From: Jakub Jelinek <jakub@redhat.com>
To: Richard Biener <rguenther@suse.de>
Cc: gcc-patches@gcc.gnu.org
Subject: [PATCH] tree-ssa-math-opts: Fix up uaddc/usubc pattern matching [PR110271]
Date: Fri, 16 Jun 2023 16:22:06 +0200 [thread overview]
Message-ID: <ZIxwDtDoomPI9d5n@tucnak> (raw)
Hi!
The following testcase ICEs, because I misremembered what the return value
from match_arith_overflow is. It isn't true if __builtin_*_overflow was
matched, but it is true only in the BIT_NOT_EXPR case if stmt was removed.
So, if match_arith_overflow matches something, gsi_stmt (gsi) will not
be stmt and match_uaddc_usubc will be confused and can ICE.
The following patch fixes it by checking if gsi_stmt (gsi) == stmt,
in that case we know it is still a PLUS_EXPR/MINUS_EXPR and we can try to
pattern match it further as UADDC/USUBC.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2023-06-16 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/110271
* tree-ssa-math-opts.cc (math_opts_dom_walker::after_dom_children)
<case PLUS_EXPR>: Ignore return value from match_arith_overflow,
instead call match_uaddc_usubc only if gsi_stmt (gsi) is still stmt.
* gcc.c-torture/compile/pr110271.c: New test.
--- gcc/tree-ssa-math-opts.cc.jj 2023-06-15 09:12:28.777829348 +0200
+++ gcc/tree-ssa-math-opts.cc 2023-06-16 10:44:31.231798664 +0200
@@ -5558,9 +5558,12 @@ math_opts_dom_walker::after_dom_children
case PLUS_EXPR:
case MINUS_EXPR:
- if (!convert_plusminus_to_widen (&gsi, stmt, code)
- && !match_arith_overflow (&gsi, stmt, code, m_cfg_changed_p))
- match_uaddc_usubc (&gsi, stmt, code);
+ if (!convert_plusminus_to_widen (&gsi, stmt, code))
+ {
+ match_arith_overflow (&gsi, stmt, code, m_cfg_changed_p);
+ if (gsi_stmt (gsi) == stmt)
+ match_uaddc_usubc (&gsi, stmt, code);
+ }
break;
case BIT_NOT_EXPR:
--- gcc/testsuite/gcc.c-torture/compile/pr110271.c.jj 2023-06-16 10:57:32.757621687 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr110271.c 2023-06-16 10:57:15.298871335 +0200
@@ -0,0 +1,24 @@
+/* PR tree-optimization/110271 */
+
+unsigned a, b, c, d, e;
+
+void
+foo (unsigned *x, int y, unsigned int *z)
+{
+ for (int i = 0; i < y; i++)
+ {
+ b += d;
+ a += b < d;
+ a += c = (__PTRDIFF_TYPE__) x > 3;
+ d = z[1] + (a < c);
+ a += e;
+ d += a < e;
+ }
+}
+
+void
+bar (unsigned int *z)
+{
+ unsigned *x = x;
+ foo (x, 9, z);
+}
Jakub
next reply other threads:[~2023-06-16 14:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-16 14:22 Jakub Jelinek [this message]
2023-06-16 17:04 ` Richard Biener
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=ZIxwDtDoomPI9d5n@tucnak \
--to=jakub@redhat.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=rguenther@suse.de \
/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).