[Bug middle-end/105409] New: ICE in simplify_subreg, at simplify-rtx.cc:7351

[ro at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105409

            Bug ID: 105409
           Summary: ICE in simplify_subreg, at simplify-rtx.cc:7351
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: gaius at gcc dot gnu.org
  Target Milestone: ---
            Target: sparcv9-sun-solaris2.11

As (incorrectly) reported in PR modula2/105408, for a 64-bit-default
Solaris/SPARC
build of the devel/modula-2 branch, 2000+ 32-bit testcases FAIL like this:

FAIL: gm2/calling-c/datatypes/unbounded/run/pass/m.mod compilation,  -O 
(internal compiler error: ^[[m^[[Kin simplify_subreg, at simplify-rtx.cc:7351)

However, it turns out that this has nothing to do with gm2, because the same
ICE
occurs on trunk as well (but only for a 64-bit-default g++, 32-bit-default
compiles
the testcase just fine):

$ cc1plus -m32 -quiet m.x0-m_m2.cpp
m.x0-m_m2.cpp:111:1: internal compiler error: in simplify_subreg, at
simplify-rtx.cc:7351
  111 | }
      | ^
0x101360647 simplify_context::simplify_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<1u, unsigned long>)
        /vol/gcc/src/hg/master/local/gcc/simplify-rtx.cc:7351
0x1017e071b simplify_subreg(machine_mode, rtx_def*, machine_mode, poly_int<1u,
unsigned long>)
        /vol/gcc/src/hg/master/local/gcc/rtl.h:3498
0x1017e071b assemble_integer(rtx_def*, unsigned int, unsigned int, int)
        /vol/gcc/src/hg/master/local/gcc/varasm.cc:2922
0x100db88eb dw2_asm_output_encoded_addr_rtx(int, rtx_def*, bool, char const*,
...)
        /vol/gcc/src/hg/master/local/gcc/dwarf2asm.cc:1122
0x100dc919f output_call_frame_info
        /vol/gcc/src/hg/master/local/gcc/dwarf2out.cc:929