[Bug c++/86159] New: g++ ICE at -O1 and above on valid code: incorrect type of vector CONSTRUCTOR elements

["helloqirun at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86159

            Bug ID: 86159
           Summary: g++ ICE at -O1 and above on valid code: incorrect type
                    of vector CONSTRUCTOR elements
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: helloqirun at gmail dot com
  Target Milestone: ---

It appears to be a recent regression.

It happens at "-O1" and above but g++-trunk compiles. g++-8.1 also compiles at
"-O1" and above.

$ g++-trunk -v
Using built-in specs.
COLLECT_GCC=g++-trunk
COLLECT_LTO_WRAPPER=/home/absozero/trunk/root-gcc/libexec/gcc/x86_64-pc-linux-gnu/9.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/home/absozero/trunk/root-gcc
--enable-languages=c,c++ --disable-werror --enable-multilib
Thread model: posix
gcc version 9.0.0 20180614 (experimental) [trunk revision 261591] (GCC) 


$ g++-8.1 abc.c -c -O1
$ g++-trunk abc.c -c -O1
abc.c: In function ‘vec fn1()’:
abc.c:2:9: warning: AVX vector return without AVX enabled changes the ABI
[-Wpsabi]
 vec fn1() {
         ^
abc.c:2:5: error: incorrect type of vector CONSTRUCTOR elements
 vec fn1() {
     ^~~
{_7, _10, _13, _16, _19, _22, _25, _28}

_1 = {_7, _10, _13, _16, _19, _22, _25, _28};
during GIMPLE pass: veclower2
abc.c:2:5: internal compiler error: verify_gimple failed
0xee2941 verify_gimple_in_cfg(function*, bool)
        ../../gcc/gcc/tree-cfg.c:5405
0xdccf7f execute_function_todo
        ../../gcc/gcc/passes.c:1943
0xdcde8e execute_todo
        ../../gcc/gcc/passes.c:1997
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.



$ cat abc.c
typedef int vec __attribute__((vector_size(32)));
vec fn1() {
  vec x, zero{};
  vec one = zero + 1;
  return x < zero ? one : zero;
}