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* [Bug c/38945] New: No warning when using unset variable
@ 2009-01-23 14:36 fredrik at hederstierna dot com
2009-01-24 16:05 ` [Bug c/38945] No warning when using uninitialized variable manu at gcc dot gnu dot org
2009-01-26 19:27 ` pinskia at gcc dot gnu dot org
0 siblings, 2 replies; 3+ messages in thread
From: fredrik at hederstierna dot com @ 2009-01-23 14:36 UTC (permalink / raw)
To: gcc-bugs
The 4.x compilers does not warn when using unset variables.
The 3.x compilers did warn on this:
Example:
int use_unset_variable(int y)
{
int x;
switch(y) {
case 0:
x = 0;
break;
default:
break;
}
x++;
return x;
}
Variable x could be unset when returning.
I use all warnings possible:
-Wall -W -Wextra
Best Regards
Fredrik
--
Summary: No warning when using unset variable
Product: gcc
Version: 4.3.2
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: fredrik at hederstierna dot com
GCC build triplet: arm-elf-gcc
GCC host triplet: x86-intel
GCC target triplet: arm-elf-gcc
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38945
^ permalink raw reply [flat|nested] 3+ messages in thread* [Bug c/38945] No warning when using uninitialized variable 2009-01-23 14:36 [Bug c/38945] New: No warning when using unset variable fredrik at hederstierna dot com @ 2009-01-24 16:05 ` manu at gcc dot gnu dot org 2009-01-26 19:27 ` pinskia at gcc dot gnu dot org 1 sibling, 0 replies; 3+ messages in thread From: manu at gcc dot gnu dot org @ 2009-01-24 16:05 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from manu at gcc dot gnu dot org 2009-01-24 16:05 ------- I am almost sure that this is CCP again assuming that the undefined value is the same as the constant assigned, hence x++ is converted to 0++. This can be checked using -fdump-tree-all-all-lineno. If so, a duplicate of bug 18501. -- manu at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |manu at gcc dot gnu dot org OtherBugsDependingO| |24639 nThis| | Summary|No warning when using unset |No warning when using |variable |uninitialized variable http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38945 ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c/38945] No warning when using uninitialized variable 2009-01-23 14:36 [Bug c/38945] New: No warning when using unset variable fredrik at hederstierna dot com 2009-01-24 16:05 ` [Bug c/38945] No warning when using uninitialized variable manu at gcc dot gnu dot org @ 2009-01-26 19:27 ` pinskia at gcc dot gnu dot org 1 sibling, 0 replies; 3+ messages in thread From: pinskia at gcc dot gnu dot org @ 2009-01-26 19:27 UTC (permalink / raw) To: gcc-bugs ------- Comment #2 from pinskia at gcc dot gnu dot org 2009-01-26 19:27 ------- Yes this is a dup of bug 18501. *** This bug has been marked as a duplicate of 18501 *** -- pinskia at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution| |DUPLICATE http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38945 ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2009-01-26 19:27 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2009-01-23 14:36 [Bug c/38945] New: No warning when using unset variable fredrik at hederstierna dot com 2009-01-24 16:05 ` [Bug c/38945] No warning when using uninitialized variable manu at gcc dot gnu dot org 2009-01-26 19:27 ` pinskia at gcc dot gnu dot org
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