[Bug target/116955] New: [15 Regression] GCN '-march=gfx1100': [-PASS:-]{+FAIL:+} gcc.dg/vect/pr81740-2.c execution test

[tschwinge at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116955

            Bug ID: 116955
           Summary: [15 Regression] GCN '-march=gfx1100':
                    [-PASS:-]{+FAIL:+} gcc.dg/vect/pr81740-2.c execution
                    test
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: testsuite-fail, wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tschwinge at gcc dot gnu.org
                CC: ams at gcc dot gnu.org, rguenth at gcc dot gnu.org
  Target Milestone: ---
            Target: GCN

Some changes after 2024-09-20's commit
r15-3743-g2828ec526eaf5612178b62d48bfd8443c7ecd674 appear to cause a regression
for '--target=amdgcn-amdhsa' '-march=gfx1100' (but not '-march=gfx908'!):

    PASS: gcc.dg/vect/pr81740-2.c (test for excess errors)
    [-PASS:-]{+FAIL:+} gcc.dg/vect/pr81740-2.c execution test
    PASS: gcc.dg/vect/pr81740-2.c scan-tree-dump vect "OUTER LOOP VECTORIZED"

    GCN Kernel Aborted
    Kernel aborted

'--param=gcn-preferred-vectorization-factor=32' vs.
'--param=gcn-preferred-vectorization-factor=64' doesn't make a difference: both
FAIL for '-march=gfx1100', both PASS for '-march=gfx908'.