[Bug tree-optimization/94717] New: [10 Regression] ICE: SIGSEGV in output_merged_store (gimple-ssa-store-merging.c:4307) with -O2 -fnon-call-exceptions -ftracer

["zsojka at seznam dot cz" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94717

            Bug ID: 94717
           Summary: [10 Regression] ICE: SIGSEGV in output_merged_store
                    (gimple-ssa-store-merging.c:4307) with -O2
                    -fnon-call-exceptions -ftracer
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu

Created attachment 48355
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48355&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-g++ -O2 -fnon-call-exceptions -ftracer testcase.C
-wrapper valgrind,-q
==19787== Invalid read of size 4
==19787==    at 0x1C19FA2: (anonymous
namespace)::imm_store_chain_info::output_merged_store((anonymous
namespace)::merged_store_group*) (gimple-ssa-store-merging.c:4307)
==19787==    by 0x1C1C81A: output_merged_stores
(gimple-ssa-store-merging.c:4363)
==19787==    by 0x1C1C81A: terminate_and_process_chain
(gimple-ssa-store-merging.c:4407)
==19787==    by 0x1C1C81A: (anonymous
namespace)::pass_store_merging::terminate_and_process_chain((anonymous
namespace)::imm_store_chain_info*) (gimple-ssa-store-merging.c:2207)
==19787==    by 0x1C1DDEF: terminate_and_process_all_chains
(gimple-ssa-store-merging.c:2142)
==19787==    by 0x1C1DDEF: (anonymous
namespace)::pass_store_merging::execute(function*)
(gimple-ssa-store-merging.c:4953)
==19787==    by 0x1150047: execute_one_pass(opt_pass*) (passes.c:2502)
==19787==    by 0x11509BF: execute_pass_list_1(opt_pass*) (passes.c:2590)
==19787==    by 0x11509D1: execute_pass_list_1(opt_pass*) (passes.c:2591)
==19787==    by 0x11509F8: execute_pass_list(function*, opt_pass*)
(passes.c:2601)
==19787==    by 0xDB2AAB: cgraph_node::expand() (cgraphunit.c:2300)
==19787==    by 0xDB3CBF: expand_all_functions (cgraphunit.c:2471)
==19787==    by 0xDB3CBF: symbol_table::compile() [clone .part.0]
(cgraphunit.c:2822)
==19787==    by 0xDB602C: compile (cgraphunit.c:2735)
==19787==    by 0xDB602C: symbol_table::finalize_compilation_unit()
(cgraphunit.c:3002)
==19787==    by 0x123C10E: compile_file() (toplev.c:483)
==19787==    by 0xA81BF7: do_compile (toplev.c:2273)
==19787==    by 0xA81BF7: toplev::main(int, char**) (toplev.c:2412)
==19787==  Address 0x24 is not stack'd, malloc'd or (recently) free'd
==19787== 
during GIMPLE pass: store-merging
testcase.C: In function 'void foo(S*)':
testcase.C:18:1: internal compiler error: Segmentation fault
   18 | foo (S *x)
      | ^~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.

$ x86_64-pc-linux-gnu-g++ -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest/bin/x86_64-pc-linux-gnu-g++
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r10-7870-20200422110559-g413232a55b9-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/10.0.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--with-cloog --with-ppl --with-isl --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu
--with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r10-7870-20200422110559-g413232a55b9-checking-yes-rtl-df-extra-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 10.0.1 20200422 (experimental) (GCC)