Fix false negative in -Wuninitialized involving a () wrapping an lvalue-to-rvalue conversion in a DeclStmt.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@135525 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 13 insertions, 8 deletions

diff --git a/lib/Analysis/UninitializedValues.cpp b/lib/Analysis/UninitializedValues.cpp
index a64c1db530..b84b4309d9 100644
--- a/lib/Analysis/UninitializedValues.cpp
+++ b/lib/Analysis/UninitializedValues.cpp
@@ -464,14 +464,19 @@ void TransferFunctions::VisitDeclStmt(DeclStmt *ds) {
           if (init == lastLoad) {
             DeclRefExpr *DR =
               cast<DeclRefExpr>(lastLoad->getSubExpr()->IgnoreParens());
-            vals[vd] = (DR->getDecl() == vd) ? Uninitialized : Initialized;
-            lastLoad = 0;
-            if (lastDR == DR)
+            if (DR->getDecl() == vd) {
+              // int x = x;
+              // Propagate uninitialized value, but don't immediately report
+              // a problem.
+              vals[vd] = Uninitialized;
+              lastLoad = 0;
               lastDR = 0;
+              return;
+            }
           }
-          else {
-            vals[vd] = Initialized;
-          }
+
+          // All other cases: treat the new variable as initialized.
+          vals[vd] = Initialized;
         }
       }
     }
diff --git a/test/Sema/uninit-variables.c b/test/Sema/uninit-variables.c
index 6c3c7c71c8..914156da8b 100644
--- a/test/Sema/uninit-variables.c
+++ b/test/Sema/uninit-variables.c
@@ -354,8 +354,8 @@ int test52(int a, int b) {
 }
 
 void test53() {
-  int x;
-  int y = (x);
+  int x; // expected-note {{variable 'x' is declared here}} expected-note {{add initialization to silence this warning}}
+  int y = (x);  // expected-warning {{variable 'x' is uninitialized when used here}}
 }
 
 // This CFG caused the uninitialized values warning to inf-loop.