return seq;
}
+/* Notes like REG_EQUAL and REG_EQUIV refer to a set in an instruction.
+ Return the set in INSN that such notes describe, or NULL if the notes
+ have no meaning for INSN. */
+
+rtx
+set_for_reg_notes (rtx insn)
+{
+ rtx pat, reg;
+
+ if (!INSN_P (insn))
+ return NULL_RTX;
+
+ pat = PATTERN (insn);
+ if (GET_CODE (pat) == PARALLEL)
+ {
+ /* We do not use single_set because that ignores SETs of unused
+ registers. REG_EQUAL and REG_EQUIV notes really do require the
+ PARALLEL to have a single SET. */
+ if (multiple_sets (insn))
+ return NULL_RTX;
+ pat = XVECEXP (pat, 0, 0);
+ }
+
+ if (GET_CODE (pat) != SET)
+ return NULL_RTX;
+
+ reg = SET_DEST (pat);
+
+ /* Notes apply to the contents of a STRICT_LOW_PART. */
+ if (GET_CODE (reg) == STRICT_LOW_PART)
+ reg = XEXP (reg, 0);
+
+ /* Check that we have a register. */
+ if (!(REG_P (reg) || GET_CODE (reg) == SUBREG))
+ return NULL_RTX;
+
+ return pat;
+}
+
/* Place a note of KIND on insn INSN with DATUM as the datum. If a
note of this type already exists, remove it first. */
{
case REG_EQUAL:
case REG_EQUIV:
- /* Don't add REG_EQUAL/REG_EQUIV notes if the insn
- has multiple sets (some callers assume single_set
- means the insn only has one set, when in fact it
- means the insn only has one * useful * set). */
- if (GET_CODE (PATTERN (insn)) == PARALLEL && multiple_sets (insn))
- {
- gcc_assert (!note);
- return NULL_RTX;
- }
+ if (!set_for_reg_notes (insn))
+ return NULL_RTX;
/* Don't add ASM_OPERAND REG_EQUAL/REG_EQUIV notes.
It serves no useful purpose and breaks eliminate_regs. */
if (GET_CODE (datum) == ASM_OPERANDS)
return NULL_RTX;
-
- if (note)
- {
- XEXP (note, 0) = datum;
- df_notes_rescan (insn);
- return note;
- }
break;
default:
- if (note)
- {
- XEXP (note, 0) = datum;
- return note;
- }
break;
}
- add_reg_note (insn, kind, datum);
+ if (note)
+ XEXP (note, 0) = datum;
+ else
+ {
+ add_reg_note (insn, kind, datum);
+ note = REG_NOTES (insn);
+ }
switch (kind)
{
break;
}
- return REG_NOTES (insn);
+ return note;
}
/* Like set_unique_reg_note, but don't do anything unless INSN sets DST. */
rtx
set_dst_reg_note (rtx insn, enum reg_note kind, rtx datum, rtx dst)
{
- rtx set = single_set (insn);
+ rtx set = set_for_reg_notes (insn);
if (set && SET_DEST (set) == dst)
return set_unique_reg_note (insn, kind, datum);