[cfe-commits] r110353 - in /cfe/trunk: lib/Checker/UnreachableCodeChecker.cpp test/Analysis/unreachable-code-path.c

[Tom Care]

Author: tcare
Date: Thu Aug  5 12:53:44 2010
New Revision: 110353

URL: http://llvm.org/viewvc/llvm-project?rev=110353&view=rev
Log:
Fixed logic error in UnreachableCodeChecker's marking algorithm that would sometimes allow for multiple sequential statements to be flagged.

Modified:
    cfe/trunk/lib/Checker/UnreachableCodeChecker.cpp
    cfe/trunk/test/Analysis/unreachable-code-path.c

Modified: cfe/trunk/lib/Checker/UnreachableCodeChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Checker/UnreachableCodeChecker.cpp?rev=110353&r1=110352&r2=110353&view=diff
==============================================================================
--- cfe/trunk/lib/Checker/UnreachableCodeChecker.cpp (original)
+++ cfe/trunk/lib/Checker/UnreachableCodeChecker.cpp Thu Aug  5 12:53:44 2010
@@ -149,10 +149,13 @@
   for (CFGBlock::const_pred_iterator I = CB->pred_begin(); I != CB->pred_end();
       ++I) {
     // Recurse over all unreachable blocks
-    if (!reachable.count((*I)->getBlockID())
-        && !visited.count((*I)->getBlockID())) {
-      FindUnreachableEntryPoints(*I);
+    if (!reachable.count((*I)->getBlockID())) {
+      // At least one predeccessor was unreachable
       allPredecessorsReachable = false;
+
+      // Only visit the block once
+      if (!visited.count((*I)->getBlockID()))
+        FindUnreachableEntryPoints(*I);
     }
   }
 

Modified: cfe/trunk/test/Analysis/unreachable-code-path.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/unreachable-code-path.c?rev=110353&r1=110352&r2=110353&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/unreachable-code-path.c (original)
+++ cfe/trunk/test/Analysis/unreachable-code-path.c Thu Aug  5 12:53:44 2010
@@ -88,3 +88,17 @@
   a = 5;
 }
 
+// Check for bugs where multiple statements are reported
+void test9(unsigned a) {
+  switch (a) {
+    if (a) // expected-warning{{never executed}}
+      foo(a + 5); // no-warning
+    else // no-warning
+      foo(a); // no-warning
+    case 1:
+    case 2:
+      break;
+    default:
+      break;
+  }
+}