Fix -Wlogical-not-parentheses to work better with C code.

Remove the assumption of a Boolean type by checking if an expression is known
to have a boolean value.  Disable warning in two other tests.

llvm-svn: 245507

1 files changed, 2 insertions, 5 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 0d3913448f3..76b9aecdac8 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -8374,19 +8374,16 @@ static void diagnoseLogicalNotOnLHSofComparison(Sema &S, ExprResult &LHS,
                                                 ExprResult &RHS,
                                                 SourceLocation Loc,
                                                 unsigned OpaqueOpc) {
-  // This checking requires bools.
-  if (!S.getLangOpts().Bool) return;
-
   // Check that left hand side is !something.
   UnaryOperator *UO = dyn_cast<UnaryOperator>(LHS.get()->IgnoreImpCasts());
   if (!UO || UO->getOpcode() != UO_LNot) return;
 
   // Only check if the right hand side is non-bool arithmetic type.
-  if (RHS.get()->getType()->isBooleanType()) return;
+  if (RHS.get()->isKnownToHaveBooleanValue()) return;
 
   // Make sure that the something in !something is not bool.
   Expr *SubExpr = UO->getSubExpr()->IgnoreImpCasts();
-  if (SubExpr->getType()->isBooleanType()) return;
+  if (SubExpr->isKnownToHaveBooleanValue()) return;
 
   // Emit warning.
   S.Diag(UO->getOperatorLoc(), diag::warn_logical_not_on_lhs_of_comparison)