[Bug sanitizer/80067] New: ICE in fold_comparison with -fsanitize=undefined

[vsevolod.livinskij at frtk dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80067

            Bug ID: 80067
           Summary: ICE in fold_comparison with -fsanitize=undefined
           Product: gcc
           Version: 7.0.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: sanitizer
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vsevolod.livinskij at frtk dot ru
                CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
                    jakub at gcc dot gnu.org, kcc at gcc dot gnu.org
  Target Milestone: ---

Created attachment 40984
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40984&action=edit
Reproducer.

GCC crashes with with -fsanitize=undefined option.

Reproducer:
extern signed char a;
void foo () { 
    0 << ((647 > a) - 1); 
}

Error:
>$ g++ -fsanitize=undefined -c repr.cpp 
repr.cpp: In function ‘void foo()’:
repr.cpp:3:24: internal compiler error: tree check: expected class
‘expression’, have ‘constant’ (integer_cst) in fold_comparison, at
fold-const.c:8707
     0 << ((647 > a) - 1);
                        ^
0x10100b7 tree_class_check_failed(tree_node const*, tree_code_class, char
const*, int, char const*)
        /home/vsevolod/workspace/gcc-dev/trunk/gcc/tree.c:9867
0xa94317 expr_check(tree_node*, char const*, int, char const*)
        /home/vsevolod/workspace/gcc-dev/trunk/gcc/tree.h:3233
0xa94317 fold_comparison
        (...)

GCC version:
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/home/vsevolod/workspace/gcc-dev/bin-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/vsevolod/workspace/gcc-dev/trunk/configure
--prefix=/home/vsevolod/workspace/gcc-dev/bin-trunk
Thread model: posix
gcc version 7.0.1 20170315 (experimental) (GCC)