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riscv-gcc-1
Commit 38d8473f by Richard Kenner
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(distribute_notes): If can't find place for REG_DEAD note, add an INSN 

with a USE to hold it.

From-SVN: r8625
parent 61314cb4
Showing with 51 additions and 39 deletions
gcc/combine.c
...@@ -10515,49 +10515,50 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1) ...@@ -10515,49 +10515,50 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
reg_n_refs[REGNO (XEXP (note, 0))] = 3; reg_n_refs[REGNO (XEXP (note, 0))] = 3;
if (place == 0) if (place == 0)
for (tem = prev_nonnote_insn (i3); {
tem && (GET_CODE (tem) == INSN for (tem = prev_nonnote_insn (i3);
|| GET_CODE (tem) == CALL_INSN); place == 0 && tem
tem = prev_nonnote_insn (tem)) && (GET_CODE (tem) == INSN || GET_CODE (tem) == CALL_INSN);
{ tem = prev_nonnote_insn (tem))
/* If the register is being set at TEM, see if that is all {
TEM is doing. If so, delete TEM. Otherwise, make this /* If the register is being set at TEM, see if that is all
into a REG_UNUSED note instead. */ TEM is doing. If so, delete TEM. Otherwise, make this
if (reg_set_p (XEXP (note, 0), PATTERN (tem))) into a REG_UNUSED note instead. */
{ if (reg_set_p (XEXP (note, 0), PATTERN (tem)))
rtx set = single_set (tem); {
rtx set = single_set (tem);
/* Verify that it was the set, and not a clobber that /* Verify that it was the set, and not a clobber that
modified the register. */ modified the register. */
if (set != 0 && ! side_effects_p (SET_SRC (set)) if (set != 0 && ! side_effects_p (SET_SRC (set))
&& rtx_equal_p (XEXP (note, 0), SET_DEST (set))) && rtx_equal_p (XEXP (note, 0), SET_DEST (set)))
{ {
/* Move the notes and links of TEM elsewhere. /* Move the notes and links of TEM elsewhere.
This might delete other dead insns recursively. This might delete other dead insns recursively.
First set the pattern to something that won't use First set the pattern to something that won't use
any register. */ any register. */
PATTERN (tem) = pc_rtx; PATTERN (tem) = pc_rtx;
distribute_notes (REG_NOTES (tem), tem, tem, distribute_notes (REG_NOTES (tem), tem, tem,
NULL_RTX, NULL_RTX, NULL_RTX); NULL_RTX, NULL_RTX, NULL_RTX);
distribute_links (LOG_LINKS (tem)); distribute_links (LOG_LINKS (tem));
PUT_CODE (tem, NOTE); PUT_CODE (tem, NOTE);
NOTE_LINE_NUMBER (tem) = NOTE_INSN_DELETED; NOTE_LINE_NUMBER (tem) = NOTE_INSN_DELETED;
NOTE_SOURCE_FILE (tem) = 0; NOTE_SOURCE_FILE (tem) = 0;
} }
else else
{ {
PUT_REG_NOTE_KIND (note, REG_UNUSED); PUT_REG_NOTE_KIND (note, REG_UNUSED);
/* If there isn't already a REG_UNUSED note, put one /* If there isn't already a REG_UNUSED note, put one
here. */ here. */
if (! find_regno_note (tem, REG_UNUSED, if (! find_regno_note (tem, REG_UNUSED,
REGNO (XEXP (note, 0)))) REGNO (XEXP (note, 0))))
place = tem; place = tem;
break; break;
} }
} }
else if (reg_referenced_p (XEXP (note, 0), PATTERN (tem)) else if (reg_referenced_p (XEXP (note, 0), PATTERN (tem))
...@@ -10567,7 +10568,18 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1) ...@@ -10567,7 +10568,18 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
place = tem; place = tem;
break; break;
} }
} }
/* If we haven't found an insn for the death note and it
is still a REG_DEAD note, but we have hit a CODE_LABEL,
insert a USE insn for the register at that label and
put the death node there. This prevents problems with
call-state tracking in caller-save.c. */
if (REG_NOTE_KIND (note) == REG_DEAD && place == 0 && tem != 0)
place
= emit_insn_after (gen_rtx (USE, VOIDmode, XEXP (note, 0)),
tem);
}
/* If the register is set or already dead at PLACE, we needn't do /* If the register is set or already dead at PLACE, we needn't do
anything with this note if it is still a REG_DEAD note. anything with this note if it is still a REG_DEAD note.
......
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