[Bug target/112851] New: [14 Regression] RISCV ICE: vsetvl pass: in partial_subreg_p, at rtl.h:3187 on rv32gcv_zvl256b

["patrick at rivosinc dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112851

            Bug ID: 112851
           Summary: [14 Regression] RISCV ICE: vsetvl pass: in
                    partial_subreg_p, at rtl.h:3187 on rv32gcv_zvl256b
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: patrick at rivosinc dot com
  Target Milestone: ---

Created attachment 56800
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56800&action=edit
-freport-bug output

Seen on rv32gcv_zvl{256|512|1024}b:
pr112755
pr112756
pr112757

FAIL: gcc.dg/torture/pr109219.c   -O3 -fomit-frame-pointer -funroll-loops
-fpeel-loops -ftracer -finline-functions  (internal compiler error: in
partial_subreg_p, at rtl.h:3187)

Command:
> /scratch/tc-testing/tc-dec-4-trunk/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc -march=rv32gcv_zvl256b -mabi=ilp32d -O3 -funroll-loops -ftracer pr109219.c -freport-bug
during RTL pass: vsetvl
pr109219.c: In function 'g_97':
pr109219.c:21:1: internal compiler error: in partial_subreg_p, at rtl.h:3187
   21 | }
      | ^
0xb3a42b partial_subreg_p(machine_mode, machine_mode)
        ../../../gcc/gcc/rtl.h:3187
0xb3a42b partial_subreg_p(machine_mode, machine_mode)
        ../../../gcc/gcc/rtl.h:3181
0xb3a42b
rtl_ssa::function_info::record_use(rtl_ssa::function_info::build_info&,
rtl_ssa::insn_info*, rtx_obj_reference)
        ../../../gcc/gcc/rtl-ssa/insns.cc:524
0x23ee521
rtl_ssa::function_info::add_insn_to_block(rtl_ssa::function_info::build_info&,
rtx_insn*)
        ../../../gcc/gcc/rtl-ssa/insns.cc:662
0x2a0876d
rtl_ssa::function_info::add_block_contents(rtl_ssa::function_info::build_info&)
        ../../../gcc/gcc/rtl-ssa/blocks.cc:948
0x2a08e8a
rtl_ssa::function_info::start_block(rtl_ssa::function_info::build_info&,
rtl_ssa::bb_info*)
        ../../../gcc/gcc/rtl-ssa/blocks.cc:1064
0x2a08f1c
rtl_ssa::function_info::bb_walker::before_dom_children(basic_block_def*)
        ../../../gcc/gcc/rtl-ssa/blocks.cc:117
0x225c207 dom_walker::walk(basic_block_def*)
        ../../../gcc/gcc/domwalk.cc:311
0x2a0a5c9 rtl_ssa::function_info::process_all_blocks()
        ../../../gcc/gcc/rtl-ssa/blocks.cc:1281
0x23ebb68 rtl_ssa::function_info::function_info(function*)
        ../../../gcc/gcc/rtl-ssa/functions.cc:50
0x1734d12 pre_vsetvl::pre_vsetvl()
        ../../../gcc/gcc/config/riscv/riscv-vsetvl.cc:2218
0x1733527 pass_vsetvl::lazy_vsetvl()
        ../../../gcc/gcc/config/riscv/riscv-vsetvl.cc:3454
0x173391f pass_vsetvl::execute(function*)
        ../../../gcc/gcc/config/riscv/riscv-vsetvl.cc:3518
0x173391f pass_vsetvl::execute(function*)
        ../../../gcc/gcc/config/riscv/riscv-vsetvl.cc:3501
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Preprocessed source stored into /scratch/tmp/ccMXNexu.out file, please attach
this to your bugreport.

Testcase:
https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/testsuite/gcc.dg/torture/pr109219.c;h=2b5c514ad858e583e5f610101303429bcbf06780;hb=HEAD

Godbolt:
https://godbolt.org/z/PMjeGhzEz