[analyzer] Don't attempt to create a floating-point value of "1" for ++/--.

The current logic would actually create a float- or double-sized signed
integer value of 1, which is not at all the same.

No test because the value would be swallowed by an Unknown as soon as it
gets added or subtracted to the original value, but it enables the cleanup
in the next patch.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163068 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Core/ExprEngineC.cpp b/lib/StaticAnalyzer/Core/ExprEngineC.cpp
index 8881f26..3bf16fa 100644
--- a/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -857,8 +857,10 @@
     
     if (U->getType()->isAnyPointerType())
       RHS = svalBuilder.makeArrayIndex(1);
-    else
+    else if (U->getType()->isIntegralOrEnumerationType())
       RHS = svalBuilder.makeIntVal(1, U->getType());
+    else
+      RHS = UnknownVal();
     
     SVal Result = evalBinOp(state, Op, V2, RHS, U->getType());