From c6654ec498698919ae8388c53fe91d0366ac24c7 Mon Sep 17 00:00:00 2001
From: Mon P Wang <wangmp@apple.com>
Date: Mon, 1 Feb 2010 19:03:18 +0000
Subject: [PATCH] Fixed a couple of optimization with EXTRACT_VECTOR_ELT that
 assumes the result type is the same as the element type of the vector. 
 EXTRACT_VECTOR_ELT can be used to extended the width of an integer type. 
 This fixes a bug for Generic/vector-casts.ll on a ppc750.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94990 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/DAGCombiner.cpp  | 15 +++++++++++----
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp |  2 +-
 2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 640bdc091ca..6729a93fd71 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5403,12 +5403,19 @@ SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
   SDValue InVec = N->getOperand(0);
 
  if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) {
-   // If the operand is wider than the vector element type then it is implicitly
-   // truncated.  Make that explicit here.
+   // Check if the result type doesn't match the inserted element type. A
+   // SCALAR_TO_VECTOR may truncate the inserted element and the
+   // EXTRACT_VECTOR_ELT may widen the extracted vector.
    EVT EltVT = InVec.getValueType().getVectorElementType();
    SDValue InOp = InVec.getOperand(0);
-   if (InOp.getValueType() != EltVT)
-     return DAG.getNode(ISD::TRUNCATE, InVec.getDebugLoc(), EltVT, InOp);
+   EVT NVT = N->getValueType(0);
+   if (InOp.getValueType() != NVT) {
+     assert(InOp.getValueType().isInteger() && NVT.isInteger());
+     if (NVT.getSizeInBits() > InOp.getValueType().getSizeInBits())
+       return DAG.getNode(ISD::SIGN_EXTEND, InVec.getDebugLoc(), NVT, InOp);
+     else
+       return DAG.getNode(ISD::TRUNCATE, InVec.getDebugLoc(), NVT, InOp);
+   }
    return InOp;
  }
 
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 4f26cdeaeb4..2e92f8f1fd1 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2765,7 +2765,7 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, EVT VT,
     // operations are lowered to scalars.
     if (N1.getOpcode() == ISD::INSERT_VECTOR_ELT) {
       // If the indices are the same, return the inserted element.
-      if (N1.getOperand(2) == N2)
+      if (N1.getOperand(2) == N2 && VT == N1.getOperand(1).getValueType())
         return N1.getOperand(1);
       // If the indices are known different, extract the element from
       // the original vector.
-- 
2.34.1