lra: Handle SUBREG in lra_rtx_hash [PR119307]

lra: Handle SUBREG in lra_rtx_hash [PR119307]

The following testcase ICEs starting with r15-3213 in
decompose_normal_address and starting with r15-3288 ICEs
in lra_rtx_hash, which since r8-5466 can't handle SUBREG
(previously SUBREG was "ei" and lra_rtx_hash can handle
that through
val += lra_rtx_hash (XEXP (x, i));
for e and
val += XINT (x, i);
for i, now it is "ep" where p stands for poly_uint16).

The following patch fixes it by handling SUBREG directly, a variant
could be instead add
        case 'p':
          for (int i = 0; i < NUM_POLY_INT_COEFFS; ++i)
            val += SUBREG_BYTE (x).coeffs[i];
          break;
if you prefer that more (p is used solely for SUBREG and e.g. rtx_equal_p
has
        case 'p':
          if (maybe_ne (SUBREG_BYTE (x), SUBREG_BYTE (y)))
            return false;
          break;
).  Given the above rtx_equal_p snippet and that lra_rtx_hash
is solely used in invariant_hash (and recursion) and invariant_eq_p
uses rtx_equal_p we'll never consider different SUBREGs of the same thing
as the same invariant.

2025-03-18  Jakub Jelinek  <jakub@redhat.com>

	PR rtl-optimization/119307
	* lra.cc (lra_rtx_hash): Handle SUBREG.

	* gcc.target/i386/pr119307.c: New test.