Don't recalculate the loop info and loop dominators analyses if they're

preserved.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45596 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/RegAllocLinearScan.cpp

@@ -104,6 +104,8 @@ namespace {
       // to coalescing and which analyses coalescing invalidates.
       AU.addRequiredTransitive<RegisterCoalescer>();
       AU.addRequired<MachineLoopInfo>();
+      AU.addPreserved<MachineLoopInfo>();
+      AU.addPreservedID(MachineDominatorsID);
       MachineFunctionPass::getAnalysisUsage(AU);
     }