[Bug target/96263] New: [10/11 Regression] ICE: in lra_assign, at lra-assigns.c:1648 with -O -flive-range-shrinkage -fnon-call-exceptions -msse4 --param=max-sched-ready-insns=1

["zsojka at seznam dot cz" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96263

            Bug ID: 96263
           Summary: [10/11 Regression] ICE: in lra_assign, at
                    lra-assigns.c:1648 with -O -flive-range-shrinkage
                    -fnon-call-exceptions -msse4
                    --param=max-sched-ready-insns=1
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Created attachment 48904
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48904&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O -flive-range-shrinkage -fnon-call-exceptions
-msse4 --param=max-sched-ready-insns=1 testcase.c 
testcase.c: In function 'm':
testcase.c:12:1: warning: AVX512F vector return without AVX512F enabled changes
the ABI [-Wpsabi]
   12 | a m(unsigned short n, __int128 o) {
      | ^
during RTL pass: reload
testcase.c:27:1: internal compiler error: in lra_assign, at lra-assigns.c:1648
   27 | }
      | ^
0xefe25b lra_assign(bool&)
        /repo/gcc-trunk/gcc/lra-assigns.c:1648
0xef7f3c lra(_IO_FILE*)
        /repo/gcc-trunk/gcc/lra.c:2465
0xea7949 do_reload
        /repo/gcc-trunk/gcc/ira.c:5525
0xea7949 execute
        /repo/gcc-trunk/gcc/ira.c:5711
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r11-2246-20200721142816-gc850a642e1d-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--disable-bootstrap --with-cloog --with-ppl --with-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r11-2246-20200721142816-gc850a642e1d-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.0.0 20200721 (experimental) (GCC)