[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

[Nate Begeman]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

DAGCombiner.cpp updated: 1.97 -> 1.98
---
Log message:

fold c1 << (x + c2) into (c1 << c2) << x.  fix a warning.


---
Diffs of the changes:  (+7 -1)

 DAGCombiner.cpp |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletion(-)


Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.97 
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.98
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.97  Sun Feb  5 01:36:48 2006
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp       Sun Feb  5 02:07:24 2006
@@ -838,7 +838,7 @@
   if (N1.getOpcode() == ISD::SHL) {
     if (ConstantSDNode *SHC = dyn_cast<ConstantSDNode>(N1.getOperand(0))) {
       if (isPowerOf2_64(SHC->getValue())) {
-        SDOperand Add = DAG.getNode(ISD::ADD, VT, N1, DAG.getConstant(-1, VT));
+        SDOperand Add = DAG.getNode(ISD::ADD, VT, 
N1,DAG.getConstant(~0ULL,VT));
         WorkList.push_back(Add.Val);
         return DAG.getNode(ISD::AND, VT, N0, Add);
       }
@@ -1288,6 +1288,12 @@
   // fold (shl 0, x) -> 0
   if (N0C && N0C->isNullValue())
     return N0;
+  // fold (shl c1, (add x, c2)) -> (shl c1 << c2, x)
+  if (N0C && N1.getOpcode() == ISD::ADD && 
+      N1.getOperand(1).getOpcode() == ISD::Constant) {
+    SDOperand LHS = DAG.getNode(ISD::SHL, VT, N0, N1.getOperand(1));
+    return DAG.getNode(ISD::SHL, VT, LHS, N1.getOperand(0));
+  }
   // fold (shl x, c >= size(x)) -> undef
   if (N1C && N1C->getValue() >= OpSizeInBits)
     return DAG.getNode(ISD::UNDEF, VT);



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