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* [gcc/devel/c++-modules] Allow try_split to split RTX_FRAME_RELATED_P insns
@ 2020-08-28 15:59 Nathan Sidwell
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From: Nathan Sidwell @ 2020-08-28 15:59 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:e7d55c6b81733335d81e35f7c0116bbdffccb682
commit e7d55c6b81733335d81e35f7c0116bbdffccb682
Author: Senthil Kumar Selvaraj <saaadhu@gcc.gnu.org>
Date: Thu Aug 13 13:19:26 2020 +0530
Allow try_split to split RTX_FRAME_RELATED_P insns
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.
Diff:
---
gcc/emit-rtl.c | 19 ++++++--
gcc/recog.c | 134 +++++++++++++++++++++++++++++++--------------------------
gcc/recog.h | 2 +
3 files changed, 90 insertions(+), 65 deletions(-)
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index f9b0e9714d9..3706f0a03fd 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -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);
diff --git a/gcc/recog.c b/gcc/recog.c
index 25f19b1b1cf..ce83b7f5218 100644
--- a/gcc/recog.c
+++ b/gcc/recog.c
@@ -3277,6 +3277,78 @@ peep2_reinit_state (regset live)
COPY_REG_SET (peep2_insn_data[MAX_INSNS_PER_PEEP2].live_before, live);
}
+/* Copies frame related info of an insn (OLD_INSN) to the single
+ insn (NEW_INSN) that was obtained by splitting OLD_INSN. */
+
+void
+copy_frame_info_to_split_insn (rtx_insn *old_insn, rtx_insn *new_insn)
+{
+ bool any_note = false;
+ rtx note;
+
+ if (!RTX_FRAME_RELATED_P (old_insn))
+ return;
+
+ RTX_FRAME_RELATED_P (new_insn) = 1;
+
+ /* Allow the backend to fill in a note during the split. */
+ for (note = REG_NOTES (new_insn); note ; note = XEXP (note, 1))
+ switch (REG_NOTE_KIND (note))
+ {
+ case REG_FRAME_RELATED_EXPR:
+ case REG_CFA_DEF_CFA:
+ case REG_CFA_ADJUST_CFA:
+ case REG_CFA_OFFSET:
+ case REG_CFA_REGISTER:
+ case REG_CFA_EXPRESSION:
+ case REG_CFA_RESTORE:
+ case REG_CFA_SET_VDRAP:
+ any_note = true;
+ break;
+ default:
+ break;
+ }
+
+ /* If the backend didn't supply a note, copy one over. */
+ if (!any_note)
+ for (note = REG_NOTES (old_insn); note ; note = XEXP (note, 1))
+ switch (REG_NOTE_KIND (note))
+ {
+ case REG_FRAME_RELATED_EXPR:
+ case REG_CFA_DEF_CFA:
+ case REG_CFA_ADJUST_CFA:
+ case REG_CFA_OFFSET:
+ case REG_CFA_REGISTER:
+ case REG_CFA_EXPRESSION:
+ case REG_CFA_RESTORE:
+ case REG_CFA_SET_VDRAP:
+ add_reg_note (new_insn, REG_NOTE_KIND (note), XEXP (note, 0));
+ any_note = true;
+ break;
+ default:
+ break;
+ }
+
+ /* If there still isn't a note, make sure the unwind info sees the
+ same expression as before the split. */
+ if (!any_note)
+ {
+ rtx old_set, new_set;
+
+ /* The old insn had better have been simple, or annotated. */
+ old_set = single_set (old_insn);
+ gcc_assert (old_set != NULL);
+
+ new_set = single_set (new_insn);
+ if (!new_set || !rtx_equal_p (new_set, old_set))
+ add_reg_note (new_insn, REG_FRAME_RELATED_EXPR, old_set);
+ }
+
+ /* Copy prologue/epilogue status. This is required in order to keep
+ proper placement of EPILOGUE_BEG and the DW_CFA_remember_state. */
+ 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
@@ -3297,9 +3369,6 @@ peep2_attempt (basic_block bb, rtx_insn *insn, int match_len, rtx_insn *attempt)
old_insn = peep2_insn_data[peep2_current].insn;
if (RTX_FRAME_RELATED_P (old_insn))
{
- bool any_note = false;
- rtx note;
-
if (match_len != 0)
return NULL;
@@ -3313,64 +3382,7 @@ peep2_attempt (basic_block bb, rtx_insn *insn, int match_len, rtx_insn *attempt)
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. */
- for (note = REG_NOTES (new_insn); note ; note = XEXP (note, 1))
- switch (REG_NOTE_KIND (note))
- {
- case REG_FRAME_RELATED_EXPR:
- case REG_CFA_DEF_CFA:
- case REG_CFA_ADJUST_CFA:
- case REG_CFA_OFFSET:
- case REG_CFA_REGISTER:
- case REG_CFA_EXPRESSION:
- case REG_CFA_RESTORE:
- case REG_CFA_SET_VDRAP:
- any_note = true;
- break;
- default:
- break;
- }
-
- /* If the backend didn't supply a note, copy one over. */
- if (!any_note)
- for (note = REG_NOTES (old_insn); note ; note = XEXP (note, 1))
- switch (REG_NOTE_KIND (note))
- {
- case REG_FRAME_RELATED_EXPR:
- case REG_CFA_DEF_CFA:
- case REG_CFA_ADJUST_CFA:
- case REG_CFA_OFFSET:
- case REG_CFA_REGISTER:
- case REG_CFA_EXPRESSION:
- case REG_CFA_RESTORE:
- case REG_CFA_SET_VDRAP:
- add_reg_note (new_insn, REG_NOTE_KIND (note), XEXP (note, 0));
- any_note = true;
- break;
- default:
- break;
- }
-
- /* If there still isn't a note, make sure the unwind info sees the
- same expression as before the split. */
- if (!any_note)
- {
- rtx old_set, new_set;
-
- /* The old insn had better have been simple, or annotated. */
- old_set = single_set (old_insn);
- gcc_assert (old_set != NULL);
-
- new_set = single_set (new_insn);
- if (!new_set || !rtx_equal_p (new_set, old_set))
- add_reg_note (new_insn, REG_FRAME_RELATED_EXPR, old_set);
- }
-
- /* Copy prologue/epilogue status. This is required in order to keep
- proper placement of EPILOGUE_BEG and the DW_CFA_remember_state. */
- maybe_copy_prologue_epilogue_insn (old_insn, new_insn);
+ copy_frame_info_to_split_insn (old_insn, new_insn);
}
/* If we are splitting a CALL_INSN, look for the CALL_INSN
diff --git a/gcc/recog.h b/gcc/recog.h
index 3e4b55bdf3f..ae3675f5c82 100644
--- a/gcc/recog.h
+++ b/gcc/recog.h
@@ -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.
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