[Bug target/125746] New: [16/17 Regression] ICE in gen_rtx_SUBREG, at emit-rtl.cc:1043 since r16-718

[mjires at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125746

            Bug ID: 125746
           Summary: [16/17 Regression] ICE in gen_rtx_SUBREG, at
                    emit-rtl.cc:1043 since r16-718
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mjires at gcc dot gnu.org
                CC: dimitar at gcc dot gnu.org
  Target Milestone: ---
            Target: x86_64-pc-linux-gnu

Compiling reduced testcase gcc.target/i386/pr104974.c results in ICE since
r16-718-geb2ea476db2182.

$ cat pr104974.c
void foo() {
  register short b __asm("%xmm1") = 0;

  asm("" : "+v"(b));
}


$ gcc pr104974.c -mno-sse2
during RTL pass: reload
pr104974.c: In function ‘foo’:
pr104974.c:5:1: internal compiler error: in gen_rtx_SUBREG, at emit-rtl.cc:1047
    5 | }
      | ^
0x26541bd internal_error(char const*, ...)
        /home/mjires/git/GCC/master/gcc/diagnostic-global-context.cc:787
0x265f6a3 fancy_abort(char const*, int, char const*)
        /home/mjires/git/GCC/master/gcc/diagnostics/context.cc:1813
0xb3b9e3 gen_rtx_SUBREG(machine_mode, rtx_def*, poly_int<1u, unsigned long>)
        /home/mjires/git/GCC/master/gcc/emit-rtl.cc:1047
0xb3ba0c gen_lowpart_SUBREG(machine_mode, rtx_def*)
        /home/mjires/git/GCC/master/gcc/emit-rtl.cc:1062
0xe4aad9 emit_spill_move
        /home/mjires/git/GCC/master/gcc/lra-constraints.cc:1373
0xe5992d curr_insn_transform
        /home/mjires/git/GCC/master/gcc/lra-constraints.cc:4607
0xe5ca16 lra_constraints(bool)
        /home/mjires/git/GCC/master/gcc/lra-constraints.cc:5792
0xe42287 lra(_IO_FILE*, int)
        /home/mjires/git/GCC/master/gcc/lra.cc:2504
0xdf4b4f do_reload
        /home/mjires/git/GCC/master/gcc/ira.cc:6084
0xdf4b4f execute
        /home/mjires/git/GCC/master/gcc/ira.cc:6272
/home/mjires/built/master/libexec/gcc/x86_64-pc-linux-gnu/17.0.0/cc1 -quiet
pr104974.c -quiet -dumpdir a- -dumpbase pr104974.c -dumpbase-ext .c -mno-sse2
-mtune=generic -march=x86-64 -o /tmp/ccvw9F7u.s
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.


$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/home/mjires/built/master/libexec/gcc/x86_64-pc-linux-gnu/17.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /home/mjires/git/GCC/master/configure
--prefix=/home/mjires/built/master --disable-bootstrap
--enable-languages=c,c++,fortran,lto --disable-multilib --disable-libsanitizer
--enable-checking : (reconfigured) /home/mjires/git/GCC/master/configure
--prefix=/home/mjires/built/master --disable-bootstrap
--enable-languages=c,c++,fortran,lto --disable-multilib --disable-libsanitizer
--enable-checking : (reconfigured) /home/mjires/git/GCC/master/configure
--prefix=/home/mjires/built/master --disable-bootstrap --disable-multilib
--disable-libsanitizer --enable-checking --enable-languages=c,c++,fortran,lto
--no-create --no-recursion
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 17.0.0 20260611 (experimental) (GCC)