter nested loops.Jakob Stoklund Olesen2012-07-301-14/+29
| | | | | | | | | | | This lets traces include the final iteration of a nested loop above the center block, and the first iteration of a nested loop below the center block. We still don't allow traces to contain backedges, and traces are truncated where they would leave a loop, as seen from the center block. llvm-svn: 161003
* Assert that all trace candidate blocks have been visited by the PO.Jakob Stoklund Olesen2012-07-301-11/+6
| | | | | | | | | | When computing a trace, all the candidates for pred/succ must have been visited. Filter out back-edges first, though. The PO traversal ignores them. Thanks to Andy for spotting this in review. llvm-svn: 160995
* Hook into PassManager's analysis verification.Jakob Stoklund Olesen2012-07-301-1/+1
| | | | | | | By overriding Pass::verifyAnalysis(), the pass contents will be verified by the pass manager. llvm-svn: 160994
* Add MachineInstr::isTransient().Jakob Stoklund Olesen2012-07-301-23/+1
| | | | | | | | | | | This is a cleaned up version of the isFree() function in MachineTraceMetrics.cpp. Transient instructions are very unlikely to produce any code in the final output. Either because they get eliminated by RegisterCoalescing, or because they are pseudo-instructions like labels and debug values. llvm-svn: 160977
* Add MachineTraceMetrics::verify().Jakob Stoklund Olesen2012-07-301-10/+46
| | | | | | | This function verifies the consistency of cached data in the MachineTraceMetrics analysis. llvm-svn: 160976
* Verify that the CFG hasn't changed during invalidate().Jakob Stoklund Olesen2012-07-301-2/+12
| | | | | | | The MachineTraceMetrics analysis must be invalidated before modifying the CFG. This will catch some of the violations of that rule. llvm-svn: 160969
* Add more debug output to MachineTraceMetrics.Jakob Stoklund Olesen2012-07-271-1/+32
| | | | llvm-svn: 160905
* Keep track of the head and tail of the trace through each block.Jakob Stoklund Olesen2012-07-271-4/+12
| | | | | | | This makes it possible to quickly detect blocks that are outside the trace. llvm-svn: 160904
* Use an otherwise unused variable.Jakob Stoklund Olesen2012-07-261-1/+1
| | | | llvm-svn: 160798
* Start scaffolding for a MachineTraceMetrics analysis pass.Jakob Stoklund Olesen2012-07-261-0/+477
This is still a work in progress. Out-of-order CPUs usually execute instructions from multiple basic blocks simultaneously, so it is necessary to look at longer traces when estimating the performance effects of code transformations. The MachineTraceMetrics analysis will pick a typical trace through a given basic block and provide performance metrics for the trace. Metrics will include: - Instruction count through the trace. - Issue count per functional unit. - Critical path length, and per-instruction 'slack'. These metrics can be used to determine the performance limiting factor when executing the trace, and how it will be affected by a code transformation. Initially, this will be used by the early if-conversion pass. llvm-svn: 160796
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