New entry.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33569 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/README-Thumb.txt b/lib/Target/ARM/README-Thumb.txt
index e9e943d0ae2a5ca20f4129f60372235a2c662413..c64457fe153d2d816f9d37119f46f3f8e6a1a8c9 100644 (file)
--- a/lib/Target/ARM/README-Thumb.txt
+++ b/lib/Target/ARM/README-Thumb.txt
@@ -15,3 +15,7 @@
 * Make better use of high registers r8, r10, r11, r12 (ip). Some variants of add
   and cmp instructions can use high registers. Also, we can use them as
   temporaries to spill values into.
+
+* If we know function size is less than (1 << 16) * 2 bytes, we can use 16-bit
+  jumptable entries (e.g. (L1 - L2) >> 1). Or even smaller entries if the
+  function is even smaller. This also applies to ARM.