Improve unreachable code warnings for with respect to compound

assignments.

llvm-svn: 94086

clang/lib/Sema/SemaChecking.cpp

@@ -2102,6 +2102,12 @@ static SourceLocation GetUnreachableLoc(CFGBlock &b, SourceRange &R1,
     R1 = UO->getSubExpr()->getSourceRange();
     return UO->getOperatorLoc();
   }
+  case Expr::CompoundAssignOperatorClass: {
+    const CompoundAssignOperator *CAO = cast<CompoundAssignOperator>(S);
+    R1 = CAO->getLHS()->getSourceRange();
+    R2 = CAO->getRHS()->getSourceRange();
+    return CAO->getOperatorLoc();
+  }
   case Stmt::CXXTryStmtClass: {
     return cast<CXXTryStmt>(S)->getHandler(0)->getCatchLoc();
   }

clang/test/Sema/warn-unreachable.c

@@ -24,6 +24,7 @@ void test1() {
 }
 
 void test2() {
+  int i;
   switch (live()) {
   case 1:
     halt(),
@@ -78,5 +79,9 @@ void test2() {
       dead();
     -           // expected-warning {{will never be executed}}
       halt();
+  case 8:
+    i
+      +=        // expected-warning {{will never be executed}}
+      halt();
   }
 }