On 11/20/23 11:56, Dimitar Dimitrov wrote:
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 ())
Yes, absolutely. It'll be fixed in the next update.
This also highlighted that I never added pru-elf to the configurations
in my tester. I remember thinking that it needed to be added, but
obviously that mental TODO got lost. I've just fixed that.
jeff
