This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [tree-ssa] must-alias fixes...
On Fri, Nov 21, 2003 at 03:11:08PM +0100, Jan Hubicka wrote:
> I also don't get the:
> /* FIXME lose the STRIP_NOPS once we are more clever about builtins. */
> STRIP_NOPS (tmp);
> if (TREE_CODE (tmp) == ADDR_EXPR
> && TREE_CODE (TREE_OPERAND (tmp, 0)) == STRING_CST)
> return true;
> why we do allow ADDR_EXPRs of STRING_CST to be nopped and other
> ADDR_EXPRs not? This is how NOP_EXPRs can leak into PLUS_EXPR the
> current implementation.
Ah hah. I wonder if we can do something kinky here and instead allow
this to be one case where ADDR_EXPR changes types slightly, and in a
controlled way (char to const char or such). That would be a better
hack than this, I think.
Of course, these casts might also be declared unnecessary now, after
I fixed a case of missing TYPE_MAIN_VARIANT there. Which might be
the best sort of fix.
> It seems to me that we should allow nopped ADDR_EXPRs in general and also
> nopped PLUS_EXPR with ADDR_EXPR and INTEGER_CST operands, shouldn't we?
No, because then we can't fold them into more natural constructs.
r~