------- Comment #10 from pinskia at gcc dot gnu dot org 2007-06-11 00:47
-------
There are a couple of issues here, first pointer_plus improves the aliasing set
issue, but then PRE comes around and messes it up because it does not add
pointer types which have DECL_BASED_ON_RESTRICT_P/DECL_GET_RESTRICT_BASE setup
correctly.
Disabling PRE on powerpc-linux-gnu (on the pointer_plus branch) is enough to
get the RTL optimizers to optimize away the extra loads and we get for the
inner loop:
.L3:
stfsx 0,9,3
addi 9,9,4
bdnz .L3
Which is almost the best you can do :).
One more issue (for x86) is expand emits code that causes the rtl optimizers
not to optimize well as they only look into loads in sets. I don't know how to
fix that issue without fixing restrict at the tree level.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16913
