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* [Bug optimization/10992] New: invalid instruction reordering with -O2 / -fschedule-insns2
@ 2003-05-27 9:08 rgrosseboerger@dspace.de
2003-05-27 9:12 ` [Bug optimization/10992] " rgrosseboerger@dspace.de
2003-06-02 22:53 ` bangerth@dealii.org
0 siblings, 2 replies; 3+ messages in thread
From: rgrosseboerger@dspace.de @ 2003-05-27 9:08 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10992
Summary: invalid instruction reordering with -O2 / -fschedule-
insns2
Product: gcc
Version: 3.2.1
Status: UNCONFIRMED
Severity: major
Priority: P2
Component: optimization
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: rgrosseboerger@dspace.de
CC: gcc-bugs@gcc.gnu.org
GCC build triplet: i686-pc-linux-gnu
GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu
GCC 3.2.x and 3.3 generate incorrect code for the simple test case below.
The problems occurs, if the C code is compiled with -O2, but does not occur
at -O1 or "-O2 -fno-schedule-insns2" (->GCC does invalid instruction reordering
?).
The problem disappears, if uint_value is declared as volatile.
The correct output for the test program is :
uint_value : 00570047 , value 00570047
...
uint_value : 006B005B , value 006B005B
Whereas the miscompilation with -O2 gives :
uint_value : 00570047 , value BFFFF8E8
...
uint_value : 006B005B , value 00660056
I have the same problem on gcc/x86-64, but the code works OK with the Intel
compiler.
#include <stdio.h>
typedef unsigned int UInt32;
typedef unsigned int UInt16;
typedef float Float32;
float f_array[25];
UInt32 u32_array[25];
int j = 5;
inline void func(UInt32 count, UInt32* address, volatile Float32* float_value)
{
unsigned int i;
UInt16 value_low = 0x42;
UInt16 value_high = 0x52;
/*volatile*/ UInt32 uint_value;
for (i = 0; i < count; i++)
{
value_high = value_high +5;
value_low = value_low +5;
uint_value = (((UInt32)value_high) << 16);
uint_value |= value_low;
float_value[i] = *((volatile float*)(&uint_value));
printf(" uint_value : %08X , value %08X \n", uint_value, *((UInt32 *)
&(float_value[i])));
}
}
int main()
{
func( j, u32_array , f_array);
}
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* [Bug optimization/10992] invalid instruction reordering with -O2 / -fschedule-insns2
2003-05-27 9:08 [Bug optimization/10992] New: invalid instruction reordering with -O2 / -fschedule-insns2 rgrosseboerger@dspace.de
@ 2003-05-27 9:12 ` rgrosseboerger@dspace.de
2003-06-02 22:53 ` bangerth@dealii.org
1 sibling, 0 replies; 3+ messages in thread
From: rgrosseboerger@dspace.de @ 2003-05-27 9:12 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10992
rgrosseboerger@dspace.de changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
------- Additional Comments From rgrosseboerger@dspace.de 2003-05-27 09:01 -------
*** This bug has been marked as a duplicate of 5328 ***
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* [Bug optimization/10992] invalid instruction reordering with -O2 / -fschedule-insns2
2003-05-27 9:08 [Bug optimization/10992] New: invalid instruction reordering with -O2 / -fschedule-insns2 rgrosseboerger@dspace.de
2003-05-27 9:12 ` [Bug optimization/10992] " rgrosseboerger@dspace.de
@ 2003-06-02 22:53 ` bangerth@dealii.org
1 sibling, 0 replies; 3+ messages in thread
From: bangerth@dealii.org @ 2003-06-02 22:53 UTC (permalink / raw)
To: gcc-bugs
PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10992
bangerth@dealii.org changed:
What |Removed |Added
----------------------------------------------------------------------------
BugsThisDependsOn| |11070
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2003-05-27 9:08 [Bug optimization/10992] New: invalid instruction reordering with -O2 / -fschedule-insns2 rgrosseboerger@dspace.de
2003-05-27 9:12 ` [Bug optimization/10992] " rgrosseboerger@dspace.de
2003-06-02 22:53 ` bangerth@dealii.org
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