add a note

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28384 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/README.txt b/lib/Target/README.txt
index fd862fe63a9feec2902999562b518efb3fae79dc..54bd94811d764e08761517b842e2f64cf2406415 100644 (file)
--- a/lib/Target/README.txt
+++ b/lib/Target/README.txt
@@ -190,3 +190,21 @@ The rlwinm (an and by 65535) is dead.  The dag combiner should propagate bits
 better than that to see this.
 
 //===---------------------------------------------------------------------===//
+
+Add support for conditional increments, and other related patterns.  Instead
+of:
+
+       movl 136(%esp), %eax
+       cmpl $0, %eax
+       je LBB16_2      #cond_next
+LBB16_1:       #cond_true
+       incl _foo
+LBB16_2:       #cond_next
+
+emit:
+       movl    _foo, %eax
+       cmpl    $1, %edi
+       sbbl    $-1, %eax
+       movl    %eax, _foo
+
+//===---------------------------------------------------------------------===//