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From: "sirl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/108821] [11/12/13 Regression] LIM reissuing a violatile store when it cannot/should not Date: Thu, 16 Feb 2023 17:27:41 +0000 [thread overview] Message-ID: <bug-108821-4-gKsxJs3ZCG@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-108821-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108821 Franz Sirl <sirl at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |rguenther at suse dot de --- Comment #2 from Franz Sirl <sirl at gcc dot gnu.org> --- Started with commit b6ff3ddecfa93d53867afaaa078f85fc848abbbd: tree-optimization/94988 - enhance SM some more This enhances store-order preserving store motion to handle the case of non-invariant dependent stores in the sequence of unconditionally executed stores on exit by re-issueing them as part of the sequence of stores on the exit. This fixes the observed regression of gcc.target/i386/pr64110.c which relies on store-motion of 'b' for a loop like for (int i = 0; i < j; ++i) *b++ = x; where for correctness we now no longer apply store-motion. With the patch we emit the correct tem = b; for (int i = 0; i < j; ++i) { tem = tem + 1; *tem = x; } b = tem; *tem = x; preserving the original order of stores. A testcase reflecting the miscompilation done by earlier GCC is added as well. This also fixes the reported ICE in PR95025 and adds checking code to catch it earlier - the issue was not-supported refs propagation leaving stray refs in the sequence. 2020-05-11 Richard Biener <rguenther@suse.de> PR tree-optimization/94988 PR tree-optimization/95025 * tree-ssa-loop-im.c (seq_entry): Make a struct, add from. (sm_seq_push_down): Take extra parameter denoting where we moved the ref to. (execute_sm_exit): Re-issue sm_other stores in the correct order. (sm_seq_valid_bb): When always executed, allow sm_other to prevail inbetween sm_ord and record their stored value. (hoist_memory_references): Adjust refs_not_supported propagation and prune sm_other from the end of the ordered sequences. * gcc.dg/torture/pr94988.c: New testcase. * gcc.dg/torture/pr95025.c: Likewise. * gcc.dg/torture/pr95045.c: Likewise. * g++.dg/asan/pr95025.C: New testcase.
next prev parent reply other threads:[~2023-02-16 17:27 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-02-16 15:25 [Bug tree-optimization/108821] New: Extra volatile access with -O2 -ftree-loop-im since GCC-11 sirl at gcc dot gnu.org 2023-02-16 17:20 ` [Bug tree-optimization/108821] [11/12/13 Regression] LIM reissuing a violatile store when it cannot/should not pinskia at gcc dot gnu.org 2023-02-16 17:27 ` sirl at gcc dot gnu.org [this message] 2023-02-17 8:00 ` rguenth at gcc dot gnu.org 2023-02-17 11:38 ` cvs-commit at gcc dot gnu.org 2023-02-17 11:39 ` [Bug tree-optimization/108821] [11/12 " rguenth at gcc dot gnu.org 2023-03-15 9:48 ` cvs-commit at gcc dot gnu.org 2023-05-02 13:24 ` [Bug tree-optimization/108821] [11 " cvs-commit at gcc dot gnu.org 2023-05-02 13:26 ` rguenth at gcc dot gnu.org
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