rather than either constant-folding or manipulating NIL-VALUE or
NULL-TN directly.
--------------------------------------------------------------------------------
-#19
- (let ((dx (if (foo)
- (list x)
- (list y z))))
- (declare (dynamic-extent dx))
- ...)
-
-DX is not allocated on stack.
---------------------------------------------------------------------------------
#20
(defun-with-dx foo (x)
(flet ((make (x)
Result of MAKE is not stack allocated, which means that
stack-allocation of structures is impossible.
--------------------------------------------------------------------------------
-#21
-(defun-with-dx foo ()
- (let ((dx (list (list 1 2) (list 3 4))))
- (declare (dynamic-extent dx))
- ...))
-
-External list in DX is allocated on stack, but internal are not.
---------------------------------------------------------------------------------
#22
IR2 does not perform unused code flushing.
--------------------------------------------------------------------------------
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.
+
+(This is harder than it might look at first glance, as MAKE-ARRAY is smart
+enough to eliminate something like ':initial-element 0'. Such an optimization
+is valid if the vector is being allocated in the heap, but not if it is being
+allocated on the stack. You could remove this optimization, but that makes
+the heap-allocated case somewhat slower...)
--------------------------------------------------------------------------------
#28
a. Accessing raw slots in structure instances is more inefficient than
altogether. The former option is probably easier than the latter.
--------------------------------------------------------------------------------
-#37
+#38
+
+(setf (subseq s1 start1 end1) (subseq s2 start2 end1))
+
+could be transformed into
+
+(let ((#:s2 s2)
+ (#:start2 start2)
+ (#:end2 end2))
+ (replace s1 #:s2 :start1 start1 :end1 end1 :start2 #:start2 :end2 #:end2))
+
+when the return value is unused, avoiding the need to cons up the new sequence.
+
+--------------------------------------------------------------------------------
+#39
+
+(let ((*foo* 42)) ...)
-Dynamic extent allocation doesn't currently work for one-element lists,
-since there's a source transform from (LIST X) to (CONS X NIL).
+currently compiles to code that ensures the TLS index at runtime, which
+is both a decently large chunk of code and unnecessary, as we could ensure
+the TLS index at load-time as well.