[-Wunreachable-code] constexpr functions can be used as configuration…

… values. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@204308 91177308-0d34-0410-b5e6-96231b3b80d8
augmify · Mar 20, 2014 · b17a3aa · b17a3aa
1 parent a80944a
commit b17a3aa
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Showing 2 changed files with 27 additions and 1 deletion.
diff --git a/lib/Analysis/ReachableCode.cpp b/lib/Analysis/ReachableCode.cpp
@@ -139,6 +139,11 @@ static bool isConfigurationValue(const Stmt *S,
     S = Ex->IgnoreParenCasts();
 
   switch (S->getStmtClass()) {
+    case Stmt::CallExprClass: {
+      const FunctionDecl *Callee =
+        dyn_cast_or_null<FunctionDecl>(cast<CallExpr>(S)->getCalleeDecl());
+      return Callee ? Callee->isConstexpr() : false;
+    }
     case Stmt::DeclRefExprClass: {
       const DeclRefExpr *DR = cast<DeclRefExpr>(S);
       const ValueDecl *D = DR->getDecl();

diff --git a/test/SemaCXX/warn-unreachable.cpp b/test/SemaCXX/warn-unreachable.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 %s -fcxx-exceptions -fexceptions -fsyntax-only -verify -fblocks -Wunreachable-code-aggressive -Wno-unused-value
+// RUN: %clang_cc1 %s -fcxx-exceptions -fexceptions -fsyntax-only -verify -fblocks -std=c++11 -Wunreachable-code-aggressive -Wno-unused-value
 
 int &halt() __attribute__((noreturn));
 int &live();
@@ -234,3 +234,24 @@ Frobozz test_return_object_control_flow(int flag) {
   return Frobozz(flag ? 42 : 24); // expected-warning {{code will never be executed}}
 }
 
+void somethingToCall();
+
+ static constexpr bool isConstExprConfigValue() { return true; }
+
+ int test_const_expr_config_value() {
+   if (isConstExprConfigValue()) {
+     somethingToCall();
+     return 0;
+   }
+   somethingToCall(); // no-warning
+   return 1;
+ }
+ int test_const_expr_config_value_2() {
+   if (!isConstExprConfigValue()) {
+     somethingToCall(); // no-warning
+     return 0;
+   }
+   somethingToCall();
+   return 1;
+ }
+