[Bug target/113229] [14 Regression] gcc.dg/torture/pr70083.c ICEs when compiled with -march=armv9-a+sve2

["pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113229

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to avieira from comment #6)
> Oh forgot to mention, this is triggering because of the div optimization in:
> https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;
> h=c69db3ef7f7d82a50f46038aa5457b7c8cc2d643
> 
> But I suspect that too is just an enabler and not the root cause? Unless we
> aren't supposed to use subregs for sve modes...

Note there is another paths which lead to crashing in paradoxical_subreg_p
still via simplify_const_vector_subreg (but not with the gen_divv4si3 in the
trace) in a different testcase; testsuite/gcc.dg/pr69896.c .



```
/home/apinski/src/upstream-full-cross/gcc/gcc/testsuite/gcc.dg/pr69896.c:22:1:
internal compiler error: in paradoxical_subreg_p, at rtl.h:3213
0x80c65b paradoxical_subreg_p(machine_mode, machine_mode)
        ../../gcc/rtl.h:3213
0x80cfc8 paradoxical_subreg_p(machine_mode, machine_mode)
        ../../gcc/poly-int.h:2179
0x80cfc8 simplify_const_vector_subreg
        ../../gcc/simplify-rtx.cc:7423
0x80cfc8 simplify_context::simplify_subreg(machine_mode, rtx_def*,
machine_mode, poly_int<2u, unsigned long>)
        ../../gcc/simplify-rtx.cc:7595
0xfae1c9 insn_propagation::apply_to_rvalue_1(rtx_def**)
        ../../gcc/recog.cc:1176
0xfadcab insn_propagation::apply_to_rvalue_1(rtx_def**)
        ../../gcc/recog.cc:1117
0xfade93 insn_propagation::apply_to_rvalue_1(rtx_def**)
        ../../gcc/recog.cc:1254
0xfae63f insn_propagation::apply_to_pattern(rtx_def**)
        ../../gcc/recog.cc:1396
0x1cfdb66 try_fwprop_subst_pattern
        ../../gcc/fwprop.cc:440
0x1cfdb66 try_fwprop_subst
        ../../gcc/fwprop.cc:613
0x1cfe500 forward_propagate_and_simplify
        ../../gcc/fwprop.cc:809
0x1cfe500 forward_propagate_into
        ../../gcc/fwprop.cc:872
0x1cfe89d forward_propagate_into
        ../../gcc/fwprop.cc:821
0x1cfe89d fwprop_insn
        ../../gcc/fwprop.cc:929
0x1cfe9c1 fwprop
        ../../gcc/fwprop.cc:981
```