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.

llvm-svn: 146739

llvm/docs/ReleaseNotes.html

@@ -366,8 +366,8 @@ Release Notes</a>.</h1>
 <p>New features of the ARM target include:</p>
 
 <ul>
-  <li>....</li>
-</ul>
+  <li>The constant island pass now supports basic block and constant pool entry
+  alignments greater than 4 bytes.</li> </ul>
 </div>
 
 

llvm/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"));