Fix a crasher trying to fold each element in a comparison between two vectors

if one of the vectors didn't have elements (such as undef). Fixes PR 6096.

Fix an issue in the constant folder where fcmp (<2 x %ty>, <2 x %ty>) would
have <2 x i1> type if constant folding was successful and i1 type if it wasn't.
This exposed a related issue in the bitcode reader.

llvm-svn: 94069

llvm/lib/Bitcode/Reader/BitcodeReader.cpp

@@ -1167,7 +1167,7 @@ bool BitcodeReader::ParseConstants() {
       Constant *Op0 = ValueList.getConstantFwdRef(Record[1], OpTy);
       Constant *Op1 = ValueList.getConstantFwdRef(Record[2], OpTy);
 
-      if (OpTy->isFloatingPoint())
+      if (OpTy->isFPOrFPVector())
         V = ConstantExpr::getFCmp(Record[3], Op0, Op1);
       else
         V = ConstantExpr::getICmp(Record[3], Op0, Op1);