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frv.c (frv_ifcvt_modify_insn): Don't leave alone scratch insns that set a register live at the join point.

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* config/frv/frv.c (frv_ifcvt_modify_insn): Don't leave alone
scratch insns that set a register live at the join point.

From-SVN: r91344
This commit is contained in:
Alexandre Oliva 2004-11-26 18:53:47 +00:00 committed by Alexandre Oliva
parent 532815a787
commit 9a228f097b
2 changed files with 26 additions and 3 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
2004-11-26 Alexandre Oliva <aoliva@redhat.com>
* config/frv/frv.c (frv_ifcvt_modify_insn): Don't leave alone
scratch insns that set a register live at the join point.
2004-11-26 Kazu Hirata <kazu@cs.umass.edu>
* cse.c, tree-ssa-operands.c: Fix comment typos.

24
gcc/config/frv/frv.c
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@ -7418,10 +7418,28 @@ frv_ifcvt_modify_insn (ce_if_block_t *ce_info,
else if (frv_ifcvt.scratch_insns_bitmap
&& bitmap_bit_p (frv_ifcvt.scratch_insns_bitmap,
INSN_UID (insn))
/* We must not unconditionally set a reg set used as
scratch in the THEN branch if the same reg is live
in the ELSE branch. */
&& REG_P (SET_DEST (set))
/* We must not unconditionally set a scratch reg chosen
for a nested if-converted block if its incoming
value from the TEST block (or the result of the THEN
branch) could/should propagate to the JOIN block.
It suffices to test whether the register is live at
the JOIN point: if it's live there, we can infer
that we set it in the former JOIN block of the
nested if-converted block (otherwise it wouldn't
have been available as a scratch register), and it
is either propagated through or set in the other
conditional block. It's probably not worth trying
to catch the latter case, and it could actually
limit scheduling of the combined block quite
severely. */
&& ce_info->join_bb
&& ! (REGNO_REG_SET_P
(ce_info->join_bb->global_live_at_start,
REGNO (SET_DEST (set))))
/* Similarly, we must not unconditionally set a reg
used as scratch in the THEN branch if the same reg
is live in the ELSE branch. */
&& (! ce_info->else_bb
|| BLOCK_FOR_INSN (insn) == ce_info->else_bb
|| ! (REGNO_REG_SET_P