r246347 - PR24612: Don't bail out of checking a constexpr function before checking

[Richard Smith via cfe-commits]

Author: rsmith
Date: Fri Aug 28 17:33:53 2015
New Revision: 246347

URL: http://llvm.org/viewvc/llvm-project?rev=246347&view=rev
Log:
PR24612: Don't bail out of checking a constexpr function before checking
whether it can ever produce a constant expression in the case where it has a
void return type and no return statements.

Modified:
    cfe/trunk/lib/Sema/SemaDeclCXX.cpp
    cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp

Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=246347&r1=246346&r2=246347&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Fri Aug 28 17:33:53 2015
@@ -1230,9 +1230,9 @@ bool Sema::CheckConstexprFunctionBody(co
       Diag(Dcl->getLocation(),
            OK ? diag::warn_cxx11_compat_constexpr_body_no_return
               : diag::err_constexpr_body_no_return);
-      return OK;
-    }
-    if (ReturnStmts.size() > 1) {
+      if (!OK)
+        return false;
+    } else if (ReturnStmts.size() > 1) {
       Diag(ReturnStmts.back(),
            getLangOpts().CPlusPlus14
              ? diag::warn_cxx11_compat_constexpr_body_multiple_return

Modified: cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp?rev=246347&r1=246346&r2=246347&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp (original)
+++ cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp Fri Aug 28 17:33:53 2015
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -triple x86_64-unknown-unknown -verify -std=c++11 -fcxx-exceptions %s
+// RUN: %clang_cc1 -fsyntax-only -triple x86_64-unknown-unknown -verify -std=c++14 -fcxx-exceptions %s
 // RUN: %clang_cc1 -fsyntax-only -triple x86_64-unknown-unknown -std=c++11 -fcxx-exceptions -Wno-invalid-constexpr %s -DNO_INVALID_CONSTEXPR
 
 namespace StdExample {
@@ -102,7 +103,10 @@ X x = cmin(X(), X()); // ok, not constex
 template<typename T>
 struct Y {
   constexpr Y() {}
-  constexpr int get() { return T(); } // expected-warning {{C++14}}
+  constexpr int get() { return T(); }
+#if __cplusplus < 201402L
+  // expected-warning at -2 {{C++14}}
+#endif
 };
 struct Z { operator int(); };
 
@@ -118,7 +122,7 @@ namespace PR14550 {
   // marks some functions as constexpr which use builtins which we don't
   // support constant folding). Ensure that we don't mark those functions
   // as invalid after suppressing the diagnostic.
-# 122 "p5.cpp" 1 3
+# 126 "p5.cpp" 1 3
   int n;
   struct A {
     static constexpr int f() { return n; }
@@ -126,7 +130,11 @@ namespace PR14550 {
   template<typename T> struct B {
     B() { g(T::f()); } // expected-error {{undeclared identifier 'g'}}
   };
-# 130 "p5.cpp" 2
+# 134 "p5.cpp" 2
   template class B<A>; // expected-note {{here}}
 }
 #endif
+
+#if __cplusplus >= 201402L
+constexpr void f() { throw; } // expected-error {{never produces}} expected-note {{subexpression}}
+#endif