Don't load values out of global constants with weak

linkage: the value may be replaced with something
different at link time.  (Frontends that want to
allow values to be loaded out of weak constants can
give their constants weak_odr linkage).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67407 91177308-0d34-0410-b5e6-96231b3b80d8

test/FrontendC/weak_constant.c

@@ -0,0 +1,12 @@
+// RUN: %llvmgcc -S %s -O1 -o - | grep {ret.*123}
+// Check for bug compatibility with gcc.
+
+const int x __attribute((weak)) = 123;
+
+int* f(void) {
+  return &x;
+}
+
+int g(void) {
+  return *f();
+}