On Sun, Nov 19, 2023 at 05:47:56PM -0700, Jeff Law wrote: ... > +/* Process uses in INSN. Set appropriate bits in LIVENOW for any chunks of > + pseudos that become live, potentially filtering using bits from LIVE_TMP. > + > + If MODIFIED is true, then optimize sign/zero extensions to SUBREGs when > + the extended bits are never read and mark pseudos which had extensions > + eliminated in CHANGED_PSEUDOS. */ > + > +static void > +ext_dce_process_uses (rtx insn, bitmap livenow, bitmap live_tmp, > + bool modify, bitmap changed_pseudos) > +{ > + /* A nonlocal goto implicitly uses the frame pointer. */ > + if (JUMP_P (insn) && find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX)) > + { > + bitmap_set_range (livenow, FRAME_POINTER_REGNUM * 4, 4); > + if (!HARD_FRAME_POINTER_IS_FRAME_POINTER) > + bitmap_set_range (livenow, HARD_FRAME_POINTER_REGNUM * 4, 4); > + } > + > + subrtx_var_iterator::array_type array_var; > + rtx pat = PATTERN (insn); > + FOR_EACH_SUBRTX_VAR (iter, array_var, pat, NONCONST) > + { > + /* An EXPR_LIST (from call fusage) ends in NULL_RTX. */ > + rtx x = *iter; > + if (x == NULL_RTX) > + continue; > + > + /* So the basic idea in this FOR_EACH_SUBRTX_VAR loop is to > + handle SETs explicitly, possibly propagating live information > + into the uses. > + > + We may continue the loop at various points which will cause > + iteration into the next level of RTL. Breaking from the loop > + is never safe as it can lead us to fail to process some of the > + RTL and thus not make objects live when necessary. */ > + enum rtx_code xcode = GET_CODE (x); > + if (xcode == SET) > + { > + const_rtx dst = SET_DEST (x); > + rtx src = SET_SRC (x); > + const_rtx y; > + unsigned HOST_WIDE_INT bit = 0; > + > + /* The code of the RHS of a SET. */ > + enum rtx_code code = GET_CODE (src); > + > + /* ?!? How much of this should mirror SET handling, potentially > + being shared? */ > + if (SUBREG_BYTE (dst).is_constant () && SUBREG_P (dst))
Shouldn't SUBREG_P be checked first like: if (SUBREG_P (dst) && SUBREG_BYTE (dst).is_constant ()) On pru-unknown-elf with RTL checking I get: conftest.c:16:1: internal compiler error: RTL check: expected code 'subreg', have 'reg' in ext_dce_process_uses, at ext-dce.cc:421 16 | } | ^ 0x158b39e rtl_check_failed_code1(rtx_def const*, rtx_code, char const*, int, char const*) /mnt/nvme/dinux/local-workspace/gcc/gcc/rtl.cc:770 0x223a486 ext_dce_process_uses /mnt/nvme/dinux/local-workspace/gcc/gcc/ext-dce.cc:421 0x223b5ba ext_dce_process_bb /mnt/nvme/dinux/local-workspace/gcc/gcc/ext-dce.cc:651 0x223bdd3 ext_dce /mnt/nvme/dinux/local-workspace/gcc/gcc/ext-dce.cc:802 0x223c0ac execute /mnt/nvme/dinux/local-workspace/gcc/gcc/ext-dce.cc:868 Regards, Dimitar