Observation of rematerialization.

llvm-svn: 41809
2007-09-10 22:11:18 +00:00 · 2007-09-10 22:11:18 +00:00 · 3b9f777f47
parent 6777b72659
commit 3b9f777f47
1 changed files with 5 additions and 0 deletions
--- a/llvm/lib/CodeGen/README.txt
+++ b/llvm/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.