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regrename: Avoid disrupting SMS schedule [PR95696]

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SMS is performed before reload, and each insn in SMS schedule uses
pseudo-register.  After reload, regrename pass try to adjust the hard
registers with def/use chain created by build_def_use.  For now, regrename
pass isn't aware of VLIW bundles created by SMS, it may updated a register
which may not be really unused, which will causes invalid VLIW bundles.
Before the final schedule, we recheck the validation of VLIW bundles and
reschedule the conflicted insns to avoid the above issue.  Rescheduling
the conflicted insns will destroy SMS schedule of the kernel loop, which
would be harmful to performance.

2020-08-03  Yunde Zhong  <zhongyunde@huawei.com>

gcc/
	PR rtl-optimization/95696
	* regrename.c (regrename_analyze): New param include_all_block_p
	with default value TRUE.  If set to false, avoid disrupting SMS
	schedule.
	* regrename.h (regrename_analyze): Adjust prototype.
This commit is contained in:
Yunde Zhong 2020-08-03 15:05:02 +01:00 • committed by Richard Sandiford
parent b32c5d0b72
commit d1773f58f3
2 changed files with 14 additions and 4 deletions
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16
gcc/regrename.c
View file

@ -695,10 +695,12 @@ merge_chains (du_head_p c1, du_head_p c2)
c1->cannot_rename |= c2->cannot_rename;
}
/* Analyze the current function and build chains for renaming. */
/* Analyze the current function and build chains for renaming.
If INCLUDE_ALL_BLOCKS_P is set to true, process all blocks,
ignoring BB_DISABLE_SCHEDULE. The default value is true. */
void
regrename_analyze (bitmap bb_mask)
regrename_analyze (bitmap bb_mask, bool include_all_block_p)
{
class bb_rename_info *rename_info;
int i;
@ -748,6 +750,14 @@ regrename_analyze (bitmap bb_mask)
if (dump_file)
fprintf (dump_file, "\nprocessing block %d:\n", bb1->index);
if (!include_all_block_p && (bb1->flags & BB_DISABLE_SCHEDULE) != 0)
{
if (dump_file)
fprintf (dump_file, "avoid disrupting the sms schedule of bb %d\n",
bb1->index);
continue;
}
init_rename_info (this_info, bb1);
success = build_def_use (bb1);
@ -1962,7 +1972,7 @@ regrename_optimize (void)
regrename_init (false);
regrename_analyze (NULL);
regrename_analyze (NULL, false);
rename_chains ();

2
gcc/regrename.h
View file

@ -100,7 +100,7 @@ extern vec<insn_rr_info> insn_rr;
extern void regrename_init (bool);
extern void regrename_finish (void);
extern void regrename_analyze (bitmap);
extern void regrename_analyze (bitmap, bool = true);
extern du_head_p regrename_chain_from_id (unsigned int);
extern int find_rename_reg (du_head_p, enum reg_class, HARD_REG_SET *, int,
bool);