fixes a problem caused by gcc 4.6 optimization (by Paul Pluzhnikov)

include/gtest/internal/gtest-port.h

@@ -662,6 +662,13 @@
 # define GTEST_API_
 #endif
 
+#if defined(__GNUC__)
+// Ask the compiler to never inline a given function.
+#define GTEST_NO_INLINE_ __attribute__((noinline))
+#else
+#define GTEST_NO_INLINE_
+#endif  // __GNUC__
+
 namespace testing {
 
 class Message;

src/gtest-death-test.cc

@@ -932,6 +932,11 @@ static int ExecDeathTestChildMain(void* child_arg) {
 // This could be accomplished more elegantly by a single recursive
 // function, but we want to guard against the unlikely possibility of
 // a smart compiler optimizing the recursion away.
+//
+// GTEST_NO_INLINE_ is required to prevent GCC 4.6 from inlining
+// StackLowerThanAddress into StackGrowsDown, which then doesn't give
+// correct answer.
+bool StackLowerThanAddress(const void* ptr) GTEST_NO_INLINE_;
 bool StackLowerThanAddress(const void* ptr) {
   int dummy;
   return &dummy < ptr;