Change how FP immediates are handled.

1) ConstantFP is now expand by default
2) ConstantFP is not turned into TargetConstantFP during Legalize
   if it is legal.

This allows ConstantFP to be handled like Constant, allowing for 
targets that can encode FP immediates as MachineOperands.

As a bonus, fix up Itanium FP constants, which now correctly match,
and match more constants!  Hooray.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47121 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/ScheduleDAG.h

@@ -272,6 +272,7 @@ namespace llvm {
     ///
     static bool isPassiveNode(SDNode *Node) {
       if (isa<ConstantSDNode>(Node))       return true;
+      if (isa<ConstantFPSDNode>(Node))     return true;
       if (isa<RegisterSDNode>(Node))       return true;
       if (isa<GlobalAddressSDNode>(Node))  return true;
       if (isa<BasicBlockSDNode>(Node))     return true;