Fold does not fold two comparisons in a row if the intermediate type differs
in being a pointer vs. an integer variable. This also is the reason for not
folding (Foo *)(char *)foo with foo being of Foo& type (we can fold that to
(Foo *)foo).
There's code to do that I think, but it's just missing adjustment for pointers:
/* In addition to the cases of two conversions in a row
handled below, if we are converting something to its own
type via an object of identical or wider precision, neither
conversion is needed. */
if (TYPE_MAIN_VARIANT (inside_type) == TYPE_MAIN_VARIANT (type)
&& ((inter_int && final_int)
|| (inter_float && final_float))
&& inter_prec >= final_prec)
return fold_build1 (code, type, TREE_OPERAND (op0, 0));
I have a patch. Of course RTL doesn't care.
--
Summary: Does not fold (char *)(size_t)char_ptr or (size_t)(char
*)size_t_var
Product: gcc
Version: 4.2.0
Status: UNCONFIRMED
Keywords: missed-optimization, TREE
Severity: enhancement
Priority: P3
Component: middle-end
AssignedTo: rguenth at gcc dot gnu dot org
ReportedBy: rguenth at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27529
