From: Feng Xue OS <fxue@os.amperecomputing.com>
To: Jan Hubicka <hubicka@ucw.cz>
Cc: Martin Jambor <mjambor@suse.cz>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: [PATCH 2/2 V3] Use post-dom info to update if/switch predicate (PR ipa/91089)
Date: Mon, 16 Sep 2019 10:16:00 -0000 [thread overview]
Message-ID: <BYAPR01MB48690113E7A250FD7B343006F78C0@BYAPR01MB4869.prod.exchangelabs.com> (raw)
In-Reply-To: <20190914155710.kjmnk42tdkdgmzd7@kam.mff.cuni.cz>
This one is split from original patch.
Feng
---
diff --git a/gcc/ipa-fnsummary.c b/gcc/ipa-fnsummary.c
index 1bf1806eaf8..5423756d275 100644
--- a/gcc/ipa-fnsummary.c
+++ b/gcc/ipa-fnsummary.c
@@ -1197,8 +1197,14 @@ set_cond_stmt_execution_predicate (struct ipa_func_body_info *fbi,
? code : inverted_code);
/* invert_tree_comparison will return ERROR_MARK on FP
comparsions that are not EQ/NE instead of returning proper
- unordered one. Be sure it is not confused with NON_CONSTANT. */
- if (this_code != ERROR_MARK)
+ unordered one. Be sure it is not confused with NON_CONSTANT.
+
+ And if the edge's target is the final block of diamond CFG graph
+ of this conditional statement, we do not need to compute
+ predicate for the edge because the final block's predicate must
+ be at least as that of the first block of the statement. */
+ if (this_code != ERROR_MARK
+ && !dominated_by_p (CDI_POST_DOMINATORS, bb, e->dest))
{
predicate p
= add_condition (summary, index, size, &aggpos, this_code,
@@ -1282,6 +1288,14 @@ set_switch_stmt_execution_predicate (struct ipa_func_body_info *fbi,
*(predicate *) e->aux = false;
}
+ e = gimple_switch_edge (cfun, last, 0);
+ /* Set BOUND_COUNT to maximum count to bypass computing predicate for
+ default case if its target basic block is in convergence point of all
+ switch cases, which can be determined by checking whether it
+ post-dominates the switch statement. */
+ if (dominated_by_p (CDI_POST_DOMINATORS, bb, e->dest))
+ bound_count = INT_MAX;
+
n = gimple_switch_num_labels (last);
for (case_idx = 1; case_idx < n; ++case_idx)
{
@@ -1293,7 +1307,12 @@ set_switch_stmt_execution_predicate (struct ipa_func_body_info *fbi,
min = CASE_LOW (cl);
max = CASE_HIGH (cl);
- if (!max)
+ /* The case's target basic block is in convergence point of all switch
+ cases, its predicate should be at least as that of the switch
+ statement. */
+ if (dominated_by_p (CDI_POST_DOMINATORS, bb, e->dest))
+ p = true;
+ else if (!max)
p = add_condition (summary, index, size, &aggpos, EQ_EXPR,
unshare_expr_without_location (min));
else
@@ -1463,10 +1482,10 @@ compute_bb_predicates (struct ipa_func_body_info *fbi,
break;
}
}
- if (p == false)
- gcc_checking_assert (!bb->aux);
- else
+ if (p != false)
{
+ basic_block pdom_bb;
+
if (!bb->aux)
{
done = false;
@@ -1485,6 +1504,34 @@ compute_bb_predicates (struct ipa_func_body_info *fbi,
*((predicate *) bb->aux) = p;
}
}
+
+ /* For switch/if statement, we can OR-combine predicates of all
+ its cases/branches to get predicate for basic block in their
+ convergence point, but sometimes this will generate very
+ complicated predicate. Actually, we can get simplified
+ predicate in another way by using the fact that predicate
+ for a basic block must also hold true for its post dominators.
