[Bug target/99829] New: MVE: ICE in lra_assign at -O3

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99829

            Bug ID: 99829
           Summary: MVE: ICE in lra_assign at -O3
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: acoplan at gcc dot gnu.org
  Target Milestone: ---

The following fails:

$ arm-eabi-gcc -c -xc++ gcc/testsuite/c-c++-common/torture/vshuf-v16qi.c
-march=armv8.1-m.main+mve -mfloat-abi=hard -mtune=cortex-m7 -O3
during RTL pass: reload
In file included from gcc/testsuite/c-c++-common/torture/vshuf-v16qi.c:5:
gcc/testsuite/c-c++-common/torture/vshuf-main.inc: In function 'int main()':
gcc/testsuite/c-c++-common/torture/vshuf-main.inc:26:1: internal compiler
error: in lra_assign, at lra-assigns.c:1649
   26 | }
      | ^
0xe2d8fe lra_assign(bool&)
        /home/alecop01/toolchain/src/gcc/gcc/lra-assigns.c:1649
0xe298f2 lra(_IO_FILE*)
        /home/alecop01/toolchain/src/gcc/gcc/lra.c:2387
0xddb586 do_reload
        /home/alecop01/toolchain/src/gcc/gcc/ira.c:5835
0xddb586 execute
        /home/alecop01/toolchain/src/gcc/gcc/ira.c:6021
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.

On the GCC 10 branch, we ICE even without the -mtune option (the default
scheduling for MVE changed for GCC 11).