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authorEvan Cheng <evan.cheng@apple.com>2007-09-10 22:11:18 +0000
committerEvan Cheng <evan.cheng@apple.com>2007-09-10 22:11:18 +0000
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Observation of rematerialization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41809 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/README.txt')
-rw-r--r--lib/CodeGen/README.txt5
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diff --git a/lib/CodeGen/README.txt b/lib/CodeGen/README.txt
index 4fff15c..8767191 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.