Update ARM frame index scavenging description
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102101 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html
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@@ -737,8 +737,11 @@
helpful information if migrating code from GCC to LLVM-GCC.</li>
<li>The ARM and Thumb code generators now use register scavenging for stack
- object address materialization.(FIXME: WHAT BENEFIT DOES THIS PROVIDE?)</li>
-
+ object address materialization. This allows the use of R3 as a general
+ purpose register in Thumb1 code, as it was previous reserved for use in
+ stack address materialization. Secondly, sequential uses of the same
+ value will now re-use the materialized constant.</li>
+
<li>The ARM backend now has good support for ARMv4 targets and has been tested
on StrongARM hardware. Previously, LLVM only supported ARMv4T and
newer chips.</li>