-Wuninitialized: Split the classification of DeclRefExprs as initialization or

use out of TransferFunctions, and compute it in advance rather than on-the-fly.

This allows us to handle compound assignments with DeclRefExprs on the RHS
correctly, and also makes it trivial to treat const& function parameters as not
initializing the argument. The patch also makes both of those changes.

llvm-svn: 160330

2 files changed, 21 insertions, 2 deletions

diff --git a/clang/test/Sema/uninit-variables.c b/clang/test/Sema/uninit-variables.c
index 2630b70ec08..4e3d74b3eaf 100644
--- a/clang/test/Sema/uninit-variables.c
+++ b/clang/test/Sema/uninit-variables.c
@@ -33,8 +33,8 @@ int test5() {
 
 int test6() {
   int x; // expected-note{{initialize the variable 'x' to silence this warning}}
-  x += 2; // expected-warning{{variable 'x' is uninitialized when used here}}
-  return x;
+  x += 2;
+  return x; // expected-warning{{variable 'x' is uninitialized when used here}}
 }
 
 int test7(int y) {
@@ -485,3 +485,16 @@ int returns_twice() {
   }
   return a;
 }
+
+int compound_assign(int *arr, int n) {
+  int sum; // expected-note {{initialize}}
+  for (int i = 0; i < n; ++i)
+    sum += arr[i];
+  return sum / n; // expected-warning {{variable 'sum' is uninitialized}}
+}
+
+void compound_assign_2(int n) {
+  volatile int ignore;
+  for (int j = 0; j < n; ++j)
+    ignore += test1(); // ok
+}
diff --git a/clang/test/SemaCXX/uninit-variables.cpp b/clang/test/SemaCXX/uninit-variables.cpp
index eb6428d631f..687bfd2638d 100644
--- a/clang/test/SemaCXX/uninit-variables.cpp
+++ b/clang/test/SemaCXX/uninit-variables.cpp
@@ -141,3 +141,9 @@ void test_bitcasts_2() {
   int y = (float &)x; // expected-warning {{uninitialized when used here}}
 }
 
+void consume_const_ref(const int &n);
+int test_const_ref() {
+  int n; // expected-note {{variable}}
+  consume_const_ref(n);
+  return n; // expected-warning {{uninitialized when used here}}
+}