[Bug tree-optimization/102776] New: [12 regression] g++.dg/vect/slp-pr98855.cc XPASSes

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102776

            Bug ID: 102776
           Summary: [12 regression] g++.dg/vect/slp-pr98855.cc XPASSes
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: rguenth at gcc dot gnu.org
  Target Milestone: ---
            Target: i?86-*-*, x86-*-*, armv8l-unknown-linux-gnueabihf,
                    aarch64-suse-linux-gnu

Between 20210904 (7b7395409c7aaef493337479c7fd586e52aea3d1) and 20210906
(78b34cd8a803aa89e64949e99ce2e6b4f64d6b54),
32-bit g++.dg/vect/slp-pr98855.cc began to XPASS on several targets:

XPASS: g++.dg/vect/slp-pr98855.cc  -std=c++14  scan-tree-dump-times slp1 "not
vectorized: vectorization is not profitable" 2
XPASS: g++.dg/vect/slp-pr98855.cc  -std=c++17  scan-tree-dump-times slp1 "not
vectorized: vectorization is not profitable" 2
XPASS: g++.dg/vect/slp-pr98855.cc  -std=c++2a  scan-tree-dump-times slp1 "not
vectorized: vectorization is not profitable" 2
XPASS: g++.dg/vect/slp-pr98855.cc  -std=c++98  scan-tree-dump-times slp1 "not
vectorized: vectorization is not profitable" 2

This might be due to

commit a3fb781d4b341c0d50ef1b92cd3e8734e673ef18
Author: Richard Biener <rguenther@suse.de>
Date:   Thu Sep 2 14:48:10 2021 +0200

    tree-optimization/102176 - locally compute participating SLP stmts