Add a new MVT::untyped. This will be used in future work for modelling ISA features like register pairs and lists with "interesting" constraints (such as ARM NEON contiguous register lists or even-odd paired registers). We need to be able to generate these instructions (often from intrinsics), but don't want to have to assign a legal type to them. Instead, we'll use an "untyped" edge to bypass the type-checking and simply ensure that the register classes match.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133106 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 47 insertions, 9 deletions

diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index 15ce11cb15..f09b38164a 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -276,6 +276,33 @@ private:
 };
 }  // end anonymous namespace
 
+/// GetCostForDef - Looks up the register class and cost for a given definition.
+/// Typically this just means looking up the representative register class,
+/// but for untyped values (MVT::untyped) it means inspecting the node's
+/// opcode to determine what register class is being generated.
+static void GetCostForDef(const ScheduleDAGSDNodes::RegDefIter &RegDefPos,
+                          const TargetLowering *TLI,
+                          const TargetInstrInfo *TII,
+                          const TargetRegisterInfo *TRI,
+                          unsigned &RegClass, unsigned &Cost) {
+  EVT VT = RegDefPos.GetValue();
+
+  // Special handling for untyped values.  These values can only come from
+  // the expansion of custom DAG-to-DAG patterns.
+  if (VT == MVT::untyped) {
+    unsigned Opcode = RegDefPos.GetNode()->getMachineOpcode();
+    unsigned Idx = RegDefPos.GetIdx();
+    const TargetInstrDesc Desc = TII->get(Opcode);
+    const TargetRegisterClass *RC = Desc.getRegClass(Idx, TRI);
+    RegClass = RC->getID();
+    // FIXME: Cost arbitrarily set to 1 because there doesn't seem to be a
+    // better way to determine it.
+    Cost = 1;
+  } else {
+    RegClass = TLI->getRepRegClassFor(VT)->getID();
+    Cost = TLI->getRepRegClassCostFor(VT);
+  }
+}
 
 /// Schedule - Schedule the DAG using list scheduling.
 void ScheduleDAGRRList::Schedule() {
@@ -1807,8 +1834,10 @@ bool RegReductionPQBase::HighRegPressure(const SUnit *SU) const {
     for (ScheduleDAGSDNodes::RegDefIter RegDefPos(PredSU, scheduleDAG);
          RegDefPos.IsValid(); RegDefPos.Advance()) {
       EVT VT = RegDefPos.GetValue();
-      unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
-      unsigned Cost = TLI->getRepRegClassCostFor(VT);
+
+      unsigned RCId, Cost;
+      GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost);
+
       if ((RegPressure[RCId] + Cost) >= RegLimit[RCId])
         return true;
     }
@@ -1919,9 +1948,10 @@ void RegReductionPQBase::ScheduledNode(SUnit *SU) {
          RegDefPos.IsValid(); RegDefPos.Advance(), --SkipRegDefs) {
       if (SkipRegDefs)
         continue;
-      EVT VT = RegDefPos.GetValue();
-      unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
-      RegPressure[RCId] += TLI->getRepRegClassCostFor(VT);
+
+      unsigned RCId, Cost;
+      GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost);
+      RegPressure[RCId] += Cost;
       break;
     }
   }
@@ -1934,16 +1964,16 @@ void RegReductionPQBase::ScheduledNode(SUnit *SU) {
        RegDefPos.IsValid(); RegDefPos.Advance(), --SkipRegDefs) {
     if (SkipRegDefs > 0)
       continue;
-    EVT VT = RegDefPos.GetValue();
-    unsigned RCId = TLI->getRepRegClassFor(VT)->getID();
-    if (RegPressure[RCId] < TLI->getRepRegClassCostFor(VT)) {
+    unsigned RCId, Cost;
+    GetCostForDef(RegDefPos, TLI, TII, TRI, RCId, Cost);
+    if (RegPressure[RCId] < Cost) {
       // Register pressure tracking is imprecise. This can happen. But we try
       // hard not to let it happen because it likely results in poor scheduling.
       DEBUG(dbgs() << "  SU(" << SU->NodeNum << ") has too many regdefs\n");
       RegPressure[RCId] = 0;
     }
     else {
-      RegPressure[RCId] -= TLI->getRepRegClassCostFor(VT);
+      RegPressure[RCId] -= Cost;
     }
   }
   dumpRegPressure();
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.h b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.h
index b5f68f3055..3ad2bd6ca6 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.h
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.h
@@ -135,6 +135,14 @@ namespace llvm {
         return ValueType;
       }
 
+      const SDNode *GetNode() const {
+        return Node;
+      }
+
+      unsigned GetIdx() const {
+        return DefIdx;
+      }
+
       void Advance();
     private:
       void InitNodeNumDefs();