From 8cd08bf4ac67b9d711fd1f72e6f5e00425d8c6ad Mon Sep 17 00:00:00 2001
From: James Molloy <james.molloy@arm.com>
Date: Mon, 10 Sep 2012 14:01:21 +0000
Subject: [PATCH] Fix an assertion failure when optimising a shufflevector
 incorrectly into concat_vectors, and a followup bug with
 SelectionDAG::getNode() creating nodes with invalid types.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163511 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/DAGCombiner.cpp  |  6 ++++++
 lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 16 ++++++----------
 test/CodeGen/ARM/crash-shufflevector.ll   | 10 ++++++++++
 3 files changed, 22 insertions(+), 10 deletions(-)
 create mode 100644 test/CodeGen/ARM/crash-shufflevector.ll

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 4caafa5b574..d7fa00962a6 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -8095,6 +8095,12 @@ SDValue DAGCombiner::visitBUILD_VECTOR(SDNode *N) {
       if (VecIn1.getValueType().getSizeInBits()*2 != VT.getSizeInBits())
         return SDValue();
 
+      // If the input vector type has a different base type to the output
+      // vector type, bail out.
+      if (VecIn1.getValueType().getVectorElementType() !=
+          VT.getVectorElementType())
+        return SDValue();
+
       // Widen the input vector by adding undef values.
       VecIn1 = DAG.getNode(ISD::CONCAT_VECTORS, N->getDebugLoc(), VT,
                            VecIn1, DAG.getUNDEF(VecIn1.getValueType()));
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 928385a0ad1..a2265c23a5d 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2934,17 +2934,13 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, EVT VT,
     // expanding large vector constants.
     if (N2C && N1.getOpcode() == ISD::BUILD_VECTOR) {
       SDValue Elt = N1.getOperand(N2C->getZExtValue());
-      EVT VEltTy = N1.getValueType().getVectorElementType();
-      if (Elt.getValueType() != VEltTy) {
+
+      if (VT != Elt.getValueType())
         // If the vector element type is not legal, the BUILD_VECTOR operands
-        // are promoted and implicitly truncated.  Make that explicit here.
-        Elt = getNode(ISD::TRUNCATE, DL, VEltTy, Elt);
-      }
-      if (VT != VEltTy) {
-        // If the vector element type is not legal, the EXTRACT_VECTOR_ELT
-        // result is implicitly extended.
-        Elt = getNode(ISD::ANY_EXTEND, DL, VT, Elt);
-      }
+        // are promoted and implicitly truncated, and the result implicitly
+        // extended. Make that explicit here.
+        Elt = getAnyExtOrTrunc(Elt, DL, VT);
+      
       return Elt;
     }
 
diff --git a/test/CodeGen/ARM/crash-shufflevector.ll b/test/CodeGen/ARM/crash-shufflevector.ll
new file mode 100644
index 00000000000..bdc0e0ea4db
--- /dev/null
+++ b/test/CodeGen/ARM/crash-shufflevector.ll
@@ -0,0 +1,10 @@
+; RUN: llc < %s -mtriple=armv7
+
+declare void @g(<16 x i8>)
+define void @f(<4 x i8> %param1, <4 x i8> %param2) {
+   %y1 = shufflevector <4 x i8> %param1, <4 x i8> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+   %y2 = shufflevector <4 x i8> %param2, <4 x i8> undef, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+   %z = shufflevector <16 x i8> %y1, <16 x i8> %y2, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 16, i32 17, i32 18, i32 19>
+   call void @g(<16 x i8> %z)
+   ret void
+}
\ No newline at end of file
-- 
2.34.1