Note ARM constant island alignment in the release notes.

The command line option should be removed, but not until the feature has
gotten a lot of testing. The ARMConstantIslandPass tends to have subtle
bugs that only show up after a while.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146739 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMConstantIslandPass.cpp

@@ -52,6 +52,7 @@ static cl::opt<bool>
 AdjustJumpTableBlocks("arm-adjust-jump-tables", cl::Hidden, cl::init(true),
           cl::desc("Adjust basic block layout to better use TB[BH]"));
 
+// FIXME: This option should be removed once it has received sufficient testing.
 static cl::opt<bool>
 AlignConstantIslands("arm-align-constant-islands", cl::Hidden, cl::init(true),
           cl::desc("Align constant islands in code"));