Bug 103682

Summary: [12 regression] ICE on atomics: gimple check: expected gimple_assign(error_mark), have gimple_nop() in gimple_assign_rhs_code, at gimple.h:2852 since r12-5486-g7df89377a7ae3906
Product: gcc Reporter: Sergei Trofimovich <slyfox>
Component: tree-optimizationAssignee: Not yet assigned to anyone <unassigned>
Status: RESOLVED FIXED    
Severity: normal CC: crazylht, liuhongt, marxin
Priority: P3 Keywords: ice-on-valid-code
Version: 12.0   
Target Milestone: 12.0   
Host: Target: x86_64-unknown-linux-gnu
Build: Known to work: 11.2.0
Known to fail: 12.0 Last reconfirmed: 2021-12-13 00:00:00

Description Sergei Trofimovich 2021-12-13 12:36:54 UTC
ICE extracted from a real project:

$ cat bug.cpp

  #include <atomic>

  bool bug(std::atomic<unsigned> & ready, unsigned u) {
    return (ready.fetch_and(~u) & u);
  }

$ g++-12.0.0 -Ofast -c bug.cpp
during GIMPLE pass: fab
bug.cpp: In function 'bool bug(std::atomic<unsigned int>&, unsigned int)':
bug.cpp:6:6: internal compiler error: gimple check: expected gimple_assign(error_mark), have gimple_nop() in gimple_assign_rhs_code, at gimple.h:2852
    6 | bool bug(std::atomic<unsigned> & ready, unsigned u) {
      |      ^~~
0x20a58f7 internal_error(char const*, ...)
        ???:0
0x7c76dd gimple_check_failed(gimple const*, char const*, int, char const*, gimple_code, tree_code)
        ???:0

$ g++-12.0.0 -v
Using built-in specs.
COLLECT_GCC=/nix/store/3x3yy5hhikzn8zvhq5fj14a2m9qyxbc8-gcc-12.0.0/bin/g++
COLLECT_LTO_WRAPPER=/nix/store/3x3yy5hhikzn8zvhq5fj14a2m9qyxbc8-gcc-12.0.0/libexec/gcc/x86_64-unknown-linux-gnu/12.0.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with:
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 12.0.0 20211212 (experimental) (GCC)
Comment 1 Martin Liška 2021-12-13 12:43:38 UTC
Confirmed, started with r12-5486-g7df89377a7ae3906.
Comment 2 Andrew Pinski 2021-12-13 12:44:42 UTC
Confirmed.
C testcase:
int bug(unsigned *ready, unsigned u) {
   return __atomic_fetch_and (ready, ~u, 0) & u;
}
Comment 3 Hongtao.liu 2021-12-14 01:12:59 UTC
Mine.
Comment 4 GCC Commits 2021-12-14 23:40:27 UTC
The master branch has been updated by hongtao Liu <liuhongt@gcc.gnu.org>:

https://gcc.gnu.org/g:a2a0c91b47537b16908981e206f4e42db8425eca

commit r12-5981-ga2a0c91b47537b16908981e206f4e42db8425eca
Author: liuhongt <hongtao.liu@intel.com>
Date:   Tue Dec 14 09:47:08 2021 +0800

    Fix ICE. [PR103682]
    
    Check is_gimple_assign before gimple_assign_rhs_code.
    
    gcc/ChangeLog:
    
            PR target/103682
            * tree-ssa-ccp.c (optimize_atomic_bit_test_and): Check
            is_gimple_assign before gimple_assign_rhs_code.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.c-torture/compile/pr103682.c: New test.
Comment 5 Hongtao.liu 2021-12-14 23:47:08 UTC
Fixed in GCC12.
Comment 6 Andrew Pinski 2021-12-14 23:52:54 UTC
.