[llvm-commits] [llvm] r109519 - in /llvm/trunk: lib/CodeGen/SelectionDAG/DAGCombiner.cpp test/CodeGen/Generic/2010-07-27-DAGCombineCrash.ll

[Nate Begeman]

Author: sampo
Date: Tue Jul 27 13:02:18 2010
New Revision: 109519

URL: http://llvm.org/viewvc/llvm-project?rev=109519&view=rev
Log:
Fix a crash in the dag combiner caused by ConstantFoldBIT_CONVERTofBUILD_VECTOR calling itself
recursively and returning a SCALAR_TO_VECTOR node, but assuming the input was always a BUILD_VECTOR.

Added:
    llvm/trunk/test/CodeGen/Generic/2010-07-27-DAGCombineCrash.ll
Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=109519&r1=109518&r2=109519&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Tue Jul 27 13:02:18 2010
@@ -4489,6 +4489,16 @@
   // If this is a conversion of N elements of one type to N elements of another
   // type, convert each element.  This handles FP<->INT cases.
   if (SrcBitSize == DstBitSize) {
+    EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT,
+                              BV->getValueType(0).getVectorNumElements());
+
+    // Due to the FP element handling below calling this routine recursively,
+    // we can end up with a scalar-to-vector node here.
+    if (BV->getOpcode() == ISD::SCALAR_TO_VECTOR)
+      return DAG.getNode(ISD::SCALAR_TO_VECTOR, BV->getDebugLoc(), VT, 
+                         DAG.getNode(ISD::BIT_CONVERT, BV->getDebugLoc(),
+                                     DstEltVT, BV->getOperand(0)));
+      
     SmallVector<SDValue, 8> Ops;
     for (unsigned i = 0, e = BV->getNumOperands(); i != e; ++i) {
       SDValue Op = BV->getOperand(i);
@@ -4500,8 +4510,6 @@
                                 DstEltVT, Op));
       AddToWorkList(Ops.back().getNode());
     }
-    EVT VT = EVT::getVectorVT(*DAG.getContext(), DstEltVT,
-                              BV->getValueType(0).getVectorNumElements());
     return DAG.getNode(ISD::BUILD_VECTOR, BV->getDebugLoc(), VT,
                        &Ops[0], Ops.size());
   }

Added: llvm/trunk/test/CodeGen/Generic/2010-07-27-DAGCombineCrash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/Generic/2010-07-27-DAGCombineCrash.ll?rev=109519&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/Generic/2010-07-27-DAGCombineCrash.ll (added)
+++ llvm/trunk/test/CodeGen/Generic/2010-07-27-DAGCombineCrash.ll Tue Jul 27 13:02:18 2010
@@ -0,0 +1,6 @@
+; RUN: llc < %s
+
+define float @test1()
+{
+	ret float extractelement (<2 x float> bitcast (<1 x double> <double 0x3f800000> to <2 x float>), i32 1);
+}