From: JiangNing OS <jiangning@os.amperecomputing.com>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: [PATCH] PR91195: fix -Wmaybe-uninitialized warning for conditional store optimization
Date: Tue, 23 Jul 2019 05:52:00 -0000 [thread overview]
Message-ID: <MN2PR01MB5424AEF5B753FFAEB6FEB00E9CC70@MN2PR01MB5424.prod.exchangelabs.com> (raw)
This patch is to fix PR91195. Is it OK for trunk?
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 711a31ea597..4db36644160 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-07-22 Jiangning Liu <jiangning.liu@amperecomputing.com>
+
+ PR middle-end/91195
+ * tree-ssa-phiopt.c (cond_store_replacement): Work around
+ -Wmaybe-uninitialized warning.
+
2019-07-22 Stafford Horne <shorne@gmail.com>
* config/or1k/or1k.c (or1k_expand_compare): Check for int before
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index b64bde695f4..7a86007d087 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -2240,6 +2240,14 @@ cond_store_replacement (basic_block middle_bb, basic_block join_bb,
tree base = get_base_address (lhs);
if (!auto_var_p (base) || TREE_ADDRESSABLE (base))
return false;
+
+ /* The transformation below will inherently introduce a memory load,
+ for which LHS may not be initialized yet if it is not in NOTRAP,
+ so a -Wmaybe-uninitialized warning message could be triggered.
+ Since it's a bit hard to have a very accurate uninitialization
+ analysis to memory reference, we disable the warning here to avoid
+ confusion. */
+ TREE_NO_WARNING (lhs) = 1;
}
/* Now we've checked the constraints, so do the transformation:
Thanks,
-Jiangning
next reply other threads:[~2019-07-23 4:26 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-23 5:52 JiangNing OS [this message]
2019-07-23 16:31 ` Martin Sebor
2019-07-24 15:28 ` Jeff Law
2019-07-24 17:00 ` Martin Sebor
2019-07-24 17:23 ` Jeff Law
2019-07-24 18:09 ` Martin Sebor
2019-07-25 6:27 ` JiangNing OS
2019-07-25 19:09 ` Martin Sebor
2019-07-26 5:07 ` Jeff Law
2019-07-29 16:10 ` Jakub Jelinek
2019-07-30 8:35 ` Richard Biener
2019-07-30 8:36 ` Jakub Jelinek
2019-07-30 8:49 ` Richard Biener
2019-07-30 14:51 ` Martin Sebor
2019-08-07 22:17 ` Jeff Law
2019-09-03 20:22 ` Jeff Law
2019-07-24 16:00 ` Jeff Law
2019-07-29 16:03 ` Jakub Jelinek
2019-09-03 20:27 ` Jeff Law
2019-11-20 0:14 ` Jakub Jelinek
2019-11-20 2:33 ` Jeff Law
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=MN2PR01MB5424AEF5B753FFAEB6FEB00E9CC70@MN2PR01MB5424.prod.exchangelabs.com \
--to=jiangning@os.amperecomputing.com \
--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).