+ To be specific, basic block in convergence point of
+ conditional statement should include predicate of the
+ statement. */
+ pdom_bb = get_immediate_dominator (CDI_POST_DOMINATORS, bb);
+ if (pdom_bb == EXIT_BLOCK_PTR_FOR_FN (my_function) || !pdom_bb)
+ ;
+ else if (!pdom_bb->aux)
+ {
+ done = false;
+ pdom_bb->aux = edge_predicate_pool.allocate ();
+ *((predicate *) pdom_bb->aux) = p;
+ }
+ else if (p != *(predicate *) pdom_bb->aux)
+ {
+ p = p.or_with (summary->conds, *(predicate *)pdom_bb->aux);
+ if (p != *(predicate *) pdom_bb->aux)
+ {
+ done = false;
+ *((predicate *) pdom_bb->aux) = p;
+ }
+ }
}
}
}
@@ -2089,6 +2136,7 @@ analyze_function_body (struct cgraph_node *node, bool early)
if (opt_for_fn (node->decl, optimize))
{
calculate_dominance_info (CDI_DOMINATORS);
+ calculate_dominance_info (CDI_POST_DOMINATORS);
if (!early)
loop_optimizer_init (LOOPS_NORMAL | LOOPS_HAVE_RECORDED_EXITS);
else
@@ -2469,6 +2517,7 @@ analyze_function_body (struct cgraph_node *node, bool early)
else if (!ipa_edge_args_sum)
ipa_free_all_node_params ();
free_dominance_info (CDI_DOMINATORS);
+ free_dominance_info (CDI_POST_DOMINATORS);
}
if (dump_file)
{
diff --git a/gcc/testsuite/gcc.dg/ipa/pr91089.c b/gcc/testsuite/gcc.dg/ipa/pr91089.c
index e9e206fc24d..92b5550aa76 100644
--- a/gcc/testsuite/gcc.dg/ipa/pr91089.c
+++ b/gcc/testsuite/gcc.dg/ipa/pr91089.c
@@ -41,6 +41,52 @@ int callee (int i)
return data += i;
}
+int fn2 ();
+
+int callee_complex_predicate (int i)
+{
+ switch (i )
+ {
+ case 0:
+ fn ();
+ fn ();
+ fn ();
+ case 1:
+ fn ();
+ fn ();
+ case -1:
+ fn ();
+ case -2:
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ fn ();
+ data += i;
+ break;
+ }
+
+ if (i == 1000)
+ {
+ int j;
+
+ for (j = 0; j < 100; j++)
+ fn2 ();
+ }
+ return i + 3;
+}
+
int caller ()
{
return callee (-127) +
@@ -60,3 +106,4 @@ int caller ()
/* { dg-final { scan-ipa-dump "op0 != 0" "fnsummary" } } */
/* { dg-final { scan-ipa-dump "op0 < 5" "fnsummary" } } */
/* { dg-final { scan-ipa-dump "op0 > 7" "fnsummary" } } */
+/* { dg-final { scan-ipa-dump "loop depth: 1 .+ time:\[ \]*\[0-9\]+ predicate: \\(op0 == 1000\\)" "fnsummary" } } */
--
2.17.1
next prev parent reply other threads:[~2019-09-16 10:16 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 8:51 [PATCH] Setup predicate for switch default case in IPA " Feng Xue OS
2019-08-29 15:14 ` Martin Jambor
2019-08-30 8:32 ` Feng Xue OS
2019-09-02 3:06 ` [PATCH V2] " Feng Xue OS
2019-09-14 15:57 ` Jan Hubicka
2019-09-16 10:11 ` [PATCH 1/2 V3] " Feng Xue OS
2019-09-16 15:04 ` Jan Hubicka
2019-09-17 13:51 ` Feng Xue OS
2019-09-16 10:16 ` Feng Xue OS [this message]
2019-09-16 15:05 ` [PATCH 2/2 V3] Use post-dom info to update if/switch predicate " Jan Hubicka
2019-09-17 13:54 ` Feng Xue OS
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=BYAPR01MB48690113E7A250FD7B343006F78C0@BYAPR01MB4869.prod.exchangelabs.com \
--to=fxue@os.amperecomputing.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=hubicka@ucw.cz \
--cc=mjambor@suse.cz \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).