0.9.2:

[sbcl.git] / OPTIMIZATIONS

diff --git a/OPTIMIZATIONS b/OPTIMIZATIONS
index d8d018f..a702c7d 100644 (file)
--- a/OPTIMIZATIONS
+++ b/OPTIMIZATIONS
@@ -218,3 +218,17 @@ SBCL cannot derive upper bound for I and uses generic arithmetic here:
 
 (So the constraint propagator or a possible future SSA-convertor
 should know the connection between an NLE and its CLEANUP.)
+--------------------------------------------------------------------------------
+#27
+Initialization of stack-allocated arrays is inefficient: we always
+fill the vector with zeroes, even when it is not needed (as for
+platforms with conservative GC or for arrays of unboxed objectes) and
+is performed later explicitely.
+--------------------------------------------------------------------------------
+#28
+a. Accessing raw slots in structure instances is more inefficient than
+it could be; if we placed raw slots before the header word, we would
+not need to do arithmetic at runtime to access them.  (But beware:
+this would complicate handling of the interior pointer).
+
+b. (Also note that raw slots are currently disabled on HPPA)
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