https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94988
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:b6ff3ddecfa93d53867afaaa078f85fc848abbbd commit r11-272-gb6ff3ddecfa93d53867afaaa078f85fc848abbbd Author: Richard Biener <rguent...@suse.de> Date: Fri May 8 12:03:30 2020 +0200 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 <rguent...@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.
