Hi, On Tue, Jul 20 2021, Richard Biener wrote: > On Tue, Jul 20, 2021 at 10:54 AM JiangNing OS via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: >> >> > -----Original Message----- >> > From: Gcc-patches <gcc-patches- >> > bounces+jiangning=os.amperecomputing....@gcc.gnu.org> On Behalf Of >> > Martin Jambor >> > Sent: Wednesday, June 30, 2021 4:19 AM >> > To: GCC Patches <gcc-patches@gcc.gnu.org> >> > Cc: Jan Hubicka <hubi...@ucw.cz> >> > Subject: [RFC] ipa: Adjust references to identify read-only globals >> > >> > Hi, >> > >> > this patch has been motivated by SPEC 2017's 544.nab_r in which there is a >> > static variable which is never written to and so zero throughout the >> > run-time >> > of the benchmark. However, it is passed by reference to a function in >> > which >> > it is read and (after some multiplications) passed into __builtin_exp >> > which in >> > turn unnecessarily consumes almost 10% of the total benchmark run-time. >> >> I do see ~8.5% runtime reduction on aarch64. >> >> > The situation is illustrated by the added testcase remref-3.c. >> > >> > The patch adds a flag to ipa-prop descriptor of each parameter to mark such >> > parameters. IPA-CP and inling then take the effort to remove IPA_REF_ADDR >> > references in the caller and only add IPA_REF_LOAD reference to the >> > clone/overall inlined function. This is sufficient for subsequent symbol >> > table >> > analysis code to identify the read-only variable as such and optimize the >> > code. >> > >> > I plan to compile a number of packages with the patch to test it some more >> > and get a bit better idea of its impact. But it has passed bootstrap, >> > LTObootstrap and testing on x86_64-linux and i686-linux and so unless I >> > find >> > any problem, I would like to commit it at some point next month without any >> > major changes, so I'd be grateful for any feedback even now. >> >> I see 3 cases in SPEC2017 failed to compile on aarch64, i.e. 521.wrf_r, >> 527.cam4_r, 554.roms_r. For example, >> >> pre_step3d.fppized.f90:1260:35: internal compiler error: Segmentation fault >> 1260 | CALL wclock_on (ng, iNLM, 22) >> | ^ >> 0x1645c6b internal_error(char const*, ...) >> ???:0 >> 0xe1f4f4 place_block_symbol(rtx_def*) >> ???:0 >> 0x84ab33 use_anchored_address(rtx_def*) >> ???:0 >> 0x868203 expand_expr_real_1(tree_node*, rtx_def*, machine_mode, >> expand_modifier, rtx_def**, bool) >> ???:0 >> 0x868793 expand_expr_real_1(tree_node*, rtx_def*, machine_mode, >> expand_modifier, rtx_def**, bool) >> ???:0 >> 0x75b593 expand_call(tree_node*, rtx_def*, int) >> ???:0 >> 0x86a09f expand_expr_real_1(tree_node*, rtx_def*, machine_mode, >> expand_modifier, rtx_def**, bool) >> ???:0 >> Please submit a full bug report > > Please file a bugreport and provide a (possibly reduced) testcase. >
The patch is not yet committed, so I don't think a bug-report (in bugzilla) is in order. At least after I fixed a bug pointed out in Honza's review, I cannot replicate any ICE building any of 521.wrf_r, 527.cam4_r, 554.roms_r on x86_64, at least without LTO. But with LTO, I get an undefined symbol link error building 527.cam4_r which is of course certainly a bug in the patch. I will investigate and hopefully fix it and re-post the patch but then I would appreciate if you checked it on aarch64 for me. Thanks, Martin
