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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: [PATCH 2/6] posix: Suppress -Os warnings on fnmatch
Date: Wed, 21 Sep 2022 10:51:04 -0300	[thread overview]
Message-ID: <20220921135108.3324737-3-adhemerval.zanella@linaro.org> (raw)
In-Reply-To: <20220921135108.3324737-1-adhemerval.zanella@linaro.org>

GCC with -Os issues some may uninitialized warnings on fnmatch code.
All of the variables are already set when they are accessed on the
loop prior.

Checked on x86_64-linux-gnu and i686-linux-gnu.
---
 posix/fnmatch_loop.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/posix/fnmatch_loop.c b/posix/fnmatch_loop.c
index 9445ed9c58..23eeffc79c 100644
--- a/posix/fnmatch_loop.c
+++ b/posix/fnmatch_loop.c
@@ -530,6 +530,14 @@ FCT (const CHAR *pattern, const CHAR *string, const CHAR *string_end,
                               {
                                 /* Compare the byte sequence but only if
                                    this is not part of a range.  */
+
+				/* The compiler might warn that idx may be
+				   used uninitialized, however it will be
+				   reached iff elem < table_size which means
+				   that it was properly set in the loop
+				   above.   */
+                                DIAG_PUSH_NEEDS_COMMENT;
+                                DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
                                 if (! is_range
 
 # if WIDE_CHAR_VERSION
@@ -542,11 +550,19 @@ FCT (const CHAR *pattern, const CHAR *string, const CHAR *string_end,
                                     n += c1 - 1;
                                     goto matched;
                                   }
+                                DIAG_POP_NEEDS_COMMENT;
 
                                 /* Get the collation sequence value.  */
                                 is_seqval = true;
 # if WIDE_CHAR_VERSION
+                                /* The compile might warn that wextra may be
+				   used uninitialized and similar to 'idx'
+				   above it will be properly set by the loop.
+				   */
+                                DIAG_PUSH_NEEDS_COMMENT;
+                                DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
                                 cold = wextra[1 + wextra[0]];
+                                DIAG_POP_NEEDS_COMMENT;
 # else
                                 idx += 1 + extra[idx];
                                 /* Adjust for the alignment.  */
@@ -723,9 +739,24 @@ FCT (const CHAR *pattern, const CHAR *string, const CHAR *string_end,
                                     /* Get the collation sequence value.  */
                                     is_seqval = true;
 # if WIDE_CHAR_VERSION
+                                    /* The compiler might warn that wextra may
+                                       be used uninitialized, however it will
+                                       be reached iff elem < table_size which
+                                       means that it was properly set in the
+                                       loop above.   */
+                                    DIAG_PUSH_NEEDS_COMMENT;
+                                    DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
                                     cend = wextra[1 + wextra[0]];
+                                    DIAG_POP_NEEDS_COMMENT;
 # else
+				    /* The compile might warn that idx may
+				       be used uninitialized and similar to
+				       wextra above it will be properly set by
+				       the loop.   */
+                                    DIAG_PUSH_NEEDS_COMMENT;
+                                    DIAG_IGNORE_Os_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
                                     idx += 1 + extra[idx];
+                                    DIAG_POP_NEEDS_COMMENT;
                                     /* Adjust for the alignment.  */
                                     idx = (idx + 3) & ~3;
                                     cend = *((int32_t *) &extra[idx]);
-- 
2.34.1


  parent reply	other threads:[~2022-09-21 13:51 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-21 13:51 [PATCH 0/6] Fix -Os build Adhemerval Zanella
2022-09-21 13:51 ` [PATCH 1/6] locale: prevent maybe-uninitialized errors with -Os [BZ #19444] Adhemerval Zanella
2022-10-05 13:39   ` Carlos O'Donell
2022-09-21 13:51 ` Adhemerval Zanella [this message]
2022-10-05 13:47   ` [PATCH 2/6] posix: Suppress -Os warnings on fnmatch Carlos O'Donell
2022-10-05 20:01     ` Paul Eggert
2022-09-21 13:51 ` [PATCH 3/6] posix: Suppress -Os may be used uninitialized warnings on regexec Adhemerval Zanella
2022-10-05 13:49   ` Carlos O'Donell
2022-09-21 13:51 ` [PATCH 4/6] rt: Initialize mq_send input on tst-mqueue{5,6} Adhemerval Zanella
2022-10-05 13:51   ` Carlos O'Donell
2022-09-21 13:51 ` [PATCH 5/6] sunrpc: Suppress GCC -Os warning on user2netname Adhemerval Zanella
2022-10-05 13:52   ` Carlos O'Donell
2022-09-21 13:51 ` [PATCH 6/6] x86: Fix -Os build (BZ #29576) Adhemerval Zanella
2022-10-05 14:10   ` Carlos O'Donell
2022-10-05 17:21     ` H.J. Lu
2022-10-05 17:38       ` Adhemerval Zanella Netto
2022-10-05 18:06         ` H.J. Lu
2022-10-05 20:43           ` Adhemerval Zanella Netto
2022-10-05 21:27             ` H.J. Lu
2022-10-05 13:40 ` [PATCH 0/6] Fix -Os build Carlos O'Donell

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