Factor live variable analysis so it does not do register coalescing

simultaneously.  Move that pass to SimpleRegisterCoalescing.

This makes it easier to implement alternative register allocation and
coalescing strategies while maintaining reuse of the existing live
interval analysis.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37520 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/RegAllocLinearScan.cpp

@@ -96,6 +96,7 @@ namespace {
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.addRequired<LiveIntervals>();
+      AU.addRequiredID(SimpleRegisterCoalescingID);
       MachineFunctionPass::getAnalysisUsage(AU);
     }