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loop-unswitch-2.c: New testcase.

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* gcc.dg/loop-unswitch-2.c: New testcase.
	* gcc.dg/loop-unswitch-1.c: New testcase.
	* tree-ssa-loop-unswitch.c (hoist_guard): Update profile.

From-SVN: r245311
This commit is contained in:
Jan Hubicka 2017-02-09 19:13:35 +01:00 • committed by Jan Hubicka
parent 192b048b5c
commit 0b90c54148
5 changed files with 75 additions and 1 deletions
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4
gcc/ChangeLog
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@ -1,3 +1,7 @@
2017-02-09 Jan Hubicka <hubicka@ucw.cz>
* tree-ssa-loop-unswitch.c (hoist_guard): Update profile.
2017-02-09 Jakub Jelinek <jakub@redhat.com>
* omp-offload.c (oacc_loop_auto_partitions): Use || instead of |

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2017-02-09 Jan Hubicka <hubicka@ucw.cz>
* gcc.dg/loop-unswitch-2.c: Update testcase.
* gcc.dg/loop-unswitch-1.c: Update testcase.
2017-02-09 Marek Polacek <polacek@redhat.com>
PR c/79428

1
gcc/testsuite/gcc.dg/loop-unswitch-2.c
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@ -12,4 +12,5 @@ void foo (float **a, float **b, float *c, int n, int m, int l)
}
/* { dg-final { scan-tree-dump-times "guard hoisted" 3 "unswitch" } } */
/* { dg-final { scan-tree-dump-not "Invalid sum" "unswitch" } } */

1
gcc/testsuite/gcc.dg/loop-unswitch-3.c
View file

@ -22,5 +22,6 @@ float *foo(int ustride, int size, float *src)
}
/* { dg-final { scan-tree-dump-times "guard hoisted" 1 "unswitch" } } */
/* { dg-final { scan-tree-dump-not "Invalid sum" "unswitch" } } */

65
gcc/tree-ssa-loop-unswitch.c
View file

@ -787,6 +787,7 @@ hoist_guard (struct loop *loop, edge guard)
edge te, fe, e, new_edge;
gimple *stmt;
basic_block guard_bb = guard->src;
edge not_guard;
gimple_stmt_iterator gsi;
int flags = 0;
bool fix_dom_of_exit;
@ -818,18 +819,80 @@ hoist_guard (struct loop *loop, edge guard)
update_stmt (cond_stmt);
/* Create new loop pre-header. */
e = split_block (pre_header, last_stmt (pre_header));
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Moving guard %i->%i (prob %i) to bb %i, "
"new preheader is %i\n",
guard->src->index, guard->dest->index, guard->probability,
e->src->index, e->dest->index);
gcc_assert (loop_preheader_edge (loop)->src == e->dest);
if (guard == fe)
{
e->flags = EDGE_TRUE_VALUE;
flags |= EDGE_FALSE_VALUE;
not_guard = te;
}
else
{
e->flags = EDGE_FALSE_VALUE;
flags |= EDGE_TRUE_VALUE;
not_guard = fe;
}
new_edge = make_edge (pre_header, exit->dest, flags);
/* Determine the probability that we skip the loop. Assume that loop has
same average number of iterations regardless outcome of guard. */
new_edge->probability = guard->probability;
int skip_count = guard->src->count
? RDIV (guard->count * pre_header->count, guard->src->count)
: apply_probability (guard->count, new_edge->probability);
if (skip_count > e->count)
{
fprintf (dump_file, " Capping count; expect profile inconsistency\n");
skip_count = e->count;
}
new_edge->count = skip_count;
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Estimated probability of skipping loop is %i\n",
new_edge->probability);
/* Update profile after the transform:
First decrease count of path from newly hoisted loop guard
to loop header... */
e->count -= skip_count;
e->probability = REG_BR_PROB_BASE - new_edge->probability;
e->dest->count = e->count;
e->dest->frequency = EDGE_FREQUENCY (e);
/* ... now update profile to represent that original guard will be optimized
away ... */
guard->probability = 0;
guard->count = 0;
not_guard->probability = REG_BR_PROB_BASE;
/* This count is wrong (frequency of not_guard does not change),
but will be scaled later. */
not_guard->count = guard->src->count;
/* ... finally scale everything in the loop except for guarded basic blocks
where profile does not change. */
basic_block *body = get_loop_body (loop);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " Scaling nonguarded BBs in loop:");
for (unsigned int i = 0; i < loop->num_nodes; i++)
{
basic_block bb = body[i];
if (!dominated_by_p (CDI_DOMINATORS, bb, not_guard->dest))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " %i", bb->index);
scale_bbs_frequencies_int (&bb, 1, e->probability, REG_BR_PROB_BASE);
}
}
if (fix_dom_of_exit)
set_immediate_dominator (CDI_DOMINATORS, exit->dest, pre_header);
/* Add NEW_ADGE argument for all phi in post-header block. */
@ -856,7 +919,7 @@ hoist_guard (struct loop *loop, edge guard)
}
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, " guard hoisted.\n");
fprintf (dump_file, "\n guard hoisted.\n");
}
/* Return true if phi argument for exit edge can be used