[Bug c++/70252] New: ICE in vect_get_vec_def_for_stmt_copy with -O3 -march=skylake-avx512.

["vsevolod.livinskij at frtk dot ru" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70252

            Bug ID: 70252
           Summary: ICE in vect_get_vec_def_for_stmt_copy with -O3
                    -march=skylake-avx512.
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vsevolod.livinskij at frtk dot ru
  Target Milestone: ---

Created attachment 37986
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37986&action=edit
Reproducer.

Testcase produces ICE with -O3 -march=skylake-avx512. Everything works fine
with -O2.

Error:
> g++ -O3 -march=skylake-avx512 -S repr.cpp
repr.cpp: In function âvoid foo()â:
repr.cpp:7:6: internal compiler error: in vect_get_vec_def_for_stmt_copy, at
tree-vect-stmts.c:1490
 void foo () {
      ^~~
0xc50433 vect_get_vec_def_for_stmt_copy(vect_def_type, tree_node*)
        ../.././gcc/tree-vect-stmts.c:1490
0xc55e8c vectorizable_condition(gimple*, gimple_stmt_iterator*, gimple**,
tree_node*, int, _slp_tree*)
        ../.././gcc/tree-vect-stmts.c:7640
0xc65c26 vect_transform_stmt(gimple*, gimple_stmt_iterator*, bool*, _slp_tree*,
_slp_instance*)
        ../.././gcc/tree-vect-stmts.c:8212
0xc6960a vect_transform_loop(_loop_vec_info*)
        ../.././gcc/tree-vect-loop.c:6885
0xc843bc vectorize_loops()
        ../.././gcc/tree-vectorizer.c:554
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.

GCC version:
> g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/export/users/vlivinsk/gcc-trunk/bin/libexec/gcc/x86_64-pc-linux-gnu/6.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /export/users/vlivinsk/gcc-trunk/gcc/configure
--with-arch=corei7 --with-cpu=corei7 --enable-clocale=gnu --with-system-zlib
--enable-shared --with-demangler-in-ld --enable-cloog-backend=isl
--with-fpmath=sse --enable-checking=release --enable-languages=c,c++,lto
--with-gmp=/export/users/vlivinsk/gcc-trunk/gmp-6.1.0/bin
--with-mpfr=/export/users/vlivinsk/gcc-trunk/mpfr-3.1.3/bin
--with-mpc=/export/users/vlivinsk/gcc-trunk/mpc-1.0.3/bin
--prefix=/export/users/vlivinsk/gcc-trunk/bin
Thread model: posix
gcc version 6.0.0 20160315 (experimental) (Revision=234226)

Test:

extern unsigned char a [150];
extern unsigned char b [150];
extern unsigned char c [150];
extern unsigned char d [150];
extern unsigned char e [150];

void foo () {
    for (int i = 92; i <= 141; i += 2) {
        int tmp = (d [i] && b [i]) <= (a [i] > c [i]);
        e [i] = tmp >> b [i];
    }
}