Created attachment 55973 [details]
Reproducer source code

This issue was identified building SPEC CPU 2017 602.gcc_s.

Reproducer (test.c):

a, c, d;
*b;
h() {
  int e;
  i();
  for (;;) {
    unsigned f;
    char *g;
    f = a;
    for (; f; f--) {
      if (*g == '"')
        e = !e;
      *b = g++;
    }
    if (c)
      break;
    f = d;
    for (; d;)
      if (e)
        b++;
  }
}

Compile with:

riscv64-unknown-linux-gnu-gcc -w -march=rv64gcv -mabi=lp64d -c -Ofast \
    -ftree-vectorize --param=riscv-autovec-preference=scalable test.c

Output is:
during RTL pass: vsetvl
test.c: In function 'h':
test.c:22:1: internal compiler error: in validate_change_or_fail, at config/riscv/riscv-vsetvl.cc:788
   22 | }
      | ^
0xa6ef0b validate_change_or_fail
	/home/jeremy/gittrees/mustang/gcc/gcc/config/riscv/riscv-vsetvl.cc:788
0xa6f0bb validate_change_or_fail
	/home/jeremy/gittrees/mustang/gcc/gcc/hash-set.h:64
0xa6f0bb change_insn
	/home/jeremy/gittrees/mustang/gcc/gcc/config/riscv/riscv-vsetvl.cc:804
0x165d292 pass_vsetvl::earliest_fusion()
	/home/jeremy/gittrees/mustang/gcc/gcc/config/riscv/riscv-vsetvl.cc:3415
0x165da61 pass_vsetvl::vsetvl_fusion()
	/home/jeremy/gittrees/mustang/gcc/gcc/config/riscv/riscv-vsetvl.cc:3457
0x165f950 pass_vsetvl::lazy_vsetvl()
	/home/jeremy/gittrees/mustang/gcc/gcc/config/riscv/riscv-vsetvl.cc:4373
0x165fad1 pass_vsetvl::execute(function*)
	/home/jeremy/gittrees/mustang/gcc/gcc/config/riscv/riscv-vsetvl.cc:4413
0x165fad1 pass_vsetvl::execute(function*)
	/home/jeremy/gittrees/mustang/gcc/gcc/config/riscv/riscv-vsetvl.cc:4394
Please submit a full bug report, with preprocessed source (by using -freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

System information
==================

Using built-in specs.
COLLECT_GCC=riscv64-unknown-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/home/jeremy/gittrees/mustang/install/libexec/gcc/riscv64-unknown-linux-gnu/14.0.0/lto-wrapper
Target: riscv64-unknown-linux-gnu
Configured with: /home/jeremy/gittrees/mustang/gcc/configure --target=riscv64-unknown-linux-gnu --prefix=/home/jeremy/gittrees/mustang/install --with-sysroot=/home/jeremy/gittrees/mustang/install/sysroot --with-pkgversion=g59d27cc55a0 --with-system-zlib --enable-shared --enable-tls --enable-languages=c,c++,fortran --disable-libmudflap --disable-libssp --disable-libquadmath --disable-libsanitizer --disable-nls --disable-bootstrap --src=/home/jeremy/gittrees/mustang/gcc --enable-multilib --with-abi=lp64d --with-arch=rv64gc --with-tune= --with-isa-spec=20191213 'CFLAGS_FOR_TARGET=-O2    -mcmodel=medany' 'CXXFLAGS_FOR_TARGET=-O2    -mcmodel=medany'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 14.0.0 20230923 (experimental) (g59d27cc55a0)