[Bug tree-optimization/31602] Overflow warning causes GDB -Werror build failure

[ian at gcc dot gnu dot org]

--- Comment #5 from ian at gcc dot gnu dot org  2007-04-24 21:44 ---
Subject: Bug 31602

Author: ian
Date: Tue Apr 24 21:44:45 2007
New Revision: 124120

URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=124120
Log:
./:
PR tree-optimization/31602
* tree-ssa-loop-ch.c (copy_loop_headers): Set TREE_NO_WARNING for
conditionals in the copied loop header.
* tree-cfg.c (fold_cond_expr_cond): Don't issue undefined overflow
warnings if TREE_NO_WARNING is set.
* doc/invoke.texi (Warning Options): Clarify that
-Wstrict-overflow does not warn about loops.
testsuite/:
PR tree-optimization/31602
* gcc.dg/Wstrict-overflow-11.c: We no longer issue a warning.

Modified:
trunk/gcc/ChangeLog
trunk/gcc/doc/invoke.texi
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/gcc.dg/Wstrict-overflow-11.c
trunk/gcc/tree-cfg.c
trunk/gcc/tree-ssa-loop-ch.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31602

[Bug tree-optimization/31602] Overflow warning causes GDB -Werror build failure

[ian at gcc dot gnu dot org]

--- Comment #6 from ian at gcc dot gnu dot org  2007-04-24 22:54 ---
Subject: Bug 31602

Author: ian
Date: Tue Apr 24 22:54:22 2007
New Revision: 124127

URL: http://gcc.gnu.org/viewcvs?root=gccview=revrev=124127
Log:
PR tree-optimization/31602
* tree-ssa-loop-ch.c (copy_loop_headers): Set TREE_NO_WARNING for
conditionals in the copied loop header.
* tree-cfg.c (fold_cond_expr_cond): Don't issue undefined overflow
warnings if TREE_NO_WARNING is set.
* doc/invoke.texi (Warning Options): Clarify that
-Wstrict-overflow does not warn about loops.

Modified:
branches/gcc-4_2-branch/gcc/ChangeLog
branches/gcc-4_2-branch/gcc/doc/invoke.texi
branches/gcc-4_2-branch/gcc/tree-cfg.c
branches/gcc-4_2-branch/gcc/tree-ssa-loop-ch.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31602

[Bug tree-optimization/31602] Overflow warning causes GDB -Werror build failure

[ian at airs dot com]

--- Comment #7 from ian at airs dot com  2007-04-24 23:27 ---
Fixed on mainline and 4.2 branch.


-- 

ian at airs dot com changed:

   What|Removed |Added

 Status|NEW |RESOLVED
 Resolution||FIXED
   Target Milestone|--- |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31602

[Bug tree-optimization/31602] Overflow warning causes GDB -Werror build failure

[ian at airs dot com]

--- Comment #3 from ian at airs dot com  2007-04-20 16:17 ---
Created an attachment (id=13394)
 -- (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13394action=view)
Proposed patch

This patch fixes the test case in the PR.  I am testing it.  It would be
interesting to hear whether it also fixes the actual code in gdb.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31602

[Bug tree-optimization/31602] Overflow warning causes GDB -Werror build failure

[drow at gcc dot gnu dot org]

--- Comment #4 from drow at gcc dot gnu dot org  2007-04-20 20:04 ---
Subject: Re:  Overflow warning causes GDB
-Werror build failure

On Fri, Apr 20, 2007 at 03:17:19PM -, ian at airs dot com wrote:
 This patch fixes the test case in the PR.  I am testing it.  It would be
 interesting to hear whether it also fixes the actual code in gdb.

With this patch I can successfully build GDB for mips-linux - thanks!
(barring PR31605).


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31602

[Bug tree-optimization/31602] Overflow warning causes GDB -Werror build failure

[ian at airs dot com]

--- Comment #2 from ian at airs dot com  2007-04-18 15:14 ---
Yes, the warning is happening because gcc relies on undefined signed overflow
when assuming that it will execute the loop at least once.  Of course when
using -fwrapv the loop should not be executed at all when num  INT_MAX - 10.

I'll try to figure out what to do about this.


-- 

ian at airs dot com changed:

   What|Removed |Added

 CC|ian at gcc dot gnu dot org  |ian at airs dot com
 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2007-04-18 15:14:27
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31602

[Bug tree-optimization/31602] Overflow warning causes GDB -Werror build failure

[drow at false dot org]

--- Comment #1 from drow at gcc dot gnu dot org  2007-04-17 13:26 ---
Subject: Re:   New: Overflow warning causes
GDB -Werror build failure

On Tue, Apr 17, 2007 at 12:21:36PM -, drow at gcc dot gnu dot org wrote:
 GCC HEAD now warns about this testcase for mips-linux, reduced from
 gdb/value.c.

The warning also occurs once in top.c:

for (offset = num; offset  num + Hist_print  offset  hist_len; offset++)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31602