More info about Thumb1 predication support.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75220 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/README-Thumb.txt b/lib/Target/ARM/README-Thumb.txt
index 3b27ed3889ace0bfc221d0f9dc66c005c38da9b4..eed3c54372a6153f931de4317457cc71854e2e5c 100644 (file)
--- a/lib/Target/ARM/README-Thumb.txt
+++ b/lib/Target/ARM/README-Thumb.txt
@@ -236,4 +236,5 @@ to avoid extra work when we convert Thumb2 instructions to Thumb1 instructions.
 //===---------------------------------------------------------------------===//
 
 We need to make (some of the) Thumb1 instructions predicable. That will allow
-shrinking of predicated Thumb2 instructions.
+shrinking of predicated Thumb2 instructions. To allow this, we need to be able
+to toggle the 's' bit since they do not set CPSR when they are inside IT blocks.