From 8a7f7426eeb18fef58c3471db23fc829b67bc350 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Fri, 18 Jun 2010 01:05:21 +0000
Subject: Fold the ShrinkDemandedOps pass into the regular DAGCombiner pass,
 which is faster, simpler, and less surprising.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106263 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'lib/CodeGen/SelectionDAG/SelectionDAG.cpp')

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 49f3101..ca3746c 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2474,10 +2474,18 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL,
             VT.getVectorNumElements() ==
             Operand.getValueType().getVectorNumElements()) &&
            "Vector element count mismatch!");
+
     if (OpOpcode == ISD::ZERO_EXTEND || OpOpcode == ISD::SIGN_EXTEND ||
         OpOpcode == ISD::ANY_EXTEND)
       // (ext (zext x)) -> (zext x)  and  (ext (sext x)) -> (sext x)
       return getNode(OpOpcode, DL, VT, Operand.getNode()->getOperand(0));
+
+    // (ext (trunx x)) -> x
+    if (OpOpcode == ISD::TRUNCATE) {
+      SDValue OpOp = Operand.getNode()->getOperand(0);
+      if (OpOp.getValueType() == VT)
+        return OpOp;
+    }
     break;
   case ISD::TRUNCATE:
     assert(VT.isInteger() && Operand.getValueType().isInteger() &&
-- 
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