On Mon, Oct 15, 2012 at 5:28 AM, Aldy Hernandez <al...@redhat.com> wrote: > > Here we have a store data race because noce_can_store_speculate_p() > incorrectly returns true. The problem is that memory_modified_in_insn_p() > returns true if an instruction *MAY* modify a memory location, but the store > can only be speculated if we are absolutely sure the store will happen on > all subsequent paths. > > My approach is to implement a memory_SURELY_modified_in_insn_p(), which will > trigger this optimization less often, but at least it will be correct.
I don't see a reason to add this new function. I would just inline it into noce_can_store_speculate_p, replacing the call to memory_modified_in_p. And I'm not sure I see a reason to change the comment for memory_modified_in_p, it seems to already be accurate. Clearly we could consider the possibility of a PARALLEL of SET insns, but of course most the compiler won't handle that anyhow. I suppose that would be a reason to use memory_surely_modified_in_insn_p, but in that case you might as well handle the PARALLEL case now. Ian
