| Message ID | 20170426112537.GO1809@tucnak |
|---|---|
| State | New |
| Headers | show |
On 04/26/2017 05:25 AM, Jakub Jelinek wrote: > On Tue, Apr 25, 2017 at 09:31:00PM +0200, Jakub Jelinek wrote: >> This patch let us search for x's setter earlier in the bb. >> During testing I found that modified_in_p/modified_in_between_p don't >> actually take into account calls that could change MEMs, so the patch >> handles that too. > > Or shall we just: > --- gcc/alias.c 2017-04-25 15:51:31.072923325 +0200 > +++ gcc/alias.c 2017-04-26 13:23:55.595048464 +0200 > @@ -3221,6 +3221,8 @@ memory_modified_in_insn_p (const_rtx mem > { > if (!INSN_P (insn)) > return false; > + if (CALL_P (insn)) > + return true; > memory_modified = false; > note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); > return memory_modified; > > instead of the call_crossed hacks? Then modified_between_p and > modified_in_p would return true for !MEM_READONLY_P MEMs crossing a call. This seems like a good idea as well. I'm a bit surprised we're not handling it this way already. If you want to go w ith this and simplify the patch for 80491, that's fine too. jeff
On Wed, Apr 26, 2017 at 1:25 PM, Jakub Jelinek wrote: > Or shall we just: > --- gcc/alias.c 2017-04-25 15:51:31.072923325 +0200 > +++ gcc/alias.c 2017-04-26 13:23:55.595048464 +0200 > @@ -3221,6 +3221,8 @@ memory_modified_in_insn_p (const_rtx mem > { > if (!INSN_P (insn)) > return false; > + if (CALL_P (insn)) > + return true; +"&& ! RTL_CONST_OR_PURE_CALL_P (insn)" ? Ciao! Steven > memory_modified = false; > note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); > return memory_modified; > > instead of the call_crossed hacks? Then modified_between_p and > modified_in_p would return true for !MEM_READONLY_P MEMs crossing a call. > > Jakub
On Sat, Apr 29, 2017 at 10:43:52PM +0200, Steven Bosscher wrote: > On Wed, Apr 26, 2017 at 1:25 PM, Jakub Jelinek wrote: > > Or shall we just: > > --- gcc/alias.c 2017-04-25 15:51:31.072923325 +0200 > > +++ gcc/alias.c 2017-04-26 13:23:55.595048464 +0200 > > @@ -3221,6 +3221,8 @@ memory_modified_in_insn_p (const_rtx mem > > { > > if (!INSN_P (insn)) > > return false; > > + if (CALL_P (insn)) > > + return true; > > +"&& ! RTL_CONST_OR_PURE_CALL_P (insn)" ? Without detailed analysis of the MEM I'm not convinced it is safe. I believe even const or pure calls invalidate e.g. the argument stack slots, at least in the ABIs where stack slots are owned by callee, not caller. Jakub
--- gcc/alias.c 2017-04-25 15:51:31.072923325 +0200 +++ gcc/alias.c 2017-04-26 13:23:55.595048464 +0200 @@ -3221,6 +3221,8 @@ memory_modified_in_insn_p (const_rtx mem { if (!INSN_P (insn)) return false; + if (CALL_P (insn)) + return true; memory_modified = false; note_stores (PATTERN (insn), memory_modified_1, CONST_CAST_RTX(mem)); return memory_modified;