It has finally happened. Spiller is now using live interval info.

This fixes a very subtle bug. vr defined by an implicit_def is allowed overlap with any register since it doesn't actually modify anything. However, if it's used as a two-address use, its live range can be extended and it can be spilled. The spiller must take care not to emit a reload for the vn number that's defined by the implicit_def. This is both a correctness and performance issue.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69743 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/LiveIntervalAnalysis.cpp

@@ -1304,7 +1304,7 @@ rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI,
 
     // Update stack slot spill weight if we are splitting.
     float Weight = getSpillWeight(HasDef, HasUse, loopDepth);
-      if (!TrySplit)
+    if (!TrySplit)
       SSWeight += Weight;
 
     // Create a new virtual register for the spill interval.
@@ -1338,7 +1338,7 @@ rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI,
           HasUse = false;
           HasDef = false;
           CanFold = false;
-          if (isRemoved(MI)) {
+          if (isNotInMIMap(MI)) {
             SSWeight -= Weight;
             break;
           }
@@ -1393,7 +1393,7 @@ rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI,
     if (DefIsReMat && ImpUse)
       MI->addOperand(MachineOperand::CreateReg(ImpUse, false, true));
 
-    // create a new register interval for this spill / remat.
+    // Create a new register interval for this spill / remat.
     LiveInterval &nI = getOrCreateInterval(NewVReg);
     if (CreatedNewVReg) {
       NewLIs.push_back(&nI);