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
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index f74ea5c..e58c2f7 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -174,6 +174,13 @@
     // These operations default to expand.
     setOperationAction(ISD::FGETSIGN, (MVT::ValueType)VT, Expand);
   }
+  
+  // ConstantFP nodes default to expand.  Targets can either change this to 
+  // Legal, in which case all fp constants are legal, or use addLegalFPImmediate
+  // to optimize expansions for certain constants.
+  setOperationAction(ISD::ConstantFP, MVT::f32, Expand);
+  setOperationAction(ISD::ConstantFP, MVT::f64, Expand);
+  setOperationAction(ISD::ConstantFP, MVT::f80, Expand);
 
   // Default ISD::TRAP to expand (which turns it into abort).
   setOperationAction(ISD::TRAP, MVT::Other, Expand);