[cfe-commits] r127727 - in /cfe/trunk: lib/Analysis/CFG.cpp test/SemaCXX/array-bounds.cpp

[Ted Kremenek]

Author: kremenek
Date: Tue Mar 15 23:32:01 2011
New Revision: 127727

URL: http://llvm.org/viewvc/llvm-project?rev=127727&view=rev
Log:
Teach CFGBuilder that the 'default' branch of a switch statement is dead if all enum values in a switch conditioned are handled.

Modified:
    cfe/trunk/lib/Analysis/CFG.cpp
    cfe/trunk/test/SemaCXX/array-bounds.cpp

Modified: cfe/trunk/lib/Analysis/CFG.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Analysis/CFG.cpp?rev=127727&r1=127726&r2=127727&view=diff
==============================================================================
--- cfe/trunk/lib/Analysis/CFG.cpp (original)
+++ cfe/trunk/lib/Analysis/CFG.cpp Tue Mar 15 23:32:01 2011
@@ -2249,9 +2249,11 @@
   }
 
   // If we have no "default:" case, the default transition is to the code
-  // following the switch body.
+  // following the switch body.  Moreover, take into account if all the
+  // cases of a switch are covered (e.g., switching on an enum value).
   addSuccessor(SwitchTerminatedBlock,
-               switchExclusivelyCovered ? 0 : DefaultCaseBlock);
+               switchExclusivelyCovered || Terminator->isAllEnumCasesCovered()
+               ? 0 : DefaultCaseBlock);
 
   // Add the terminator and condition in the switch block.
   SwitchTerminatedBlock->setTerminator(Terminator);

Modified: cfe/trunk/test/SemaCXX/array-bounds.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/array-bounds.cpp?rev=127727&r1=127726&r2=127727&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/array-bounds.cpp (original)
+++ cfe/trunk/test/SemaCXX/array-bounds.cpp Tue Mar 15 23:32:01 2011
@@ -160,3 +160,16 @@
   }
 }
 
+// Test that if all the values of an enum covered, that the 'default' branch
+// is unreachable.
+enum Values { A, B, C, D };
+void test_all_enums_covered(enum Values v) {
+  int x[2];
+  switch (v) {
+  case A: return;
+  case B: return;
+  case C: return;
+  case D: return;
+  }
+  x[2] = 0; // no-warning
+}