The point of a constexpr if statement is to determine which branch to
take at compile time, so warning on unreachable code is meaningless in
these situations.
Fixes #57123.
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D131818
if (isa<BinaryOperator>(Term)) {
return isConfigurationValue(Term, PP);
}
+ // Do not treat constexpr if statement successors as unreachable in warnings
+ // since the point of these statements is to determine branches at compile
+ // time.
+ if (const auto *IS = dyn_cast<IfStmt>(Term);
+ IS != nullptr && IS->isConstexpr())
+ return true;
}
const Stmt *Cond = B->getTerminatorCondition(/* stripParens */ false);
-// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only -Wunreachable-code-aggressive -fblocks -verify %s
+// RUN: %clang_cc1 -std=c++17 -fcxx-exceptions -fexceptions -fsyntax-only -Wunreachable-code-aggressive -fblocks -verify %s
int j;
int bar();
}
}
+
+namespace gh57123 {
+ bool foo() {
+ if constexpr (true) {
+ if (true)
+ return true;
+ else
+ return false; // expected-warning {{will never be executed}}
+ }
+ else
+ return false; // no-warning
+ }
+
+ bool bar() {
+ if (true)
+ return true;
+ else
+ return false; // expected-warning {{will never be executed}}
+ }
+
+ bool baz() {
+ if constexpr (true)
+ return true;
+ else {
+ if (true)
+ return true;
+ else
+ return false; // expected-warning {{will never be executed}}
+ }
+ }
+}