Fix rdar://8139785 "implement warning on dead expression in comma operator"
As a bonus, fix the warning for || and && operators; it was emitted even if one of the operands had side effects, e.g:
x || test_logical_foo1();
emitted a bogus "expression result unused" for 'x'.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107274 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 4a80686..e84f73a 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -974,7 +974,8 @@
switch (BO->getOpcode()) {
default:
break;
- // Consider ',', '||', '&&' to have side effects if the LHS or RHS does.
+ // Consider the RHS of comma for side effects. LHS was checked by
+ // Sema::CheckCommaOperands.
case BinaryOperator::Comma:
// ((foo = <blah>), 0) is an idiom for hiding the result (and
// lvalue-ness) of an assignment written in a macro.
@@ -982,10 +983,14 @@
dyn_cast<IntegerLiteral>(BO->getRHS()->IgnoreParens()))
if (IE->getValue() == 0)
return false;
+ return BO->getRHS()->isUnusedResultAWarning(Loc, R1, R2, Ctx);
+ // Consider '||', '&&' to have side effects if the LHS or RHS does.
case BinaryOperator::LAnd:
case BinaryOperator::LOr:
- return (BO->getLHS()->isUnusedResultAWarning(Loc, R1, R2, Ctx) ||
- BO->getRHS()->isUnusedResultAWarning(Loc, R1, R2, Ctx));
+ if (!BO->getLHS()->isUnusedResultAWarning(Loc, R1, R2, Ctx) ||
+ !BO->getRHS()->isUnusedResultAWarning(Loc, R1, R2, Ctx))
+ return false;
+ break;
}
if (BO->isAssignmentOp())
return false;