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-rw-r--r--lib/CodeGen/README.txt5
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diff --git a/lib/CodeGen/README.txt b/lib/CodeGen/README.txt
index 4fff15c1e3..8767191320 100644
--- a/lib/CodeGen/README.txt
+++ b/lib/CodeGen/README.txt
@@ -143,3 +143,8 @@ load [T + 7]
...
load [T + 15]
//===---------------------------------------------------------------------===//
+
+It's not always a good idea to choose rematerialization over spilling. If all
+the load / store instructions would be folded then spilling is cheaper because
+it won't require new live intervals / registers. See 2003-05-31-LongShifts for
+an example.