On 27/06/13 10:02, Zhenqiang Chen wrote:
Hi,
Shrink-wrap optimization sinks some instructions for more
opportunities. It uses DF_LR_BB_INFO (bb)->def to check whether BB
clobbers SRC. But for ARM, gcc might generate cond_exec insns before
shrink-wrapping. And DF_LR_BB_INFO (bb)->def does not include def info
from cond_exec insns. So the check in function
move_insn_for_shrink_wrap is not enough.
The patch is to add more check bases on DF_LIVE_BB_INFO (bb)->gen if
df-live is available.
Bootstrap and no make check regression on x86-64 and Panda board.
Is is OK for trunk?
Thanks!
-Zhenqiang
ChangeLog:
2013-06-27 Zhenqiang Chen <zhenqiang.c...@linaro.org>
PR target/57637
* function.c (move_insn_for_shrink_wrap): Check
DF_LIVE_BB_INFO (bb)->gen.
First off, this isn't really my area, so all this might be off base.
Did you really mean Richard Sandiford?
The code you're looking at here looks a bit odd. We have
live_out = df_get_live_out (bb);
live_in = df_get_live_in (next_block);
bb = next_block;
/* Check whether BB uses DEST or clobbers DEST. We need to add
INSN to BB if so. Either way, DEST is no longer live on entry,
except for any part that overlaps SRC (next loop). */
bb_uses = &DF_LR_BB_INFO (bb)->use;
bb_defs = &DF_LR_BB_INFO (bb)->def;
The setting of live_out and live in uses
if (df_live)
return DF_LIVE_OUT (bb);
else
return DF_LR_OUT (bb);
but for bb_uses and bb_defs, we unconditionally use the LR problem and
never consider live.
That seems strange to me.
Perhaps a better fix would be to set bb_uses and bb_defs based on
whether or not df_live was valid. ie
live_out = df_get_live_out (bb);
live_in = df_get_live_in (next_block);
bb = next_block;
/* Check whether BB uses DEST or clobbers DEST. We need to add
INSN to BB if so. Either way, DEST is no longer live on entry,
except for any part that overlaps SRC (next loop). */
if (df_live)
{
bb_uses = &DF_LIVE_BB_INFO (bb)->use;
bb_defs = &DF_LIVE_BB_INFO (bb)->def;
}
else
{
bb_uses = &DF_LR_BB_INFO (bb)->use;
bb_defs = &DF_LR_BB_INFO (bb)->def;
}
Richard (S), what are your thoughts?
R.
diff --git a/gcc/function.c b/gcc/function.c
index 3e33fc7..08ca4a1 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -5508,7 +5508,8 @@ move_insn_for_shrink_wrap (basic_block bb, rtx insn,
bb_defs = &DF_LR_BB_INFO (bb)->def;
for (i = dregno; i < end_dregno; i++)
{
- if (REGNO_REG_SET_P (bb_uses, i) || REGNO_REG_SET_P (bb_defs, i))
+ if (REGNO_REG_SET_P (bb_uses, i) || REGNO_REG_SET_P (bb_defs, i)
+ || (df_live && REGNO_REG_SET_P (&DF_LIVE_BB_INFO (bb)->gen, i)))
next_block = NULL;
CLEAR_REGNO_REG_SET (live_out, i);
CLEAR_REGNO_REG_SET (live_in, i);
@@ -5518,7 +5519,8 @@ move_insn_for_shrink_wrap (basic_block bb, rtx insn,
Either way, SRC is now live on entry. */
for (i = sregno; i < end_sregno; i++)
{
- if (REGNO_REG_SET_P (bb_defs, i))
+ if (REGNO_REG_SET_P (bb_defs, i)
+ || (df_live && REGNO_REG_SET_P (&DF_LIVE_BB_INFO (bb)->gen, i)))
next_block = NULL;
SET_REGNO_REG_SET (live_out, i);
SET_REGNO_REG_SET (live_in, i);
