Remove attribution from file headers, per discussion on llvmdev.

[oota-llvm.git] / lib / CodeGen / SelectionDAG / DAGCombiner.cpp

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index a1d8ad95de5198491879d17e5453e26261388f91..e581ed3d948a3acb4473e0db2741c59eb2998870 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2,8 +2,8 @@
 //
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by Nate Begeman and is distributed under the
-// University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
@@ -141,7 +141,7 @@ namespace {
     /// it can be simplified or if things it uses can be simplified by bit
     /// propagation.  If so, return true.
     bool SimplifyDemandedBits(SDOperand Op, uint64_t Demanded = ~0ULL) {
-      TargetLowering::TargetLoweringOpt TLO(DAG);
+      TargetLowering::TargetLoweringOpt TLO(DAG, AfterLegalize);
       uint64_t KnownZero, KnownOne;
       Demanded &= MVT::getIntVTBitMask(Op.getValueType());
       if (!TLI.SimplifyDemandedBits(Op, Demanded, KnownZero, KnownOne, TLO))
@@ -3672,6 +3672,10 @@ SDOperand DAGCombiner::visitFP_EXTEND(SDNode *N) {
   ConstantFPSDNode *N0CFP = dyn_cast<ConstantFPSDNode>(N0);
   MVT::ValueType VT = N->getValueType(0);
   
+  // If this is fp_round(fpextend), don't fold it, allow ourselves to be folded.
+  if (N->hasOneUse() && (*N->use_begin())->getOpcode() == ISD::FP_ROUND)
+    return SDOperand();
+  
   // fold (fp_extend c1fp) -> c1fp
   if (N0CFP && VT != MVT::ppcf128)
     return DAG.getNode(ISD::FP_EXTEND, VT, N0);
@@ -4223,7 +4227,7 @@ SDOperand DAGCombiner::visitSTORE(SDNode *N) {
   if (CombineToPreIndexedLoadStore(N) || CombineToPostIndexedLoadStore(N))
     return SDOperand(N, 0);
 
-  // FIXME: is there such a think as a truncating indexed store?
+  // FIXME: is there such a thing as a truncating indexed store?
   if (ST->isTruncatingStore() && ST->getAddressingMode() == ISD::UNINDEXED &&
       MVT::isInteger(Value.getValueType())) {
     // See if we can simplify the input to this truncstore with knowledge that
@@ -4243,6 +4247,18 @@ SDOperand DAGCombiner::visitSTORE(SDNode *N) {
       return SDOperand(N, 0);
   }
   
+  // If this is a load followed by a store to the same location, then the store
+  // is dead/noop.
+  if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) {
+    if (Chain.Val == Ld && Ld->getBasePtr() == Ptr &&
+        ST->getAddressingMode() == ISD::UNINDEXED &&
+        ST->getStoredVT() == Ld->getLoadedVT() &&
+        !ST->isVolatile()) {
+      // The store is dead, remove it.
+      return Chain;
+    }
+  }
+  
   return SDOperand();
 }