On Mon, Nov 15, 2010 at 07:58:48PM +0100, Jakub Jelinek wrote:
> Now, not sure why this happens, as there is
>     case GIMPLE_ASM:
>       for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
>         {
>           tree op = gimple_asm_clobber_op (stmt, i);
>           if (simple_cst_equal(TREE_VALUE (op), memory_identifier_string) == 1)
>             {
>               if (dump_file)
>                 fprintf (dump_file, "    memory asm clobber is not const/pure");
>               /* Abandon all hope, ye who enter here. */
>               local->pure_const_state = IPA_NEITHER;
>             }
>         }
> Debugging...

Ah, the problem is that memory_identifier_string is only initialized in
ipa-reference.c's initialization, so it can be (and is in this case) NULL in
ipa-pure-const.c.

Two possible fixes (the latter is apparently what is used in
tree-ssa-operands.c, so is probably sufficient).  Guess ipa-reference.c
should be changed to do the same and just drop memory_identifier_string.

	Jakub