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(distribute_notes, case REG_UNUSED): Ignore notes when
from_insn != i3 only if the notes would remain as REG_UNUSED notes.

From-SVN: r7942
This commit is contained in:
Jim Wilson 1994-08-18 11:09:33 -07:00
parent 0179115349
commit 07d0cbddd4
1 changed files with 9 additions and 8 deletions
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17
gcc/combine.c
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@ -10342,10 +10342,7 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
switch (REG_NOTE_KIND (note))
{
case REG_UNUSED:
/* If this note is from any insn other than i3, then we have no
use for it, and must ignore it.
Any clobbers for i3 may still exist, and so we must process
/* Any clobbers for i3 may still exist, and so we must process
REG_UNUSED notes from that insn.
Any clobbers from i2 or i1 can only exist if they were added by
@ -10355,14 +10352,18 @@ distribute_notes (notes, from_insn, i3, i2, elim_i2, elim_i1)
if it is for the same register as the original i3 dest.
In that case, we will notice that the register is set in i3,
and then add a REG_UNUSED note for the destination of i3, which
is wrong. */
if (from_insn != i3)
break;
is wrong. However, it is possible to have REG_UNUSED notes from
i2 or i1 for register which were both used and clobbered, so
we keep notes from i2 or i1 if they will turn into REG_DEAD
notes. */
/* If this register is set or clobbered in I3, put the note there
unless there is one already. */
else if (reg_set_p (XEXP (note, 0), PATTERN (i3)))
if (reg_set_p (XEXP (note, 0), PATTERN (i3)))
{
if (from_insn != i3)
break;
if (! (GET_CODE (XEXP (note, 0)) == REG
? find_regno_note (i3, REG_UNUSED, REGNO (XEXP (note, 0)))
: find_reg_note (i3, REG_UNUSED, XEXP (note, 0))))