1 files changed, 12 insertions, 2 deletions

diff --git a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
index 892e713d241f..ccd8e9a18b00 100644
--- a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
+++ b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UnreachableCodeChecker.cpp
@@ -147,6 +147,14 @@ void UnreachableCodeChecker::checkEndAnalysis(ExplodedGraph &G,
     PathDiagnosticLocation DL;
     SourceLocation SL;
     if (const Stmt *S = getUnreachableStmt(CB)) {
+      // In macros, 'do {...} while (0)' is often used. Don't warn about the
+      // condition 0 when it is unreachable.
+      if (S->getLocStart().isMacroID())
+        if (const auto *I = dyn_cast<IntegerLiteral>(S))
+          if (I->getValue() == 0ULL)
+            if (const Stmt *Parent = PM->getParent(S))
+              if (isa<DoStmt>(Parent))
+                continue;
       SR = S->getSourceRange();
       DL = PathDiagnosticLocation::createBegin(S, B.getSourceManager(), LC);
       SL = DL.asLocation();
@@ -191,8 +199,10 @@ void UnreachableCodeChecker::FindUnreachableEntryPoints(const CFGBlock *CB,
 // Find the Stmt* in a CFGBlock for reporting a warning
 const Stmt *UnreachableCodeChecker::getUnreachableStmt(const CFGBlock *CB) {
   for (CFGBlock::const_iterator I = CB->begin(), E = CB->end(); I != E; ++I) {
-    if (Optional<CFGStmt> S = I->getAs<CFGStmt>())
-      return S->getStmt();
+    if (Optional<CFGStmt> S = I->getAs<CFGStmt>()) {
+      if (!isa<DeclStmt>(S->getStmt()))
+        return S->getStmt();
+    }
   }
   if (const Stmt *S = CB->getTerminator())
     return S;