[llvm-branch-commits] [llvm-branch] r156376 - in /llvm/branches/release_31: ./ lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp

[Bill Wendling]

Author: void
Date: Tue May  8 02:58:10 2012
New Revision: 156376

URL: http://llvm.org/viewvc/llvm-project?rev=156376&view=rev
Log:
New Revision: 155749

URL: http://llvm.org/viewvc/llvm-project?rev=155749&view=rev
Log:
Reapply 155668: Fix the SD scheduler to avoid gluing the same node twice.

This time, also fix the caller of AddGlue to properly handle
incomplete chains. AddGlue had failure modes, but shamefully hid them
from its caller. It's luck ran out.

Fixes rdar://11314175: BuildSchedUnits assert.


Modified:
    llvm/branches/release_31/   (props changed)
    llvm/branches/release_31/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp

Propchange: llvm/branches/release_31/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Tue May  8 02:58:10 2012
@@ -1,3 +1,3 @@
 /llvm/branches/Apple/Pertwee:110850,110961
 /llvm/branches/type-system-rewrite:133420-134817
-/llvm/trunk:155166,155230,155284-155288,155307,155342,155466,155536,155668,155809,155813,155817-155818,155844,155895,155902,155954,155984
+/llvm/trunk:155166,155230,155284-155288,155307,155342,155466,155536,155668,155749,155809,155813,155817-155818,155844,155895,155902,155954,155984

Modified: llvm/branches/release_31/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_31/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp?rev=156376&r1=156375&r2=156376&view=diff
==============================================================================
--- llvm/branches/release_31/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp (original)
+++ llvm/branches/release_31/lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp Tue May  8 02:58:10 2012
@@ -131,30 +131,16 @@
   }
 }
 
-static void AddGlue(SDNode *N, SDValue Glue, bool AddGlue, SelectionDAG *DAG) {
-  SmallVector<EVT, 4> VTs;
-  SDNode *GlueDestNode = Glue.getNode();
-
-  // Don't add glue from a node to itself.
-  if (GlueDestNode == N) return;
-
-  // Don't add glue to something that already has it, either as a use or value.
-  if (N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue ||
-      N->getValueType(N->getNumValues() - 1) == MVT::Glue) {
-    return;
-  }
-  for (unsigned I = 0, E = N->getNumValues(); I != E; ++I)
-    VTs.push_back(N->getValueType(I));
-
-  if (AddGlue)
-    VTs.push_back(MVT::Glue);
-
+// Helper for AddGlue to clone node operands.
+static void CloneNodeWithValues(SDNode *N, SelectionDAG *DAG,
+                                SmallVectorImpl<EVT> &VTs,
+                                SDValue ExtraOper = SDValue()) {
   SmallVector<SDValue, 4> Ops;
   for (unsigned I = 0, E = N->getNumOperands(); I != E; ++I)
     Ops.push_back(N->getOperand(I));
 
-  if (GlueDestNode)
-    Ops.push_back(Glue);
+  if (ExtraOper.getNode())
+    Ops.push_back(ExtraOper);
 
   SDVTList VTList = DAG->getVTList(&VTs[0], VTs.size());
   MachineSDNode::mmo_iterator Begin = 0, End = 0;
@@ -173,6 +159,46 @@
     MN->setMemRefs(Begin, End);
 }
 
+static bool AddGlue(SDNode *N, SDValue Glue, bool AddGlue, SelectionDAG *DAG) {
+  SmallVector<EVT, 4> VTs;
+  SDNode *GlueDestNode = Glue.getNode();
+
+  // Don't add glue from a node to itself.
+  if (GlueDestNode == N) return false;
+
+  // Don't add a glue operand to something that already uses glue.
+  if (GlueDestNode &&
+      N->getOperand(N->getNumOperands()-1).getValueType() == MVT::Glue) {
+    return false;
+  }
+  // Don't add glue to something that already has a glue value.
+  if (N->getValueType(N->getNumValues() - 1) == MVT::Glue) return false;
+
+  for (unsigned I = 0, E = N->getNumValues(); I != E; ++I)
+    VTs.push_back(N->getValueType(I));
+
+  if (AddGlue)
+    VTs.push_back(MVT::Glue);
+
+  CloneNodeWithValues(N, DAG, VTs, Glue);
+
+  return true;
+}
+
+// Cleanup after unsuccessful AddGlue. Use the standard method of morphing the
+// node even though simply shrinking the value list is sufficient.
+static void RemoveUnusedGlue(SDNode *N, SelectionDAG *DAG) {
+  assert((N->getValueType(N->getNumValues() - 1) == MVT::Glue &&
+          !N->hasAnyUseOfValue(N->getNumValues() - 1)) &&
+         "expected an unused glue value");
+
+  SmallVector<EVT, 4> VTs;
+  for (unsigned I = 0, E = N->getNumValues()-1; I != E; ++I)
+    VTs.push_back(N->getValueType(I));
+
+  CloneNodeWithValues(N, DAG, VTs);
+}
+
 /// ClusterNeighboringLoads - Force nearby loads together by "gluing" them.
 /// This function finds loads of the same base and different offsets. If the
 /// offsets are not far apart (target specific), it add MVT::Glue inputs and
@@ -240,19 +266,23 @@
   // Cluster loads by adding MVT::Glue outputs and inputs. This also
   // ensure they are scheduled in order of increasing addresses.
   SDNode *Lead = Loads[0];
-  AddGlue(Lead, SDValue(0, 0), true, DAG);
-
-  SDValue InGlue = SDValue(Lead, Lead->getNumValues() - 1);
+  SDValue InGlue = SDValue(0, 0);
+  if (AddGlue(Lead, InGlue, true, DAG))
+    InGlue = SDValue(Lead, Lead->getNumValues() - 1);
   for (unsigned I = 1, E = Loads.size(); I != E; ++I) {
     bool OutGlue = I < E - 1;
     SDNode *Load = Loads[I];
 
-    AddGlue(Load, InGlue, OutGlue, DAG);
+    // If AddGlue fails, we could leave an unsused glue value. This should not
+    // cause any
+    if (AddGlue(Load, InGlue, OutGlue, DAG)) {
+      if (OutGlue)
+        InGlue = SDValue(Load, Load->getNumValues() - 1);
 
-    if (OutGlue)
-      InGlue = SDValue(Load, Load->getNumValues() - 1);
-
-    ++LoadsClustered;
+      ++LoadsClustered;
+    }
+    else if (!OutGlue && InGlue.getNode())
+      RemoveUnusedGlue(InGlue.getNode(), DAG);
   }
 }