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From: "Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com> To: Richard Biener <richard.guenther@gmail.com> Cc: Andrew Stubbs <ams@codesourcery.com>, "gcc-regression@gcc.gnu.org" <gcc-regression@gcc.gnu.org>, "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>, "haochen.jiang@intel.com" <haochen.jiang@intel.com> Subject: Re: [r13-7135 Regression] FAIL: gcc.dg/vect/vect-simd-clone-18f.c scan-tree-dump-times vect "[\\n\\r] [^\\n]* = foo\\.simdclone" 2 on Linux/x86_64 Date: Thu, 13 Apr 2023 15:25:00 +0100 [thread overview] Message-ID: <c7ddab89-cb41-a373-649d-ae5f0db4a4a6@arm.com> (raw) In-Reply-To: <CAFiYyc1SD7tgatF1R0ARh-ENv8TbqOsdw-Lu8n4AGU7qzChZ+g@mail.gmail.com> On 13/04/2023 15:00, Richard Biener wrote: > On Thu, Apr 13, 2023 at 3:00 PM Andre Vieira (lists) via Gcc-patches > <gcc-patches@gcc.gnu.org> wrote: >> >> >> >> On 13/04/2023 11:01, Andrew Stubbs wrote: >>> Hi Andre, >>> >>> I don't have a cascadelake device to test on, nor any knowledge about >>> what makes it different from regular x86_64. >> >> Not sure you need one, but yeah I don't know either, it looks like it >> fails because: >> in-branch vector clones are not yet supported for integer mask modes. >> >> A quick look tells me this is because mask_mode is not VOIDmode. >> i386.cc's TARGET_SIMD_CLONE_COMPUTE_VECSIZE_AND_SIMDLEN will set >> mask_mode to either DI or SI mode when TARGET_AVX512F. So I suspect >> cascadelake is TARGET_AVX512F. >> >> This is where I bail out as I really don't want to dive into the target >> specific simd clone handling of x86 ;) >> >>> >>> If the cascadelake device is supposed to work the same as other x86_64 >>> devices for these vectors then the test has found a bug in the compiler >>> and you should be looking to fix that, not fudge the testcase. >>> >>> Alternatively, if the device's capabilities really are different and the >>> tests should behave differently, then the actual expectations need to be >>> encoded in the dejagnu directives. If you can't tell the difference by >>> looking at the "x86_64*-*-*" target selector alone then the correct >>> solution is to invent a new "effective-target" selector. There are lots >>> of examples of using these throughout the testsuite (you could use >>> dg-require-effective-target to disable the whole testcase, or just use >>> the name in the scan-tree-dump-times directive to customise the >>> expectations), and the definitions can be found in the >>> lib/target-supports.exp and lib/target-supports-dg.exp scripts. Some are >>> fixed expressions and some run the compiler to probe the configuration, >>> but in this case you probably want to do something with "check-flags". >> >> Even though I agree with you, I'm not the right person to do this >> digging for such target specific stuff. So for now I'd probably suggest >> xfailing this for avx512f. >>> >>> For the unroll problem, you can probably tweak the optimization options >>> to disable that, the same as has been done for the epilogues feature >>> that had the same problem. >> >> I mistaken the current behaviour for unrolling, it's actually because of >> a latent bug. The vectorizer calls `vect_get_smallest_scalar_type` to >> determine the vectype of a stmt. For a function like foo, that has the >> same type (long long) everywhere this wouldn't be a problem, however, >> because you transformed it into a MASK_CALL that has a function pointer >> (which is 32-bit in -m32) that now becomes the 'smallest' type. >> >> This is all a red-herring though, I don't think we should be calling >> this function for potential simdclone calls as the type on which the >> veclen is not necessarily the 'smallest' type. And some arguments (like >> uniform and linear) should be ignored anyway as they won't be mapped to >> vectors. So I do think this might have been broken even before your >> changes, but needs further investigation. >>> Since these are new tests for a new feature, I don't really understand >>> why this is classed as a regression? >>> >>> Andrew >>> >>> P.S. there was a commit to these tests in the last few days, so make >>> sure you pull that before making changes. >> >> The latest commit to these tests was mine, it's the one Haochen is >> reporting this regression against. My commit was to fix the issue richi >> had introduced that was preventing the feature you introduced from >> working. The reason nobody noticed was because the tests you introduced >> didn't actually test your feature, since you didn't specify 'inbranch' >> the omp declare simd pragma was allowing the use of not-inbranch simd >> clones and the vectorizer was being smart enough to circumvent the >> conditional and was still able to use simdclones (non inbranch ones) so >> when the inbranch stopped working, the test didn't notice. >> >> The other changes to this test were already after the fix for 108888 >> that broke the inbranch feature you added, and so it was fixing a >> cascadelake testism but for the not-inbranch simdclones. So basically >> fixing a testism of a testism :/ >> >> >> I am working on simdclone's for AArch64 for next Stage 1 so I don't mind >> looking at the issue with the vectype being chosen wrongly, as for the >> other x86 specific testisms I'll leave them to someone else. > > Btw, the new testsuite FAILs could be just epiloge vectorizations, so > maybe try the usual --param vect-epilogues-nomask=0 ... It already has those, Jakub added them. But that's not it, I've been looking at it, and there is code in place that does what I expected which is defer the choice of vectype for simd clones until vectorizable_simd_clone_call, unfortunately it has a mistaken assumption that simdclones don't return :/ see vect_get_vector_types_for_stmt: ... if (gimple_get_lhs (stmt) == NULL_TREE /* MASK_STORE has no lhs, but is ok. */ && !gimple_call_internal_p (stmt, IFN_MASK_STORE)) { if (is_a <gcall *> (stmt)) { /* Ignore calls with no lhs. These must be calls to #pragma omp simd functions, and what vectorization factor it really needs can't be determined until vectorizable_simd_clone_call. */ if (dump_enabled_p ()) dump_printf_loc (MSG_NOTE, vect_location, "defer to SIMD clone analysis.\n"); return opt_result::success (); } return opt_result::failure_at (stmt, "not vectorized: irregular stmt.%G", stmt); } ... I'm working on a patch. > >> Kind Regards, >> Andre
next prev parent reply other threads:[~2023-04-13 14:25 UTC|newest] Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-04-13 1:48 haochen.jiang 2023-04-13 9:15 ` Andre Simoes Dias Vieira 2023-04-13 10:01 ` Andrew Stubbs 2023-04-13 12:59 ` Andre Vieira (lists) 2023-04-13 14:00 ` Richard Biener 2023-04-13 14:25 ` Andre Vieira (lists) [this message] 2023-04-14 6:55 ` Richard Biener 2023-04-14 8:43 ` Andre Vieira (lists) 2023-04-14 9:09 ` Richard Biener 2023-04-14 9:14 ` Richard Biener 2023-04-14 9:42 ` Andre Vieira (lists) 2023-04-14 11:47 ` Richard Biener 2023-04-14 12:57 ` Andre Vieira (lists)
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