Move the warning about unused relational comparison from -Wunused-value to

-Wunused-comparison.  Also, newly warn on unused result from overloaded
relational comparisons, now also in -Wunused-comparison.

llvm-svn: 203535

1 files changed, 11 insertions, 4 deletions

diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 0b8948e5fa4..2f5f14f38e3 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -2064,15 +2064,22 @@ bool Expr::isUnusedResultAWarning(const Expr *&WarnE, SourceLocation &Loc,
     return true;
 
   case CXXOperatorCallExprClass: {
-    // We warn about operator== and operator!= even when user-defined operator
+    // Warn about operator ==,!=,<,>,<=, and >= even when user-defined operator
     // overloads as there is no reasonable way to define these such that they
     // have non-trivial, desirable side-effects. See the -Wunused-comparison
-    // warning: these operators are commonly typo'ed, and so warning on them
+    // warning: operators == and != are commonly typo'ed, and so warning on them
     // provides additional value as well. If this list is updated,
     // DiagnoseUnusedComparison should be as well.
     const CXXOperatorCallExpr *Op = cast<CXXOperatorCallExpr>(this);
-    if (Op->getOperator() == OO_EqualEqual ||
-        Op->getOperator() == OO_ExclaimEqual) {
+    switch (Op->getOperator()) {
+    default:
+      break;
+    case OO_EqualEqual:
+    case OO_ExclaimEqual:
+    case OO_Less:
+    case OO_Greater:
+    case OO_GreaterEqual:
+    case OO_LessEqual:
       WarnE = this;
       Loc = Op->getOperatorLoc();
       R1 = Op->getSourceRange();