Change inferred cast creation calls to more specific cast creations.

llvm-svn: 32460
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 4d5d3da..4cbc9fe 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -790,7 +790,7 @@
           // Only do this if the target has a native EXTLOAD instruction from
           // f32.
           TLI.isLoadXLegal(ISD::EXTLOAD, MVT::f32)) {
-        LLVMC = cast<ConstantFP>(ConstantExpr::getCast(LLVMC, Type::FloatTy));
+        LLVMC = cast<ConstantFP>(ConstantExpr::getFPCast(LLVMC, Type::FloatTy));
         VT = MVT::f32;
         Extend = true;
       }