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re PR middle-end/36262 (Extreme memory usage of VRP compared to older versions)

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2019-09-04  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/36262
	* postreload-gcse.c: Include intl.h and gcse.h.
	(insert_expr_in_table): Insert at the head of cur_expr->avail_occr
	to avoid linear list walk.
	(record_last_mem_set_info): Gate off if not computing transparentness.
	(get_bb_avail_insn): If transparentness isn't computed give up
	early.
	(gcse_after_reload_main): Skip compute_transp and extended PRE
	if gcse_or_cprop_is_too_expensive says so.

From-SVN: r275365
This commit is contained in:
Richard Biener 2019-09-04 07:27:42 +00:00 • committed by Richard Biener
parent f8e36f0aef
commit dc91c65378
2 changed files with 44 additions and 32 deletions
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12
gcc/ChangeLog
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@ -1,3 +1,15 @@
2019-09-04 Richard Biener <rguenther@suse.de>
PR rtl-optimization/36262
* postreload-gcse.c: Include intl.h and gcse.h.
(insert_expr_in_table): Insert at the head of cur_expr->avail_occr
to avoid linear list walk.
(record_last_mem_set_info): Gate off if not computing transparentness.
(get_bb_avail_insn): If transparentness isn't computed give up
early.
(gcse_after_reload_main): Skip compute_transp and extended PRE
if gcse_or_cprop_is_too_expensive says so.
2019-09-03 Jozef Lawrynowicz <jozef.l@mittosystems.com>
* config/msp430/msp430.c (msp430_init_sections): Remove handling of the

64
gcc/postreload-gcse.c
View file

@ -38,7 +38,9 @@ along with GCC; see the file COPYING3. If not see
#include "params.h"
#include "tree-pass.h"
#include "dbgcnt.h"
#include "intl.h"
#include "gcse-common.h"
#include "gcse.h"
/* The following code implements gcse after reload, the purpose of this
pass is to cleanup redundant loads generated by reload and other
@ -364,7 +366,7 @@ insert_expr_in_table (rtx x, rtx_insn *insn)
int do_not_record_p;
hashval_t hash;
struct expr *cur_expr, **slot;
struct occr *avail_occr, *last_occr = NULL;
struct occr *avail_occr;
hash = hash_expr (x, &do_not_record_p);
@ -405,38 +407,22 @@ insert_expr_in_table (rtx x, rtx_insn *insn)
cur_expr = *slot;
}
/* Search for another occurrence in the same basic block. */
/* Search for another occurrence in the same basic block. We insert
insns blockwise from start to end, so keep appending to the
start of the list so we have to check only a single element. */
avail_occr = cur_expr->avail_occr;
while (avail_occr
&& BLOCK_FOR_INSN (avail_occr->insn) != BLOCK_FOR_INSN (insn))
{
/* If an occurrence isn't found, save a pointer to the end of
the list. */
last_occr = avail_occr;
avail_occr = avail_occr->next;
}
if (avail_occr)
/* Found another instance of the expression in the same basic block.
Prefer this occurrence to the currently recorded one. We want
the last one in the block and the block is scanned from start
to end. */
if (avail_occr
&& BLOCK_FOR_INSN (avail_occr->insn) == BLOCK_FOR_INSN (insn))
avail_occr->insn = insn;
else
{
/* First occurrence of this expression in this basic block. */
avail_occr = (struct occr *) obstack_alloc (&occr_obstack,
sizeof (struct occr));
/* First occurrence of this expression in any block? */
if (cur_expr->avail_occr == NULL)
cur_expr->avail_occr = avail_occr;
else
last_occr->next = avail_occr;
avail_occr->insn = insn;
avail_occr->next = NULL;
avail_occr->next = cur_expr->avail_occr;
avail_occr->deleted_p = 0;
cur_expr->avail_occr = avail_occr;
}
}
@ -710,6 +696,9 @@ record_last_reg_set_info_regno (rtx_insn *insn, int regno)
static void
record_last_mem_set_info (rtx_insn *insn)
{
if (!transp)
return;
struct modifies_mem *list_entry;
list_entry = (struct modifies_mem *) obstack_alloc (&modifies_mem_obstack,
@ -995,7 +984,8 @@ get_bb_avail_insn (basic_block bb, struct occr *orig_occr, int bitmap_index)
/* If we could not find an occurrence in BB, see if BB
has a single predecessor with an occurrence that is
transparent through BB. */
if (single_pred_p (bb)
if (transp
&& single_pred_p (bb)
&& bitmap_bit_p (transp[bb->index], bitmap_index)
&& (occr = get_bb_avail_insn (single_pred (bb), orig_occr, bitmap_index)))
{
@ -1371,6 +1361,10 @@ delete_redundant_insns (void)
static void
gcse_after_reload_main (rtx f ATTRIBUTE_UNUSED)
{
/* Disable computing transparentness if it is too expensive. */
bool do_transp
= !gcse_or_cprop_is_too_expensive (_("using simple load CSE after register "
"allocation"));
memset (&stats, 0, sizeof (stats));
@ -1392,15 +1386,21 @@ gcse_after_reload_main (rtx f ATTRIBUTE_UNUSED)
increase the number of redundant loads found. So compute transparency
information for each memory expression in the hash table. */
df_analyze ();
/* This cannot be part of the normal allocation routine because
we have to know the number of elements in the hash table. */
transp = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
expr_table->elements ());
bitmap_vector_ones (transp, last_basic_block_for_fn (cfun));
expr_table->traverse <FILE *, compute_expr_transp> (dump_file);
if (do_transp)
{
/* This cannot be part of the normal allocation routine because
we have to know the number of elements in the hash table. */
transp = sbitmap_vector_alloc (last_basic_block_for_fn (cfun),
expr_table->elements ());
bitmap_vector_ones (transp, last_basic_block_for_fn (cfun));
expr_table->traverse <FILE *, compute_expr_transp> (dump_file);
}
else
transp = NULL;
eliminate_partially_redundant_loads ();
delete_redundant_insns ();
sbitmap_vector_free (transp);
if (do_transp)
sbitmap_vector_free (transp);
if (dump_file)
{