that this merely obscures, not solves, the underlying problem; as and when
underlying problems are fixed, it would be worth trying again to provoke
this problem.
+
+288: fundamental cross-compilation issues (from old UGLINESS file)
+ 288a: Using host floating point numbers to represent target
+ floating point numbers, or host characters to represent
+ target characters, is theoretically shaky. (The characters
+ are OK as long as the characters are in the ANSI-guaranteed
+ character set, though, so they aren't a real problem as
+ long as the sources don't need anything but that.)
+ 288b: The compiler still makes assumptions about cross-compilation-host
+ implementation of ANSI CL:
+ 288b1: Simple bit vectors are distinct from simple vectors (in
+ DEFINE-STORAGE-BASE and elsewhere). (Actually, I'm not *sure*
+ that things would really break if this weren't so, but I
+ strongly suspect that they would.)
+ 288b2: SINGLE-FLOAT is distinct from DOUBLE-FLOAT. (This is
+ in a sense just one aspect of bug 288a.)
+
+289: "type checking and source-transforms"
+ a.
+ (block nil (let () (funcall #'+ (eval 'nil) (eval '1) (return :good))))
+ signals type error.
+
+ Our policy is to check argument types at the moment of a call. It
+ disagrees with ANSI, which says that type assertions are put
+ immediately onto argument expressions, but is easier to implement in
+ IR1 and is more compatible to type inference, inline expansion,
+ etc. IR1-transforms automatically keep this policy, but source
+ transforms for associative functions (such as +), being applied
+ during IR1-convertion, do not. It may be tolerable for direct calls
+ (+ x y z), but for (FUNCALL #'+ x y z) it is non-conformant.
+
+ b. Another aspect of this problem is efficiency. [x y + z +]
+ requires less registers than [x y z + +]. This transformation is
+ currently performed with source transforms, but it would be good to
+ also perform it in IR1 optimization phase.
+
+290: Alpha floating point and denormalized traps
+ In SBCL 0.8.3.6x on the alpha, we work around what appears to be a
+ hardware or kernel deficiency: the status of the enable/disable
+ denormalized-float traps bit seems to be ambiguous; by the time we
+ get to os_restore_fp_control after a trap, denormalized traps seem
+ to be enabled. Since we don't want a trap every time someone uses a
+ denormalized float, in general, we mask out that bit when we restore
+ the control word; however, this clobbers any change the user might
+ have made.
+
+292:
+ (fixed in 0.8.3.74)
projects / sbcl.git / blobdiff