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Allow try_split to split RTX_FRAME_RELATED_P insns

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Instead of rejecting RTX_FRAME_RELATED_P insns, allow try_split to split
such insns, provided the split is after reload, and the result of the split
is a single insn.

recog.c:peep2_attempt already splits an RTX_FRAME_RELATED_P insn splitting
to a single insn. This patch refactors existing code copying frame related
info to a separate function (copy_frame_info_to_split_insn) and calls it
from both peep2_attempt and try_split.

2020-08-21  Senthil Kumar Selvaraj  <saaadhu@gcc.gnu.org>

gcc/ChangeLog:

	* emit-rtl.c (try_split): Call copy_frame_info_to_split_insn
	to split certain RTX_FRAME_RELATED_P insns.
	* recog.c (copy_frame_info_to_split_insn): New function.
	(peep2_attempt): Split copying of frame related info of
	RTX_FRAME_RELATED_P insns into above function and call it.
	* recog.h (copy_frame_info_to_split_insn): Declare it.
This commit is contained in:
Senthil Kumar Selvaraj 2020-08-13 13:19:26 +05:30
parent 988fb2f597
commit e7d55c6b81
3 changed files with 90 additions and 65 deletions
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19
gcc/emit-rtl.c
View File

@ -3822,10 +3822,6 @@ try_split (rtx pat, rtx_insn *trial, int last)
int njumps = 0;
rtx_insn *call_insn = NULL;
/* We're not good at redistributing frame information. */
if (RTX_FRAME_RELATED_P (trial))
return trial;
if (any_condjump_p (trial)
&& (note = find_reg_note (trial, REG_BR_PROB, 0)))
split_branch_probability
@ -3842,6 +3838,7 @@ try_split (rtx pat, rtx_insn *trial, int last)
if (!seq)
return trial;
int split_insn_count = 0;
/* Avoid infinite loop if any insn of the result matches
the original pattern. */
insn_last = seq;
@ -3850,11 +3847,25 @@ try_split (rtx pat, rtx_insn *trial, int last)
if (INSN_P (insn_last)
&& rtx_equal_p (PATTERN (insn_last), pat))
return trial;
split_insn_count++;
if (!NEXT_INSN (insn_last))
break;
insn_last = NEXT_INSN (insn_last);
}
/* We're not good at redistributing frame information if
the split occurs before reload or if it results in more
than one insn. */
if (RTX_FRAME_RELATED_P (trial))
{
if (!reload_completed || split_insn_count != 1)
return trial;
rtx_insn *new_insn = seq;
rtx_insn *old_insn = trial;
copy_frame_info_to_split_insn (old_insn, new_insn);
}
/* We will be adding the new sequence to the function. The splitters
may have introduced invalid RTL sharing, so unshare the sequence now. */
unshare_all_rtl_in_chain (seq);

72
gcc/recog.c
View File

@ -3277,42 +3277,18 @@ peep2_reinit_state (regset live)
COPY_REG_SET (peep2_insn_data[MAX_INSNS_PER_PEEP2].live_before, live);
}
/* While scanning basic block BB, we found a match of length MATCH_LEN,
starting at INSN. Perform the replacement, removing the old insns and
replacing them with ATTEMPT. Returns the last insn emitted, or NULL
if the replacement is rejected. */
/* Copies frame related info of an insn (OLD_INSN) to the single
insn (NEW_INSN) that was obtained by splitting OLD_INSN. */
static rtx_insn *
peep2_attempt (basic_block bb, rtx_insn *insn, int match_len, rtx_insn *attempt)
{
int i;
rtx_insn *last, *before_try, *x;
rtx eh_note, as_note;
rtx_insn *old_insn;
rtx_insn *new_insn;
bool was_call = false;
/* If we are splitting an RTX_FRAME_RELATED_P insn, do not allow it to
match more than one insn, or to be split into more than one insn. */
old_insn = peep2_insn_data[peep2_current].insn;
if (RTX_FRAME_RELATED_P (old_insn))
void
copy_frame_info_to_split_insn (rtx_insn *old_insn, rtx_insn *new_insn)
{
bool any_note = false;
rtx note;
if (match_len != 0)
return NULL;
if (!RTX_FRAME_RELATED_P (old_insn))
return;
/* Look for one "active" insn. I.e. ignore any "clobber" insns that
may be in the stream for the purpose of register allocation. */
if (active_insn_p (attempt))
new_insn = attempt;
else
new_insn = next_active_insn (attempt);
if (next_active_insn (new_insn))
return NULL;
/* We have a 1-1 replacement. Copy over any frame-related info. */
RTX_FRAME_RELATED_P (new_insn) = 1;
/* Allow the backend to fill in a note during the split. */
@ -3373,6 +3349,42 @@ peep2_attempt (basic_block bb, rtx_insn *insn, int match_len, rtx_insn *attempt)
maybe_copy_prologue_epilogue_insn (old_insn, new_insn);
}
/* While scanning basic block BB, we found a match of length MATCH_LEN,
starting at INSN. Perform the replacement, removing the old insns and
replacing them with ATTEMPT. Returns the last insn emitted, or NULL
if the replacement is rejected. */
static rtx_insn *
peep2_attempt (basic_block bb, rtx_insn *insn, int match_len, rtx_insn *attempt)
{
int i;
rtx_insn *last, *before_try, *x;
rtx eh_note, as_note;
rtx_insn *old_insn;
rtx_insn *new_insn;
bool was_call = false;
/* If we are splitting an RTX_FRAME_RELATED_P insn, do not allow it to
match more than one insn, or to be split into more than one insn. */
old_insn = peep2_insn_data[peep2_current].insn;
if (RTX_FRAME_RELATED_P (old_insn))
{
if (match_len != 0)
return NULL;
/* Look for one "active" insn. I.e. ignore any "clobber" insns that
may be in the stream for the purpose of register allocation. */
if (active_insn_p (attempt))
new_insn = attempt;
else
new_insn = next_active_insn (attempt);
if (next_active_insn (new_insn))
return NULL;
/* We have a 1-1 replacement. Copy over any frame-related info. */
copy_frame_info_to_split_insn (old_insn, new_insn);
}
/* If we are splitting a CALL_INSN, look for the CALL_INSN
in SEQ and copy our CALL_INSN_FUNCTION_USAGE and other
cfg-related call notes. */

2
gcc/recog.h
View File

@ -150,6 +150,8 @@ extern rtx_insn *peephole2_insns (rtx, rtx_insn *, int *);
extern int store_data_bypass_p (rtx_insn *, rtx_insn *);
extern int if_test_bypass_p (rtx_insn *, rtx_insn *);
extern void copy_frame_info_to_split_insn (rtx_insn *, rtx_insn *);
#ifndef GENERATOR_FILE
/* Try recognizing the instruction INSN,
and return the code number that results.