r202349 - [-Wunreachable-code] Don't warn about unreachable 'default:' cases.

[Ted Kremenek]

Author: kremenek
Date: Wed Feb 26 23:42:07 2014
New Revision: 202349

URL: http://llvm.org/viewvc/llvm-project?rev=202349&view=rev
Log:
[-Wunreachable-code] Don't warn about unreachable 'default:' cases.

They are covered by -Wcovered-switch-default.

Modified:
    cfe/trunk/lib/Analysis/ReachableCode.cpp
    cfe/trunk/test/Sema/warn-unreachable.c

Modified: cfe/trunk/lib/Analysis/ReachableCode.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/ReachableCode.cpp?rev=202349&r1=202348&r2=202349&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/ReachableCode.cpp (original)
+++ cfe/trunk/lib/Analysis/ReachableCode.cpp Wed Feb 26 23:42:07 2014
@@ -284,6 +284,12 @@ void DeadCodeScan::reportDeadCode(const
   if (isBreakPrecededByNoReturn(B, S))
     return;
 
+  // Was this an unreachable 'default' case?  Such cases are covered
+  // by -Wcovered-switch-default, if the user so desires.
+  const Stmt *Label = B->getLabel();
+  if (Label && isa<DefaultStmt>(Label))
+    return;
+
   SourceRange R1, R2;
   SourceLocation Loc = GetUnreachableLoc(S, R1, R2);
   CB.HandleUnreachable(Loc, R1, R2);

Modified: cfe/trunk/test/Sema/warn-unreachable.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/warn-unreachable.c?rev=202349&r1=202348&r2=202349&view=diff
==============================================================================
--- cfe/trunk/test/Sema/warn-unreachable.c (original)
+++ cfe/trunk/test/Sema/warn-unreachable.c Wed Feb 26 23:42:07 2014
@@ -109,7 +109,7 @@ int test_enum_cases(enum Cases C) {
     case C3:
       return 1;
     default: {
-      int i = 0; // expected-warning{{will never be executed}}
+      int i = 0; // no-warning
       ++i;
       return i;
     }
@@ -164,3 +164,26 @@ int test_break_preceded_by_noreturn(int
   }
   return i;
 }
+
+// Don't warn about unreachable 'default' cases, as that is covered
+// by -Wcovered-switch-default.
+typedef enum { Value1 = 1 } MyEnum;
+void unreachable_default(MyEnum e) {
+  switch (e) {
+    case Value1:
+    calledFun();
+    break;
+  default:
+    calledFun(); // no-warning
+    break;
+  }
+}
+void unreachable_in_default(MyEnum e) {
+  switch (e) {
+  default:
+    raze();
+    calledFun(); // expected-warning {{will never be executed}}
+    break;
+  }
+}
+