Revert changes made by r290413 until regression is fixed.

llvm-svn: 290415

1 files changed, 17 insertions, 7 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
index 3e6343813ec..f1238f6d357 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp
@@ -665,13 +665,23 @@ void ExprEngine::VisitLogicalExpr(const BinaryOperator* B, ExplodedNode *Pred,
     if (RHSVal.isUndef()) {
       X = RHSVal;
     } else {
-      // We evaluate "RHSVal != 0" expression which result in 0 if the value is
-      // known to be false, 1 if the value is known to be true and a new symbol
-      // when the assumption is unknown.
-      nonloc::ConcreteInt Zero(getBasicVals().getValue(0, B->getType()));
-      X = evalBinOp(N->getState(), BO_NE, 
-                    svalBuilder.evalCast(RHSVal, B->getType(), RHS->getType()),
-                    Zero, B->getType());
+      DefinedOrUnknownSVal DefinedRHS = RHSVal.castAs<DefinedOrUnknownSVal>();
+      ProgramStateRef StTrue, StFalse;
+      std::tie(StTrue, StFalse) = N->getState()->assume(DefinedRHS);
+      if (StTrue) {
+        if (StFalse) {
+          // We can't constrain the value to 0 or 1.
+          // The best we can do is a cast.
+          X = getSValBuilder().evalCast(RHSVal, B->getType(), RHS->getType());
+        } else {
+          // The value is known to be true.
+          X = getSValBuilder().makeIntVal(1, B->getType());
+        }
+      } else {
+        // The value is known to be false.
+        assert(StFalse && "Infeasible path!");
+        X = getSValBuilder().makeIntVal(0, B->getType());
+      }
     }
   }
   Bldr.generateNode(B, Pred, state->BindExpr(B, Pred->getLocationContext(), X));