Improve unreachable code warnings for with respect to c-style casts.

llvm-svn: 94094

clang/lib/Sema/SemaChecking.cpp

@@ -2116,6 +2116,11 @@ static SourceLocation GetUnreachableLoc(CFGBlock &b, SourceRange &R1,
     const ConditionalOperator *CO = cast<ConditionalOperator>(S);
     return CO->getQuestionLoc();
   }
+  case Expr::CStyleCastExprClass: {
+    const CStyleCastExpr *CSC = cast<CStyleCastExpr>(S);
+    R1 = CSC->getSubExpr()->getSourceRange();
+    return CSC->getLParenLoc();
+  }
   case Expr::ImplicitCastExprClass:
     ++sn;
     goto top;

clang/test/Sema/warn-unreachable.c

@@ -87,5 +87,8 @@ void test2() {
     halt()
       ?         // expected-warning {{will never be executed}}
       dead() : dead();
+  case 10:
+    (           // expected-warning {{will never be executed}}
+      float)halt();
   }
 }