[Bug tree-optimization/84811] ICE on valid code at -O3 in 64-bit mode on x86_64-linux-gnu: in smallest_mode_for_size, at stor-layout.c:355

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84811

--- Comment #3 from Zhendong Su <su at cs dot ucdavis.edu> ---
I still see the ICE with rev. 258447. 

$ gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/home/su/software/tmp/gcc/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/8.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/home/su/software/tmp/gcc/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 8.0.1 20180312 (experimental) [trunk revision 258447] (GCC) 
$ 
$ gcctk -O3 -c small.c
during RTL pass: dse1
small.c: In function ‘fn1’:
small.c:12:1: internal compiler error: in smallest_mode_for_size, at
stor-layout.c:355
 }
 ^
0xc95b2b smallest_mode_for_size(poly_int<1u, unsigned long>, mode_class)
        ../../gcc-source-trunk/gcc/stor-layout.c:355
0x146b5fb smallest_int_mode_for_size
        ../../gcc-source-trunk/gcc/machmode.h:842
0x146b5fb find_shift_sequence
        ../../gcc-source-trunk/gcc/dse.c:1701
0x146b5fb get_stored_val
        ../../gcc-source-trunk/gcc/dse.c:1847
0x146e183 record_store
        ../../gcc-source-trunk/gcc/dse.c:1557
0x146f08e scan_insn
        ../../gcc-source-trunk/gcc/dse.c:2545
0x146f08e dse_step1
        ../../gcc-source-trunk/gcc/dse.c:2657
0x146f08e rest_of_handle_dse
        ../../gcc-source-trunk/gcc/dse.c:3574
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.
$