[-Wunreachable-code] Tweak isTrivialDoWhile() to handle implicit casts.

llvm-svn: 204376

2 files changed, 9 insertions, 1 deletions

diff --git a/clang/lib/Analysis/ReachableCode.cpp b/clang/lib/Analysis/ReachableCode.cpp
index 0a9e82bb0ad..4220000cd33 100644
--- a/clang/lib/Analysis/ReachableCode.cpp
+++ b/clang/lib/Analysis/ReachableCode.cpp
@@ -51,7 +51,7 @@ static bool isTrivialDoWhile(const CFGBlock *B, const Stmt *S) {
   // condition.
   if (const Stmt *Term = B->getTerminator()) {
     if (const DoStmt *DS = dyn_cast<DoStmt>(Term)) {
-      const Expr *Cond = DS->getCond();
+      const Expr *Cond = DS->getCond()->IgnoreParenCasts();
       return Cond == S && isTrivialExpression(Cond);
     }
   }
diff --git a/clang/test/SemaCXX/warn-unreachable.cpp b/clang/test/SemaCXX/warn-unreachable.cpp
index 7f74732a630..eab8d8e6b97 100644
--- a/clang/test/SemaCXX/warn-unreachable.cpp
+++ b/clang/test/SemaCXX/warn-unreachable.cpp
@@ -218,6 +218,14 @@ int test_treat_non_const_bool_local_as_non_config_value() {
   return 0;
 }
 
+void test_do_while(int x) {
+  // Handle trivial expressions with
+  // implicit casts to bool.
+  do {
+    break;
+  } while (0); // no-warning
+}
+
 class Frobozz {
 public:
   Frobozz(int x);