RegisterPressure: Simplify close{Top|Bottom}()

[MatzeB]

Summary

• There are no duplicate registers in LiveRegs list we are copying from and so we do not need to sort the registers.
• Simply use SmallVector::apend instead of a loop between begin() and end() with push_back().

[atrick]

The sorting was needed at one point, but since you're integrating the register pressure result into the tracker it should be self-contained and safe.

llvm/trunk/lib/CodeGen/RegisterPressure.cpp

void RegPressureTracker::closeTop() {
   if (RequireIntervals)
     static_cast<IntervalPressure&>(P).TopIdx = getCurrSlot();
   else
     static_cast<RegionPressure&>(P).TopPos = CurrPos;
 
   assert(P.LiveInRegs.empty() && "inconsistent max pressure result");
   P.LiveInRegs.reserve(LiveRegs.PhysRegs.size() + LiveRegs.VirtRegs.size());
   P.LiveInRegs.append(LiveRegs.PhysRegs.begin(), LiveRegs.PhysRegs.end());
-  for (SparseSet<unsigned>::const_iterator I =
-         LiveRegs.VirtRegs.begin(), E = LiveRegs.VirtRegs.end(); I != E; ++I)
-    P.LiveInRegs.push_back(*I);
-  std::sort(P.LiveInRegs.begin(), P.LiveInRegs.end());
-  P.LiveInRegs.erase(std::unique(P.LiveInRegs.begin(), P.LiveInRegs.end()),
-                     P.LiveInRegs.end());
+  P.LiveInRegs.append(LiveRegs.VirtRegs.begin(), LiveRegs.VirtRegs.end());
 }
 
 /// Set the boundary for the bottom of the region and summarize live outs.
 void RegPressureTracker::closeBottom() {
   if (RequireIntervals)
     static_cast<IntervalPressure&>(P).BottomIdx = getCurrSlot();
   else
     static_cast<RegionPressure&>(P).BottomPos = CurrPos;
 
   assert(P.LiveOutRegs.empty() && "inconsistent max pressure result");
   P.LiveOutRegs.reserve(LiveRegs.PhysRegs.size() + LiveRegs.VirtRegs.size());
   P.LiveOutRegs.append(LiveRegs.PhysRegs.begin(), LiveRegs.PhysRegs.end());
-  for (SparseSet<unsigned>::const_iterator I =
-         LiveRegs.VirtRegs.begin(), E = LiveRegs.VirtRegs.end(); I != E; ++I)
-    P.LiveOutRegs.push_back(*I);
-  std::sort(P.LiveOutRegs.begin(), P.LiveOutRegs.end());
-  P.LiveOutRegs.erase(std::unique(P.LiveOutRegs.begin(), P.LiveOutRegs.end()),
-                      P.LiveOutRegs.end());
+  P.LiveOutRegs.append(LiveRegs.VirtRegs.begin(), LiveRegs.VirtRegs.end());
 }
 
 /// Finalize the region boundaries and record live ins and live outs.
 void RegPressureTracker::closeRegion() {
   if (!isTopClosed() && !isBottomClosed()) {
     assert(LiveRegs.PhysRegs.empty() && LiveRegs.VirtRegs.empty() &&
            "no region boundary");
     return;