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

[Evan Cheng]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

DAGCombiner.cpp updated: 1.64 -> 1.65
---
Log message:

Fold (zext (load x) to (zextload x).


---
Diffs of the changes:  (+18 -1)

 DAGCombiner.cpp |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletion(-)


Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.64 
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.65
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.64  Wed Dec  7 12:02:05 2005
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp       Tue Dec 13 20:19:23 2005
@@ -1552,7 +1552,7 @@
        TLI.isOperationLegal(ISD::SIGN_EXTEND_INREG, N0.getValueType())))
     return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0),
                        DAG.getValueType(N0.getValueType()));
-  // fold (sext (load x)) -> (sextload x)
+  // fold (sext (load x)) -> (sext (truncate (sextload x)))
   if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
     SDOperand ExtLoad = DAG.getExtLoad(ISD::SEXTLOAD, VT, N0.getOperand(0),
                                        N0.getOperand(1), N0.getOperand(2),
@@ -1576,6 +1576,23 @@
   // fold (zext (zext x)) -> (zext x)
   if (N0.getOpcode() == ISD::ZERO_EXTEND)
     return DAG.getNode(ISD::ZERO_EXTEND, VT, N0.getOperand(0));
+  // fold (zext (zextload x)) -> (zextload x)
+  if (N0.getOpcode() == ISD::ZEXTLOAD && VT == N0.getValueType())
+    return N0;
+  // fold (zext (truncate x)) -> (zextinreg x) iff x size == zext size.
+  if (N0.getOpcode() == ISD::TRUNCATE && N0.getOperand(0).getValueType() == 
VT&&
+      !AfterLegalize)
+    return DAG.getZeroExtendInReg(N0.getOperand(0), VT);
+  // fold (zext (load x)) -> (zext (truncate (zextload x)))
+  if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse()) {
+    SDOperand ExtLoad = DAG.getExtLoad(ISD::ZEXTLOAD, VT, N0.getOperand(0),
+                                       N0.getOperand(1), N0.getOperand(2),
+                                       N0.getValueType());
+    WorkList.push_back(N);
+    CombineTo(N0.Val, DAG.getNode(ISD::TRUNCATE, N0.getValueType(), ExtLoad),
+              ExtLoad.getValue(1));
+    return SDOperand();
+  }
   return SDOperand();
 }
 



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