regcprop: Return from copy_value for unordered modes

The ICE in PR120276 resulted from a comparison of VNx4QI and V8QI using
partial_subreg_p in the function copy_value during the RTL pass
regcprop, failing the assertion in

inline bool
partial_subreg_p (machine_mode outermode, machine_mode innermode)
{
  /* Modes involved in a subreg must be ordered.  In particular, we must
     always know at compile time whether the subreg is paradoxical.  */
  poly_int64 outer_prec = GET_MODE_PRECISION (outermode);
  poly_int64 inner_prec = GET_MODE_PRECISION (innermode);
  gcc_checking_assert (ordered_p (outer_prec, inner_prec));
  return maybe_lt (outer_prec, inner_prec);
}

Returning from the function if the modes are not ordered before reaching
the call to partial_subreg_p resolves the ICE and passes bootstrap and
testing without regression.
OK for mainline?

Signed-off-by: Jennifer Schmitz <jschmitz@nvidia.com>

gcc/
	PR middle-end/120276
	* regcprop.cc (copy_value): Return in case of unordered modes.

gcc/testsuite/
	PR middle-end/120276
	* gcc.dg/torture/pr120276.c: New test.

0 files changed, 0 insertions, 0 deletions