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[ftracer] Add caching of can_duplicate_bb_p

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The fix "[omp, ftracer] Don't duplicate blocks in SIMT region" adds iteration
over insns in ignore_bb_p, which makes it more expensive.

Counteract this by piggybacking the computation of can_duplicate_bb_p onto
count_insns, which is called at the start of ftracer.

Bootstrapped and reg-tested on x86_64-linux.

gcc/ChangeLog:

2020-10-05  Tom de Vries  <tdevries@suse.de>

	* tracer.c (count_insns): Rename to ...
	(analyze_bb): ... this.
	(cache_can_duplicate_bb_p, cached_can_duplicate_bb_p): New function.
	(ignore_bb_p): Use cached_can_duplicate_bb_p.
	(tail_duplicate): Call cache_can_duplicate_bb_p.
This commit is contained in:
Tom de Vries 2020-10-04 12:01:34 +02:00
parent 9d63e3ab40
commit e6d995fdde
1 changed files with 41 additions and 6 deletions
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47
gcc/tracer.c
View file

@ -53,7 +53,7 @@
#include "fibonacci_heap.h"
#include "tracer.h"
static int count_insns (basic_block);
static void analyze_bb (basic_block, int *);
static bool better_p (const_edge, const_edge);
static edge find_best_successor (basic_block);
static edge find_best_predecessor (basic_block);
@ -143,6 +143,33 @@ can_duplicate_bb_p (const_basic_block bb)
return true;
}
static sbitmap can_duplicate_bb;
/* Cache VAL as value of can_duplicate_bb_p for BB. */
static inline void
cache_can_duplicate_bb_p (const_basic_block bb, bool val)
{
if (val)
bitmap_set_bit (can_duplicate_bb, bb->index);
}
/* Return cached value of can_duplicate_bb_p for BB. */
static bool
cached_can_duplicate_bb_p (const_basic_block bb)
{
if (can_duplicate_bb)
{
unsigned int size = SBITMAP_SIZE (can_duplicate_bb);
if ((unsigned int)bb->index < size)
return bitmap_bit_p (can_duplicate_bb, bb->index);
/* Assume added bb's should not be duplicated. */
return false;
}
return can_duplicate_bb_p (bb);
}
/* Return true if we should ignore the basic block for purposes of tracing. */
bool
ignore_bb_p (const_basic_block bb)
@ -152,24 +179,27 @@ ignore_bb_p (const_basic_block bb)
if (optimize_bb_for_size_p (bb))
return true;
return !can_duplicate_bb_p (bb);
return !cached_can_duplicate_bb_p (bb);
}
/* Return number of instructions in the block. */
static int
count_insns (basic_block bb)
static void
analyze_bb (basic_block bb, int *count)
{
gimple_stmt_iterator gsi;
gimple *stmt;
int n = 0;
bool can_duplicate = can_duplicate_bb_no_insn_iter_p (bb);
for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
{
stmt = gsi_stmt (gsi);
n += estimate_num_insns (stmt, &eni_size_weights);
can_duplicate = can_duplicate && can_duplicate_insn_p (stmt);
}
return n;
*count = n;
cache_can_duplicate_bb_p (bb, can_duplicate);
}
/* Return true if E1 is more frequent than E2. */
@ -317,6 +347,8 @@ tail_duplicate (void)
resize it. */
bb_seen = sbitmap_alloc (last_basic_block_for_fn (cfun) * 2);
bitmap_clear (bb_seen);
can_duplicate_bb = sbitmap_alloc (last_basic_block_for_fn (cfun));
bitmap_clear (can_duplicate_bb);
initialize_original_copy_tables ();
if (profile_info && profile_status_for_fn (cfun) == PROFILE_READ)
@ -330,7 +362,8 @@ tail_duplicate (void)
FOR_EACH_BB_FN (bb, cfun)
{
int n = count_insns (bb);
int n;
analyze_bb (bb, &n);
if (!ignore_bb_p (bb))
blocks[bb->index] = heap.insert (-bb->count.to_frequency (cfun), bb);
@ -420,6 +453,8 @@ tail_duplicate (void)
free_original_copy_tables ();
sbitmap_free (bb_seen);
sbitmap_free (can_duplicate_bb);
can_duplicate_bb = NULL;
free (trace);
free (counts);