From: Richard Biener <rguenther@suse.de>
To: gcc-patches@gcc.gnu.org
Subject: [PATCH] tree-optimization/102893 - properly DCE empty loops inside infinite loops
Date: Fri, 22 Oct 2021 13:42:52 +0200 (CEST) [thread overview]
Message-ID: <rs8n479p-r1sp-138o-39qp-83788snon19p@fhfr.qr> (raw)
The following fixes the test for an exit edge I put in place for
the fix for PR45178 where I somehow misunderstood how the cyclic
list works.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2021-10-22 Richard Biener <rguenther@suse.de>
PR tree-optimization/102893
* tree-ssa-dce.c (find_obviously_necessary_stmts): Fix the
test for an exit edge.
* gcc.dg/tree-ssa/ssa-dce-9.c: New testcase.
---
gcc/testsuite/gcc.dg/tree-ssa/ssa-dce-9.c | 10 ++++++++++
gcc/tree-ssa-dce.c | 2 +-
2 files changed, 11 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/ssa-dce-9.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-dce-9.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dce-9.c
new file mode 100644
index 00000000000..e1ffa7f038d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-dce-9.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-cddce1" } */
+
+int main()
+{
+ while(1)
+ for(int i=0; i<9000000; i++){}
+}
+
+/* { dg-final { scan-tree-dump-not "if" "cddce1" } } */
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index c4907af923c..372e0691ae6 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -436,7 +436,7 @@ find_obviously_necessary_stmts (bool aggressive)
for (auto loop : loops_list (cfun, 0))
/* For loops without an exit do not mark any condition. */
- if (loop->exits->next && !finite_loop_p (loop))
+ if (loop->exits->next->e && !finite_loop_p (loop))
{
if (dump_file)
fprintf (dump_file, "cannot prove finiteness of loop %i\n",
--
2.31.1
reply other threads:[~2021-10-22 11:42 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
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=rs8n479p-r1sp-138o-39qp-83788snon19p@fhfr.qr \
--to=rguenther@suse.de \
--cc=gcc-patches@gcc.gnu.org \
/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).