GCC 4.6.3 O3 miscompiles on ARM

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176090 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/GettingStarted.rst b/docs/GettingStarted.rst
index 048d4a0..4890de2 100644
--- a/docs/GettingStarted.rst
+++ b/docs/GettingStarted.rst
@@ -362,6 +362,9 @@
 ``-O0``. A test failure in ``test/Assembler/alignstack.ll`` is one symptom of
 the problem.
 
+**GCC 4.6.3 on ARM**: Miscompiles ``llvm-readobj`` at ``-O3``. A test failure
+in ``test/Object/readobj-shared-object.test`` is one symptom of the problem.
+
 **GNU ld 2.16.X**. Some 2.16.X versions of the ld linker will produce very long
 warning messages complaining that some "``.gnu.linkonce.t.*``" symbol was
 defined in a discarded section. You can safely ignore these messages as they are