[Bug middle-end/68672] New: [4.9/5/6 Regression] g++.dg/torture/pr68470.C: ICE: cannot update SSA form: statement uses released SSA name

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68672

            Bug ID: 68672
           Summary: [4.9/5/6 Regression] g++.dg/torture/pr68470.C: ICE:
                    cannot update SSA form: statement uses released SSA
                    name
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---

Created attachment 36896
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36896&action=edit
preprocessed g++.dg/torture/pr68470.C

Compiler output:
$ x86_64-pc-linux-gnu-gcc -v -O -finline-small-functions -fpartial-inlining
--param=partial-inlining-entry-probability=100 pr68470.ii
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-231194-checking-yes-rtl-df-nographite/bin/../libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-checking=yes,rtl,df --without-cloog --without-ppl --without-isl
--disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-231194-checking-yes-rtl-df-nographite
Thread model: posix
gcc version 6.0.0 20151202 (experimental) (GCC) 
/repo/gcc-trunk/gcc/testsuite/g++.dg/torture/pr68470.C: In member function
'virtual void I::m_fn3()':
/repo/gcc-trunk/gcc/testsuite/g++.dg/torture/pr68470.C:35:1: error: statement
uses released SSA name:
 }
 ^

# .MEM_20 = VDEF <.MEM>
MEM[(struct  &)_12] ={v} {CLOBBER};
The use of _12 should have been replaced
/repo/gcc-trunk/gcc/testsuite/g++.dg/torture/pr68470.C:35:1: internal compiler
error: cannot update SSA form
0xdfa08c update_ssa(unsigned int)
        /repo/gcc-trunk/gcc/tree-into-ssa.c:3190
0xc5f257 execute_function_todo
        /repo/gcc-trunk/gcc/passes.c:1926
0xc5fc9b execute_todo
        /repo/gcc-trunk/gcc/passes.c:2010
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.

Tested revisions:
trunk r231194 - ICE
5-branch r231055 - ICE
4_9-branch 231054 - ICE
4_8-branch r224828 - OK