[Bug target/87439] New: [9 regression] ICE in ix86_mode_needed, at config/i386/i386.c:18907

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87439

            Bug ID: 87439
           Summary: [9 regression] ICE in ix86_mode_needed, at
                    config/i386/i386.c:18907
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: ubizjak at gmail dot com
  Target Milestone: ---
              Host: i386-pc-solaris2.11
            Target: i386-pc-solaris2.11
             Build: i386-pc-solaris2.11

Between 20180924 (r264536) and 20180925 (r264580), two testcases started to
FAIL
on 32-bit Solaris/x86:

+FAIL: gcc.target/i386/avx-vzeroupper-16.c (internal compiler error)
+FAIL: gcc.target/i386/avx-vzeroupper-16.c (test for excess errors)
+UNRESOLVED: gcc.target/i386/avx-vzeroupper-16.c scan-assembler-times
avx_vzeroupper 1
+FAIL: gcc.target/i386/avx-vzeroupper-17.c (internal compiler error)
+FAIL: gcc.target/i386/avx-vzeroupper-17.c (test for excess errors)
+UNRESOLVED: gcc.target/i386/avx-vzeroupper-17.c scan-assembler-times
avx_vzeroupper 1

Excess errors:
during RTL pass: vzeroupper
/vol/gcc/src/hg/trunk/local/gcc/testsuite/gcc.target/i386/avx-vzeroupper-16.c:14:1:
internal compiler error: in ix86_mode_needed, at config/i386/i386.c:18907
0x9372f22 ix86_mode_needed
        /vol/gcc/src/hg/trunk/local/gcc/config/i386/i386.c:18907
0x992c83f optimize_mode_switching
        /vol/gcc/src/hg/trunk/local/gcc/mode-switching.c:604
0x992c83f execute
        /vol/gcc/src/hg/trunk/local/gcc/mode-switching.c:892
0x8ef162a gcc::pass_manager::execute_pass_mode_switching()
        /vol/gcc/src/hg/trunk/local/gcc/passes.c:126
0x935b949 rest_of_handle_insert_vzeroupper
        /vol/gcc/src/hg/trunk/local/gcc/config/i386/i386.c:888
0x935b949 execute
        /vol/gcc/src/hg/trunk/local/gcc/config/i386/i386.c:2508