r175425 - Disable dead stores checker for template instantations. Fixes <rdar://problem/13213575>.

[Ted Kremenek]

Author: kremenek
Date: Mon Feb 18 01:18:28 2013
New Revision: 175425

URL: http://llvm.org/viewvc/llvm-project?rev=175425&view=rev
Log:
Disable dead stores checker for template instantations.  Fixes <rdar://problem/13213575>.

Modified:
    cfe/trunk/lib/StaticAnalyzer/Checkers/DeadStoresChecker.cpp
    cfe/trunk/test/Analysis/dead-stores.cpp

Modified: cfe/trunk/lib/StaticAnalyzer/Checkers/DeadStoresChecker.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Checkers/DeadStoresChecker.cpp?rev=175425&r1=175424&r2=175425&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/DeadStoresChecker.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/DeadStoresChecker.cpp Mon Feb 18 01:18:28 2013
@@ -419,6 +419,15 @@ class DeadStoresChecker : public Checker
 public:
   void checkASTCodeBody(const Decl *D, AnalysisManager& mgr,
                         BugReporter &BR) const {
+
+    // Don't do anything for template instantiations.
+    // Proving that code in a template instantiation is "dead"
+    // means proving that it is dead in all instantiations.
+    // This same problem exists with -Wunreachable-code.
+    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
+      if (FD->isTemplateInstantiation())
+        return;
+
     if (LiveVariables *L = mgr.getAnalysis<LiveVariables>(D)) {
       CFG &cfg = *mgr.getCFG(D);
       AnalysisDeclContext *AC = mgr.getAnalysisDeclContext(D);

Modified: cfe/trunk/test/Analysis/dead-stores.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/dead-stores.cpp?rev=175425&r1=175424&r2=175425&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/dead-stores.cpp (original)
+++ cfe/trunk/test/Analysis/dead-stores.cpp Mon Feb 18 01:18:28 2013
@@ -156,3 +156,21 @@ void testCXX11Using() {
   Int value;
   value = 1; // expected-warning {{never read}}
 }
+
+//===----------------------------------------------------------------------===//
+// Dead stores in template instantiations (do not warn).
+//===----------------------------------------------------------------------===//
+
+template <bool f> int radar13213575_testit(int i) {
+  int x = 5+i; // warning: Value stored to 'x' during its initialization is never read
+  int y = 7;
+  if (f)
+    return x;
+  else
+    return y;
+}
+
+int radar_13213575() {
+  return radar13213575_testit<true>(5) + radar13213575_testit<false>(3);
+}
+