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* [Bug tree-optimization/17046] New: An unused array is not optimized away.
@ 2004-08-16 6:56 kazu at cs dot umass dot edu
2004-08-16 7:02 ` [Bug tree-optimization/17046] " pinskia at gcc dot gnu dot org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: kazu at cs dot umass dot edu @ 2004-08-16 6:56 UTC (permalink / raw)
To: gcc-bugs
Consider:
static const int banana[] = { 0, 1, 2, 3 };
int
foo (void)
{
int a = banana[2];
return a * 0;
}
./cc1 -O2 -fomit-frame-pointer generates:
.file "test.c"
.section .rodata
.align 4
.type banana, @object
.size banana, 16
banana:
.long 0
.long 1
.long 2
.long 3
.text
.p2align 2,,3
.globl foo
.type foo, @function
foo:
xorl %eax, %eax
ret
.size foo, .-foo
.ident "GCC: (GNU) 3.5.0 20040816 (experimental)"
.section .note.GNU-stack,"",@progbits
Note that array "banana" is not optimized away.
--
Summary: An unused array is not optimized away.
Product: gcc
Version: 3.5.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P2
Component: tree-optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: kazu at cs dot umass dot edu
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17046
^ permalink raw reply [flat|nested] 4+ messages in thread* [Bug tree-optimization/17046] An unused array is not optimized away. 2004-08-16 6:56 [Bug tree-optimization/17046] New: An unused array is not optimized away kazu at cs dot umass dot edu @ 2004-08-16 7:02 ` pinskia at gcc dot gnu dot org 2004-08-16 7:31 ` kazu at cs dot umass dot edu 2005-05-04 2:16 ` pinskia at gcc dot gnu dot org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2004-08-16 7:02 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2004-08-16 07:02 ------- Confirmed, I think this is a case where we are marking the static variable as referenced too early. -- What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Ever Confirmed| |1 Last reconfirmed|0000-00-00 00:00:00 |2004-08-16 07:02:20 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17046 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/17046] An unused array is not optimized away. 2004-08-16 6:56 [Bug tree-optimization/17046] New: An unused array is not optimized away kazu at cs dot umass dot edu 2004-08-16 7:02 ` [Bug tree-optimization/17046] " pinskia at gcc dot gnu dot org @ 2004-08-16 7:31 ` kazu at cs dot umass dot edu 2005-05-04 2:16 ` pinskia at gcc dot gnu dot org 2 siblings, 0 replies; 4+ messages in thread From: kazu at cs dot umass dot edu @ 2004-08-16 7:31 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From kazu at cs dot umass dot edu 2004-08-16 07:31 ------- Yes. In fact, the following piece of code does *not* generate the array in the assembly output. static const int banana[] = { 0, 1, 2, 3 }; int foo (void) { return banana[2] * 0; } Note that the fix for this bug is important so that we can cleanly fix PR 14841 because uses of "static const arrays" may disappear during tree optimization. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17046 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug tree-optimization/17046] An unused array is not optimized away. 2004-08-16 6:56 [Bug tree-optimization/17046] New: An unused array is not optimized away kazu at cs dot umass dot edu 2004-08-16 7:02 ` [Bug tree-optimization/17046] " pinskia at gcc dot gnu dot org 2004-08-16 7:31 ` kazu at cs dot umass dot edu @ 2005-05-04 2:16 ` pinskia at gcc dot gnu dot org 2 siblings, 0 replies; 4+ messages in thread From: pinskia at gcc dot gnu dot org @ 2005-05-04 2:16 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2005-05-04 02:16 ------- Fixed for 4.1.0, most likely by the patches by Jan Honza. -- What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution| |FIXED Target Milestone|--- |4.1.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17046 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2005-05-04 2:16 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2004-08-16 6:56 [Bug tree-optimization/17046] New: An unused array is not optimized away kazu at cs dot umass dot edu 2004-08-16 7:02 ` [Bug tree-optimization/17046] " pinskia at gcc dot gnu dot org 2004-08-16 7:31 ` kazu at cs dot umass dot edu 2005-05-04 2:16 ` pinskia at gcc dot gnu dot org
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