[Bug debug/81307] New: [8 regression] g++.dg/debug/debug9.C -gstabs FAILs

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81307

            Bug ID: 81307
           Summary: [8 regression] g++.dg/debug/debug9.C -gstabs FAILs
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: debug
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: hubicka at gcc dot gnu.org
  Target Milestone: ---
            Target: i386-pc-solaris2.*, x86_64-pc-linux-gnu,
                    i686-pc-linux-gnu

Between 20170702 (r249882) and 20170703 (r249926), we got a couple of testsuite
regressions:

+FAIL: g++.dg/debug/debug9.C -gstabs -O2 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs -O3 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs+ -O2 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs+ -O3 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs+1 -O2 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs+1 -O3 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs+3 -O2 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs+3 -O3 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs1 -O2 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs1 -O3 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs3 -O2 (test for excess errors)
+FAIL: g++.dg/debug/debug9.C -gstabs3 -O3 (test for excess errors)

32 and 64-bit x86 (both Solaris and Linux).  Solaris /bin/as complains

Excess errors:
Assembler: debug9.C
        "/var/tmp//ccmj.nsd.s", line 142 : Symbols must be in same section:
".LM7", ".LFBB1"

One label is in .text.startup (main) while the other is in .text.unlikely
(main.cold.1).

Perhaps this is due to

changeset:   39228:a5b972ae27b8
user:        hubicka@138bc75d-0d04-0410-961f-82ee72b054a4
date:        Mon Jul 03 14:40:46 2017 +0000
files:       gcc/ChangeLog gcc/predict.c gcc/profile-count.h
gcc/testsuite/Chang
eLog gcc/testsuite/gcc.c-torture/compile/pr81290.c gcc/tree-ssa-threadupdate.c
description:
PR middle-end/81290
        * predict.c (force_edge_cold): Be more careful about propagation
        backward.
        * profile-count.h (profile_probability::guessed,
        profile_probability::fdo, profile_count::guessed, profile_count::fdo):
        New.
        * tree-ssa-threadupdate.c (recompute_probabilities): Result is guessed.

        * gcc.c-torture/compile/pr81290.c: New.

  Rainer