Eliminate some false positives due to a thinko in the "'blah' is

always zero in this context" warning logic. Also, make the diagnostic
itself more precise when referring to pointer values ("NULL" vs. "zero").

llvm-svn: 86143

1 files changed, 7 insertions, 11 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index f1d6f2bb17c..f94017129b0 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -814,22 +814,18 @@ Sema::ActOnDeclarationNameExpr(Scope *S, SourceLocation Loc,
     // information to check this property.
     if (Var->isDeclaredInCondition() && Var->getType()->isScalarType()) {
       Scope *CheckS = S;
-      while (CheckS) {
+      while (CheckS && CheckS->getControlParent()) {
         if (CheckS->isWithinElse() &&
             CheckS->getControlParent()->isDeclScope(DeclPtrTy::make(Var))) {
-          if (Var->getType()->isBooleanType())
-            ExprError(Diag(Loc, diag::warn_value_always_false)
-                      << Var->getDeclName());
-          else
-            ExprError(Diag(Loc, diag::warn_value_always_zero)
-                      << Var->getDeclName());
+          ExprError(Diag(Loc, diag::warn_value_always_zero)
+            << Var->getDeclName()
+            << (Var->getType()->isPointerType()? 2 :
+                Var->getType()->isBooleanType()? 1 : 0));
           break;
         }
 
-        // Move up one more control parent to check again.
-        CheckS = CheckS->getControlParent();
-        if (CheckS)
-          CheckS = CheckS->getParent();
+        // Move to the parent of this scope.
+        CheckS = CheckS->getParent();
       }
     }
   } else if (FunctionDecl *Func = dyn_cast<FunctionDecl>(D)) {